Jamming-resistant microwave detection method and microwave detection device

Abstract

The application provides an anti-interference microwave detection method and a microwave detection device, wherein the anti-interference microwave detection method can avoid using multiple filtering methods to accurately eliminate interference signals in the corresponding Doppler intermediate frequency signals, which have any frequency relationship with the local oscillator signal of the microwave detection device, such as the same frequency, adjacent frequency and multiple frequency, so as to guarantee the integrity of the Doppler intermediate frequency signals and the accuracy of the feedback of the Doppler intermediate frequency signals to the movement of the object in the corresponding detection space, which is beneficial to realize the combined detection of action characteristics such as human movement, micro movement, breathing and heartbeat, and the detection function of the microwave detection device is rich and suitable for intelligent detection applications with multiple functions.

Description

Technical Field

[0001] This invention relates to the field of Doppler microwave detection, and more particularly to an interference-resistant microwave detection method and microwave detection device. Background Technology

[0002] With the development of IoT technology, artificial intelligence, smart homes, and smart security technologies have increasingly higher demands for the accuracy of environmental detection, especially the detection of human presence, movement, and micro-movement characteristics. Only by obtaining real-time and stable detection results can accurate judgments be provided for smart terminal devices. Among these technologies, radio technology, including microwave detection technology based on the Doppler effect, serves as a crucial hub connecting people and objects, and objects themselves, and possesses unique advantages in behavior and presence detection. It can detect moving objects, such as human motion characteristics, movement characteristics, and micro-movement characteristics, and even heartbeat and breathing characteristics, without infringing on human privacy, thus having broad application prospects.

[0003] correspond Figure 1 The circuit structure of the Doppler microwave detection device is illustrated. The corresponding antenna 10P, used to transmit and / or receive microwaves, is fed by a local oscillator signal via a mixer 20P to transmit a detection beam corresponding to the frequency of the local oscillator signal, forming a corresponding detection space. It also receives an echo formed by the reflection of the detection beam from an object within the detection space, generating a feedback signal. The mixer 20P receives the feedback signal and outputs a Doppler intermediate frequency (IF) signal corresponding to the frequency difference between the local oscillator signal and the feedback signal using a mixing and detection method. Based on the Doppler effect principle, the Doppler IF signal... The amplitude fluctuation of the signal theoretically corresponds to the motion of the object within the detection space. Based on the above-mentioned working principle of the Doppler microwave detection device, on the one hand, the environmental interference signal that can be received by the antenna body 10P will be superimposed on the Doppler intermediate frequency signal to form the first type of interference signal in the Doppler intermediate frequency signal; on the other hand, the signal in the environmental interference signal that can be received by the antenna body 10P and has any frequency relationship with the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) will also be superimposed on the feedback signal to participate in the mixing and detection process, forming the second type of interference signal that is mixed with the effective signal in the Doppler intermediate frequency signal.

[0004] For the first type of interference signal, the main current approach is to filter out the first type of interference signal superimposed on the Doppler intermediate frequency signal within the corresponding frequency range, or simultaneously narrow the receiving frequency range of the antenna 10P for environmental interference signals by narrowing the bandwidth of the antenna body 10P. However, based on the working principle of filtering, using filtering will, on the one hand, simultaneously filter out the effective signal of the corresponding frequency in the Doppler intermediate frequency signal, thus destroying the integrity of the Doppler intermediate frequency signal output by filtering; on the other hand, it will also form an integral processing of the effective signal of the corresponding frequency in the Doppler intermediate frequency signal, making it difficult to guarantee the correspondence between the corresponding parameters of the Doppler intermediate frequency signal output by filtering and their physical meaning; furthermore, refer to the accompanying drawings of this invention. Figure 2 As shown, in the state where there is no object movement in the detection space, when the Doppler intermediate frequency signal output by the mixer 20P is filtered by the corresponding filtering circuit, the Doppler intermediate frequency signals sampled at the input and output ends of the filtering circuit are compared in a vertical arrangement. Since the current filtering of the Doppler intermediate frequency signal is essentially to select the signal in the corresponding frequency range of the Doppler intermediate frequency signal for integral smoothing, it cannot achieve true elimination, especially when the signal strength in this frequency range is high. Therefore, multiple filtering processes are usually required. Thus, based on the aforementioned filtering method, the Doppler intermediate frequency signal output by the filtered signal is affected by multiple aspects, making it difficult to guarantee the accuracy of the feedback of the motion of the object in the detection space, especially the accuracy of the feedback of micro-movements in the detection space.

[0005] For the second type of interference signal, even when the frequency range of the environmental interference signal generated by the interference source is known, due to the uncertainty of the frequency change rate of the interference source, and the frequency difference between the Doppler intermediate frequency signal and the local oscillator signal and the feedback signal (superimposed with the environmental interference signal), when the Doppler intermediate frequency signal output by the mixer 20P is filtered by the corresponding filtering circuit, on the one hand, the accuracy and stability of the correspondence between the parameter design of the filtering circuit and the frequency range of the second type of interference signal are difficult to guarantee, so that the corresponding second type of interference signal is difficult to be separated and filtered out from the Doppler intermediate frequency signal by filtering; on the other hand, the parameter design of the filtering circuit does not have a correspondence with the frequency range of the first type of interference signal, and is prone to mutual influence and multiple filtering processes on the Doppler intermediate frequency signal; in addition, based on the two aspects of the influence of the filtering method on the filtered output Doppler intermediate frequency signal, the accuracy of the feedback of the motion of the object in the detection space by the filtered output Doppler intermediate frequency signal is also difficult to guarantee. Therefore, the most reasonable approach to suppressing type II interference signals is currently considered to be to reduce the probability of the local oscillator signal forming any frequency relationship (same frequency, adjacent frequency, or harmonic frequency) with the environmental interference signal for an extended period through frequency hopping / conversion. However, this method can only reduce the probability of type II interference signals existing in the Doppler intermediate frequency signal for a long time; it still cannot separate and filter out type II interference signals from the Doppler intermediate frequency signal.

[0006] In summary, the filtering method used to simultaneously filter both type I and type II interference signals in the Doppler intermediate frequency (IF) signal essentially involves integrating and smoothing signals within corresponding frequency ranges of the Doppler IF signal. This method cannot achieve true elimination and therefore typically requires multiple filtering processes. Furthermore, for type II interference signals, the correspondence between the filter circuit parameters and the frequency range of the type II interference signal is unstable and inaccurate, and there is no corresponding relationship with the frequency range of the type I interference signal, leading to mutual influence and multiple filtering processes on the Doppler IF signal. Therefore, based on the aforementioned multiple influences of the filtering method on the filtered Doppler IF signal from two aspects, the accuracy of the Doppler IF signal's feedback on the motion of objects within the detection space cannot be guaranteed. Summary of the Invention

[0007] One object of the present invention is to provide an anti-interference microwave detection method and a microwave detection device, wherein the anti-interference microwave detection method can accurately eliminate the second type of interference signal formed in the corresponding Doppler intermediate frequency signal by interference signals in the environment that have any frequency relationship with the local oscillator signal of the microwave detection device, such as the same frequency, adjacent frequency, or harmonic frequency, thereby improving the feedback accuracy of the Doppler intermediate frequency signal on the motion of objects in the corresponding detection space.

[0008] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device. By forming a differential signal-shaped Doppler intermediate frequency (IF) signal, based on the formation process of a first type of interference signal and a second type of interference signal, the first and second types of interference signals, respectively, exist as common-mode interference and differential-mode interference in the differential signal-shaped Doppler IF signal and can be distinguished. Furthermore, the first and second types of interference signals in the differential signal-shaped Doppler IF signal can be suppressed or eliminated independently based on different signal processing methods. This helps to ensure the integrity of the Doppler IF signal and the accuracy of its feedback on the motion of objects within the corresponding detection space. It also facilitates the combined detection of movement characteristics including human movement, micro-movements, breathing, and heartbeat. Consequently, the microwave detection device has rich detection functions and is suitable for intelligent detection applications with multi-functional requirements.

[0009] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device, wherein a second type of interference signal is applied to the differential signal form of the Doppler intermediate frequency signal in the form of differential mode interference. The second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal is eliminated by cancellation. Therefore, it is beneficial to avoid the use of multiple filtering methods and to ensure the integrity of the Doppler intermediate frequency signal and the correspondence between the corresponding parameters of the Doppler intermediate frequency signal and their physical meaning, thereby improving the feedback accuracy of the Doppler intermediate frequency signal for the motion of objects in the corresponding detection space.

[0010] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device. In practical applications, environmental interference signals with frequencies that are at the same, adjacent, or harmonic of the local oscillator signal of the microwave detection device are primarily wireless communication signals. Through exploration of the principles of wireless communication and actual testing of different products, it has been found that in wireless communication signals that express communication information through frequency changes based on the working principle of frequency modulation, the rate of frequency change is much higher than the rate of frequency change of feedback signals corresponding to normally moving objects based on the Doppler effect. Correspondingly, the second type of interference signal exists as a high-frequency spike in the differential signal form of the Doppler intermediate frequency signal. Therefore, the second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal can be accurately eliminated by frequency selection cancellation within the corresponding frequency range. This ensures the microwave detection device's ability to resist communication interference, thus possessing significant practical value and commercial significance.

[0011] One objective of this invention is to provide an anti-interference microwave detection method and a microwave detection device. The anti-interference microwave detection method can avoid using multiple filtering methods to suppress or eliminate the first type of interference signal and the second type of interference signal in the differential signal-shaped Doppler intermediate frequency signal, thereby avoiding signal delay caused by filtering. The immediacy of the Doppler intermediate frequency signal is guaranteed, which is beneficial for realizing real-time detection of human actions such as breathing and heartbeat.

[0012] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device. In applications involving multiple microwave detection devices, environmental interference signals with the same frequency as the local oscillator signal of the microwave detection device may also be signals emitted by other microwave detection devices at the same frequency. Correspondingly, first and second types of interference signals exist as glitches in the differential signal form of the Doppler intermediate frequency signal. Before eliminating the second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal using frequency selective cancellation, the microwave detection device may optionally connect a ground capacitor with the same parameter settings to both poles of the differential signal form of the Doppler intermediate frequency signal. This suppresses the first and second types of interference signals formed as glitches in the differential signal form of the differential signal form by the same-frequency interference in the fixed-frequency form of the same-frequency interference, thereby ensuring the anti-interference capability of the microwave detection device in applications involving multiple microwave detection devices.

[0013] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein a first type of interference signal exists as common-mode interference in the differential signal form of the Doppler intermediate frequency signal. Therefore, it is suitable to suppress the first type of interference signal in the differential signal form of the Doppler intermediate frequency signal by differential amplification of the differential signal form of the Doppler intermediate frequency signal, while simultaneously amplifying the differential signal form of the Doppler intermediate frequency signal. This suppresses the interference of the first type of interference signal formed by environmental interference signals that can be received by the microwave detection device on the Doppler intermediate frequency signal, thereby improving the feedback accuracy of the Doppler intermediate frequency signal on the motion of objects in the corresponding detection space.

[0014] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein a first type of interference signal exists as common-mode interference in the differential signal form of the Doppler intermediate frequency signal, and is therefore suitable for suppressing and eliminating common-mode interference during the conversion of the differential signal form of the Doppler intermediate frequency signal to the single-ended signal form of the Doppler intermediate frequency signal. By converting the differential signal form of the Doppler intermediate frequency signal to the single-ended signal form of the Doppler intermediate frequency signal for data identification and processing, the interference of the first type of interference signal formed by environmental interference signals that can be received by the microwave detection device on the Doppler intermediate frequency signal is suppressed and eliminated, and the feedback accuracy of the Doppler intermediate frequency signal on the motion of the object is guaranteed.

[0015] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein by forming a differential signal-shaped Doppler intermediate frequency signal, the external radiation of the differential signal-shaped Doppler intermediate frequency signal can cancel each other out, thereby suppressing the interference of the Doppler intermediate frequency signal to the environment and corresponding lines, which is beneficial to improving the anti-interference capability of the microwave detection device.

[0016] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device. By forming a differential signal-shaped Doppler intermediate frequency (IF) signal, a first type of interference signal corresponds to common-mode interference existing in the differential signal-shaped Doppler IF signal. Differential amplification of the differential signal-shaped Doppler IF signal and / or conversion to a single-ended signal-shaped Doppler IF signal can amplify and anti-interference the Doppler IF signal while ensuring the integrity of the feedback from the Doppler IF signal to the motion of objects within the corresponding detection space. This facilitates the acquisition of accurate and stable detection results of human activities, including human movement, micro-movements, respiration, and heartbeat, based on the Doppler IF signal.

[0017] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein the differential amplification processing of the Doppler intermediate frequency signal in differential signal form and / or the conversion of the Doppler intermediate frequency signal in single-ended signal form can significantly reduce or even avoid the use of capacitor elements in the transmission path of the Doppler intermediate frequency signal compared with the filtering method, thereby ensuring the immediacy of the Doppler intermediate frequency signal and facilitating the real-time detection of actions such as human breathing and heartbeat.

[0018] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein when the initial Doppler intermediate frequency signal is in the form of a single-ended signal, the single-ended Doppler intermediate frequency signal is converted into a differential signal form, which is beneficial to ensuring the initial strength of the differential signal form of the Doppler intermediate frequency signal and thus ensuring the feedback accuracy of the Doppler intermediate frequency signal to the motion of objects in the corresponding detection space.

[0019] According to one aspect of the present invention, an interference-resistant microwave detection method is provided, the interference-resistant microwave detection method comprising the following steps:

[0020] (A) A probe beam corresponding to the frequency of a local oscillator signal is emitted to form a corresponding probe space;

[0021] (B) Receive the echo formed by the detection beam being reflected by an object in the detection space and generate a feedback signal;

[0022] (C) Output a Doppler intermediate frequency signal in differential signal form, wherein the Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0023] (D) The differential signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form is eliminated by frequency selective cancellation, so that the differential mode interference generated in the Doppler intermediate frequency signal by the wireless communication signal that has any frequency relationship with the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) superimposed on the environmental interference signal of the feedback signal can be eliminated.

[0024] In one embodiment, in step (D), a frequency-selective cancellation circuit performs frequency-selective cancellation processing on the Doppler intermediate frequency signal in differential signal form output in step (C) to output the frequency-selective cancellation processed Doppler intermediate frequency signal. The frequency-selective cancellation circuit includes a first equivalent resistor, a second equivalent resistor, and an equivalent capacitor. One end of the first equivalent resistor is electrically connected to one end of the equivalent capacitor, and one end of the second equivalent resistor is electrically connected to the other end of the equivalent capacitor. The frequency-selective cancellation circuit has the other ends of the first and second equivalent resistors as two input terminals and the two ends of the equivalent capacitor as two output terminals. The Doppler intermediate frequency signal in differential signal form output in step (C) is input from the two input terminals, and the frequency-selective cancellation processed Doppler intermediate frequency signal is output from the two output terminals.

[0025] In one embodiment, the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and the equivalent capacitance is set to a capacitance value of approximately 47 nF within a 25% error range.

[0026] In one embodiment, the equivalent capacitor is equivalently configured as two capacitors connected in series, wherein the two capacitors are configured to be capacitors of the same type.

[0027] In one embodiment, the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and both capacitors are set to a capacitance value of approximately 100 nF within a 25% error range.

[0028] In one embodiment, the frequency selective cancellation circuit is grounded between the two capacitors connected in series.

[0029] In one embodiment, each of the two input terminals of the frequency selective cancellation circuit is electrically connected to a pair of ground capacitors.

[0030] In one embodiment, the interference-resistant microwave detection method further includes the following steps between step (C) and step (D), and / or after step (D):

[0031] (E) The Doppler intermediate frequency signal in differential signal form is differentially amplified.

[0032] In one embodiment, the anti-interference microwave detection method further includes the following step after step (D):

[0033] F. The Doppler intermediate frequency signal in the form of a differential signal is converted to a Doppler intermediate frequency signal in the form of a single-ended signal.

[0034] In one embodiment, in step (C), the Doppler intermediate frequency signal, corresponding to the differential signal form of the frequency / phase difference between the local oscillator signal and the feedback signal, is directly output in a mixing manner.

[0035] In one embodiment, step (C) includes the following steps:

[0036] C1. Mix the local oscillator signal and the feedback signal so that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal can be extracted;

[0037] C2. Output a Doppler intermediate frequency signal in single-ended signal form, corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0038] C3. By inverting the Doppler intermediate frequency signal in single-ended signal form and outputting a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal, the Doppler intermediate frequency signal in single-ended signal form is converted into a Doppler intermediate frequency signal in differential signal form.

[0039] According to another aspect of the present invention, the present invention also provides a microwave detection device, the microwave detection device comprising:

[0040] An oscillation unit, wherein the oscillation unit is configured to generate a local oscillator signal;

[0041] An antenna element is fed to the oscillation element to transmit a probe beam corresponding to the frequency of the local oscillator signal to form a corresponding probe space, and to receive an echo formed by the probe beam being reflected by an object in the probe space to generate a feedback signal.

[0042] A Doppler differential output circuit, wherein the Doppler differential output circuit is electrically connected to the antenna unit and the oscillation unit to output a Doppler intermediate frequency signal in differential signal form, wherein the Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0043] At least one frequency-selective cancellation circuit is electrically connected to the Doppler differential output circuit to eliminate the differential signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form by frequency-selective cancellation. This enables the differential-mode interference generated in the Doppler intermediate frequency signal by wireless communication signals that have any frequency relationship with the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) superimposed on the environmental interference signal of the feedback signal to be eliminated.

[0044] In one embodiment, the frequency selective cancellation circuit includes a first equivalent resistor, a second equivalent resistor, and an equivalent capacitor. One end of the first equivalent resistor is electrically connected to one end of the equivalent capacitor, and one end of the second equivalent resistor is electrically connected to the other end of the equivalent capacitor. The frequency selective cancellation circuit has the other ends of the first and second equivalent resistors as two input terminals and the two ends of the equivalent capacitor as two output terminals. The Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit is input from the two input terminals, and the Doppler intermediate frequency signal that has undergone frequency selective cancellation is output from the two output terminals.

[0045] In one embodiment, the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and the equivalent capacitance is set to a capacitance value of approximately 47 nF within a 25% error range.

[0046] In one embodiment, the equivalent capacitor is equivalently configured as two capacitors connected in series, wherein the two capacitors are configured to be capacitors of the same type.

[0047] In one embodiment, the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and both capacitors are set to a capacitance value of approximately 100 nF within a 25% error range.

[0048] In one embodiment, the frequency selective cancellation circuit is grounded between the two capacitors connected in series.

[0049] In one embodiment, each of the two input terminals of the frequency selective cancellation circuit is electrically connected to a pair of ground capacitors.

[0050] In one embodiment, the Doppler differential output circuit and the oscillation unit are configured as integrated circuits and integrated into a microwave chip.

[0051] In one embodiment, the first equivalent resistor and the second equivalent resistor of the frequency selective cancellation circuit are integrated into the microwave chip.

[0052] In one embodiment, the Doppler differential output circuit is configured to directly output the Doppler intermediate frequency signal, corresponding to the differential signal shape of the frequency / phase difference between the local oscillator signal and the feedback signal, based on a mixing process.

[0053] In one embodiment, the Doppler differential output circuit includes a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOSFET, and a second MOSFET. One end of the first load is electrically connected to one end of the second load, the other end of the first load is electrically connected to the drain of the first MOSFET, the other end of the second load is electrically connected to the drain of the second MOSFET, and the source of the first MOSFET is electrically connected to the source of the second MOSFET. Thus, with power supplied to both ends of the interconnected first and second loads, the feedback signal supplied to the two sources of the interconnected first and second MOSFETs, and the inverted local oscillator signals supplied to the gates of the first and second MOSFETs respectively, a Doppler intermediate frequency signal in differential signal form can be output from the drains of the first and second MOSFETs.

[0054] In one embodiment, the Doppler differential output circuit includes a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor. The drain of the first MOS transistor is electrically connected to the drain of the second MOS transistor, the drain of the third MOS transistor is electrically connected to the drain of the fourth MOS transistor, the source of the first MOS transistor is electrically connected to the source of the third MOS transistor, and the source of the second MOS transistor is electrically connected to the source of the fourth MOS transistor. This allows inverted feedback signals to be connected between the two drains of the interconnected first and second MOS transistors, and between the two drains of the interconnected third and fourth MOS transistors. Furthermore, in a state where the four gates of the first, second, third, and fourth MOS transistors are connected to sequentially inverted local oscillator signals, a differential Doppler intermediate frequency signal can be output between the two sources of the first and third MOS transistors, and between the two sources of the second and fourth MOS transistors.

[0055] In one embodiment, the Doppler differential output circuit includes a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOSFET, a second MOSFET, and a third MOSFET. One end of the first load is electrically connected to one end of the second load, the other end of the first load is electrically connected to the drain of the first MOSFET, the other end of the second load is electrically connected to the drain of the second MOSFET, the source of the first MOSFET and the source of the second MOSFET are respectively electrically connected to the drain of the third MOSFET, and the source of the third MOSFET is grounded. This allows the circuit to output a Doppler intermediate frequency signal in differential signal form from the drains of the first MOSFET and the second MOSFET when power is applied to both ends of the interconnected first and second loads, the feedback signal is applied to the gate of the third MOSFET, and the inverted local oscillator signal is applied to the gates of the first and second MOSFETs.

[0056] In one embodiment, the Doppler differential output circuit includes a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOSFET, a second MOSFET, a third MOSFET, a fourth MOSFET, a fifth MOSFET, a sixth MOSFET, and a current source. One end of the first load is electrically connected to one end of the second load. The other end of the first load is electrically connected to the drain of the first MOSFET and the drain of the third MOSFET, respectively. The other end of the second load is electrically connected to the drain of the second MOSFET and the drain of the fourth MOSFET, respectively. The sources of the first MOSFET and the second MOSFET are electrically connected to the drain of the fifth MOSFET, and the sources of the third MOSFET and the fourth MOSFET are electrically connected to... The drain of the sixth MOS transistor, wherein the sources of the fifth MOS transistor and the sixth MOS transistor are electrically connected to the current source, such that the gates of the fifth MOS transistor and the sixth MOS transistor are respectively connected to the inverted feedback signal, the gates of the first MOS transistor and the second MOS transistor are respectively connected to the inverted local oscillator signal, the gates of the third MOS transistor and the fourth MOS transistor are respectively connected to the inverted local oscillator signal, wherein the local oscillator signal connected to the gate of the second MOS transistor is in phase with the local oscillator signal connected to the gate of the third MOS transistor, and the power supply is connected to both ends of the interconnected first load and the second load, so that the Doppler intermediate frequency signal in the form of a differential signal can be output at the other end of the first load and the other end of the second load.

[0057] In one embodiment, the Doppler differential output circuit includes a mixer circuit and a single-ended signal to differential signal circuit. The mixer circuit is electrically connected to the antenna unit and the oscillator unit to receive the feedback signal and the local oscillator signal and outputs the Doppler intermediate frequency (IF) signal in a single-ended signal form corresponding to the frequency / phase difference between the feedback signal and the local oscillator signal via a mixing and detection method. The single-ended to differential circuit is electrically connected to the mixer circuit to receive the single-ended Doppler IF signal and convert the single-ended Doppler IF signal into a differential Doppler IF signal by inverting the single-ended Doppler IF signal.

[0058] In one embodiment, the single-ended signal to differential signal circuit includes a transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, and a capacitor. The emitter of the transistor is grounded through the first resistor, the collector of the transistor is connected to a power supply through the second resistor, the base of the transistor is connected to a power supply through the third resistor and grounded through the fourth resistor, and connected to the single-ended Doppler intermediate frequency signal through the capacitor, so as to output the differential Doppler intermediate frequency signal between the collector and emitter of the transistor.

[0059] In one embodiment, the single-ended signal to differential signal circuit includes an operational amplifier, a first resistor, and a second resistor. The operational amplifier has a reference voltage connected to its non-inverting input terminal, and its inverting input terminal electrically connected to the output terminal of the operational amplifier via the first resistor. The single-ended Doppler intermediate frequency signal is connected to the second resistor, thereby outputting a differential Doppler intermediate frequency signal between the end of the second resistor connected to the single-ended Doppler intermediate frequency signal and the output terminal of the operational amplifier.

[0060] In one embodiment, the single-ended signal to differential signal circuit includes a first operational amplifier circuit and a second operational amplifier circuit. The first operational amplifier circuit receives a single-ended Doppler intermediate frequency signal at its input terminal and is electrically connected to the input terminal of the second operational amplifier circuit at its output terminal. The first operational amplifier circuit outputs the differential Doppler intermediate frequency signal between the output terminals of the first and second operational amplifier circuits.

[0061] In one embodiment, the first operational amplifier circuit includes a first operational amplifier, with the non-inverting input terminal of the first operational amplifier as the input terminal to receive the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier as the output terminal. The second operational amplifier circuit includes a second operational amplifier, a first resistor, and a second resistor, with the inverting input terminal of the second operational amplifier as the input terminal and the output terminal of the second operational amplifier as the output terminal. The second operational amplifier has a reference voltage connected to its non-inverting input terminal and is electrically connected to its output terminal via the second resistor. The output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier via the first resistor. The inverting input terminal and the output terminal of the first operational amplifier are electrically connected, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first and second operational amplifiers.

[0062] In one embodiment, the first operational amplifier circuit includes a first operational amplifier, a first resistor, and a second resistor. The first operational amplifier has its inverting input terminal connected to a single-ended Doppler intermediate frequency (IF) signal, and its output terminal connected to the output terminal. The first operational amplifier has its inverting input terminal connected to the IF signal via the first resistor, and its non-inverting input terminal connected to a reference voltage. The inverting input terminal and the output terminal of the first operational amplifier are electrically connected via the second resistor. The second operational amplifier circuit includes a second operational amplifier, a third resistor, and a fourth resistor. The second operational amplifier has its inverting input terminal connected to the input terminal and its output terminal connected to the output terminal. The first operational amplifier's output terminal is electrically connected to the inverting input terminal of the second operational amplifier via the third resistor, and the inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor. Thus, a differential Doppler IF signal is output between the output terminals of the first and second operational amplifiers.

[0063] In one embodiment, the first operational amplifier circuit includes a first operational amplifier, a first resistor, a second resistor, a first capacitor, a second capacitor, and a third capacitor. The first operational amplifier has its inverting input terminal as its input terminal, receiving the single-ended Doppler intermediate frequency signal, and its output terminal as its output terminal. The first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the third capacitor, and sequentially connected to its output terminal via the first resistor and the second resistor. The single-ended Doppler intermediate frequency signal is then sequentially received via the first resistor and the first capacitor. The circuit is grounded sequentially via the first resistor and the second capacitor. The second operational amplifier circuit includes a second operational amplifier, a third resistor, and a fourth resistor. The inverting input terminal of the second operational amplifier is used as the input terminal, and the output terminal of the second operational amplifier is used as the output terminal. The output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier via the third resistor. The inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor. In this way, a differential signal in the form of a Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier and the output terminals of the second operational amplifier.

[0064] In one embodiment, the oscillation unit, the mixer circuit, and the first operational amplifier circuit of the single-ended signal to differential signal circuit are configured as integrated circuits and integrated into a microwave chip, wherein the second operational amplifier circuit of the single-ended signal to differential signal circuit is externally located on the microwave chip.

[0065] In one embodiment, the single-ended signal to differential signal circuit includes a first operational amplifier circuit and a second operational amplifier circuit. The first operational amplifier circuit is electrically connected to the input terminals of the second operational amplifier circuit and receives a Doppler intermediate frequency signal in single-ended signal form. The first operational amplifier circuit outputs the Doppler intermediate frequency signal in differential signal form between the output terminals of the first operational amplifier circuit and the output terminals of the second operational amplifier circuit.

[0066] In one embodiment, the first operational amplifier circuit includes a first operational amplifier, a first resistor, a second resistor, and a first capacitor. The first operational amplifier's non-inverting input is used as the input terminal to receive the single-ended Doppler intermediate frequency signal, and its output terminal is the output terminal. The first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the first resistor, and then grounded sequentially via the second resistor and the first capacitor. The second operational amplifier circuit includes a second operational amplifier, a third resistor, and a fourth resistor. The second operational amplifier's inverting input terminal is used as the input terminal, and its output terminal is the output terminal. The first operational amplifier's non-inverting input terminal is electrically connected to the inverting input terminal of the second operational amplifier via the third resistor. The inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor. A reference voltage is connected to the second operational amplifier's non-inverting input terminal, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first and second operational amplifiers.

[0067] In one embodiment, the first operational amplifier circuit includes a first operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor. The first operational amplifier has its non-inverting input terminal connected to the single-ended Doppler intermediate frequency signal, and its output terminal connected to the first operational amplifier. The first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the fourth resistor and grounded via the third resistor. The first operational amplifier has its non-inverting input terminal connected to the single-ended Doppler intermediate frequency signal via the first resistor and grounded via the second resistor. The second operational amplifier... The circuit includes a second operational amplifier, a fifth resistor, and a sixth resistor, with the inverting input of the second operational amplifier as its input and the output of the second operational amplifier as its output. The first operational amplifier is electrically connected from its non-inverting input to the inverting input of the second operational amplifier via the first and fifth resistors. The inverting input and output of the second operational amplifier are electrically connected via the sixth resistor. A reference voltage is connected to the non-inverting input of the second operational amplifier, thereby outputting a differential Doppler intermediate frequency signal between the outputs of the first and second operational amplifiers.

[0068] In one embodiment, the oscillation unit, the mixer circuit, and the first operational amplifier circuit of the single-ended signal to differential signal circuit are configured as integrated circuits and integrated into a microwave chip, wherein the second operational amplifier circuit of the single-ended signal to differential signal circuit is externally located on the microwave chip.

[0069] In one embodiment, the single-ended signal to differential signal circuit includes a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor. The first operational amplifier has a reference voltage connected to its non-inverting input terminal and a single-ended Doppler intermediate frequency signal connected to its inverting input terminal via the first resistor. Its output terminal is electrically connected to the output terminal of the second operational amplifier sequentially via the third and fourth resistors. The inverting input terminal and output terminal of the first operational amplifier are electrically connected via the second resistor, and the inverting input terminal and output terminal of the second operational amplifier are electrically connected via the fourth resistor. The non-inverting input terminal of the second operational amplifier is electrically connected to the inverting input terminal of the first operational amplifier, thereby outputting a differential Doppler intermediate frequency signal between the output terminals of the first and second operational amplifiers.

[0070] In one embodiment, the oscillation unit, the mixer circuit, and the first operational amplifier of the single-ended signal to differential signal circuit are configured as integrated circuits and integrated into a microwave chip, wherein the second operational amplifier of the single-ended signal to differential signal circuit is externally located on the microwave chip.

[0071] In one embodiment, the single-ended signal to differential signal circuit includes a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor. The first operational amplifier has a reference voltage connected to its non-inverting input terminal, and its inverting input terminal electrically connected to the inverting input terminal of the second operational amplifier. Its output terminal is electrically connected to the non-inverting input terminal of the second operational amplifier via the fourth resistor. The inverting input terminal and output terminal of the first operational amplifier are electrically connected via the third resistor. The second operational amplifier receives the single-ended Doppler intermediate frequency signal via the first resistor from its non-inverting input terminal. The inverting input terminal and output terminal of the second operational amplifier are electrically connected via the second resistor, thereby outputting the differential Doppler intermediate frequency signal between the output terminals of the first and second operational amplifiers.

[0072] In one embodiment, the oscillation unit, the mixer circuit, and the first operational amplifier of the single-ended signal to differential signal circuit are configured as integrated circuits and integrated into a microwave chip, wherein the second operational amplifier of the single-ended signal to differential signal circuit is externally located on the microwave chip.

[0073] In one embodiment, the oscillation unit and the mixer circuit of the Doppler differential output circuit are configured as integrated circuits and integrated into a microwave chip, and the single-ended signal to differential signal circuit of the Doppler differential output circuit is externally located on the microwave chip.

[0074] In one embodiment, the microwave detection device further includes at least one differential amplifier circuit, wherein the differential amplifier circuit is disposed between the Doppler differential output circuit and the frequency selective cancellation circuit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit.

[0075] In one embodiment, the microwave detection device further includes at least one differential amplifier circuit, wherein the differential amplifier circuit is disposed at both output terminals of the frequency selective cancellation circuit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the frequency selective cancellation circuit.

[0076] In one embodiment, the microwave detection device further includes a differential signal to single-ended signal circuit to receive the differential signal in the form of the Doppler intermediate frequency signal after frequency selection and cancellation processing, and to convert the differential signal in the form of the Doppler intermediate frequency signal into the single-ended signal in the form of the Doppler intermediate frequency signal for output.

[0077] The further objects and advantages of the invention will become fully apparent from the following description and accompanying drawings.

[0078] These and other objects, features and advantages of the present invention will be fully realized through the following detailed description, drawings and claims. Attached Figure Description

[0079] Figure 1 This is a schematic diagram of the circuit structure of an existing Doppler microwave detection device.

[0080] Figure 2 This is a schematic diagram comparing the Doppler intermediate frequency signal output by an existing Doppler microwave detection device before and after filtering.

[0081] Figure 3 This is a schematic diagram illustrating the structural principle of a microwave detection device according to an embodiment of the present invention.

[0082] Figure 4AThis is a schematic diagram comparing the Doppler intermediate frequency signal output by the microwave detection device according to the above embodiments of the present invention before and after the frequency-selective cancellation processing.

[0083] Figure 4B This is a schematic diagram comparing the Doppler intermediate frequency signal output by the microwave detection device according to the above embodiments of the present invention before and after the frequency-selective cancellation processing.

[0084] Figure 5A This is a schematic diagram illustrating the structural principle of the microwave detection device according to a modified embodiment of the above-described embodiments of the present invention.

[0085] Figure 5B This is a schematic diagram illustrating a further modified structure of the microwave detection device according to the above-described modified embodiment of the present invention.

[0086] Figure 6A This is a schematic diagram illustrating the structural principle of the microwave detection device according to another modified embodiment of the above-described embodiments of the present invention.

[0087] Figure 6B This is a comparative schematic diagram of the Doppler intermediate frequency signals output by the microwave detection device according to the above-described modified embodiment of the present invention at different positions.

[0088] Figure 7A This is a schematic diagram of the series structure of the frequency selection cancellation circuit of the microwave detection device according to the above embodiments of the present invention.

[0089] Figure 7B This is a schematic diagram of the parallel structure of the frequency selection cancellation circuit of the microwave detection device according to the above embodiments of the present invention.

[0090] Figures 8A to 8D The diagrams above illustrate the different circuit structures of the Doppler differential output circuits of the microwave detection device according to the above embodiments of the present invention.

[0091] Figure 9 This is a schematic diagram of the circuit structure of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0092] Figure 10A This is a schematic diagram of a circuit structure for the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0093] Figure 10B This is a schematic diagram of another circuit structure of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0094] Figures 11A to 11DThe above-described schematic diagrams show different circuit structures of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0095] Figures 12A to 12C The above-described schematic diagrams show different circuit structures of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0096] Figure 13A This is a schematic diagram of another circuit structure of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0097] Figure 13B This is a schematic diagram of another circuit structure of the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0098] Figure 14A This is a partial circuit diagram of the microwave detection device according to another embodiment of the present invention.

[0099] Figure 14B This is a partial circuit diagram of the microwave detection device according to another embodiment of the present invention.

[0100] Figure 15A This is a schematic diagram of a circuit structure for a microwave detection device according to the above embodiments of the present invention, further comprising a differential amplifier circuit.

[0101] Figure 15B This is a schematic diagram illustrating another circuit structure principle of the microwave detection device according to the above embodiments of the present invention, which further includes a differential amplifier circuit.

[0102] Figure 16 This is a schematic diagram of a differential amplifier circuit of the microwave detection device according to the above embodiments of the present invention.

[0103] Figure 17A This is a schematic diagram of a circuit structure for further providing a differential signal to single-ended signal circuit in the microwave detection device according to the above embodiments of the present invention.

[0104] Figure 17B This is a schematic diagram illustrating another circuit structure principle of the microwave detection device according to the above embodiments of the present invention, which further includes a differential signal to single-ended signal conversion circuit.

[0105] Figure 18 This is a schematic diagram of a differential signal to single-ended signal circuit of the microwave detection device according to the above embodiments of the present invention. Detailed Implementation

[0106] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0107] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0108] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0109] This invention provides an interference-resistant microwave detection method and microwave detection device, as shown in the accompanying drawings of the invention. Figure 3 As shown, the structural principle of the microwave detection device according to an embodiment of the present invention is illustrated. The microwave detection device includes an antenna unit 10, an oscillation unit 20, a Doppler differential output circuit 30, and at least one frequency selection cancellation circuit 40. The oscillation unit 20 is configured to generate a local oscillator signal. The antenna unit 10 is fed and connected to the oscillation unit 20 to emit a detection beam corresponding to the frequency of the local oscillator signal to form a corresponding detection space, and to receive an echo formed by the reflection of the detection beam by an object in the detection space to generate a feedback signal. The Doppler differential output circuit 30 is electrically connected to the antenna unit 10 and the oscillation unit 20 to output a Doppler intermediate frequency signal in differential signal form. The Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal. The frequency selection cancellation circuit 40 is electrically connected to the Doppler differential output circuit 30 to eliminate the differential signal in the corresponding frequency range of the Doppler intermediate frequency signal in differential signal form by frequency selection cancellation.

[0110] It is worth mentioning that, in some embodiments of the present invention, the antenna unit 10 is configured to use the same antenna body as both a transmitting antenna and a receiving antenna, and is simultaneously fed and connected to the oscillation unit 20 and electrically connected to the Doppler differential output circuit 30. In other embodiments of the present invention, the antenna unit 10 is configured to use different antenna bodies as a transmitting antenna fed and connected to the oscillation unit 20 and a receiving antenna electrically connected to the Doppler differential output circuit 30, respectively. The present invention does not limit this, and the number and shape of the corresponding antenna bodies do not constitute a limitation on the present invention.

[0111] It is also worth mentioning that, in the state where the oscillation unit 20 is fed to the antenna unit 10 and electrically connected to the Doppler differential output circuit 30, the connection lines between the antenna unit 10 and the oscillation unit 20 and the connection lines between the Doppler differential output circuit 30 and the oscillation unit 20 are not limited to being the same. That is, the local oscillator signal provided by the oscillation unit 20 to the antenna unit 10 and the local oscillator signal provided to the Doppler differential output circuit 30 are from the same source (both provided by the oscillation unit 20) but are not limited to being on the same path. In some embodiments of the present invention, the oscillation unit 20 amplifies and outputs the local oscillator signal to the antenna unit 10 based on corresponding circuit settings, and the present invention does not limit this.

[0112] It is understandable that, based on the above-mentioned working principle of the Doppler microwave detection device, on the one hand, the environmental interference signal that can be received by the antenna unit 10 will be superimposed on the Doppler intermediate frequency signal in the differential signal form to form the first type of interference signal in the Doppler intermediate frequency signal; on the other hand, the signal in the environmental interference signal that can be received by the antenna unit 10 and has any frequency relationship with the local oscillator signal of the same frequency, adjacent frequency, or harmonic frequency will also be superimposed on the feedback signal to participate in the mixing and detection process to form the second type of interference signal that is mixed with the effective signal in the Doppler intermediate frequency signal.

[0113] Based on the aforementioned formation process of the first and second types of interference signals, the first and second types of interference signals, respectively, correspond to the Doppler intermediate frequency signal in the differential signal form as common-mode interference and differential-mode interference, and can be distinguished. Therefore, the first and second types of interference signals in the Doppler intermediate frequency signal in the differential signal form can be suppressed or eliminated independently based on different signal processing methods. This helps to ensure the integrity of the Doppler intermediate frequency signal and the accuracy of its feedback on the motion of objects within the corresponding detection space. It also facilitates the combined detection of movement characteristics, including human movement, micro-movements, breathing, and heartbeat. Consequently, the microwave detection device has rich detection functions and is suitable for intelligent detection applications with multi-functional requirements.

[0114] Specifically, in this embodiment of the invention, the frequency selection cancellation circuit 40 is used to eliminate the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal of the differential signal form by frequency selection cancellation. The frequency selection cancellation circuit 40 includes a first equivalent resistor 401, a second equivalent resistor 402, and an equivalent capacitor 403. One end of the first equivalent resistor 401 is electrically connected to one end of the equivalent capacitor 403, and one end of the second equivalent resistor 402 is electrically connected to the equivalent capacitor 403. At the other end, the frequency selection cancellation circuit 40 has two input terminals 41, one end of the first equivalent resistor 401 and the other end of the second equivalent resistor 402, and two output terminals 42, corresponding to the frequency selection cancellation circuit 40. The frequency selection cancellation circuit 40 is electrically connected to the Doppler differential output circuit 30 at the two input terminals 41, so that the two poles of the Doppler intermediate frequency signal in differential signal form are connected from the two input terminals 41, and the Doppler intermediate frequency signal that has been frequency selected and cancelled is output at the two output terminals 42.

[0115] It is understood that the equivalent resistance is a resistor that meets the corresponding resistance value requirement, formed by one or more resistive elements in any connection method of series, parallel, or series-parallel combination, without constituting a limitation on the shape, number, or connection method of the corresponding resistive elements; similarly, the equivalent capacitance 403 is a capacitor that meets the corresponding capacitance requirement, formed by one or more capacitive elements in any connection method of series, parallel, or series-parallel combination, without constituting a limitation on the shape, number, or connection method of the corresponding capacitive elements.

[0116] It is worth mentioning that, in practical applications, environmental interference signals that have any frequency relationship with the local oscillator signal of the microwave detection device (including those with the same frequency, adjacent frequency, and harmonic frequency) are mainly wireless communication signals. Through exploration of the principles of wireless communication and actual testing of different products, it has been found that in wireless communication signals that express communication information through frequency changes based on the working principle of frequency modulation, the rate of frequency change of the signal is much higher than the rate of frequency change of the feedback signal corresponding to a normally moving object based on the Doppler effect. Correspondingly, the second type of interference signal exists as a differential mode interference in the differential signal form of the Doppler intermediate frequency signal in the differential signal form as a high-frequency spike. Therefore, the second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal can be accurately eliminated by frequency selection cancellation. This has significant practical value and commercial significance in ensuring the anti-communication interference capability of the microwave detection device.

[0117] Specifically, refer to the accompanying drawings of the specification of this invention. Figure 4A , corresponding to Figure 3The microwave detection device described in the example, in a state where there is no object activity in the detection space, compares the top-to-bottom arrangement of the Doppler intermediate frequency signal (monopole-to-ground configuration of the differential signal) sampled from one of the input terminals 41 and one of the output terminals 42 of the frequency selection cancellation circuit 40. Figure 2 The filtering method shown can accurately eliminate the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form. This is significantly different from the integral smoothing process of filtering. Therefore, it can avoid the use of multiple filtering methods, which is conducive to ensuring the integrity of the Doppler intermediate frequency signal and the correspondence between the corresponding parameters of the Doppler intermediate frequency signal and their physical meaning. This improves the feedback accuracy of the Doppler intermediate frequency signal for the motion of objects in the corresponding detection space.

[0118] Furthermore, refer to the accompanying drawings of the specification of this invention. Figure 4B , corresponding to Figure 3 The microwave detection device described in the example, in the presence of human activity in the detection space, compares the Doppler intermediate frequency signals (the complete form of the differential signal) sampled from the two input terminals 41 and the two output terminals 42 of the frequency selection cancellation circuit 40 in an up-down arrangement. It is also clearly visible that the frequency selection cancellation method can accurately eliminate the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form. Therefore, it can avoid the use of multiple filtering methods, which is conducive to ensuring the integrity of the Doppler intermediate frequency signal and ensuring the correspondence between the corresponding parameters of the Doppler intermediate frequency signal and the physical meaning, thereby improving the feedback accuracy of the Doppler intermediate frequency signal to the motion of objects in the corresponding detection space.

[0119] Furthermore, since the frequency-selective cancellation method can accurately eliminate the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form, it avoids the signal delay caused by filtering by using multiple filtering methods. Thus, the immediacy of the Doppler intermediate frequency signal is guaranteed, which is conducive to realizing real-time detection of human actions such as breathing and heartbeat.

[0120] Specifically, in order to maintain the Doppler intermediate frequency signals output from the two output terminals 42 of the frequency selection cancellation circuit 40 in a differential signal form, in this embodiment of the invention, the resistance values ​​of the first equivalent resistor 401 and the second equivalent resistor 402 are set to be similar within a 25% error range. For example, when the microwave detection device is set to operate in the 5.8 GHz ISM band, the first equivalent resistor 401 and the second equivalent resistor 402 are preferably set to a resistance value approaching 39 kΩ within a 25% error range, and the corresponding equivalent capacitor 403 is set to a capacitance approaching 47 nF within a 25% error range, such as a capacitor of type 473. This ensures that the frequency selection range of the frequency selection cancellation circuit 40 corresponds to the frequency of the second type of interference signal generated in the differential signal form of the Doppler intermediate frequency signal of the existing wireless communication signal, thereby accurately eliminating the second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal, and outputting the frequency-selective cancellation processed Doppler intermediate frequency signal in a lossless state. This ensures the integrity of the Doppler intermediate frequency signal and the correspondence between the corresponding parameters of the Doppler intermediate frequency signal and its physical meaning. Therefore, compared with the method of multiple filtering, the feedback accuracy of the Doppler intermediate frequency signal for the motion of objects in the corresponding detection space can be significantly improved.

[0121] Further reference is made to the accompanying drawings of this invention. Figure 5A As shown, in Figure 3 Based on the structure of the microwave detection device described in the example, and with variations in the number and connection method of the corresponding capacitive elements that form the equivalent capacitor 403, a structural block diagram of the microwave detection device according to a modified embodiment of the above-described embodiment of the present invention is shown. In this modified embodiment of the present invention, the equivalent capacitor 403 is equivalently arranged as two capacitors 4031 connected in series. To maintain the differential signal format of the Doppler intermediate frequency signals output from the two output terminals 42 of the frequency selection cancellation circuit 40, the two capacitors 4031 are preferably of the same type, so that the capacitances of the two capacitors 4031 tend to be the same. For example, when the microwave detection device is set to operate in the 5.8 GHz ISM band, the first equivalent resistor 401 and the second equivalent resistor 402 are preferably set to a resistance value of approximately 39 kΩ within a 25% error range, the equivalent capacitor 403 is set to a capacitance value of approximately 47 nF within a 25% error range, and the two capacitors 4031 of the same type are both set to a capacitance value of approximately 100 nF within a 25% error range, such as using a capacitor of type 104.

[0122] Further reference is made to the accompanying drawings of this invention. Figure 5B As shown, in Figure 5ABased on the structure of the microwave detection device described in the example, the frequency selection cancellation circuit 40 may optionally be further grounded between the two capacitors 4031 connected in series, so as to form a balanced grounding of the signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal, thereby ensuring that the Doppler intermediate frequency signal output from the two output terminals 42 of the frequency selection cancellation circuit 40 is in differential signal form.

[0123] Further reference is made to the accompanying drawings of this invention. Figure 6A As shown, a further improved structure of the microwave detection device according to the above embodiments of the present invention is illustrated. Since in the application scenarios of the microwave detection device, environmental interference signals with the same frequency relationship as the local oscillator signal of the microwave detection device may also be signals emitted by other microwave detection devices at the same frequency, or same-frequency interference signals formed by multiple reflections of the detection beam emitted by the microwave detection device in small spaces and / or strong reflection environments, the corresponding first and second type of interference signals exist in the differential signal form of the Doppler intermediate frequency signal in the form of spikes. The microwave detection device may optionally correspond to the second type of interference signal in the corresponding frequency range of the differential signal form of the Doppler intermediate frequency signal before eliminating the second type of interference signal in the differential signal form of the Doppler intermediate frequency signal by frequency selection cancellation. Figure 6A A pair of ground capacitors 43 are electrically connected to each of the two input terminals 41 of at least one of the frequency selection cancellation circuits 40. Based on the configuration of the two ground capacitors 43, the first and second type interference signals formed as glitches in the differential Doppler intermediate frequency signal by co-frequency interference in a fixed-frequency form are suppressed. This ensures the anti-interference capability of the microwave detection device in multi-microwave detection device application scenarios and its anti-self-oscillation interference capability in small spaces and / or strong reflection environments. To maintain the differential signal form of the Doppler intermediate frequency signal output from the two output terminals 42 of the frequency selection cancellation circuit 40, the two ground capacitors 43 are configured to be of the same type, so that the capacitances of the two ground capacitors 43 tend to be the same.

[0124] Based on the demonstration of the corresponding beneficial effects, please refer to the accompanying drawings in the specification of this invention. Figure 6B In the absence of any moving objects in the detection space, another microwave detection device operating at the same frequency is used as an interference source for the microwave detection device. Figure 6AIn the microwave detection device illustrated, the Doppler intermediate frequency signals (monopole-to-ground configuration of the differential signal) sampled from one input terminal 41 of the frequency selection cancellation circuit 40 (connected to the front end of the ground capacitor 43) and one output terminal 42 are arranged vertically for comparison. It is evident that the first and second types of interference signals, which are formed as spikes in the differential Doppler intermediate frequency signal due to the fixed-frequency co-frequency interference, can be suppressed by the ground capacitor 43. This avoids excessively high noise floor in the Doppler intermediate frequency signal output by the frequency selection cancellation circuit 40, thus further ensuring the anti-interference capability of the microwave detection device in different application scenarios.

[0125] Further reference is made to the accompanying drawings of this invention. Figure 7A and Figure 7B As shown, the frequency selection cancellation circuit 40 is configured to be multiple based on the need for multi-level and / or multi-channel frequency selection cancellation processing. The multiple frequency selection cancellation circuits 40 are not limited to series or parallel electrical connection relationships, but can also be formed by a combination of series and parallel electrical connection relationships.

[0126] Corresponding to Figure 7A The series structure between the two frequency selective cancellation circuits 40 is illustrated. Specifically, the two output terminals 42 of one frequency selective cancellation circuit 40 are electrically connected to the two input terminals 41 of the other frequency selective cancellation circuit 40, thereby forming a series structure between the two frequency selective cancellation circuits 40. The Doppler intermediate frequency signal in differential signal form is input to the two input terminals 41 of the preceding frequency selective cancellation circuit 40, and the Doppler intermediate frequency signal after multi-stage frequency selective cancellation is output to the two output terminals 42 of the following frequency selective cancellation circuit 40.

[0127] Corresponding to Figure 7B The parallel structure between the two frequency selection cancellation circuits 40 is illustrated. Specifically, the two input terminals 41 of one frequency selection cancellation circuit 40 are electrically connected to the two input terminals 41 of the other frequency selection cancellation circuit 40, thereby forming a parallel structure between the two frequency selection cancellation circuits 40, so as to output the frequency-selective cancellation processed Doppler intermediate frequency signal at the two output terminals 42 of each frequency selection cancellation circuit 40 to achieve multi-channel frequency selection cancellation processing.

[0128] Corresponding to the structure of the microwave detection device described in the above embodiments, the anti-interference microwave detection method of the present invention includes the following steps:

[0129] A. Transmit the detection beam corresponding to the frequency of the local oscillator signal to form a corresponding detection space;

[0130] B. Receive the echo formed by the detection beam being reflected by an object in the detection space and generate the feedback signal;

[0131] C. Output a Doppler intermediate frequency signal in differential signal form, wherein the Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0132] D. Output the Doppler intermediate frequency signal after frequency selection cancellation in a frequency-selective cancellation manner;

[0133] The system comprises: oscillation unit 20 providing the local oscillator signal; antenna unit 10 transmitting the probe beam and receiving the echo; Doppler differential output circuit 30, when receiving the local oscillator signal and the feedback signal, outputting a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal in an inverted manner to form the output of the Doppler intermediate frequency signal in differential signal form; and frequency selection cancellation circuit 40 performing frequency selection cancellation processing on the received differential signal form of the Doppler intermediate frequency signal to output the frequency-selected and cancelled Doppler intermediate frequency signal. The frequency selection cancellation circuit 40 includes a first equivalent resistor 401, a second equivalent resistor 402, and an equivalent capacitor 403. One end of the first equivalent resistor 401 is electrically connected to one end of the equivalent capacitor 403, and one end of the second equivalent resistor 402 is electrically connected to the other end of the equivalent capacitor 403. The frequency selective cancellation circuit 40 has two input terminals 41 with the other ends of the first equivalent resistor 401 and the second equivalent resistor 402, and two output terminals 42 with the two ends of the equivalent capacitor 403. The frequency selective cancellation circuit 40 is electrically connected to the Doppler differential output circuit 30 at the two input terminals 41 to receive the two poles of the differential signal of the Doppler intermediate frequency signal, and outputs the frequency selectively cancelled Doppler intermediate frequency signal at the two output terminals 42.

[0134] Furthermore, in some embodiments of the present invention, in step (C), the Doppler intermediate frequency signal, corresponding to the differential signal form of the frequency / phase difference between the local oscillator signal and the feedback signal, is directly output based on mixing processing. A corresponding mixing circuit is provided for the Doppler differential output circuit 30 to directly output the Doppler intermediate frequency signal in the differential signal form based on mixing processing.

[0135] Example, referring to the accompanying drawings of the specification of the present invention. Figures 8A to 8D As shown, the different circuit structures of the corresponding Doppler differential output circuit 30 are illustrated.

[0136] Corresponding to Figure 8A The Doppler differential output circuit 30 includes a first load 301 and a second load 302 formed in the form of equivalent resistance or equivalent inductance, a first MOSFET 303, and a second MOSFET 304. One end of the first load 301 is electrically connected to one end of the second load 302, the other end of the first load 301 is electrically connected to the drain of the first MOSFET 303, and the other end of the second load 302 is electrically connected to the drain of the second MOSFET 304. The source of the first MOSFET 303 is electrically connected to... With the source of the second MOS transistor 304 connected to the power supply at both ends of the interconnected first load 301 and second load 302, the feedback signal is connected to the two sources of the interconnected first MOS transistor 303 and second MOS transistor 304, and the inverted local oscillator signal is connected to the gate of the first MOS transistor 303 and the gate of the second MOS transistor 304, the Doppler intermediate frequency signal in differential signal form can be output at the drain of the first MOS transistor 303 and the drain of the second MOS transistor 304.

[0137] Corresponding to Figure 8B The Doppler differential output circuit 30 includes a first MOSFET 301, a second MOSFET 302, a third MOSFET 303, and a fourth MOSFET 304. The drain of the first MOSFET 301 is electrically connected to the drain of the second MOSFET 302, the drain of the third MOSFET 303 is electrically connected to the drain of the fourth MOSFET 304, the source of the first MOSFET 301 is electrically connected to the source of the third MOSFET 303, and the source of the second MOSFET 302 is electrically connected to the source of the fourth MOSFET 304. This allows for the interconnection of the first MOSFET 301 and the fourth MOSFET 304. With the inverted feedback signal connected between the two drains of the second MOS transistor 302 and between the two drains of the interconnected third MOS transistor 303 and fourth MOS transistor 304, and with the inverted local oscillator signal connected to the four gates of the first MOS transistor 301, the second MOS transistor 302, the third MOS transistor 303, and the fourth MOS transistor 304, a differential Doppler intermediate frequency signal can be output between the two sources of the first MOS transistor 301 and the third MOS transistor 303, and between the two sources of the second MOS transistor 302 and the fourth MOS transistor 304.

[0138] Corresponding to Figure 8CThe Doppler differential output circuit 30 includes a first load 301 and a second load 302 formed in the form of equivalent resistance or equivalent inductance, a first MOSFET 303, a second MOSFET 304, and a third MOSFET 305. One end of the first load 301 is electrically connected to one end of the second load 302, the other end of the first load 301 is electrically connected to the drain of the first MOSFET 303, and the other end of the second load 302 is electrically connected to the drain of the second MOSFET 304. The source of the first MOSFET 303 is connected to the drain of the second MOSFET 305. The source of 304 is electrically connected to the drain of the third MOS transistor 305, wherein the source of the third MOS transistor 305 is grounded. In this way, when power is connected to the two ends of the interconnected first load 301 and second load 302, the feedback signal is connected to the gate of the third MOS transistor 305, and the inverted local oscillator signal is connected to the gate of the first MOS transistor 303 and the gate of the second MOS transistor 304, the Doppler intermediate frequency signal in the form of a differential signal can be output from the drain of the first MOS transistor 303 and the drain of the second MOS transistor 304.

[0139] Corresponding to Figure 8DThe Doppler differential output circuit 30 includes a first load 301 and a second load 302 formed in the form of equivalent resistance or equivalent inductance, a first MOSFET 303, a second MOSFET 304, a third MOSFET 305, a fourth MOSFET 306, a fifth MOSFET 307, a sixth MOSFET 308, and a current source 309. One end of the first load 301 is electrically connected to one end of the second load 302. The other end of the first load 301 is electrically connected to the drain of the first MOSFET 303 and the drain of the third MOSFET 305, respectively. The other end of the second load 302 is electrically connected to the drain of the second MOSFET 304 and the drain of the fourth MOSFET 306, respectively. The sources of the first MOSFET 303 and the second MOSFET 304 are electrically connected to the drain of the fifth MOSFET 307, and the sources of the third MOSFET 305 and the fourth MOSFET 306 are electrically connected to the drain of the fifth MOSFET 307, respectively. The source of the fifth MOS transistor 307 and the source of the sixth MOS transistor 308 are electrically connected to the drain of the sixth MOS transistor 308, respectively. This allows the gates of the fifth MOS transistor 307 and the sixth MOS transistor 308 to be connected to the inverted feedback signal, the gates of the first MOS transistor 303 and the second MOS transistor 304 to be connected to the inverted local oscillator signal, and the gates of the third MOS transistor 305 and the fourth MOS transistor 306 to be connected to the inverted local oscillator signal. The local oscillator signal connected to the gate of the second MOS transistor 304 is in phase with the local oscillator signal connected to the gate of the third MOS transistor 305. With power supplied to both ends of the interconnected first load 301 and second load 302, a differential Doppler intermediate frequency signal can be output at the other end of the first load 301 and the other end of the second load 302.

[0140] It is understood that the above-described different Doppler differential output circuits 30 are merely examples and are applicable to the microwave detection devices described in the aforementioned different embodiments. The circuit structures of the Doppler differential output circuits 30 are diverse and cannot be listed one by one. They are not limited to independent forms of discrete components or integrated circuits, and can be implemented as a combination of discrete component forms and integrated circuit forms. This invention does not limit them in this regard.

[0141] For example, in some embodiments of the present invention, the Doppler differential output circuit 30 and the oscillation unit 20 are configured as integrated circuits and integrated into a microwave chip. In other embodiments of the present invention, the first equivalent resistance 401 and the second equivalent resistance 402 of the frequency selection cancellation circuit 40 are integrated into the microwave chip.

[0142] In particular, in some embodiments of the present invention, step (C) of the anti-interference microwave detection method includes the following steps:

[0143] C1. Mix the local oscillator signal and the feedback signal so that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal can be extracted;

[0144] C2. Using the reference ground of the antenna element 10 as ground, a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal is led out to output the Doppler intermediate frequency signal in a single-ended signal form; and

[0145] C3. By inverting the Doppler intermediate frequency signal in single-ended signal form and outputting a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal, the Doppler intermediate frequency signal in single-ended signal form is converted into a Doppler intermediate frequency signal in differential signal form.

[0146] It is worth mentioning that in step (C2), since only one signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal is output, the initial intensity of the Doppler intermediate frequency signal in the single-ended signal form output in step (C2) can be guaranteed, which is beneficial to guaranteeing the initial intensity of the Doppler intermediate frequency signal in the differential signal form output in step (C3). Correspondingly, this is beneficial to guaranteeing the feedback accuracy of the Doppler intermediate frequency signal in the differential signal form output in step (D) in the frequency-selective cancellation manner for the motion of objects in the corresponding detection space.

[0147] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 9As shown, a circuit structure principle of the Doppler differential output circuit 30 is illustrated. The Doppler differential output circuit 30 includes a mixer circuit 31 and a single-ended signal to differential signal circuit 32. The mixer circuit 31 is electrically connected to the antenna unit 10 and the oscillation unit 20 to receive the feedback signal and the local oscillator signal and output the Doppler intermediate frequency signal in a single-ended signal form corresponding to the frequency / phase difference between the feedback signal and the local oscillator signal by mixing and detection. The single-ended to differential circuit 32 is electrically connected to the mixer circuit 31 to receive the single-ended signal form of the Doppler intermediate frequency signal and convert the single-ended signal form of the Doppler intermediate frequency signal into a differential signal form of the Doppler intermediate frequency signal by inverting the phase of the single-ended signal form of the Doppler intermediate frequency signal.

[0148] Example, referring to the accompanying drawings of the specification of the present invention. Figure 10A and Figure 10B As shown, different basic circuit structures of the single-ended signal to differential signal circuit 32 are illustrated.

[0149] Corresponding to Figure 10A The single-ended signal to differential signal circuit 32 includes a transistor 321, a first resistor 322, a second resistor 323, a third resistor 324, a fourth resistor 325, and a capacitor 326. The emitter of the transistor 321 is grounded through the first resistor 322, the collector of the transistor 321 is connected to a power supply through the second resistor 323, the base of the transistor 321 is connected to a power supply through the third resistor 324 and grounded through the fourth resistor 325, and connected to the single-ended signal form of the Doppler intermediate frequency signal through the capacitor 326, so as to output the differential signal form of the Doppler intermediate frequency signal between the collector and emitter of the transistor 321.

[0150] Corresponding to Figure 10B The single-ended signal to differential signal circuit 32 includes an operational amplifier 321, a first resistor 322, and a second resistor 323. The operational amplifier 321 is connected to a reference voltage at its non-inverting input terminal and electrically connected to the output terminal of the operational amplifier 321 via the first resistor 322 at its inverting input terminal. The single-ended Doppler intermediate frequency signal is connected to the second resistor 323, so that a differential Doppler intermediate frequency signal is output between the end of the second resistor 323 connected to the single-ended Doppler intermediate frequency signal and the output terminal of the operational amplifier 321.

[0151] Example, referring to the accompanying drawings of the specification of the present invention. Figures 11A to 11DAs shown, one structural principle of the single-ended signal to differential signal circuit 32 and different basic circuit structures corresponding to this structural principle are illustrated. The single-ended signal to differential signal circuit 32 includes a first operational amplifier circuit 321 and a second operational amplifier circuit 322. The first operational amplifier circuit 321 receives a Doppler intermediate frequency signal in single-ended signal form at its input terminal and is electrically connected to the input terminal of the second operational amplifier circuit 322 at its output terminal. The first operational amplifier circuit 321 outputs the Doppler intermediate frequency signal in differential signal form between the output terminals of the first operational amplifier circuit 321 and the output terminals of the second operational amplifier circuit 322.

[0152] Corresponding to Figure 11B The first operational amplifier circuit 321 includes a first operational amplifier 3211, with the non-inverting input terminal of the first operational amplifier 3211 as the input terminal to the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier 3211 as the output terminal. The second operational amplifier circuit 322 includes a second operational amplifier 3221, a first resistor 3222, and a second resistor 3223, with the inverting input terminal of the second operational amplifier 3221 as the input terminal and the output terminal of the second operational amplifier 3221 as the output terminal. Amplifier 3221 has a reference voltage connected to its non-inverting input terminal and is electrically connected to the output terminal of the second operational amplifier 3221 via the second resistor 3223 at its inverting input terminal. The output terminal of the first operational amplifier 3211 is electrically connected to the inverting input terminal of the second operational amplifier 3221 via the first resistor 3222. The inverting input terminal and output terminal of the first operational amplifier 3211 are electrically connected, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first operational amplifier 3211 and the output terminals of the second operational amplifier 3221.

[0153] Corresponding to Figure 11CThe first operational amplifier circuit 321 includes a first operational amplifier 3211, a first resistor 3212, and a second resistor 3213. The inverting input terminal of the first operational amplifier 3211 is used as the input terminal to receive the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier 3211 is used as the output terminal. The first operational amplifier 3211 receives the single-ended Doppler intermediate frequency signal at its inverting input terminal via the first resistor 3212, and receives a reference voltage at its non-inverting input terminal. The inverting input terminal and the output terminal of the first operational amplifier 3211 are electrically connected via the second resistor 3213. The second operational amplifier circuit 32... 2 includes a second operational amplifier 3221, a third resistor 3222, and a fourth resistor 3223, with the inverting input terminal of the second operational amplifier 3221 as the input terminal and the output terminal of the second operational amplifier 3221 as the output terminal. The first operational amplifier 3211 is electrically connected at its output terminal to the inverting input terminal of the second operational amplifier 3221 via the third resistor 3222, and the inverting input terminal and the output terminal of the second operational amplifier 3221 are electrically connected via the fourth resistor 3223. Thus, a differential signal in the form of a Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier 3211 and the output terminals of the second operational amplifier 3221.

[0154] Corresponding to Figure 11DThe first operational amplifier circuit 321 includes a first operational amplifier 3211, a first resistor 3212, a second resistor 3213, a first capacitor 3214, a second capacitor 3215, and a third capacitor 3216. The first operational amplifier 3211 is connected to a single-ended Doppler intermediate frequency signal via its inverting input terminal and to its output terminal via its output terminal. The first operational amplifier 3211 is electrically connected from its inverting input terminal to its output terminal via the third capacitor 3216, and sequentially connected to its output terminal via the first resistor 3212 and the second resistor 3213. The single-ended Doppler intermediate frequency signal is connected to its output terminal sequentially via the first resistor 3212 and the first capacitor 3214, and sequentially connected to its output terminal via the third capacitor 3216. The first resistor 3212 and the second capacitor 3215 are grounded. The second operational amplifier circuit 322 includes a second operational amplifier 3221, a third resistor 3222 and a fourth resistor 3223. The inverting input terminal of the second operational amplifier 3221 is used as the input terminal and the output terminal of the second operational amplifier 3221 is used as the output terminal. The first operational amplifier 3211 is electrically connected to the inverting input terminal of the second operational amplifier 3221 via the third resistor 3222. The inverting input terminal and the output terminal of the second operational amplifier 3221 are electrically connected via the fourth resistor 3223. In this way, the Doppler intermediate frequency signal in the form of a differential signal is output between the output terminal of the first operational amplifier 3211 and the output terminal of the second operational amplifier 3221.

[0155] As a further example, refer to the accompanying drawings of the specification of this invention. Figures 12A to 12C As shown, another structural principle of the single-ended signal to differential signal circuit 32 and different basic circuit structures corresponding to this structural principle are illustrated. The single-ended signal to differential signal circuit 32 includes a first operational amplifier circuit 321 and a second operational amplifier circuit 322. The first operational amplifier circuit 321 is electrically connected to the input terminal of the second operational amplifier circuit 322 and receives a Doppler intermediate frequency signal in single-ended signal form. The Doppler intermediate frequency signal in differential signal form is output between the output terminal of the first operational amplifier circuit 321 and the output terminal of the second operational amplifier circuit 322.

[0156] Corresponding to Figure 12BThe first operational amplifier circuit 321 includes a first operational amplifier 3211, a first resistor 3212, a second resistor 3213, and a first capacitor 3214. The non-inverting input terminal of the first operational amplifier 3211 is used as the input terminal to receive the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier 3211 is used as the output terminal. The first operational amplifier 3211 is electrically connected from its inverting input terminal to its output terminal via the first resistor 3212, and is grounded sequentially via the second resistor 3213 and the first capacitor 3214. The second operational amplifier circuit 322 includes a second operational amplifier 3221, a third resistor 3222, and a... The fourth resistor 3223 is used as the input terminal of the second operational amplifier 3221 and the output terminal of the second operational amplifier 3221 is used as the output terminal. The first operational amplifier 3211 is electrically connected to the inverting input terminal of the second operational amplifier 3221 via the third resistor 3222 at its non-inverting input terminal. The inverting input terminal and the output terminal of the second operational amplifier 3221 are electrically connected via the fourth resistor 3223. The second operational amplifier 3221 is connected to a reference voltage at its non-inverting input terminal. Thus, a differential signal in the form of the Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier 3211 and the second operational amplifier 3221.

[0157] Corresponding to Figure 12CThe first operational amplifier circuit 321 includes a first operational amplifier 3211, a first resistor 3212, a second resistor 3213, a third resistor 3214, and a fourth resistor 3215. The first operational amplifier 3211 receives a single-ended Doppler intermediate frequency signal at its non-inverting input terminal and receives its output terminal at its output terminal. The first operational amplifier 3211 is electrically connected from its inverting input terminal to its output terminal via the fourth resistor 3215 and grounded via the third resistor 3214. The first operational amplifier 3211 receives a single-ended Doppler intermediate frequency signal from its non-inverting input terminal via the first resistor 3212 and is grounded via the second resistor 3213. The second operational amplifier circuit 322 includes... The system includes a second operational amplifier 3221, a fifth resistor 3222, and a sixth resistor 3223. The inverting input terminal of the second operational amplifier 3221 is used as the input terminal, and the output terminal of the second operational amplifier 3221 is used as the output terminal. The first operational amplifier 3211 is electrically connected from its non-inverting input terminal to the inverting input terminal of the second operational amplifier 3221 via the first resistor 3222 and the fifth resistor 3222. The inverting input terminal and the output terminal of the second operational amplifier 3221 are electrically connected via the sixth resistor 3223. The second operational amplifier 3221 is connected to a reference voltage at its non-inverting input terminal. Thus, a differential signal in the form of a Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier 3211 and the second operational amplifier 3221.

[0158] As a further example, refer to the accompanying drawings of the specification of this invention. Figure 13A and Figure 13B As shown, different basic circuit structures of the single-ended signal to differential signal circuit 32 based on another structural principle are illustrated.

[0159] Corresponding to Figure 13AThe single-ended signal to differential signal circuit 32 includes a first operational amplifier 321, a second operational amplifier 322, a first resistor 323, a second resistor 324, a third resistor 325, and a fourth resistor 326. The first operational amplifier 321 has a reference voltage connected to its non-inverting input terminal, and a single-ended Doppler intermediate frequency signal connected to its inverting input terminal via the first resistor 323. Its output terminal is sequentially connected to the second operational amplifier 322 via the third resistor 325 and the fourth resistor 326. The output terminals are electrically connected, wherein the inverting input terminal and the output terminal of the first operational amplifier 321 are electrically connected via the second resistor 324, the inverting input terminal and the output terminal of the second operational amplifier 322 are electrically connected via the fourth resistor 326, and the non-inverting input terminal of the second operational amplifier 322 is electrically connected to the inverting input terminal of the first operational amplifier 321, so that the Doppler intermediate frequency signal in the form of a differential signal is output between the output terminals of the first operational amplifier 321 and the output terminals of the second operational amplifier 322.

[0160] Corresponding to Figure 13B The single-ended signal to differential signal circuit 32 includes a first operational amplifier 321, a second operational amplifier 322, a first resistor 323, a second resistor 324, a third resistor 325, and a fourth resistor 326. The first operational amplifier 321 has a reference voltage connected to its non-inverting input terminal, and its inverting input terminal electrically connected to the inverting input terminal of the second operational amplifier 322. Its output terminal is electrically connected to the non-inverting input terminal of the second operational amplifier 322 via the fourth resistor 326. The inverting input terminal and output terminal of the first operational amplifier 321 are electrically connected via the third resistor 325. The second operational amplifier 322 has a single-ended Doppler intermediate frequency signal connected to its non-inverting input terminal via the first resistor 323. The inverting input terminal and output terminal of the second operational amplifier 322 are electrically connected via the second resistor 324. Thus, a differential Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier 321 and the second operational amplifier 322.

[0161] It is also understood that the structures of the different single-ended signal to differential signal circuits 32 described above are merely examples, and the corresponding Doppler differential output circuit 30 is applicable to the microwave detection devices described in the aforementioned different embodiments. For example, corresponding to... Figure 14A , Figure 11D The single-ended signal to differential signal circuit 32 shown is applied to Figure 6A A portion of the circuit structure is illustrated. Corresponding to... Figure 14B , Figure 13AThe single-ended signal to differential signal circuit 32 shown is applied to Figure 6A The circuit structure of the time section is shown in the diagram.

[0162] It is worth mentioning that the circuit structure of the single-ended signal to differential signal circuit 32 is diverse and cannot be listed one by one. Its main structural feature is that it adopts a single-ended input and double-ended output structure. By inverting the single-ended Doppler intermediate frequency signal in single-ended signal form, it converts one single-ended Doppler intermediate frequency signal into an inverted signal, thereby forming a conversion from the single-ended Doppler intermediate frequency signal to the differential Doppler intermediate frequency signal. It is not limited to an independent form of discrete component form or integrated circuit form, and can be implemented as a combination of discrete component form and integrated circuit form. The present invention does not limit this.

[0163] For example, in some embodiments of the present invention, the oscillation unit 20 and the Doppler differential output circuit 30 are configured as integrated circuits and integrated into a microwave chip. In other embodiments of the present invention, the first equivalent resistance 401 and the second equivalent resistance 402 of the frequency selection cancellation circuit 40 are integrated into the microwave chip.

[0164] For example, in some embodiments of the present invention, the oscillation unit 20 and the mixer circuit 31 of the Doppler differential output circuit 30 are configured as integrated circuits and integrated into a microwave chip, while the single-ended signal to differential signal circuit 32 of the Doppler differential output circuit 30 is externally placed on the microwave chip.

[0165] For example, in some embodiments of the present invention, the oscillation unit 20 corresponds to the single-ended signal to differential signal circuit 32. Figures 11A to 12C The first operational amplifier circuit or corresponding to Figure 13A and Figure 13B The first operational amplifier is configured as an integrated circuit and integrated into a microwave chip, while the single-ended signal to differential signal circuit 32 corresponds to... Figures 11A to 12C The second operational amplifier circuit or corresponding to Figure 13A and Figure 13B The second operational amplifier is externally located on the microwave chip, wherein the mixer circuit 31 of the Doppler differential output circuit 30 is externally located on the microwave chip or is built into the microwave chip to form an existing microwave chip that outputs Doppler intermediate frequency signals in single-ended signal form.

[0166] In particular, in some embodiments of the present invention, the anti-interference microwave detection method further includes the step of:

[0167] E. Perform differential amplification processing on the Doppler intermediate frequency signal in differential signal form.

[0168] It is understood that step (E) is performed between step (C) and step (D), and / or after step (D), and the present invention is not limited thereto.

[0169] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 15A and Figure 15B As shown, the microwave detection device further includes at least one differential amplifier circuit 50, wherein the differential amplifier circuit 50 is disposed between the Doppler differential output circuit 30 and the frequency selective cancellation circuit 40, and / or disposed at the two output terminals 42 of the frequency selective cancellation circuit 40, to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit 30, and / or to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the frequency selective cancellation circuit 40, thereby amplifying the Doppler intermediate frequency signal in differential signal form based on the common-mode rejection characteristics of the differential amplification process of the Doppler intermediate frequency signal in differential signal form, while suppressing the amplification of the first type of interference signal in the Doppler intermediate frequency signal in differential signal form.

[0170] It is worth mentioning that when the differential amplifier circuit 50 is positioned between the Doppler differential output circuit 30 and the frequency selective cancellation circuit 40, and the two input terminals 41 of the frequency selective cancellation circuit 40 are electrically connected to the ground capacitor 43, the corresponding ground capacitor 43 can be electrically connected to the corresponding input terminal 41 of the frequency selective cancellation circuit 40 in either the state of being positioned between the differential amplifier circuit 50 and the Doppler differential output circuit 30, or electrically connected to the corresponding input terminal 41 in the state of being positioned between the differential amplifier circuit 50 and the frequency selective cancellation circuit 40.

[0171] Furthermore, it is worth mentioning that, based on the requirement of multi-level frequency selection cancellation processing, when the number of the frequency selection cancellation circuits 40 is multiple and corresponds to Figure 7AIn some embodiments of the present invention, when a series structure is adopted, a differential amplifier circuit 50 is further provided between the two series-connected frequency selective cancellation circuits 40. When the cancellation processing of differential signals of different frequency bands is achieved by adopting a multi-stage frequency selective cancellation processing method, the differential amplifier circuit 50 is provided between the two series-connected frequency selective cancellation circuits 40 to form an isolation between the two series-connected frequency selective cancellation circuits 40 and ensure the independence of the two series-connected frequency selective cancellation circuits 40. Correspondingly, the cancellation and elimination processing of differential signals of corresponding frequency bands by the two series-connected frequency selective cancellation circuits 40 can be performed without affecting each other, thus ensuring the multi-stage frequency selective cancellation effect.

[0172] To further describe the present invention, reference is made to the accompanying drawings in the specification of the present invention. Figure 16 As shown, the structural principle of the differential amplifier circuit 50 is illustrated. It can be understood that, based on the selection of the power supply method (dual power supply or single power supply) and the corresponding parameters and optimization design of the differential amplifier circuit 50, the circuit structure of the differential amplifier circuit 50 is diverse and cannot be listed one by one. It is not limited to an independent form of discrete components or integrated circuits. It can also be implemented as a combination of discrete components and integrated circuits. The main structural feature of the differential amplifier circuit 50 is that it adopts a dual-ended input and dual-ended output method, with the differential signal form of the Doppler intermediate frequency signal connected between the base of the two transistors and ground, and the differentially amplified differential signal form of the Doppler intermediate frequency signal output between the collectors of the two transistors.

[0173] Furthermore, in some embodiments of the present invention, the anti-interference microwave detection method further includes the following step after step (D):

[0174] F. The Doppler intermediate frequency signal in the form of a differential signal is converted to a Doppler intermediate frequency signal in the form of a single-ended signal.

[0175] It is understood that when the anti-interference microwave detection method includes step (E) after step (D), step (F) is performed after step (E).

[0176] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 17A and Figure 17BAs shown, the microwave detection device further includes a differential signal to single-ended signal circuit 60, wherein the differential signal to single-ended signal circuit 60 is configured to receive the Doppler intermediate frequency signal in differential signal form after frequency selection and cancellation processing, and output the Doppler intermediate frequency signal in single-ended signal form with the reference ground of the antenna element 10 as the ground during the conversion of the Doppler intermediate frequency signal in differential signal form to the Doppler intermediate frequency signal in single-ended signal form, so as to suppress and eliminate common-mode interference during the conversion of the Doppler intermediate frequency signal in differential signal form to the Doppler intermediate frequency signal in single-ended signal form, and suppress and eliminate the first type of interference signal in the Doppler intermediate frequency signal output in single-ended signal form.

[0177] To further describe the present invention, reference is made to the accompanying drawings in the specification of the present invention. Figure 18 As shown, the structural principle of the differential signal to single-ended signal circuit 60 is illustrated. It converts the differential signal to single-ended signal based on the inverse superposition of the input differential signal form Doppler intermediate frequency (IF) signal by a corresponding operational amplifier. During the conversion process, common-mode interference is mutually canceled out during the inverse superposition of the differential signal form Doppler IF signal, thus suppressing and eliminating common-mode interference. This correspondingly suppresses and eliminates the first type of interference signal in the single-ended signal output Doppler IF signal.

[0178] Similarly, it is understandable that, based on the above structural principles, and based on the selection of the power supply method (dual power supply or single power supply) and the corresponding parameters and optimization design of the differential signal to single-ended signal circuit 60, the circuit structure of the differential signal to single-ended signal circuit 60 is diverse and cannot be listed one by one. It is not limited to an independent form of discrete component form or integrated circuit form. It can also be implemented as a combination of discrete component form and integrated circuit form. This invention does not limit this.

[0179] Optionally, in some embodiments of the present invention, by performing A / D conversion on the two poles of the Doppler intermediate frequency signal in differential signal form, the suppression and elimination of common-mode interference can be achieved in subsequent data-based quantization identification and calculation, which is equivalent to achieving the anti-common-mode interference purpose of converting the Doppler intermediate frequency signal in differential signal form into a single-ended signal form.

[0180] It is worth mentioning that by forming a differential Doppler intermediate frequency (IF) signal, the external radiation of the differential Doppler IF signal can cancel each other out, thus suppressing interference from the Doppler IF signal to the environment and corresponding circuits, which is beneficial to improving the anti-interference capability of the microwave detection device. Furthermore, differential amplification of the differential Doppler IF signal and / or conversion to a single-ended Doppler IF signal, compared to filtering methods, can significantly reduce or even eliminate the use of capacitors in the transmission path of the Doppler IF signal. This ensures the immediacy of the Doppler IF signal, which is beneficial for real-time detection of actions such as human respiration and heartbeat.

[0181] It is understood that the structural principle of the microwave detection device equipped with the differential signal to single-ended signal circuit 60 is merely an example. After the microwave detection device accurately eliminates the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form by means of frequency selection cancellation based on the setting of the frequency selection cancellation circuit 40, the feedback accuracy of the Doppler intermediate frequency signal in the differential signal form output by the frequency selection cancellation circuit 40 for the motion of the object in the corresponding detection space can be guaranteed. Therefore, it is possible to identify and calculate the single-ended signal formed between any pole signal of the Doppler intermediate frequency signal in the differential signal form output by the frequency selection cancellation and the reference ground without going through the differential signal to single-ended step, and still obtain accurate and stable detection results for human activities including human movement, micro-movement, breathing and heartbeat.

[0182] It will be understood by those skilled in the art that the above embodiments are merely examples, and features of different embodiments can be combined with each other to obtain implementations that are readily conceivable according to the content disclosed in the present invention but are not explicitly shown in the accompanying drawings. The present invention is not limited in this respect.

[0183] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. An anti-interference microwave detection method, characterized in that, Includes the following steps: (A) A probe beam corresponding to the frequency of a local oscillator signal is emitted to form a corresponding probe space; (B) Receive the echo formed by the detection beam being reflected by an object in the detection space and generate a feedback signal; (C) Output a Doppler intermediate frequency signal in differential signal form, wherein the Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and (D) The differential signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form is eliminated by frequency selective cancellation, so that the differential mode interference generated in the Doppler intermediate frequency signal by the wireless communication signal that has any frequency relationship with the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) superimposed on the environmental interference signal of the feedback signal can be eliminated.

2. The anti-interference microwave detection method according to claim 1, wherein in step (D), a frequency-selective cancellation circuit performs frequency-selective cancellation processing on the Doppler intermediate frequency signal in the differential signal form output in step (C) to output the frequency-selective cancellation processed Doppler intermediate frequency signal, wherein the frequency-selective cancellation circuit includes a first equivalent resistor, a second equivalent resistor, and an equivalent capacitor, wherein one end of the first equivalent resistor is electrically connected to one end of the equivalent capacitor, and one end of the second equivalent resistor is electrically connected to the other end of the equivalent capacitor, corresponding to the frequency-selective cancellation circuit having the other ends of the first equivalent resistor and the other ends of the second equivalent resistor as two input terminals, and the two ends of the equivalent capacitor as two output terminals, wherein the Doppler intermediate frequency signal in the differential signal form output in step (C) is input from the two input terminals, and the frequency-selective cancellation processed Doppler intermediate frequency signal is output from the two output terminals.

3. The anti-interference microwave detection method according to claim 2, wherein the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39kΩ within a 25% error range, and the equivalent capacitance is set to a capacitance value of approximately 47nF within a 25% error range.

4. The anti-interference microwave detection method according to claim 2, wherein the equivalent capacitor is equivalently set as two capacitors connected in series, wherein the two capacitors are set to be capacitors of the same type.

5. The anti-interference microwave detection method according to claim 4, wherein the first equivalent resistor and the second equivalent resistor are respectively set to a resistance value of approximately 39kΩ within a 25% error range, and both capacitors are set to a capacitance value of approximately 100nF within a 25% error range.

6. The anti-interference microwave detection method according to claim 4, wherein the frequency selective cancellation circuit is grounded between the two capacitors connected in series.

7. The anti-interference microwave detection method according to claim 2, wherein the two input terminals of the frequency selective cancellation circuit are each electrically connected to a pair of ground capacitors.

8. The anti-interference microwave detection method according to any one of claims 1 to 7, wherein the anti-interference microwave detection method further comprises the following steps between step (C) and step (D), and / or after step (D): (E) The Doppler intermediate frequency signal in differential signal form is differentially amplified.

9. The anti-interference microwave detection method according to claim 8, wherein the anti-interference microwave detection method further includes the following step after step (D): F. The Doppler intermediate frequency signal in the form of a differential signal is converted to a Doppler intermediate frequency signal in the form of a single-ended signal.

10. The anti-interference microwave detection method according to any one of claims 1 to 7, wherein in step (C), the Doppler intermediate frequency signal corresponding to the differential signal form of the frequency / phase difference between the local oscillator signal and the feedback signal is directly output in a mixing manner.

11. The anti-interference microwave detection method according to any one of claims 1 to 7, wherein step (C) includes the following steps: C1. Mix the local oscillator signal and the feedback signal so that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal can be extracted; C2. Output a Doppler intermediate frequency signal in single-ended signal form, corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and C3. By inverting the Doppler intermediate frequency signal in single-ended signal form and outputting a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal, the Doppler intermediate frequency signal in single-ended signal form is converted into a Doppler intermediate frequency signal in differential signal form.

12. A microwave detection device, characterized in that, include: An oscillation unit, wherein the oscillation unit is configured to generate a local oscillator signal; An antenna element is fed to the oscillation element to transmit a probe beam corresponding to the frequency of the local oscillator signal to form a corresponding probe space, and to receive an echo formed by the probe beam being reflected by an object in the probe space to generate a feedback signal. A Doppler differential output circuit, wherein the Doppler differential output circuit is electrically connected to the antenna unit and the oscillation unit to output a Doppler intermediate frequency signal in differential signal form, wherein the Doppler intermediate frequency signal is a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and At least one frequency-selective cancellation circuit is electrically connected to the Doppler differential output circuit to eliminate the differential signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form by frequency-selective cancellation. This enables the differential-mode interference generated in the Doppler intermediate frequency signal by wireless communication signals that have any frequency relationship with the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) superimposed on the environmental interference signal of the feedback signal to be eliminated.

13. The microwave detection device according to claim 12, wherein the frequency selective cancellation circuit includes a first equivalent resistor, a second equivalent resistor, and an equivalent capacitor, wherein one end of the first equivalent resistor is electrically connected to one end of the equivalent capacitor, one end of the second equivalent resistor is electrically connected to the other end of the equivalent capacitor, and the frequency selective cancellation circuit has the other ends of the first equivalent resistor and the other ends of the second equivalent resistor as two input terminals and the two ends of the equivalent capacitor as two output terminals, wherein the Doppler intermediate frequency signal in the differential signal form output by the Doppler differential output circuit is input from the two input terminals, and the Doppler intermediate frequency signal that has undergone frequency selective cancellation is output from the two output terminals.

14. The microwave detection device according to claim 13, wherein the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and the equivalent capacitance is set to a capacitance value of approximately 47 nF within a 25% error range.

15. The microwave detection device according to claim 13, wherein the equivalent capacitor is equivalently configured as two capacitors connected in series, wherein the two capacitors are configured to be capacitors of the same type.

16. The microwave detection device according to claim 15, wherein the first equivalent resistance and the second equivalent resistance are respectively set to a resistance value of approximately 39 kΩ within a 25% error range, and both capacitors are respectively set to a capacitance value of approximately 100 nF within a 25% error range.

17. The microwave detection device according to claim 15, wherein the frequency selective cancellation circuit is grounded between the two capacitors connected in series.

18. The microwave detection device according to any one of claims 13 to 17, wherein the Doppler differential output circuit and the oscillation unit are configured in an integrated circuit form and are integrally integrated into a microwave chip.

19. The microwave detection device according to claim 18, wherein the first equivalent resistor and the second equivalent resistor of the frequency selective cancellation circuit are integrally integrated into the microwave chip.

20. The microwave detection device according to any one of claims 12 to 17, wherein the Doppler differential output circuit is configured to directly output the Doppler intermediate frequency signal corresponding to the differential signal form of the frequency / phase difference between the local oscillator signal and the feedback signal in a mixing-based manner.

21. The microwave detection device according to claim 20, wherein the Doppler differential output circuit includes a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOS transistor, and a second MOS transistor, wherein one end of the first load is electrically connected to one end of the second load, the other end of the first load is electrically connected to the drain of the first MOS transistor, the other end of the second load is electrically connected to the drain of the second MOS transistor, wherein the source of the first MOS transistor is electrically connected to the source of the second MOS transistor, such that when power is connected to both ends of the interconnected first load and second load, and the feedback signal is connected to the two sources of the interconnected first MOS transistor and second MOS transistor, and the inverted local oscillator signal is connected to the gate of the first MOS transistor and the gate of the second MOS transistor respectively, the Doppler intermediate frequency signal in the form of a differential signal can be output from the drain of the first MOS transistor and the drain of the second MOS transistor.

22. The microwave detection device according to claim 20, wherein the Doppler differential output circuit includes a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor, wherein the drain of the first MOS transistor is electrically connected to the drain of the second MOS transistor, the drain of the third MOS transistor is electrically connected to the drain of the fourth MOS transistor, the source of the first MOS transistor is electrically connected to the source of the third MOS transistor, and the source of the second MOS transistor is electrically connected to the source of the fourth MOS transistor, such that inverted feedback signals are respectively connected between the two drains of the interconnected first MOS transistor and the second MOS transistor, and between the two drains of the interconnected third MOS transistor and the fourth MOS transistor, and in a state where the four gates of the first MOS transistor, the second MOS transistor, the third MOS transistor, and the fourth MOS transistor are connected to sequentially inverted local oscillator signals, the differential signal type of the Doppler intermediate frequency signal can be output between the two sources of the first MOS transistor and the third MOS transistor, and between the two sources of the second MOS transistor and the fourth MOS transistor.

23. The microwave detection device according to claim 20, wherein the Doppler differential output circuit includes a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOS transistor, a second MOS transistor, and a third MOS transistor, wherein one end of the first load is electrically connected to one end of the second load, the other end of the first load is electrically connected to the drain of the first MOS transistor, the other end of the second load is electrically connected to the drain of the second MOS transistor, wherein the source of the first MOS transistor and the source of the second MOS transistor are respectively electrically connected to the drain of the third MOS transistor, wherein the source of the third MOS transistor is grounded, such that when power is connected to both ends of the interconnected first load and second load, and the feedback signal is connected to the gate of the third MOS transistor, and the inverted local oscillator signal is connected to the gate of the first MOS transistor and the gate of the second MOS transistor respectively, the Doppler intermediate frequency signal in the form of a differential signal can be output from the drain of the first MOS transistor and the drain of the second MOS transistor.

24. The microwave detection device according to claim 20, wherein the Doppler differential output circuit comprises a first load and a second load formed in the form of equivalent resistance or equivalent inductance, a first MOSFET, a second MOSFET, a third MOSFET, a fourth MOSFET, a fifth MOSFET, a sixth MOSFET, and a current source, wherein one end of the first load is electrically connected to one end of the second load, the other end of the first load is electrically connected to the drain of the first MOSFET and the drain of the third MOSFET, respectively, the other end of the second load is electrically connected to the drain of the second MOSFET and the drain of the fourth MOSFET, wherein the source of the first MOSFET and the source of the second MOSFET are respectively electrically connected to the drain of the fifth MOSFET, and the source of the third MOSFET and the source of the fourth MOSFET are respectively connected to the drain of the fifth MOSFET. The fifth MOS transistor and the source of the sixth MOS transistor are electrically connected to the drain of the sixth MOS transistor, respectively. The sources of the fifth MOS transistor and the sixth MOS transistor are electrically connected to the current source, so that the gates of the fifth MOS transistor and the sixth MOS transistor are respectively connected to the inverted feedback signal, the gates of the first MOS transistor and the second MOS transistor are respectively connected to the inverted local oscillator signal, the gates of the third MOS transistor and the fourth MOS transistor are respectively connected to the inverted local oscillator signal, wherein the local oscillator signal connected to the gate of the second MOS transistor is in phase with the local oscillator signal connected to the gate of the third MOS transistor, and the power supply is connected to both ends of the interconnected first load and the second load, so that the Doppler intermediate frequency signal in the form of a differential signal can be output at the other end of the first load and the other end of the second load.

25. The microwave detection device according to any one of claims 12 to 17, wherein the Doppler differential output circuit comprises a mixer circuit and a single-ended signal to differential signal circuit, wherein the mixer circuit is electrically connected to the antenna unit and the oscillator unit to receive the feedback signal and the local oscillator signal and output the Doppler intermediate frequency signal in a single-ended signal form corresponding to the frequency / phase difference between the feedback signal and the local oscillator signal by a mixing detection method, wherein the single-ended to differential circuit is electrically connected to the mixer circuit to receive the single-ended signal form of the Doppler intermediate frequency signal and convert the single-ended signal form of the Doppler intermediate frequency signal into a differential signal form of the Doppler intermediate frequency signal by inverting the phase of the single-ended signal form of the Doppler intermediate frequency signal.

26. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit comprises a transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, and a capacitor, wherein the emitter of the transistor is grounded through the first resistor, the collector of the transistor is connected to a power supply through the second resistor, the base of the transistor is connected to a power supply through the third resistor and grounded through the fourth resistor, and connected to the single-ended signal of the Doppler intermediate frequency signal through the capacitor, so as to output the differential signal of the Doppler intermediate frequency signal between the collector and emitter of the transistor.

27. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit includes an operational amplifier, a first resistor and a second resistor, wherein the operational amplifier is connected to a reference voltage at its non-inverting input terminal, and electrically connected to the output terminal of the operational amplifier via the first resistor at its inverting input terminal, and connected to the Doppler intermediate frequency signal in single-ended signal form via the second resistor, so that the Doppler intermediate frequency signal in differential signal form is output between the end of the second resistor connected to the Doppler intermediate frequency signal in single-ended signal form and the output terminal of the operational amplifier.

28. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit includes a first operational amplifier circuit and a second operational amplifier circuit, wherein the first operational amplifier circuit receives a single-ended Doppler intermediate frequency signal at its input terminal and is electrically connected to the input terminal of the second operational amplifier circuit at its output terminal, and outputs the differential Doppler intermediate frequency signal between the output terminals of the first operational amplifier circuit and the second operational amplifier circuit.

29. The microwave detection device according to claim 28, wherein the first operational amplifier circuit includes a first operational amplifier, and the single-ended Doppler intermediate frequency signal is input to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is used as the output terminal; the second operational amplifier circuit includes a second operational amplifier, a first resistor and a second resistor, and the inverting input terminal of the second operational amplifier is used as the input terminal and the output terminal of the second operational amplifier is used as the output terminal; wherein the second operational amplifier is connected to a reference voltage at its non-inverting input terminal and electrically connected to the output terminal of the second operational amplifier via the second resistor at its inverting input terminal; wherein the output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier via the first resistor; the inverting input terminal and the output terminal of the first operational amplifier are electrically connected, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first operational amplifier and the output terminals of the second operational amplifier.

30. The microwave detection device according to claim 28, wherein the first operational amplifier circuit includes a first operational amplifier, a first resistor, and a second resistor, and the inverting input terminal of the first operational amplifier is used as the input terminal to receive the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier is used as the output terminal, wherein the first operational amplifier receives the single-ended Doppler intermediate frequency signal at its inverting input terminal via the first resistor, and receives a reference voltage at its non-inverting input terminal, wherein the inverting input terminal and the output terminal of the first operational amplifier are electrically connected via the second resistor, wherein the second operational amplifier circuit includes a second operational amplifier, a third resistor, and a fourth resistor, and the inverting input terminal of the second operational amplifier is used as the input terminal and the output terminal of the second operational amplifier is used as the output terminal, wherein the output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier via the third resistor, and the inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first and second operational amplifiers.

31. The microwave detection device according to claim 28, wherein the first operational amplifier circuit comprises a first operational amplifier, a first resistor, a second resistor, a first capacitor, a second capacitor, and a third capacitor, and the inverting input terminal of the first operational amplifier is used as the input terminal to receive the single-ended Doppler intermediate frequency signal, and the output terminal of the first operational amplifier is used as the output terminal, wherein the first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the third capacitor, and is sequentially electrically connected to its output terminal via the first resistor and the second resistor, and is sequentially used to receive the single-ended Doppler signal via the first resistor and the first capacitor. The intermediate frequency signal is grounded sequentially via the first resistor and the second capacitor. The second operational amplifier circuit includes a second operational amplifier, a third resistor, and a fourth resistor. The inverting input terminal of the second operational amplifier is used as the input terminal, and the output terminal of the second operational amplifier is used as the output terminal. The output terminal of the first operational amplifier is electrically connected to the inverting input terminal of the second operational amplifier via the third resistor. The inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor. Thus, the Doppler intermediate frequency signal in differential signal form is output between the output terminals of the first operational amplifier and the output terminals of the second operational amplifier.

32. The microwave detection device according to claim 28, wherein the oscillation unit, the mixer circuit, and the first operational amplifier circuit of the single-ended signal to differential signal circuit are configured as integrated circuits and integrally integrated into a microwave chip, wherein the second operational amplifier circuit of the single-ended signal to differential signal circuit is externally located on the microwave chip.

33. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit includes a first operational amplifier circuit and a second operational amplifier circuit, wherein the first operational amplifier circuit is electrically connected to the input terminal of the second operational amplifier circuit and receives a single-ended Doppler intermediate frequency signal, and outputs the differential Doppler intermediate frequency signal between the output terminal of the first operational amplifier circuit and the output terminal of the second operational amplifier circuit.

34. The microwave detection device according to claim 33, wherein the first operational amplifier circuit comprises a first operational amplifier, a first resistor, a second resistor, and a first capacitor, and receives the Doppler intermediate frequency signal in single-ended signal form at the non-inverting input terminal of the first operational amplifier, and receives the output terminal of the first operational amplifier, wherein the first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the first resistor, and is grounded sequentially via the second resistor and the first capacitor; wherein the second operational amplifier circuit comprises a second operational amplifier, a third resistor, and a fourth resistor, and receives the inverting input terminal of the second operational amplifier as its input terminal and receives the output terminal of the second operational amplifier as its output terminal; wherein the first operational amplifier is electrically connected from its non-inverting input terminal to its inverting input terminal via the third resistor, and the inverting input terminal and output terminal of the second operational amplifier are electrically connected via the fourth resistor; wherein a reference voltage is received at the non-inverting input terminal of the second operational amplifier, thereby outputting the Doppler intermediate frequency signal in differential signal form between the output terminals of the first and second operational amplifiers.

35. The microwave detection device according to claim 33, wherein the first operational amplifier circuit comprises a first operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor, and the single-ended Doppler intermediate frequency signal is input to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is used as the output terminal, wherein the first operational amplifier is electrically connected from its inverting input terminal to its output terminal via the fourth resistor, and grounded via the third resistor, wherein the single-ended Doppler intermediate frequency signal is input to the first operational amplifier from its non-inverting input terminal via the first resistor, and grounded via the second resistor, wherein the first operational amplifier is connected to the single-ended Doppler intermediate frequency signal via the first resistor, and grounded via the second resistor, wherein the first operational amplifier is input to the first operational amplifier from its non-inverting input terminal via the first resistor, and the single-ended Doppler intermediate frequency signal is used as the input terminal ... The second operational amplifier circuit includes a second operational amplifier, a fifth resistor, and a sixth resistor. The inverting input terminal of the second operational amplifier is used as the input terminal, and the output terminal of the second operational amplifier is used as the output terminal. The first operational amplifier is electrically connected from its non-inverting input terminal to the inverting input terminal of the second operational amplifier via the first resistor and the fifth resistor. The inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the sixth resistor. The second operational amplifier is connected to a reference voltage at its non-inverting input terminal. Thus, a differential signal in the form of a Doppler intermediate frequency signal is output between the output terminals of the first operational amplifier and the output terminals of the second operational amplifier.

36. The microwave detection device according to claim 33, wherein the oscillation unit, the mixer circuit, and the first operational amplifier circuit of the single-ended signal to differential signal circuit are configured as integrated circuits and integrally integrated into a microwave chip, wherein the second operational amplifier circuit of the single-ended signal to differential signal circuit is externally located on the microwave chip.

37. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit comprises a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein the first operational amplifier has a reference voltage connected to its non-inverting input terminal and a single-ended Doppler intermediate frequency signal connected to its inverting input terminal via the first resistor, and its output terminal is electrically connected to the output terminal of the second operational amplifier sequentially via the third resistor and the fourth resistor, wherein the inverting input terminal and the output terminal of the first operational amplifier are electrically connected via the second resistor, the inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the fourth resistor, and the non-inverting input terminal of the second operational amplifier is electrically connected to the inverting input terminal of the first operational amplifier, thereby outputting a differential Doppler intermediate frequency signal between the output terminals of the first operational amplifier and the second operational amplifier.

38. The microwave detection device according to claim 37, wherein the oscillation unit, the mixer circuit, and the first operational amplifier of the single-ended signal to differential signal circuit are configured as integrated circuits and integrally integrated into a microwave chip, wherein the second operational amplifier of the single-ended signal to differential signal circuit is externally located on the microwave chip.

39. The microwave detection device according to claim 25, wherein the single-ended signal to differential signal circuit comprises a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein the first operational amplifier has a reference voltage connected to its non-inverting input terminal, and its inverting input terminal electrically connected to the inverting input terminal of the second operational amplifier, and its output terminal electrically connected to the non-inverting input terminal of the second operational amplifier via the fourth resistor, wherein the inverting input terminal and the output terminal of the first operational amplifier are electrically connected via the third resistor, wherein the second operational amplifier has the single-ended signal of the Doppler intermediate frequency signal connected to its non-inverting input terminal via the first resistor, and wherein the inverting input terminal and the output terminal of the second operational amplifier are electrically connected via the second resistor, thereby outputting the differential signal of the Doppler intermediate frequency signal between the output terminals of the first and second operational amplifiers.

40. The microwave detection device according to claim 39, wherein the oscillation unit, the mixer circuit, and the first operational amplifier of the single-ended signal to differential signal circuit are configured as integrated circuits and integrally integrated into a microwave chip, wherein the second operational amplifier of the single-ended signal to differential signal circuit is externally located on the microwave chip.

41. The microwave detection device according to claim 25, wherein the oscillation unit and the mixing circuit of the Doppler differential output circuit are configured in the form of an integrated circuit and integrated into a microwave chip, and the single-ended signal to differential signal circuit of the Doppler differential output circuit is externally located on the microwave chip.

42. The microwave detection device according to any one of claims 12 to 17, wherein the microwave detection device further comprises at least one differential amplifier circuit, wherein the differential amplifier circuit is disposed between the Doppler differential output circuit and the frequency selective cancellation circuit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit.

43. The microwave detection device according to any one of claims 12 to 17, wherein the microwave detection device further comprises at least one differential amplifier circuit, wherein the differential amplifier circuit is disposed at both output terminals of the frequency selective cancellation circuit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the frequency selective cancellation circuit.

44. The microwave detection device according to any one of claims 12 to 17, wherein the microwave detection device further comprises a differential signal to single-ended signal circuit to receive the Doppler intermediate frequency signal in differential signal form after frequency selection and cancellation processing, and to convert the Doppler intermediate frequency signal in differential signal form into the Doppler intermediate frequency signal in single-ended signal form for output.

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