Jamming-resistant microwave detection method and microwave detection device

Abstract

The application provides an anti-interference microwave detection method and a microwave detection device. The anti-interference microwave detection method is based on an algorithm frequency selection cancellation process on a digitized discrete form of a Doppler intermediate frequency signal of a differential signal form according to a differential cancellation algorithm function. The algorithm frequency selection cancellation process is a cancellation process on the digitized discrete form of the Doppler intermediate frequency signal of the differential signal form in a corresponding frequency range according to the differential cancellation algorithm function, so as to realize digitized cancellation of differential mode interference corresponding to the frequency of the frequency range. Therefore, the interference of the Doppler intermediate frequency signal by the interference signal with any frequency relationship of homochromatic, adjacent frequency and multiple frequency with the local oscillator signal of the microwave detection device in the environment can be accurately eliminated by using multiple filtering. The integrity of the Doppler intermediate frequency signal is ensured, and the accuracy of the feedback of the Doppler intermediate frequency signal to the movement of the object in the corresponding detection space is ensured.

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 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 and a second type of interference signal exist in the differential signal-shaped Doppler IF signal as common-mode interference and differential-mode interference, respectively. The differential amplification of the differential signal-shaped Doppler IF signal and / or the 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. Therefore, it is beneficial to obtain 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] One object of the present invention is to provide an anti-interference microwave detection method and microwave detection device, wherein the microwave detection device is configured with a frequency selection cancellation unit to perform algorithmic frequency selection cancellation processing on the differential signal form of the Doppler intermediate frequency signal within a corresponding frequency range. The frequency selection cancellation unit is configured with components having computational processing capabilities and performs algorithmic frequency selection cancellation processing on the digital discrete form of the differential signal form of the Doppler intermediate frequency signal based on a corresponding differential cancellation algorithm function. In this way, while simplifying the circuit, the programmable characteristics of the frequency selection cancellation unit can be used to achieve adjustable frequency selection range, thereby improving the adaptability of the microwave detection device and reducing the process cost of the microwave detection device based on different parameter requirements.

[0020] One objective of this invention is to provide an anti-interference microwave detection method and microwave detection device, wherein the Doppler intermediate frequency signal after being processed by the algorithmic frequency selection cancellation unit is in a digital discrete form and can be directly used in the subsequent data recognition and calculation process, which is beneficial to improving the response efficiency of the microwave detection device.

[0021] 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:

[0022] (A) A probe beam corresponding to the frequency of a local oscillator signal is emitted to form a corresponding probe space;

[0023] (B) Receive the echo formed by the detection beam being reflected by an object in the detection space and generate a feedback signal;

[0024] (C) The Doppler intermediate frequency signal in differential signal form is output by inverting the output signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal;

[0025] (D) Digitizing the Doppler intermediate frequency signal to obtain a digitized discrete form of the Doppler intermediate frequency signal in differential signal form; and

[0026] (E) The differential cancellation algorithm function performs frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form. The corresponding frequency selection cancellation processing process is the cancellation processing of the digital discrete form of the Doppler intermediate frequency signal in the differential signal form in the corresponding frequency range according to the differential cancellation algorithm function.

[0027] In one embodiment, step (E) further includes the step of:

[0028] The digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process is subjected to differential-to-single-ended conversion. The differential-to-single-ended conversion process is a subtraction process of the digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process.

[0029] In one embodiment, the anti-interference microwave detection method is performed by a frequency-selective cancellation unit with computational processing capabilities, performing steps (D) and (E).

[0030] In one embodiment, the frequency selection cancellation unit is implemented as one of an MCU, a microcontroller, and a central processing unit.

[0031] In one embodiment, the anti-interference microwave detection method further includes the following step between step (C) and step (D):

[0032] (F) The Doppler intermediate frequency signal in differential signal form is differentially amplified.

[0033] In one embodiment, step (C) includes the following steps:

[0034] (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;

[0035] (C2) Output a Doppler intermediate frequency signal in a single-ended signal form, corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0036] (C3) By inverting the Doppler intermediate frequency signal in single-ended signal form to output 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.

[0037] According to another aspect of the present invention, the present invention also provides a microwave detection device, the microwave detection device comprising:

[0038] An oscillation unit, wherein the oscillation unit is configured to generate a local oscillator signal;

[0039] 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.

[0040] A Doppler differential output circuit, wherein the Doppler differential output circuit is electrically connected to the antenna unit and the oscillation unit, and is configured to output a Doppler intermediate frequency signal in differential signal form based on the inverted output of the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0041] A frequency-selective cancellation unit is provided, wherein the frequency-selective cancellation unit is configured with components having computational processing capabilities and includes an AD conversion module and a frequency-selective cancellation operation module electrically connected to the AD conversion module. The AD conversion module is electrically connected to the Doppler differential output circuit to receive the Doppler intermediate frequency signal in differential signal form output from the Doppler differential output circuit, and digitizes the received Doppler intermediate frequency signal to transmit the digitized discrete form of the Doppler intermediate frequency signal in differential signal form to the frequency-selective cancellation operation module. The frequency-selective cancellation operation module is configured to perform algorithmic frequency-selective cancellation processing on the digitized discrete form of the Doppler intermediate frequency signal in differential signal form according to a corresponding differential cancellation algorithm function. The corresponding algorithmic frequency-selective cancellation processing is to perform cancellation processing on the digitized discrete form of the Doppler intermediate frequency signal in differential signal form within a corresponding frequency range according to the differential cancellation algorithm function.

[0042] In one embodiment, the frequency selection cancellation unit is implemented as one of an MCU, a microcontroller, and a central processing unit.

[0043] In one embodiment, the frequency selection cancellation unit is configured to further perform differential-to-single-ended processing on the digital discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection cancellation processing. The differential-to-single-ended processing is a subtraction process on the digital discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection cancellation processing.

[0044] In one embodiment, the two ends of the AD conversion module electrically connected to the Doppler differential output circuit are the two input terminals of the frequency selection cancellation unit, and each of the two input terminals of the frequency selection cancellation unit is electrically connected to a pair of ground capacitors.

[0045] In one embodiment, the Doppler differential output circuit includes a mixer circuit and a single-ended to differential 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.

[0046] In one embodiment, the Doppler differential output circuit and the oscillation unit are configured as an integrated circuit and integrated into a microwave chip.

[0047] In one embodiment, the oscillation unit and the mixer circuit of the Doppler differential output circuit are configured as an integrated circuit and integrated into a microwave chip, wherein the single-ended signal to differential signal circuit of the Doppler differential output circuit is externally located on the microwave chip.

[0048] 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 unit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit.

[0049] The further objects and advantages of the invention will become fully apparent from the following description and accompanying drawings.

[0050] 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

[0051] Figure 1 This is a schematic diagram of the circuit structure of an existing Doppler microwave detection device.

[0052] 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.

[0053] Figure 3 This is a schematic diagram illustrating the structural principle of a microwave detection device according to an embodiment of the present invention.

[0054] Figure 4 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.

[0055] Figure 5A 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.

[0056] Figure 5B 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.

[0057] Figures 6A to 6G This is a schematic diagram of the circuit structure of different single-ended signal to differential signal circuits in the Doppler differential output circuit of the microwave detection device according to the above embodiments of the present invention.

[0058] Figure 7A 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.

[0059] Figure 7B 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.

[0060] Figure 7C 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.

[0061] Figure 7D 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.

[0062] Figure 7E 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.

[0063] Figure 8 This is a schematic diagram illustrating the circuit structure of the microwave detection device according to the above embodiments of the present invention, which further includes a differential amplifier circuit.

[0064] Figure 9A This is a schematic diagram of a differential amplifier circuit further provided in the microwave detection device according to the above embodiments of the present invention.

[0065] Figure 9BThis is a schematic diagram of another circuit structure of the differential amplifier circuit further provided in the microwave detection device according to the above embodiments of the present invention. Detailed Implementation

[0066] 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.

[0067] 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.

[0068] 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 a frequency selection cancellation unit 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, and is configured to output a Doppler intermediate frequency signal in differential signal form based on the inverted output of the frequency / phase difference between the local oscillator signal and the feedback signal. The frequency selection cancellation unit 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Specifically, in this embodiment of the invention, the frequency selection cancellation unit 40 is used to eliminate the second type of interference signal in the corresponding frequency range of the Doppler intermediate frequency signal in the differential signal form by frequency selection cancellation. The frequency selection cancellation unit 40 is configured as a component with computing capabilities and performs algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form based on the corresponding differential cancellation algorithm function. For example, the frequency selection cancellation unit 40 is implemented as an MCU, microcontroller, central processing unit or other chip with computing capabilities. In this way, while simplifying the circuit, the programmable characteristics of the frequency selection cancellation unit 40 can be used to realize the adjustable characteristics of the corresponding frequency selection range, such as realizing the discontinuity of the corresponding frequency selection range, thereby improving the adaptability of the microwave detection device and reducing the process cost of the microwave detection device based on different parameter requirements.

[0074] It is understood that the frequency selection cancellation unit 40 performs algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form based on the differential cancellation algorithm function. The corresponding algorithmic frequency selection cancellation process is to perform cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form in the corresponding frequency range according to the differential cancellation algorithm function, so as to realize the digital cancellation of differential mode interference (second type of interference signal) corresponding to the frequency of the frequency range.

[0075] Further, the frequency selection cancellation unit 40 includes an AD conversion module 401 and a frequency selection cancellation operation module 402 electrically connected to the AD conversion module 401. The AD conversion module 401 is electrically connected to the Doppler differential output circuit 30 to receive the Doppler intermediate frequency signal in differential signal form output from the Doppler differential output circuit 30, and digitizes the received Doppler intermediate frequency signal to transmit the digitized discrete form of the Doppler intermediate frequency signal in differential signal form to the frequency selection cancellation operation module 402. The frequency selection cancellation operation module 402 is configured to perform algorithmic frequency selection cancellation processing on the digitized discrete form of the Doppler intermediate frequency signal in differential signal form according to the differential cancellation algorithm function. The corresponding algorithmic frequency selection cancellation processing is to perform cancellation processing on the digitized discrete form of the Doppler intermediate frequency signal in differential signal form in the corresponding frequency range according to the differential cancellation algorithm function.

[0076] It is worth mentioning that, in practical applications, environmental interference signals with any frequency relationship (same frequency, adjacent frequency, or harmonic frequency) with the local oscillator signal of the microwave detection device 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 peak. 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. Furthermore, since multiple filtering methods are avoided, it is beneficial 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. This is beneficial to improving the feedback accuracy of the Doppler intermediate frequency signal for the motion of objects in the corresponding detection space. Thus, ensuring the anti-communication interference capability of the microwave detection device has significant practical value and commercial significance.

[0077] 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. At the same time, the Doppler intermediate frequency signal after the algorithm frequency-selective cancellation process is in a digital discrete form and can be directly used in the subsequent data recognition and calculation process. If the frequency-selective cancellation unit 40 is implemented as an MCU, the subsequent recognition and calculation of the Doppler intermediate frequency signal in the digital discrete form can be directly performed in the MCU, which is conducive to improving the response efficiency of the microwave detection device. 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.

[0078] It is understood that the frequency selection cancellation unit 40 performs algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form based on the differential cancellation algorithm function. The differential cancellation algorithm function has different expressions depending on the selected frequency range, and can still employ different expressions even when the selected frequency range is determined. Therefore, the specific expression form of the differential cancellation algorithm function does not constitute a limitation of this invention.

[0079] Further reference is made to the accompanying drawings of this invention. Figure 4 As shown, in Figure 3Based on the structure of the microwave detection device described in the example, a further improved structure of the microwave detection device according to the above embodiment of the present invention is illustrated. Since in applications involving multiple microwave detection devices, 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, the corresponding first and second type of interference signals exist in the differential signal form of the Doppler intermediate frequency signal as glitches. 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 selective cancellation. Figure 4 A pair of ground capacitors 41 are electrically connected to each of the two input terminals of the frequency selection cancellation unit 40 (the two ends of the AD conversion module 401 that are electrically connected to the Doppler differential output circuit 30). Based on the setting of the two ground capacitors 41, the first type of interference signal and the second type of interference signal formed in the differential signal form of the Doppler intermediate frequency signal in the form of glitches by the co-frequency interference in the fixed frequency form are suppressed. This ensures the anti-interference capability of the microwave detection device in the application scenario of multiple microwave detection devices. The two ground capacitors 41 are set to use the same type of capacitor, so as to maintain the Doppler intermediate frequency signal input to the frequency selection cancellation unit 40 in a relatively balanced differential signal form.

[0080] To further understand the present invention, with the frequency selection cancellation unit 40 configured as a component with computational processing capabilities, the microwave detection method corresponding to the structure of the microwave detection device is further described, wherein the microwave detection method includes the following steps:

[0081] A. Transmit the detection beam corresponding to the frequency of the local oscillator signal to form a corresponding detection space;

[0082] B. Receive the echo formed by the detection beam being reflected by an object in the detection space and generate the feedback signal;

[0083] C. The inverted output corresponds to the frequency / phase difference between the local oscillator signal and the feedback signal, and outputs the Doppler intermediate frequency signal in differential signal form;

[0084] D. Digitize the Doppler intermediate frequency signal to obtain the digitized discrete form of the Doppler intermediate frequency signal in differential signal form;

[0085] E. According to the differential cancellation algorithm function, the digital discrete form of the Doppler intermediate frequency signal in the differential signal form is subjected to algorithmic frequency selection cancellation processing. The corresponding algorithmic frequency selection cancellation processing is the cancellation processing of the digital discrete form of the Doppler intermediate frequency signal in the differential signal form in the corresponding frequency range according to the differential cancellation algorithm function.

[0086] The system comprises: the oscillation unit 20 providing the local oscillator signal; the antenna unit 10 transmitting the probe beam and receiving the echo; the 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 the frequency selection cancellation unit 40 performing algorithmic frequency selection cancellation processing on the received Doppler intermediate frequency signal in differential signal form. The frequency selection cancellation unit 40 is configured with a component having computational processing capabilities and performs algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in differential signal form according to the differential cancellation algorithm function.

[0087] Furthermore, in some embodiments of the present invention, step (C) of the anti-interference microwave detection method includes the following steps:

[0088] C1. Mix the local oscillator signal and the feedback signal to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal;

[0089] 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

[0090] 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.

[0091] 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.

[0092] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 5AAs 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.

[0093] Specifically, the mixing circuit 31 includes a mixing bridge 311, two mixing tubes 312, and wherein the mixing bridge 311 has a local oscillator signal input port 3111 suitable for the local oscillator signal input, and sequentially has a first mixing port 3112, a second mixing port 3113, and a feedback signal input port 3114 suitable for the feedback signal input from the local oscillator signal input port 3111 along the mixing bridge 311. Correspondingly, the mixing bridge 311 has a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixing port 3112, a second high-frequency path 3116 defined between the first mixing port 3112 and the second mixing port 3113, a third high-frequency path 3117 defined between the second mixing port 3113 and the feedback signal input port 3114, and a third high-frequency path 3117 defined between the feedback signal input port 3114 and the local oscillator signal input port 3115. A fourth high-frequency path 3118 is established between the local oscillator signal input port 3111, wherein the first high-frequency path 3115 and the third high-frequency path 3117 have equal electrical lengths, and the fourth high-frequency path 3118 has an electrical length greater than or equal to one-eighth of the wavelength and less than or equal to one-half of the wavelength. The two ends of the two mixer tubes 312, which belong to different mixer tubes 312 and have different polarities, are respectively connected to the first mixer port 3112 and the second mixer port 3113. The other two ends of the two mixer tubes 312, which belong to different mixer tubes 312 and have different polarities, are connected to the same equivalent capacitance to ground. The single-ended signal to differential signal circuit 32 is set to the state of receiving the input single-ended signal form of the Doppler intermediate frequency signal, and outputs the Doppler intermediate frequency signal in the form of a differential signal in step (C3).

[0094] With the local oscillator signal connected to the local oscillator signal input port 3111 and the feedback signal connected to the feedback signal input port 3114, in step (C1), the local oscillator signal and the feedback signal are mixed and processed based on the above-described structure of the mixer bridge 311 so that a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal can be extracted. Specifically, in step (C2), a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal is led out from between the two mixer tubes 312 to output the Doppler intermediate frequency signal in single-ended signal form. In step (C3), the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal is output in phase by inverting the Doppler intermediate frequency signal in single-ended signal form, thereby forming the conversion of the Doppler intermediate frequency signal in single-ended signal form to the Doppler intermediate frequency signal in differential signal form.

[0095] Furthermore, refer to the accompanying drawings of the specification of this invention. Figure 5B As shown, another circuit structure principle of the Doppler differential output circuit 30 is illustrated, which differs from... Figure 5A The schematic diagram illustrates the circuit structure principle of the Doppler differential output circuit 30. Figure 5B In the schematic diagram of the Doppler differential output circuit 30, the two ends of the two mixer tubes 312, each with different polarities, are connected to the first mixer port 3112 and the second mixer port 3113, respectively. The other two ends of the mixer tubes 312, each with different polarities, are grounded. This allows the local oscillator signal to be input to the local oscillator signal input port 3111 and the feedback signal to be input to the feedback signal input port 3114. In step (C1), based on the mixer bridge 3... The above-described structural design of 11 performs frequency mixing processing on the local oscillator signal and the feedback signal. In step (C2), a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal is output from the mixing bridge 311 to form a single-ended Doppler intermediate frequency signal. In step (C3), the single-ended Doppler intermediate frequency signal is inverted and output to form a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal, thereby converting the single-ended Doppler intermediate frequency signal into a differential Doppler intermediate frequency signal.

[0096] It is worth mentioning that, in Figure 5A and Figure 5BIn the two circuit structure principles of the Doppler differential output circuit 30 shown, the first high-frequency path 3115 and the third high-frequency path 3117 are configured as strip transmission lines in the form of a path. The second high-frequency path 3116 and the fourth high-frequency path 3118, while ensuring the high-frequency conduction characteristics corresponding to the local oscillator signal frequency, allow at least one of a capacitor, an inductor, and a resistor to be connected in series. This invention does not limit this.

[0097] Further reference is made to the accompanying drawings of this invention. Figures 6A to 6G As shown, the circuit structure of the corresponding single-ended signal to differential signal circuit 32 is illustrated. Based on the corresponding parameter design of the single-ended signal to differential signal circuit 32, the circuit structure of the single-ended signal to differential signal circuit 32 is diverse and cannot be listed one by one. It is not limited to an independent form of discrete components or integrated circuits, and can be implemented as a combination of discrete components and integrated circuits. The main structural feature of the single-ended signal to differential signal circuit 32 is that it adopts a single-ended input and a dual-ended output structure. By inverting the single-ended Doppler intermediate frequency signal in single-ended signal form, the input single-ended Doppler intermediate frequency signal is converted into an inverted signal, thereby forming the conversion from the single-ended Doppler intermediate frequency signal to the differential Doppler intermediate frequency signal.

[0098] In particular, in some other embodiments of the present invention, step (C) of the anti-interference microwave detection method includes the following steps:

[0099] S1. Mix the local oscillator signal and the feedback signal to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; and

[0100] S2. The Doppler intermediate frequency signal in differential signal form is output by inverting the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal.

[0101] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 7A and Figure 7BAs shown, the different circuit structures of the corresponding Doppler differential output circuit 30 are illustrated. The Doppler differential output circuit 30 includes two mixing bridges 311 and two pairs of mixing transistors 312. Each mixing bridge 311 has a local oscillator signal input port 3111 suitable for the local oscillator signal input, and sequentially has a first mixing port 3112, a second mixing port 3113, and a feedback signal input port 3114 suitable for the feedback signal input. Corresponding to each mixing bridge 311... The system comprises a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixer port 3112, a second high-frequency path 3116 defined between the first mixer port 3112 and the second mixer port 3113, a third high-frequency path 3117 defined between the second mixer port 3113 and the feedback signal input port 3114, and a fourth high-frequency path 3118 defined between the feedback signal input port 3114 and the local oscillator signal input port 3111, wherein the first high-frequency path 3115 and the first mixer port 3112 have a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixer port 3112, a second high-frequency path 3116 defined between the first mixer port 3112 and the second mixer port 3113, a third high-frequency path 3117 defined between the second mixer port 3113 and the feedback signal input port 3114, and a fourth high-frequency path 3118 defined between the feedback signal input port 3114 and the local oscillator signal input port 3111. The three high-frequency paths 3117 have equal electrical lengths, wherein the fourth high-frequency path 3118 has an electrical length greater than or equal to one-eighth of the wavelength and less than or equal to one-half of the wavelength. In any pair of mixer tubes 312, the ends of the different mixer tubes 312 with different polarities are connected to a ground equivalent capacitance. The two pairs of mixer tubes 312 are connected in series in opposite directions between the first mixing port 3112 and the second mixing port 3113 of the corresponding mixer bridge 311. The positive and negative terminals of the other two ends of the frequency converter 312 are respectively connected to the first mixing port 3112 and the second mixing port 3113 of one of the frequency converter bridges 311. The positive and negative terminals of the other two ends of the frequency converter 312 are respectively connected to the second mixing port 3113 and the first mixing port 3112 of the other frequency converter bridge 311, so as to form a connection state in which the two pairs of frequency converters 312 are connected in series between the first mixing port 3112 and the second mixing port 3113 of the corresponding frequency converter bridges 311 in opposite directions.

[0102] Thus corresponding Figure 7AIn the state where the two feedback signal input ports 3114 of the two mixer bridges 311 are connected to the same feedback signal, and the two local oscillator signal input ports 3111 are connected to the same local oscillator signal, such as when the two local oscillator signal input ports 3111 are connected to the same local oscillator signal, by feeding and connecting the two feedback signal input ports 3114 of the two mixer bridges 311 to the same antenna body of the antenna element 10, the same feedback signal is received from the antenna element 10. Corresponding to step (S1), based on the above-mentioned structural design of the two mixer bridges 311, the local oscillator signal and the feedback signal are mixed and processed so that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal can be extracted, and specifically in step... In step (S2), based on the connection state of the two pairs of mixer tubes 312 connected in reverse to the first mixer port 3112 and the second mixer port 3113 of the corresponding mixer bridge 311, the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the two ends of the interconnection of one pair of mixer tubes 312 is out of phase with the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the two ends of the interconnection of the other pair of mixer tubes 312. Thus, the two pairs of mixer tubes 312 draw out the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal in reverse phase to output the Doppler intermediate frequency signal in differential signal form.

[0103] or corresponding to Figure 7BIn the state where the two feedback signal input ports 3114 of the two mixer bridges 311 are connected to different feedback signals, and the two local oscillator signal input ports 3111 are connected to the same local oscillator signal, such as when the two local oscillator signal input ports 3111 are connected to the same local oscillator signal, by feeding and connecting the two feedback signal input ports 3114 of the two mixer bridges 311 to different antenna bodies of the antenna element, the corresponding feedback signals are respectively connected from the antenna element 10. Corresponding to step (S1), based on the above-mentioned structural design of the two mixer bridges 311, the local oscillator signal and the corresponding feedback signal are mixed and processed so that the signal corresponding to the frequency / phase difference between the local oscillator signal and the corresponding feedback signal can be extracted, and specifically... In step (S2), two pairs of mixer tubes 312 are connected in series between the first mixer port 3112 and the second mixer port 3113 of the corresponding mixer bridge 311, respectively, such that the signal corresponding to the frequency / phase difference between the local oscillator signal and the corresponding feedback signal drawn from the two ends of the interconnection of one pair of mixer tubes 312 is out of phase with the signal corresponding to the frequency / phase difference between the local oscillator signal and the corresponding feedback signal drawn from the two ends of the interconnection of the other pair of mixer tubes 312. Thus, the two pairs of mixer tubes 312 output signals corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal in a differential signal form to output the Doppler intermediate frequency signal.

[0104] Further reference is made to the accompanying drawings of this invention. Figure 7CAs shown, another structural principle of the Doppler differential output circuit 30 is illustrated. The Doppler differential output circuit 30 includes a mixer bridge 311 and two pairs of mixer tubes 312. The mixer bridge 311 has a local oscillator signal input port 3111 suitable for the local oscillator signal input, and sequentially includes a first mixer port 3112, a second mixer port 3113, and a feedback signal input port 3114 suitable for the feedback signal input, corresponding to the mixer bridge 311. 1 has a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixer port 3112, a second high-frequency path 3116 defined between the first mixer port 3112 and the second mixer port 3113, a third high-frequency path 3117 defined between the second mixer port 3113 and the feedback signal input port 3114, and a fourth high-frequency path 3118 defined between the feedback signal input port 3114 and the local oscillator signal input port 3111, wherein the first high-frequency path 3115 and the third high-frequency path 3117 have equal electrical lengths, wherein the fourth high-frequency path 3118 has an electrical length greater than or equal to one-eighth of the wavelength and less than or equal to one-half of the wavelength, wherein in any pair of mixer tubes 312, the two ends of different mixer tubes 312 with different polarities are connected to a state equivalent to a capacitance to ground, and the two pairs of mixer tubes 312 are connected in reverse series between the first mixer port 3112 and the second mixer port 3113 of the mixer bridge 311, that is, wherein One pair of mixer tubes 312 has its positive and negative terminals connected to the first mixer port 3112 and the second mixer port 3113 of the mixer bridge 311, respectively. Another pair of mixer tubes 312 has its positive and negative terminals connected to the second mixer port 3113 and the first mixer port 3112 of the mixer bridge 311, respectively, to form a connection state in which the two pairs of mixer tubes 312 are connected in reverse series between the first mixer port 3112 and the second mixer port 3113 of the mixer bridge 311.

[0105] Thus, with the local oscillator signal input port 3111 of the mixer bridge 311 connected to the local oscillator signal and the feedback signal input port 3114 connected to the feedback signal, corresponding to step (S1), the mixer bridge 311, based on the above-described structure design, mixes the local oscillator signal and the feedback signal to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal. Specifically, in step (S2), two pairs of mixer tubes 312, based on inverse polarity, are respectively connected in series to the first mixer port 311 of the mixer bridge 311. The connection state between 2 and the second mixing port 3113 is such that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the two ends of the interconnection of one pair of mixing tubes 312 is out of phase with the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the two ends of the interconnection of the other pair of mixing tubes 312, thereby outputting the Doppler intermediate frequency signal in differential signal form from the two pairs of mixing tubes 312 in out-of-phase output of the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal.

[0106] Further reference is made to the accompanying drawings of this invention. Figure 7DAs shown, another structural principle of the Doppler differential output circuit 30 is illustrated. The Doppler differential output circuit 30 includes a mixer bridge 311 and two mixer tubes 312. The mixer bridge 311 has a local oscillator signal input port 3111 suitable for the local oscillator signal input, and sequentially includes a first mixer port 3112, a second mixer port 3113, and a feedback signal input port 3114 suitable for the feedback signal input. Correspondingly, the mixer bridge 311 has a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixer port 3112, and a second high-frequency path defined between the first mixer port 3112 and the second mixer port 3113. 3116, a third high-frequency path 3117 defined between the second mixer port 3113 and the feedback signal input port 3114, and a fourth high-frequency path 3118 defined between the feedback signal input port 3114 and the local oscillator signal input port 3111, wherein the first high-frequency path 3115 and the third high-frequency path 3117 have equal electrical lengths, wherein the fourth high-frequency path 3118 has an electrical length greater than or equal to one-eighth of the wavelength and less than or equal to one-half of the wavelength, wherein two ends of the same polarity of the two mixer tubes 312 are respectively connected to a state of equivalent capacitance to ground, and the other two ends of the same polarity of the two mixer tubes 312 are respectively connected to the first mixer port 3112 and the second mixer port 3113 of the mixer bridge 311.

[0107] Thus, with the local oscillator signal input port 3111 of the mixer bridge 311 connected to the local oscillator signal and the feedback signal input port 3114 connected to the feedback signal, corresponding to step (S1), the mixer bridge 311, based on the above-described structure design, mixes the local oscillator signal and the feedback signal to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal. Specifically, in step (S2), based on the same polarity of the two mixer tubes 312, two ends are respectively connected to an equivalent capacitance to ground, and the other two ends of the same polarity of the two mixer tubes 312 are respectively connected to the mixer bridge 311. The connection state of the first mixer port 3112 and the second mixer port 3113 is such that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from one end of the mixer tube 312 connected to the corresponding equivalent capacitance to ground is out of phase with the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the other mixer tube 312 connected to the corresponding equivalent capacitance to ground. Thus, the signals corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal are drawn out in opposite phase from the two ends of the mixer tubes 312 connected to the corresponding equivalent capacitance to ground to output the Doppler intermediate frequency signal in differential signal form.

[0108] Further reference is made to the accompanying drawings of this invention. Figure 7EAs shown, another structural principle of the Doppler differential output circuit 30 is illustrated. The Doppler differential output circuit 30 includes a mixer bridge 311 and two pairs of mixer tubes 312. The mixer bridge 311 has a local oscillator signal input port 3111 suitable for the local oscillator signal input, and sequentially includes a first mixer port 3112, a second mixer port 3113, and a feedback signal input port 3114 suitable for the feedback signal input from the local oscillator signal input port 3111 along the mixer bridge 311. Correspondingly, the mixer bridge 311 has a first high-frequency path 3115 defined between the local oscillator signal input port 3111 and the first mixer port 3112, a second high-frequency path 3116 defined between the first mixer port 3112 and the second mixer port 3113, and a third high-frequency path 3115 defined between the second mixer port 3113 and the feedback signal input port 3114. The system includes a first high-frequency path 3117 and a fourth high-frequency path 3118 defined between the feedback signal input port 3114 and the local oscillator signal input port 3111. The first high-frequency path 3115 and the third high-frequency path 3117 have equal electrical lengths. The fourth high-frequency path 3118 has an electrical length greater than or equal to one-eighth of the wavelength and less than or equal to one-half of the wavelength. The two high-frequency paths 3116 and the fourth high-frequency path 3118 are connected in series with an equivalent capacitor. The two ends of each pair of mixer tubes 312 with different polarities are grounded and connected to each other. The other two ends of one pair of mixer tubes 312 with different polarities are connected to the first mixer port 3112 of the mixer bridge 311, and the other two ends of the other pair of mixer tubes 312 with different polarities are connected to the second mixer port 3113 of the mixer bridge 311.

[0109] Thus, with the local oscillator signal input port 3111 of the mixer bridge 311 connected to the local oscillator signal and the feedback signal input port 3114 connected to the feedback signal, corresponding to step (S1), the mixer bridge 311 is designed to mix and process the local oscillator signal and the feedback signal to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal. Specifically, in step (S2), the equivalent capacitors are connected in series with the two high-frequency paths 3116 and the fourth high-frequency path 3118, and the two ends with different polarities of each pair of mixer tubes 312 are grounded and interconnected, and the other ends with different polarities of one pair of mixer tubes 312 are connected to each other. The connection state in which the two outer ends of the mixer tube 312 are connected to the first mixer port 3112 of the mixer bridge 311, and the other two ends of the mixer tube 312 with different polarities are connected to the second mixer port 3113 of the mixer bridge 311, is such that the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the first mixer port 3112 is out of phase with the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal drawn from the second mixer port 3113, thereby outputting the Doppler intermediate frequency signal in differential signal form by out-of-phase output of the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal from the first mixer port 3112 and the second mixer port 3113.

[0110] It is worth mentioning that in the structural principles of the Doppler differential output circuit 30 in the example, the first high-frequency path 3115 and the third high-frequency path 3117 are configured as microstrip lines in the form of paths. The second high-frequency path 3116, in order to ensure the high-frequency conduction characteristics corresponding to the local oscillator signal frequency, allows at least one of a capacitor, an inductor, and a resistor to be connected in series. The present invention does not limit this.

[0111] 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.

[0112] For example, in some embodiments of the present invention, the Doppler differential output circuit 30 and the oscillation unit 20 are configured as an integrated circuit and integrated into a single microwave chip. As another 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 an integrated circuit and integrated into a single microwave chip, while the single-ended signal to differential signal circuit 32 of the Doppler differential output circuit 30 is externally located within the microwave chip.

[0113] In particular, in some embodiments of the present invention, the anti-interference microwave detection method further includes the following step between step (C) and step (D):

[0114] F. Perform differential amplification processing on the Doppler intermediate frequency signal in differential signal form.

[0115] Accordingly, refer to the accompanying drawings of the specification of this invention. Figure 8 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 selection cancellation unit 40 to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit 30. Based on the common-mode rejection characteristics of the differential amplification process of the Doppler intermediate frequency signal in differential signal form, the Doppler intermediate frequency signal in differential signal form is amplified while suppressing the amplification of the first type of interference signal in the Doppler intermediate frequency signal in differential signal form.

[0116] To further describe the present invention, reference is made to the accompanying drawings in the specification of the present invention. Figure 9A and Figure 9B As shown, the structural principle of the differential amplifier circuit 50 of the microwave detection device according to two embodiments of the present invention is illustrated, wherein based on Figure 9A The schematic diagram illustrates the structural principle of the differential amplifier circuit 50. An example of the circuit structure of the differential amplifier circuit 50 is further illustrated below. Figure 9B As illustrated in the diagram, it is 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.

[0117] Furthermore, in some embodiments of the present invention, the anti-interference microwave detection method further includes the following step in step (E):

[0118] The digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process is subjected to differential-to-single-ended conversion. The differential-to-single-ended conversion process is a subtraction process of the digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process.

[0119] 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.

[0120] It is understandable that when the frequency selection cancellation unit 40 is configured as a component with computational processing capabilities, the differential-to-single-ended processing of the digitized discrete form of the Doppler intermediate frequency signal after the algorithm's frequency selection cancellation processing can be performed in the frequency selection cancellation unit 40. Simultaneously, the Doppler intermediate frequency signal after differential-to-single-ended processing is in a digitized discrete form and can be directly used in subsequent data recognition and processing. If the frequency selection cancellation unit 40 is implemented as an MCU, subsequent recognition and processing of the digitized discrete Doppler intermediate frequency signal can be directly performed in the MCU, which is beneficial for improving the response efficiency of the microwave detection device. This ensures the immediacy of the Doppler intermediate frequency signal, facilitating real-time detection of actions such as human breathing and heartbeat.

[0121] 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.

[0122] 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) The inverted output corresponds to the frequency / phase difference between the local oscillator signal and the feedback signal, and outputs a Doppler intermediate frequency signal in differential signal form; (D) Digitize the Doppler intermediate frequency signal to obtain a digitized discrete form of the Doppler intermediate frequency signal in differential signal form; as well as (E) A differential cancellation algorithm function is used to perform algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form. The corresponding algorithmic frequency selection cancellation process is to perform cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form in the corresponding frequency range according to the differential cancellation algorithm function. The corresponding frequency range is the frequency range of the interference signal that exists in the Doppler intermediate frequency signal in the differential signal form as differential mode interference after the environmental interference signal has any frequency relationship with the frequency of the local oscillator signal (such as same frequency, adjacent frequency, or harmonic frequency) superimposed on the feedback signal.

2. The anti-interference microwave detection method according to claim 1, wherein step (E) further includes the step of: The digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process is subjected to differential-to-single-ended conversion. The differential-to-single-ended conversion process is a subtraction process of the digitized discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection and cancellation process.

3. The anti-interference microwave detection method according to claim 2, wherein the anti-interference microwave detection method is performed by a frequency-selective cancellation unit with computational processing capability, wherein steps (D) and (E) are executed.

4. The anti-interference microwave detection method according to claim 3, wherein the frequency selection cancellation unit is implemented as one of an MCU, a microcontroller, and a central processing unit.

5. The anti-interference microwave detection method according to any one of claims 1 to 4, wherein the anti-interference microwave detection method further includes the step of: between step (C) and step (D): (F) The Doppler intermediate frequency signal in differential signal form is differentially amplified.

6. The anti-interference microwave detection method according to any one of claims 1 to 4, wherein step (C) includes the following steps: (C1) The local oscillator signal and the feedback signal are mixed to extract the signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal; (C2) Draw out a signal corresponding to the frequency / phase difference between the local oscillator signal and the feedback signal to output a Doppler intermediate frequency signal in a single-ended signal form; as well as (C3) By inverting the Doppler intermediate frequency signal in single-ended signal form to output 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 the Doppler intermediate frequency signal in differential signal form.

7. 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, and is configured to output a Doppler intermediate frequency signal in differential signal form based on the inverted output of the frequency / phase difference between the local oscillator signal and the feedback signal; and A frequency-selective cancellation unit is provided, wherein the frequency-selective cancellation unit is configured with components having computational processing capabilities and includes an AD conversion module and a frequency-selective cancellation operation module electrically connected to the AD conversion module. The AD conversion module is electrically connected to the Doppler differential output circuit to receive the Doppler intermediate frequency signal in differential signal form output from the Doppler differential output circuit, and digitizes the received Doppler intermediate frequency signal to transmit the digitized discrete form of the differential signal form of the Doppler intermediate frequency signal to the frequency-selective cancellation operation module. The frequency-selective cancellation operation module is configured to... The differential cancellation algorithm function is used to perform algorithmic frequency selection cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form. The corresponding algorithmic frequency selection cancellation process is to perform cancellation processing on the digital discrete form of the Doppler intermediate frequency signal in the differential signal form within a corresponding frequency range according to the differential cancellation algorithm function. The corresponding frequency range is the frequency range of the interference signal that exists in the Doppler intermediate frequency signal in the differential signal form as differential mode interference after the environmental interference signal has any frequency relationship with the frequency of the local oscillator signal (same frequency, adjacent frequency, or harmonic frequency) superimposed on the feedback signal.

8. The microwave detection device according to claim 7, wherein the frequency selection cancellation unit is implemented as one of an MCU, a microcontroller, and a central processing unit.

9. The microwave detection device according to claim 8, wherein the frequency selection cancellation unit is configured to further perform differential-to-single-ended processing on the digital discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection cancellation processing, and the differential-to-single-ended processing is a subtraction process on the digital discrete form of the Doppler intermediate frequency signal after the algorithm frequency selection cancellation processing.

10. The microwave detection device according to claim 8, wherein the two ends of the AD conversion module electrically connected to the Doppler differential output circuit are the two input terminals of the frequency selection cancellation unit, and the two input terminals of the frequency selection cancellation unit are respectively electrically connected to a pair of ground capacitors.

11. The microwave detection device according to claim 8, wherein the Doppler differential output circuit includes a mixer circuit and a single-ended to differential circuit, wherein the mixer circuit is electrically connected to the antenna unit and the oscillation 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 Doppler intermediate frequency signal in a single-ended signal form and convert the single-ended Doppler intermediate frequency signal in a single-ended signal form into the Doppler intermediate frequency signal in a differential signal form by inverting the phase of the single-ended Doppler intermediate frequency signal.

12. The microwave detection device according to claim 11, wherein the Doppler differential output circuit and the oscillation unit are configured in an integrated circuit form and integrated into a microwave chip.

13. The microwave detection device according to claim 11, wherein the oscillation unit and the mixing circuit of the Doppler differential output circuit are configured in an integrated circuit form and integrated into a microwave chip, wherein the single-ended signal to differential signal circuit of the Doppler differential output circuit is externally placed on the microwave chip.

14. The microwave detection device according to any one of claims 7 to 13, 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 selection cancellation unit to differentially amplify the Doppler intermediate frequency signal in differential signal form output by the Doppler differential output circuit.

Images