A microwave sensing circuit

Abstract

The utility model provides a kind of microwave sensing circuit, comprising: power input module, the input end of power input module is connected external power supply;Signal transmitting module, the output end of power input module is connected to the input end of signal transmitting module, and first double-inductor microstrip structure is equipped in signal transmitting module;Signal filtering module, the first input end of signal filtering module is connected external signal transmitting end to receive first input signal;Signal receiving module, the input end of signal receiving module is used for inductive reception second input signal, and the second input end of signal filtering module is connected to the output end of signal receiving module;First input signal or second input signal is filtered after signal filtering module and is input to signal transmitting module, and it is transmitted to external user receiving end after widening channel bandwidth by first double-inductor microstrip structure.Effect is that the utility model can realize high stability impedance matching, strong anti-interference and low crosstalk in wide band.

Description

Technical Field

[0001] This utility model relates to the technical field of microwave sensors, and more specifically, to a microwave sensing circuit. Background Technology

[0002] Microwave sensing circuits, as core components for object detection, distance measurement, and motion tracking, are widely used in automotive radar, security monitoring, and industrial control. However, traditional microwave sensing circuits generally face three major technical bottlenecks:

[0003] 1. Bandwidth limitations

[0004] Existing designs mostly use a single inductor matching network. In the 24-30GHz high-frequency band, the signal channel bandwidth is usually less than 2GHz, which leads to a reduction in short-range detection resolution. At the same time, narrowband impedance matching is prone to causing signal reflection, resulting in a decrease in the signal-to-noise ratio at the receiver.

[0005] 2. Noise interference sensitivity

[0006] High-frequency ripple and environmental electromagnetic noise from the power module can couple to the signal link. Traditional π-type filters, due to the parasitic inductance effect of discrete capacitors, have a sharp drop in out-of-band suppression capability in the millimeter-wave band, which significantly increases the false alarm rate.

[0007] 3. Inter-module signal crosstalk

[0008] When the signal transmitting module and the signal receiving module are integrated, there is a lack of effective isolation. High-power transmitted signals are easily leaked into the receiving channel, causing self-interference, which makes it difficult to meet the needs of miniaturized devices.

[0009] To address the aforementioned issues, while some studies have attempted to improve performance by increasing the number of filtering stages or optimizing wiring, these often come at the cost of reduced response speed and power consumption. Therefore, there is an urgent need for a microwave sensing circuit that can achieve high-stability impedance matching, strong anti-interference capabilities, and low crosstalk over a wide bandwidth. Utility Model Content

[0010] The technical problem to be solved by this utility model is how to achieve high stability impedance matching, strong anti-interference and low crosstalk in a wide frequency band. In order to overcome the defects of the above-mentioned prior art (or related technology), this utility model provides a microwave sensing circuit.

[0011] This utility model provides a microwave sensing circuit, including:

[0012] A power input module, wherein the input terminal of the power input module is connected to an external power source;

[0013] A signal transmitting module, wherein the input terminal of the signal transmitting module is connected to the output terminal of the power input module, and the signal transmitting module is provided with a first dual-inductor microstrip structure;

[0014] A signal filtering module, wherein the first input terminal of the signal filtering module is connected to an external signal transmitter to receive a first input signal;

[0015] A signal receiving module, wherein the input terminal of the signal receiving module is used to sense and receive a second input signal, and the output terminal of the signal receiving module is connected to the second input terminal of the signal filtering module;

[0016] The first input signal or the second input signal is filtered by the signal filtering module and then input to the signal transmitting module. After the channel bandwidth is widened by the first dual-inductor microstrip structure, it is transmitted to the external user receiving end.

[0017] Compared with the prior art, the microwave sensing circuit proposed in this application has the following advantages:

[0018] This application clearly defines the functional division of a power input module, a signal transmission module, a signal filtering module, and a signal receiving module. The power input module provides stable power supply, the signal transmission module widens the channel bandwidth and transmits signals, the signal filtering module suppresses external noise and receives external input signals (i.e., the first input signal), and the signal receiving module senses and acquires environmental sensing signals (i.e., the second input signal). It supports dual signal processing of external input signals or environmental sensing signals and is suitable for active and passive mixed sensing scenarios. The first dual-inductor microstrip structure in the signal transmission module widens the channel bandwidth of the first or second input signal, adapts to high-frequency wave signals, and reduces signal distortion. At the same time, the signal transmission module and the signal receiving module are separated by the signal filtering module, achieving high stability impedance matching, strong anti-interference, and low crosstalk in a wide frequency band.

[0019] In one possible implementation, the power input module includes:

[0020] A first resistor, one end of which is connected to the external power supply;

[0021] A first capacitor, one end of which is connected to one end of the first resistor, and the other end of which is grounded;

[0022] A second capacitor, one end of which is connected to the other end of the first resistor, and the other end of which is grounded;

[0023] A first inductor, the two ends of the first inductor being connected to the other end of the first resistor and the drain of the field-effect transistor, respectively, and the source of the field-effect transistor being grounded;

[0024] A first three-pin inductor, the first pin of the first three-pin inductor is grounded, and the second pin is connected to the gate of the field-effect transistor;

[0025] A third capacitor, the two ends of which are respectively connected to the third pin and the first pin of the first three-pin inductor;

[0026] A fourth capacitor, one end of which is connected to the drain of the field-effect transistor, and the other end of which is connected to the input terminal of the signal transmitting module;

[0027] One end of the first resistor serves as the input terminal of the power input module, and the other end of the fourth capacitor serves as the output terminal of the power input module.

[0028] Compared with the prior art, the above technical solution can suppress power ripple through a two-stage filtering structure of a first resistor, a first capacitor, a second capacitor, and a first inductor, thereby avoiding high-frequency noise interference with the operation of the field-effect transistor. The first three-pin inductor and the third capacitor form a resonant network, providing a precise bias voltage for the gate of the field-effect transistor and improving the stability of the oscillation signal.

[0029] In one possible implementation, the power input module further includes a dielectric resonator, the two ends of which are respectively connected to the gate and drain of the field-effect transistor.

[0030] Compared with existing technologies, the above technical solution can enhance oscillation efficiency and reduce phase noise by coupling the gate and drain of the field-effect transistor through a dielectric resonator.

[0031] In one possible implementation, the signal transmitting module includes:

[0032] A second inductor, one end of which is connected to the output terminal of the power input module;

[0033] A second-third-pin inductor, wherein the first pin of the second-third-pin inductor is connected to the output terminal of the power input module;

[0034] A third inductor, one end of which is connected to the other end of the second inductor and the second pin of the second three-pin inductor, and the other end of the third inductor is connected to a signal transmitter;

[0035] A fifth capacitor, one end of which is connected to the third pin of the second three-pin inductor, and the other end of which is grounded;

[0036] A sixth capacitor, one end of which is connected to the other end of the third inductor, and the other end of which is grounded;

[0037] The second inductor, the second three-prong inductor, and the fifth capacitor constitute the first dual-inductor microstrip structure;

[0038] One end of the second inductor and the first pin of the second three-pin inductor serve as the input terminals of the signal transmitting module, and the signal transmitter serves as the output terminal of the signal transmitting module.

[0039] Compared with the existing technology, the above technical solution can reduce the equivalent inductive reactance by combining the second inductor and the second three-pin inductor in parallel with the fifth capacitor to form a first dual-inductor microstrip structure, thereby expanding the bandwidth to the full frequency band of 24-30GHz. The microstrip design of the fifth capacitor reduces parasitic inductance and improves the flatness of high-frequency response. The sixth capacitor absorbs the harmonics generated by the third inductor and improves the purity of the transmitted signal.

[0040] In one possible implementation, the signal filtering module includes:

[0041] A fourth and fifth inductor are connected in parallel, with one end of each inductor connected to the input terminal of the signal transmitting module;

[0042] A seventh capacitor, one end of which is connected to the other ends of the fourth and fifth inductors, and the other end of which is grounded;

[0043] A sixth inductor, one end of which is connected to one end of the seventh capacitor, and the other end of which is grounded;

[0044] A seventh inductor, one end of which is connected to one end of a seventh capacitor, and the other end of which is connected to the other end of the seventh capacitor;

[0045] A first diode, the anode of which is connected to one end of the sixth inductor and one end of the seventh inductor, and the cathode of which is connected to the output terminal of the signal receiving module;

[0046] A second diode, the cathode of which is connected to the anode of the first diode, and the anode of which is connected to the output terminal of the signal receiving module;

[0047] An eighth capacitor is provided, one end of which is connected to one end of the sixth inductor and one end of the seventh inductor, and the other end of the eighth capacitor is grounded.

[0048] A ninth capacitor, one end of which is connected to one end of the eighth capacitor, and the other end of which is grounded;

[0049] A Schottky diode, wherein the cathode of the Schottky diode is connected to one end of the ninth capacitor, and the anode of the Schottky diode is grounded;

[0050] A second resistor is provided, one end of which is connected to the negative terminal of the Schottky diode and the signal input, and the signal input is connected to the external signal transmitter. The other end of the second resistor is grounded.

[0051] One end of the fourth inductor and one end of the fifth inductor serve as the output terminal of the signal filtering module, the signal input terminal serves as the first input terminal of the signal filtering module, and the positive terminal of the second diode serves as the second input terminal of the signal filtering module.

[0052] Compared with existing technologies, the above technical solution can form a bandpass filter by connecting the fourth and fifth inductors in parallel with the seventh capacitor to attenuate low-frequency interference, and form a π-type filter by connecting the sixth, eighth, and ninth inductors to specifically eliminate interference at specific frequency points. The first and second diodes are connected back to back to clamp the received signal voltage and prevent electrostatic discharge from damaging sensitive devices. The Schottky diode converts the microwave signal into a DC level to achieve real-time monitoring of signal strength.

[0053] In one possible implementation, the signal receiving module includes a second dual-inductor microstrip structure to broaden the channel bandwidth of the second input signal.

[0054] In one possible implementation, the signal receiving module includes:

[0055] An eighth inductor, one end of which is connected to the second input terminal of the signal filtering module;

[0056] A third three-pin inductor, wherein the first pin of the third three-pin inductor is connected to the second input terminal of the signal filtering module;

[0057] A ninth inductor, one end of which is connected to the other end of the eighth inductor and the second pin of the third three-pin inductor, and the other end of which is connected to a signal sensor;

[0058] A tenth capacitor, one end of which is connected to the third pin of the third three-prong inductor, and the other end of which is grounded;

[0059] An eleventh capacitor, one end of which is connected to the other end of the ninth inductor, and the other end of which is grounded;

[0060] The eighth inductor, the third tripod inductor, and the tenth capacitor constitute the second dual-inductor microstrip structure;

[0061] One end of the eighth inductor and the first pin of the third three-pin inductor serve as the output terminal of the signal receiving module, and the signal sensor serves as the input terminal of the signal receiving module.

[0062] Compared with existing technologies, the above technical solution can ensure that the receiving channel has the same bandwidth and improve system consistency by mirroring the structure of the signal transmitting module through the second dual-inductor microstrip structure composed of the eighth inductor, the third three-pin inductor and the tenth capacitor. The ninth inductor and the eleventh capacitor form an impedance matching network to efficiently transmit the sensed second input signal to the signal filtering module.

[0063] In one possible implementation, the microwave sensing circuit operates in the frequency range of 24 GHz to 30 GHz. Attached Figure Description

[0064] Figure 1 This is the electrical schematic diagram of this utility model;

[0065] Explanation of reference numerals in the attached figures:

[0066] 1. Power input module; 2. Signal transmission module; 3. Signal filtering module; 4. Signal receiving module. Detailed Implementation

[0067] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0068] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0069] See Figure 1 This application discloses a microwave sensing circuit, including a power input module 1, a signal transmitting module 2, a signal filtering module 3, and a signal receiving module 4. The input terminal of the power input module 1 is connected to an external power supply VCC. The input terminal of the signal transmitting module 2 is connected to the output terminal of the power input module 1. The signal transmitting module 2 has a first dual-inductor microstrip structure. The first input terminal of the signal filtering module 3 is connected to an external signal transmitting terminal to receive a first input signal. The input terminal of the signal receiving module 4 is used to sense and receive a second input signal. The output terminal of the signal receiving module 4 is connected to the second input terminal of the signal filtering module 3. The first input signal or the second input signal is filtered by the signal filtering module 3 and then input to the signal transmitting module 2. After the channel bandwidth is widened by the first dual-inductor microstrip structure, it is transmitted to an external user receiving terminal.

[0070] In this embodiment, the power input module 1 includes a first resistor R1, a first capacitor C1, a second capacitor C2, a first inductor L1, a field-effect transistor Q1, a first three-pin inductor L2, a third capacitor C3, a fourth capacitor C4, and a dielectric resonator Q2. One end of the first resistor R1 is connected to an external power supply VCC; one end of the first capacitor C1 is connected to one end of the first resistor R1, and the other end of the first capacitor C1 is grounded; one end of the second capacitor C2 is connected to the other end of the first resistor R1, and the other end of the second capacitor C2 is grounded; the two ends of the first inductor L1 are respectively connected to the other end of the first resistor R1 and the field-effect transistor Q2. The drain of transistor Q1 and the source of MOSFET Q1 are grounded. The first pin of the first three-pin inductor L2 is grounded, and the second pin is connected to the gate of MOSFET Q1. The two ends of the third capacitor C3 are connected to the third pin and the first pin of the first three-pin inductor L2, respectively. One end of the fourth capacitor C4 is connected to the drain of MOSFET Q1, and the other end of the fourth capacitor C4 is connected to the input terminal of signal transmission module 2. The two ends of dielectric resonator Q2 are connected to the gate and the drain of MOSFET Q1, respectively. One end of the first resistor R1 serves as the input terminal of power input module 1, and the other end of the fourth capacitor C4 serves as the output terminal of power input module 1.

[0071] In this embodiment, the signal transmitting module 2 includes a second inductor L3, a second three-pin inductor L4, a third inductor L5, a signal transmitter ANT1, a fifth capacitor C5, and a sixth capacitor C6. One end of the second inductor L3 is connected to the output terminal of the power input module 1, the first pin of the second three-pin inductor L4 is connected to the output terminal of the power input module 1, one end of the third inductor L5 is connected to the other end of the second inductor L3 and the second pin of the second three-pin inductor L4, and the other end of the third inductor L5 is connected to the signal transmitter ANT1. One end of the fifth capacitor C5 is connected to the third pin of the second three-pin inductor L4, and the other end of the fifth capacitor C5 is grounded. One end of the sixth capacitor C6 is connected to the other end of the third inductor L5, and the other end of the sixth capacitor C6 is grounded. The second inductor L3, the second three-pin inductor L4, and the fifth capacitor C5 constitute a first dual-inductor microstrip structure. One end of the second inductor L3 and the first pin of the second three-pin inductor L4 serve as the input terminal of the signal transmitting module 2, and the signal transmitter ANT1 serves as the output terminal of the signal transmitting module 2.

[0072] In this embodiment, the signal filtering module 3 includes a fourth inductor L6, a fifth inductor L7, a seventh capacitor C7, a sixth inductor L8, a seventh inductor L9, a first diode D1, a second diode D2, an eighth capacitor C8, a ninth capacitor C9, a Schottky diode D3, and a second resistor R2. The fourth inductor L6 and the fifth inductor L7 are connected in parallel, with one end of each connected to the input terminal of the signal transmitting module 2. One end of the seventh capacitor C7 is connected to the other end of the fourth inductor L6 and the fifth inductor L7, and the other end of the seventh capacitor C7 is grounded. One end of the sixth inductor L8 is connected to one end of the seventh capacitor C7, and the other end of the sixth inductor L8 is grounded. One end of the seventh inductor L9 is connected to one end of the seventh capacitor C7, and the other end of the seventh inductor L9 is connected to the other end of the seventh capacitor C7. The anode of the first diode D1 is connected to one end of the sixth inductor L8 and one end of the seventh inductor L9, and the cathode of the first diode D1 is connected to the signal receiving module. At the output terminal of block 4, the negative terminal of the second diode D2 is connected to the positive terminal of the first diode D1, and the positive terminal of the second diode D2 is connected to the output terminal of the signal receiving module 4. One end of the eighth capacitor C8 is connected to one end of the sixth inductor L8 and one end of the seventh inductor L9, respectively, and the other end of the eighth capacitor C8 is grounded. One end of the ninth capacitor C9 is connected to one end of the eighth capacitor C8, and the other end of the ninth capacitor C9 is grounded. The negative terminal of the Schottky diode D3 is connected to one end of the ninth capacitor C9, and the positive terminal of the Schottky diode D3 is grounded. One end of the second resistor R2 is connected to the negative terminal of the Schottky diode D3 and the signal input SIN, respectively, and is connected to the external signal transmitting terminal through the signal input SIN. The other end of the second resistor R2 is grounded. One end of the fourth inductor L6 and the fifth inductor L7 serves as the output terminal of the signal filtering module 3, the signal input SIN serves as the first input terminal of the signal filtering module 3, and the positive terminal of the second diode D2 serves as the second input terminal of the signal filtering module 3.

[0073] In this embodiment, the signal receiving module 4 is provided with a second dual-inductor microstrip structure to broaden the channel bandwidth of the second input signal. The signal receiving module includes an eighth inductor L10, a third three-pin inductor L11, a ninth inductor L12, a tenth capacitor C10, and an eleventh capacitor C11. One end of the eighth inductor L10 is connected to the second input terminal of the signal filtering module 3. The first pin of the third three-pin inductor L11 is connected to the second input terminal of the signal filtering module 3. One end of the ninth inductor L12 is connected to the other end of the eighth inductor L10 and the second pin of the third three-pin inductor L11. The other end of 12 is connected to the signal sensor ANT2. One end of the tenth capacitor C10 is connected to the third pin of the third three-pin inductor L11, and the other end of the tenth capacitor C10 is grounded. One end of the eleventh capacitor C11 is connected to the other end of the ninth inductor L12, and the other end of the eleventh capacitor C11 is grounded. The eighth inductor L10, the third three-pin inductor L11 and the tenth capacitor C10 constitute the second dual-inductor microstrip structure. One end of the eighth inductor L10 and the first pin of the third three-pin inductor L11 serve as the output terminal of the signal receiving module 4, and the signal sensor ANT2 serves as the input terminal of the signal receiving module 4.

[0074] In this embodiment, the operating frequency range of the microwave sensing circuit is 24 GHz to 30 GHz.

[0075] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0076] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A microwave sensing circuit, characterized in that, include: A power input module, wherein the input terminal of the power input module is connected to an external power source; A signal transmitting module, wherein the input terminal of the signal transmitting module is connected to the output terminal of the power input module, and the signal transmitting module is provided with a first dual-inductor microstrip structure; A signal filtering module, wherein the first input terminal of the signal filtering module is connected to an external signal transmitter to receive a first input signal; A signal receiving module, wherein the input terminal of the signal receiving module is used to sense and receive a second input signal, and the output terminal of the signal receiving module is connected to the second input terminal of the signal filtering module; The first input signal or the second input signal is filtered by the signal filtering module and then input to the signal transmitting module. After the channel bandwidth is widened by the first dual-inductor microstrip structure, it is transmitted to the external user receiving end.

2. The microwave sensing circuit according to claim 1, characterized in that, The power input module includes: A first resistor, one end of which is connected to the external power supply; A first capacitor, one end of which is connected to one end of the first resistor, and the other end of which is grounded; A second capacitor, one end of which is connected to the other end of the first resistor, and the other end of which is grounded; A first inductor, the two ends of the first inductor being connected to the other end of the first resistor and the drain of the field-effect transistor, respectively, and the source of the field-effect transistor being grounded; A first three-pin inductor, with its first pin grounded and its second pin connected to the gate of the field-effect transistor; A third capacitor, the two ends of which are respectively connected to the third pin and the first pin of the first three-pin inductor; A fourth capacitor, one end of which is connected to the drain of the field-effect transistor, and the other end of which is connected to the input terminal of the signal transmitting module; One end of the first resistor serves as the input terminal of the power input module, and the other end of the fourth capacitor serves as the output terminal of the power input module.

3. The microwave sensing circuit according to claim 2, characterized in that, The power input module also includes a dielectric resonator, the two ends of which are connected to the gate and drain of the field-effect transistor, respectively.

4. The microwave sensing circuit according to claim 1, characterized in that, The signal transmitting module includes: A second inductor, one end of which is connected to the output terminal of the power input module; A second-third-pin inductor, wherein the first pin of the second-third-pin inductor is connected to the output terminal of the power input module; A third inductor, one end of which is connected to the other end of the second inductor and the second pin of the second three-pin inductor, and the other end of the third inductor is connected to a signal transmitter; A fifth capacitor, one end of which is connected to the third pin of the second three-pin inductor, and the other end of which is grounded; A sixth capacitor, one end of which is connected to the other end of the third inductor, and the other end of which is grounded; The second inductor, the second three-prong inductor, and the fifth capacitor constitute the first dual-inductor microstrip structure; One end of the second inductor and the first pin of the second three-pin inductor serve as the input terminals of the signal transmitting module, and the signal transmitter serves as the output terminal of the signal transmitting module.

5. The microwave sensing circuit according to claim 1, characterized in that, The signal filtering module includes: A fourth and a fifth inductor are connected in parallel, with one end of each inductor connected to the input terminal of the signal transmitting module; A seventh capacitor, one end of which is connected to the other ends of the fourth and fifth inductors, and the other end of which is grounded; A sixth inductor, one end of which is connected to one end of the seventh capacitor, and the other end of which is grounded; A seventh inductor, one end of which is connected to one end of a seventh capacitor, and the other end of which is connected to the other end of the seventh capacitor; A first diode, the anode of which is connected to one end of the sixth inductor and one end of the seventh inductor, and the cathode of which is connected to the output terminal of the signal receiving module; A second diode, the cathode of which is connected to the anode of the first diode, and the anode of which is connected to the output terminal of the signal receiving module; An eighth capacitor is provided, one end of which is connected to one end of the sixth inductor and one end of the seventh inductor, and the other end of the eighth capacitor is grounded. A ninth capacitor, one end of which is connected to one end of the eighth capacitor, and the other end of which is grounded; A Schottky diode, wherein the cathode of the Schottky diode is connected to one end of the ninth capacitor, and the anode of the Schottky diode is grounded; A second resistor is provided, one end of which is connected to the negative terminal of the Schottky diode and the signal input, and the signal input is connected to the external signal transmitter. The other end of the second resistor is grounded. One end of the fourth inductor and one end of the fifth inductor serve as the output terminal of the signal filtering module, the signal input terminal serves as the first input terminal of the signal filtering module, and the positive terminal of the second diode serves as the second input terminal of the signal filtering module.

6. The microwave sensing circuit according to claim 1, characterized in that, The signal receiving module is equipped with a second dual-inductor microstrip structure to broaden the channel bandwidth of the second input signal.

7. The microwave sensing circuit according to claim 6, characterized in that, The signal receiving module includes: An eighth inductor, one end of which is connected to the second input terminal of the signal filtering module; A third three-pin inductor, wherein the first pin of the third three-pin inductor is connected to the second input terminal of the signal filtering module; A ninth inductor, one end of which is connected to the other end of the eighth inductor and the second pin of the third three-pin inductor, and the other end of which is connected to a signal sensor; A tenth capacitor, one end of which is connected to the third pin of the third three-prong inductor, and the other end of which is grounded; An eleventh capacitor, one end of which is connected to the other end of the ninth inductor, and the other end of which is grounded; The eighth inductor, the third tripod inductor, and the tenth capacitor constitute the second dual-inductor microstrip structure; One end of the eighth inductor and the first pin of the third three-pin inductor serve as the output terminal of the signal receiving module, and the signal sensor serves as the input terminal of the signal receiving module.

8. The microwave sensing circuit according to claim 1, characterized in that, The microwave sensing circuit operates in the frequency range of 24 GHz to 30 GHz.

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