Microwave receiving module

Abstract

The microwave receiving module comprises a low noise amplifier, a frequency mixer, an intermediate frequency filter, a gain amplifier and a video output module which are coupled, the frequency mixer is further connected with a local oscillator module, and the video output module comprises a detector; metal shielding covers are arranged on the peripheries of the local oscillator module and the detector, the metal shielding covers are connected with a continuous ground plane layer of a PCB (Printed Circuit Board) through welding or conductive adhesive tapes, the PCB is a multi-layer PCB, and the ground plane layer is an independent copper-clad layer in the multi-layer PCB; a via hole array is arranged below the ground plane layer located in the local oscillator module and the detector area, and the distance between adjacent via holes in the via hole array is smaller than or equal to 1 / 20 of the working wavelength; the metal shielding case is a copper cavity, a wave absorbing layer is attached to the inner wall of the metal shielding case, and honeycomb ventilation holes are formed in the metal shielding case. According to the utility model, the microwave receiving module can still work stably in a complex electromagnetic environment.

Description

Technical Field

[0001] This application relates to a microwave receiving module, belonging to the field of microwave receiving technology. Background Technology

[0002] In the field of microwave receiving technology, existing microwave receiving modules typically consist of basic components such as low-noise amplifiers, mixers, intermediate frequency filters, gain amplifiers, and video output modules to achieve signal reception and processing functions. However, in practical applications, some signals are prone to interfering with other sensitive circuits, affecting signal quality and system stability; furthermore, related devices may experience noise and distortion in the output signal due to electromagnetic interference during operation. Therefore, electromagnetic shielding is necessary to address signal interference issues. Traditional designs are often inadequate in terms of electromagnetic shielding, making it difficult to fully guarantee the reliable operation of the module in complex electromagnetic environments, thus limiting the improvement of the overall performance of microwave receiving modules and the expansion of their application scope. Utility Model Content

[0003] According to one aspect of this application, a microwave receiving module is provided that avoids external interference from adversely affecting the local oscillator signal and the detection process, thereby ensuring that the microwave receiving module can still work stably in complex electromagnetic environments.

[0004] A microwave receiving module includes a phase-coupled low-noise amplifier, a mixer, an intermediate frequency filter, a gain amplifier, and a video output module, characterized in that the mixer is further connected to a local oscillator module, and the video output module includes a detector.

[0005] Both the local oscillator module and the detector are surrounded by metal shielding covers. The metal shielding covers are connected to the continuous ground plane layer of the PCB board by welding or conductive adhesive strips. The PCB board is a multilayer PCB board, and the ground plane layer is an independent copper-clad layer in the multilayer PCB board.

[0006] A via array is provided below the ground plane in the local oscillator module and detector area, wherein the spacing between adjacent vias in the via array is less than or equal to 1 / 20 of the operating wavelength;

[0007] The metal shield is a copper cavity, the inner wall of the metal shield is attached with a wave-absorbing layer, and the metal shield is provided with honeycomb-shaped ventilation holes.

[0008] Furthermore, the grounding of the metal shield, the local oscillator module, and the detector is a star topology grounding, and the independent grounding nodes of the star topology grounding converge to the single-point grounding position of the power input terminal;

[0009] A ferrite bead is connected in series in the star grounding path to suppress high-frequency noise coupling.

[0010] Furthermore, the power layer and the ground layer of the PCB board are separated by slotting to form an independent power supply path;

[0011] Both the local oscillator module and the low-noise amplifier are equipped with low-noise LDO regulators.

[0012] Furthermore, the diameter of the honeycomb ventilation holes is ≤5mm, and the spacing between the holes is ≥10mm;

[0013] The total opening area of ​​the honeycomb ventilation holes accounts for 5%-10% of the surface area of ​​the shielding cover, and avoids the radiation direction of the local oscillator signal generated by the local oscillator module.

[0014] Furthermore, the low-noise amplifier is connected to a mixer; the mixer also acquires the local oscillator signal from the local oscillator module, which is used to mix the amplified radio frequency pulse signal to generate an intermediate frequency pulse signal.

[0015] The input terminal of the intermediate frequency filter is connected to the output terminal of the mixer, and is used to filter the intermediate frequency pulse signal;

[0016] The input terminal of the gain amplifier is connected to the output terminal of the intermediate frequency filter, and is used to amplify the gain of the filtered intermediate frequency pulse signal.

[0017] The video output module also includes an operational amplifier. The detector and the operational amplifier are connected in sequence. The input terminal of the detector is connected to the output terminal of the gain amplifier. The detector demodulates the amplified intermediate frequency pulse signal into a baseband video pulse, which is then buffered or shaped by the operational amplifier to output the video signal.

[0018] Furthermore, a bandpass filter is also connected to the input of the low-noise amplifier;

[0019] The bandpass filter is a surface acoustic wave filter or a bulk acoustic wave filter.

[0020] Furthermore, the mixer is a double-balanced mixer;

[0021] The intermediate frequency filter is a MEMS filter.

[0022] Furthermore, the detector output terminal is provided with a ground isolation line, and the distance between the ground isolation line and the adjacent radio frequency signal line is greater than 3 times the line width.

[0023] The beneficial effects that this application can produce include:

[0024] The microwave receiving module provided in this application features a metal shield surrounding the local oscillator module and detector, providing them with an independent electromagnetic environment. The metal shield blocks external electromagnetic interference signals, preventing adverse effects on the local oscillator signal output by the local oscillator module and the intermediate frequency signal detection process by the detector. This ensures the microwave receiving module can operate stably and accurately even in complex electromagnetic environments. Simultaneously, the metal shield is connected to the continuous ground plane of the PCB via soldering or conductive adhesive strips, effectively reducing impedance. This low-impedance grounding path quickly guides interference signals to ground, reducing their propagation and accumulation in the circuit, further enhancing the module's anti-interference capability and improving signal transmission quality and stability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the principle of a microwave receiving module in one embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of a metal shielding cover in one embodiment of this application;

[0027] Figure 3 This is a structural diagram of a PCB board according to one embodiment of this application;

[0028] Figure 4 This is a grounding diagram of a star topology grounding method in one embodiment of this application;

[0029] List of components and figures: 1-Low noise amplifier; 2-Mixer; 3-Intermediate frequency filter; 4-Gain amplifier; 5-Local oscillator module; 6-Detector; 7-Metal shield; 8-Absorbing layer; 9-Honeycomb ventilation holes; 10-PCB board; 11-Operational amplifier; 12-Bandpass filter. Detailed Implementation

[0030] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0031] See Figure 1-3 A microwave receiving module includes a low-noise amplifier 1, a mixer 2, an intermediate frequency filter 3, a gain amplifier 4, and a video output module, wherein the mixer 2 is further connected to a local oscillator module 5, and the video output module includes a detector 6.

[0032] Both the local oscillator module 5 and the detector 6 are surrounded by a metal shield 7. The metal shield 7 is connected to the continuous ground plane layer of the PCB board 10 by welding or conductive adhesive strips. The PCB board 10 is a multilayer PCB board, and the ground plane layer is an independent copper-clad layer in the multilayer PCB board.

[0033] An array of vias is provided below the ground plane layer in the region of the local oscillator module 5 and the detector 6, and the spacing between adjacent vias in the via array is less than or equal to 1 / 20 of the operating wavelength.

[0034] The metal shield 7 is a copper cavity, and the inner wall of the metal shield 7 is attached with a wave-absorbing layer 8, and the metal shield 7 is provided with honeycomb-shaped ventilation holes 9.

[0035] Specifically, this microwave receiving module effectively suppresses electromagnetic interference and ensures signal integrity through a multi-layered electromagnetic compatibility design. The metal shielding cover is a copper cavity, using highly conductive copper material to significantly reduce electromagnetic radiation in high-frequency bands, such as the X-band 8-12GHz. The aperture design of the honeycomb ventilation holes must meet the λ / 20 rule (λ is the operating wavelength). For example, for a 10GHz signal wavelength λ = 3cm, the aperture must be ≤1.5mm to avoid leakage. The honeycomb structure increases porosity through hexagonal arrangement, improving ventilation efficiency while maintaining shielding effectiveness. Ferrite-based absorbing materials are attached to the inner wall of the absorbing layer, such as... MFS-117 reduces cavity resonance. The absorbing layer thickness must be ≥λ / 4 (approximately 7.5mm for 10GHz) to achieve complete electromagnetic wave absorption. An independent copper layer (≥35μm thickness) is used in the multilayer PCB as a low-impedance reference plane to reduce ground bounce noise. Interlayer electrical connections are achieved through 0.5mm diameter vias with an impedance of approximately 1mΩ to meet high-speed signal return requirements. The spacing between adjacent vias is ≤λ / 10 (≤3mm for 10GHz) to create a Faraday cage effect and suppress vertical electromagnetic leakage. A via density of ≥50 vias / cm² is recommended. 2 In sensitive areas, such as below the local oscillator module, the number of holes / cm can be increased to 100. 2 This enhances the continuity of shielding.

[0036] It is worth noting that metal shields can be used to surround the interference sources of components, circuits, assemblies, or the entire system to prevent the interfering electromagnetic field from spreading outward; metal shields can also be used to surround receiving circuits, equipment, or systems to prevent them from being affected by external electromagnetic fields.

[0037] The conductive adhesive strip uses a sealant such as Chomerics CHO-BOND 536, with a volume resistivity ≤0.001Ω·cm, which is suitable for differences in thermal expansion coefficients.

[0038] The grounding of the metal shield 7, the local oscillator module 5 and the detector 6 is a star topology grounding, and the independent grounding nodes of the star topology grounding converge to the single-point grounding position of the power input terminal.

[0039] A ferrite bead is connected in series in the star grounding path to suppress high-frequency noise coupling.

[0040] Specifically, star topology grounding is a grounding method in which each component requiring grounding (such as the metal shield 7, local oscillator module 5, and detector 6 in this embodiment) has its own independent grounding path. These independent grounding paths eventually converge to a common grounding point, namely the single-point grounding location at the power input terminal. Since each component has an independent grounding path, grounding loops caused by sharing a grounding wire between different components are avoided, thereby reducing interference signals in the grounding loop and improving the electromagnetic compatibility of the system. Independent grounding paths reduce noise coupling between components, helping to improve the system's signal-to-noise ratio and ensuring accurate signal transmission and processing. A ferrite bead is connected in series in the star grounding path; its main function is to suppress high-frequency noise coupling. A ferrite bead is a component with resistive-inductive characteristics; at high frequencies, it exhibits high impedance, equivalent to a low-pass filter. When high-frequency noise signals attempt to propagate through the grounding path, the ferrite bead significantly impedes these high-frequency noises, effectively suppressing the coupling and propagation of high-frequency noise in the grounding path. Specifically, the equivalent impedance of a ferrite bead increases with frequency. For high-frequency noise signals, the ferrite bead can convert its energy into heat, significantly attenuating the amplitude of the noise signal. By suppressing high-frequency noise coupling, the ferrite bead helps maintain the purity of the grounding path, reducing the impact of noise on components such as the metal shield, local oscillator module, and detector, thereby improving the signal quality of the entire system.

[0041] In practical applications, to ensure the effectiveness of star topology grounding and ferrite bead series connection, the parameters of the ferrite bead (such as impedance and rated current) should be reasonably selected based on factors such as the system's operating frequency, noise characteristics, and the current magnitude of the grounding path. If the impedance of the ferrite bead is too low, it may not be able to effectively suppress high-frequency noise; if the impedance is too high, it may affect the transmission of normal signals. Star topology grounding requires reliable connection of each independent grounding path and low contact resistance. Otherwise, poor grounding may lead to a deterioration in grounding effect or even introduce new interference. When laying out and routing on the circuit board, the length of the grounding path should be shortened as much as possible to reduce the inductance of the grounding wire. At the same time, avoid running the grounding wire parallel to other signal lines to reduce mutual interference.

[0042] The power layer and the ground plane layer of the PCB board 10 are separated by slotting to form an independent power supply path;

[0043] Both the local oscillator module 5 and the low-noise amplifier 1 are equipped with low-noise LDO regulators.

[0044] Specifically, in PCB design, power and ground planes are critical components of signal return paths and power distribution networks. By creating slots between power and ground planes, independent power supply paths can be formed. In high-speed circuits, current variations between power and ground generate electromagnetic radiation. Slotting isolates the power paths of different circuit modules, reducing current coupling between them and thus lowering electromagnetic interference (EMI). For example, suppose a PCB contains digital and analog circuits with different sensitivities to power supply noise. By slotting between the power and ground planes, the power paths of the digital and analog circuits are separated, preventing noise from the digital circuits from coupling into the analog circuits and improving the system's electromagnetic compatibility (EMC). Simultaneously, independent power supply paths reduce the inductance and resistance of the power path, lowering power supply noise and voltage fluctuations. Each independent path can be optimized for a specific circuit module, ensuring a stable power supply. For high-frequency circuits, power supply noise has a significant impact on signal quality. Slotting provides independent, low-inductance power paths for high-frequency circuit modules, reducing power supply noise interference with signals. Slotting reduces the loop area of ​​the signal return path, thereby decreasing electromagnetic radiation and crosstalk. Simultaneously, independent power supply paths reduce the impact of power supply noise on the signal, improving signal quality.

[0045] It's worth noting that a low-noise LDO (Low Dropout) regulator is a device used to provide a stable, low-noise power supply. Configuring a low-noise LDO regulator in the local oscillator module and low-noise amplifier allows the LDO regulator to stabilize the output voltage through feedback control, while its internal design suppresses power supply noise. The low-noise LDO regulator further optimizes noise performance, providing a cleaner power supply for sensitive circuits. The local oscillator module and low-noise amplifier are particularly sensitive to power supply noise, which directly affects their performance. By configuring a low-noise LDO regulator, the impact of power supply noise on the local oscillator module and low-noise amplifier can be reduced, improving the system's signal-to-noise ratio and sensitivity. Simultaneously, the LDO regulator has low output voltage fluctuations, maintaining output voltage stability when the input voltage or load changes. The low-noise LDO regulator further improves power supply stability, providing a more reliable power supply to the circuit. In environments with large power supply voltage fluctuations, the low-noise LDO regulator ensures a stable power supply for the local oscillator module and low-noise amplifier, avoiding performance degradation caused by power supply fluctuations.

[0046] The diameter of the honeycomb ventilation holes 9 is ≤5mm, and the spacing between the holes is ≥10mm;

[0047] The total opening area of ​​the honeycomb ventilation holes 9 accounts for 5%-10% of the surface area of ​​the shielding cover, and avoids the radiation direction of the local oscillator signal generated by the local oscillator module 5.

[0048] Specifically, in the field of electromagnetic shielding, smaller apertures can effectively block the propagation of electromagnetic waves. When electromagnetic waves encounter holes much smaller than their wavelength, they are less likely to diffract and penetrate the shielding structure. Generally, for common electromagnetic interference frequency ranges, apertures of 5mm or less can effectively prevent electromagnetic wave leakage, thus ensuring that the shielding cover effectively shields the electromagnetic radiation generated by internal electronic components, reducing interference to surrounding equipment, and preventing external electromagnetic interference from entering the shielding cover and affecting the normal operation of internal components. Smaller apertures also provide some protection, preventing dust, moisture, small insects, and other foreign objects from entering the shielding cover. If these foreign objects enter the shielding cover, they may adhere to the surface of electronic components, affecting their heat dissipation performance and even causing short circuits, affecting the normal operation of the equipment.

[0049] Sufficient hole spacing ensures the structural strength of the shielding cover. If the hole spacing is too small, creating numerous honeycomb-shaped ventilation holes on the shielding cover may lead to a decrease in localized strength, making it prone to deformation or even damage under external impact or vibration, thus affecting its electromagnetic shielding performance and overall reliability. Appropriate hole spacing helps create good airflow channels between the ventilation holes, ensuring effective air exchange between the inside and outside of the shielding cover and achieving heat dissipation. If the hole spacing is too small, airflow may be obstructed, reducing ventilation and heat dissipation efficiency.

[0050] Furthermore, electronic devices generate heat during operation, requiring ventilation holes for heat dissipation. A total opening area within this range ensures sufficient airflow through the shielding cover to dissipate internal heat promptly, maintaining the normal operating temperature of internal components. If the opening area is too small, heat dissipation will be ineffective, potentially leading to overheating of components and affecting their performance and lifespan. Conversely, while a large opening area may provide better heat dissipation, it reduces the electromagnetic shielding performance of the shielding cover, increasing the risk of electromagnetic leakage. Therefore, while meeting heat dissipation requirements, electromagnetic shielding performance must also be considered. A 5%-10% opening area ratio minimizes electromagnetic wave leakage while ensuring adequate heat dissipation, effectively protecting the shielding cover from electromagnetic interference.

[0051] The local oscillator signal generated by the local oscillator module 5 is essential for the normal operation of the equipment. However, if the ventilation holes are located in the radiation direction of the local oscillator signal, the signal may leak out, interfering with other surrounding electronic equipment and affecting the electromagnetic compatibility of the entire system. Simultaneously, external electromagnetic interference may also enter the metal shielding through these ventilation holes, interfering with the local oscillator signal and causing a decrease in signal quality. This, in turn, affects the overall performance of the equipment, such as reduced receiving sensitivity and transmitted signal distortion. By rationally designing the location of the ventilation holes to avoid the radiation direction of the local oscillator signal, this interference can be effectively reduced, ensuring the stability and accuracy of the local oscillator signal. This ensures the equipment can operate normally and reliably in complex electromagnetic environments, improving its performance and reliability.

[0052] The low-noise amplifier 1 is connected to the mixer 2; the mixer 2 also acquires the local oscillator signal from the local oscillator module 5, which is used to mix the amplified radio frequency pulse signal to generate an intermediate frequency pulse signal.

[0053] The input terminal of the intermediate frequency filter 3 is connected to the output terminal of the mixer 2, and is used to filter the intermediate frequency pulse signal;

[0054] The input terminal of the gain amplifier 4 is connected to the output terminal of the intermediate frequency filter 3, and is used to perform gain amplification processing on the filtered intermediate frequency pulse signal;

[0055] The video output module also includes an operational amplifier 11. The detector 6 and the operational amplifier 11 are connected in sequence. The input terminal of the detector 6 is connected to the output terminal of the gain amplifier 4. The detector 6 demodulates the amplified intermediate frequency pulse signal into a baseband video pulse, which is then buffered or shaped by the operational amplifier 11 to output the video signal.

[0056] Specifically, the low-noise amplifier 1, as the starting point of the signal processing chain, primarily amplifies the received weak radio frequency (RF) pulse signal. Low-noise design is crucial, aiming to minimize its own noise introduction while amplifying the signal, thereby improving the overall system's signal-to-noise ratio and providing a high-quality signal source for subsequent processing. Mixer 2 receives the amplified RF pulse signal from the low-noise amplifier 1 and simultaneously acquires the local oscillator signal from the local oscillator module 5. By mixing the RF signal and the local oscillator signal, the frequency of the RF signal is converted to an intermediate frequency (IF) signal using the characteristics of nonlinear components—a process known as down-conversion. The mixed output contains sum and difference frequency components; typically, the desired difference frequency component (IF pulse signal) is selected through filtering. The input of the intermediate frequency filter 3 is connected to the output of mixer 2. Filtering the generated IF pulse signal removes the sum frequency component and other spurious signals and noise generated during mixing, preserving a clean IF signal. The filter's bandwidth must match the bandwidth of the IF signal to ensure signal integrity while effectively suppressing out-of-band interference. The input of the gain amplifier 4 is connected to the output of the intermediate frequency filter 3. The filtered intermediate frequency (IF) pulse signal is further amplified to compensate for signal loss that may be introduced during mixing and filtering, while also improving the signal's driving capability to meet the input level requirements of subsequent modules such as detector 6. The input terminal of detector 6 is connected to the output terminal of gain amplifier 4. The amplified IF pulse signal is demodulated into a baseband video pulse. Detectors typically use envelope detection or synchronous detection to extract the amplitude information of the IF signal and reconstruct the original modulation signal (baseband video pulse). Operational amplifier 11 is connected after detector 6 to buffer the baseband video pulse output by detector 6, isolating the preceding and following circuits to prevent mutual interference; it can also perform signal shaping as needed, such as adjusting the pulse rise / fall time and amplitude, to ensure that the output video signal meets the requirements of subsequent processing or display devices.

[0057] The input terminal of the low-noise amplifier 1 is also connected to a bandpass filter 12;

[0058] The bandpass filter 12 is a surface acoustic wave filter or a bulk acoustic wave filter.

[0059] Specifically, in a real electromagnetic environment, the signal received by the low-noise amplifier 1 often contains various frequency components. In addition to the desired useful radio frequency signal, there may also be a large number of out-of-band interference signals, such as communication signals in adjacent frequency bands. The bandpass filter 12 can selectively allow signals in a specific frequency band (i.e., the frequency band where the useful radio frequency signal is located) to pass through, while significantly attenuating interference signals in other frequency bands. This is equivalent to setting a "screening gate" for the signal, allowing only signals that meet the frequency requirements to enter the low-noise amplifier 1, thereby reducing the impact of interference signals on subsequent processing stages and improving the signal-to-noise ratio of the system.

[0060] It is worth noting that surface acoustic wave (SAW) filters utilize the propagation characteristics of SAW waves on piezoelectric substrates to achieve filtering functionality. They offer high-precision selection of specific frequency signals, possess a narrow bandwidth, and exhibit a steep frequency response curve. This allows for more effective suppression of out-of-band interference signals, improving the system's anti-interference capability.

[0061] Bulk acoustic wave (BAW) filters utilize the resonant characteristics of bulk acoustic waves in a piezoelectric thin film to achieve filtering. They possess a high quality factor and exhibit minimal signal attenuation during filtering, meaning low insertion loss. Low insertion loss ensures that more useful signals can pass through the filter and enter the low-noise amplifier, improving the system's sensitivity.

[0062] The mixer 2 is a double-balanced mixer;

[0063] The intermediate frequency filter 3 is a surface acoustic wave filter or a bulk acoustic wave filter.

[0064] Specifically, a double-balanced mixer employs two balanced circuits, which effectively suppresses spurious components of the input signal and leakage of the local oscillator signal, improving the mixer's linearity and anti-interference capability. A double-balanced mixer can effectively suppress spurious components of the input signal, improving the mixer's dynamic range and sensitivity. A double-balanced mixer has wide bandwidth characteristics, allowing mixing operations over a relatively wide frequency range.

[0065] The detector 6 output terminal is provided with a ground isolation line, and the distance between the ground isolation line and the adjacent radio frequency signal line is greater than 3 times the line width.

[0066] Specifically, in high-speed or radio frequency (RF) circuits, electromagnetic coupling can occur between signal lines. The detector output signal may carry certain frequency components, and adjacent RF signal lines may also radiate electromagnetic energy. Grounding isolation lines act like an "electromagnetic barrier," effectively blocking interference from RF signal lines to the detector output signal, while also preventing the detector output signal from having a reverse effect on the RF signal lines, thus ensuring signal integrity and accuracy.

[0067] The grounding shield, typically composed of a grounding conductor, wraps around the signal line. From an electromagnetic field theory perspective, the grounding conductor guides the electromagnetic field, distributing it along its surface. When the radio frequency signal line radiates electromagnetic waves, the grounding shield reflects most of these waves back towards the signal line or guides them to ground, thus reducing the impact on the detector's output signal. Simultaneously, the grounding shield also acts as a shield for the detector's output signal, preventing external interference signals from entering.

[0068] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A microwave receiving module, comprising a phase-coupled low-noise amplifier (1), a mixer (2), an intermediate frequency filter (3), a gain amplifier (4), and a video output module, characterized in that, The mixer (2) is also connected to a local oscillator module (5), and the video output module includes a detector (6); The local oscillator module (5) and the detector (6) are both provided with metal shielding covers (7). The metal shielding covers (7) are connected to the ground plane layer of the PCB board (10) by welding or conductive adhesive strips. The PCB board (10) is a multilayer PCB board, and the ground plane layer is an independent copper-clad layer in the multilayer PCB board. An array of vias is provided below the ground plane layer in the region of the local oscillator module (5) and the detector (6), and the spacing between adjacent vias in the via array is less than or equal to 1 / 20 of the operating wavelength; The metal shield (7) is a copper cavity, and the inner wall of the metal shield (7) is attached with a wave-absorbing layer (8), and the metal shield (7) is provided with honeycomb ventilation holes (9).

2. The microwave receiving module according to claim 1, characterized in that, The grounding of the metal shield (7), the local oscillator module (5) and the detector (6) is a star topology grounding, and the independent grounding nodes of the star topology grounding converge to the single-point grounding position of the power input terminal; A ferrite bead is connected in series in the star grounding path to suppress high-frequency noise coupling.

3. The microwave receiving module according to claim 2, characterized in that, The power layer and the ground plane layer of the PCB board (10) are separated by slotting to form an independent power supply path; Both the local oscillator module (5) and the low-noise amplifier (1) are equipped with low-noise LDO regulators.

4. The microwave receiving module according to claim 1, characterized in that, The diameter of the honeycomb ventilation holes (9) is ≤5mm and the spacing between the holes is ≥10mm; The total opening area of ​​the honeycomb ventilation holes (9) accounts for 5%-10% of the surface area of ​​the shield, and avoids the radiation direction of the local oscillator signal generated by the local oscillator module (5).

5. The microwave receiving module according to claim 1, characterized in that, The low-noise amplifier (1) is connected to the mixer (2); the mixer (2) also acquires the local oscillator signal from the local oscillator module (5) and uses it to mix the amplified radio frequency pulse signal to generate an intermediate frequency pulse signal; The input terminal of the intermediate frequency filter (3) is connected to the output terminal of the mixer (2) for filtering the intermediate frequency pulse signal; The input terminal of the gain amplifier (4) is connected to the output terminal of the intermediate frequency filter (3) for gain amplification of the filtered intermediate frequency pulse signal; The video output module also includes an operational amplifier (11). The detector (6) and the operational amplifier (11) are connected in sequence. The input terminal of the detector (6) is connected to the output terminal of the gain amplifier (4). The detector (6) demodulates the amplified intermediate frequency pulse signal into a baseband video pulse, which is then buffered or shaped by the operational amplifier (11) to output a video signal.

6. The microwave receiving module according to claim 4, characterized in that, The input terminal of the low-noise amplifier (1) is also connected to a bandpass filter (12); The bandpass filter (12) is a surface acoustic wave filter or a bulk acoustic wave filter.

7. The microwave receiving module according to claim 4, characterized in that, The mixer (2) is a double-balanced mixer; The intermediate frequency filter (3) is a MEMS filter.

8. The microwave receiving module according to claim 4, characterized in that, The detector (6) output terminal is provided with a ground isolation line, and the distance between the ground isolation line and the adjacent radio frequency signal line is greater than 3 times the line width.

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