Electromagnetic protection amplitude limiter and amplitude limiting method thereof

Abstract

The electromagnetic protection amplitude limiter comprises a waveguide plasma amplitude limiter, a solid-state PIN tube amplitude limiter and a third-stage amplitude limiting assembly, the waveguide plasma amplitude limiter is connected with the solid-state PIN tube amplitude limiter in series, the solid-state PIN tube amplitude limiter is connected with the third-stage amplitude limiting assembly in series, and the solid-state PIN tube amplitude limiter is connected with the third-stage amplitude limiting assembly in series. The third-stage amplitude limiting assembly comprises a microwave switch A, a low-noise amplifier, a fixed attenuator and a microwave switch B. The low-noise amplifier and the fixed attenuator are connected in parallel, the microwave switch A is connected with the input end of the low-noise amplifier and the input end of the fixed attenuator in series, and the microwave switch B is connected with the output end of the low-noise amplifier and the output end of the fixed attenuator in series. The waveguide plasma amplitude limiter and the solid PIN tube amplitude limiter are connected in series, and the microwave switch adopts a series-parallel structural design, so that the problems of long response time and large peak leakage power of the plasma amplitude limiter are solved, and the electromagnetic protection amplitude limiting requirement that an amplitude limiting level does not cause damage to a low-noise amplifier or a post-stage circuit is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic protection, and in particular relates to an electromagnetic protection limiter and a limiting method thereof. Background Art

[0002] With the development and application of modern warfare electronic countermeasure technology and high-power microwave weapons (HPMW), radar detection equipment needs to have high-power microwave electromagnetic protection capabilities in complex electronic environments. High-power microwave (HPM) electromagnetic protection technology mainly includes the "front door" protection technology and "back door" protection technology of the receiver's RF front end. Among them, the "front door" protection technology, as the core technology of electromagnetic protection, has been widely valued in various types of radar detection equipment. The "front door" protection technology mainly limits the HPM electromagnetic interference signal by adding a limiter to the front end of the receiver, thereby protecting the normal operation of the receiver. At present, there are two main types of limiters: plasma limiters and solid-state PIN tube limiters.

[0003] However, the "front door" protection of radar detection equipment using plasma limiters and solid-state PIN tube limiters has the following technical defects:

[0004] 1. The plasma limiter has defects such as high and unreliable threshold, long response time, and complex assembly and processing, and cannot attenuate instantaneous interference and interference signals with low power.

[0005] 2. The solid-state PIN tube limiter has defects such as low power capacity and fast response time resulting in low threshold value. It cannot effectively attenuate high-power interference signals, and strong signals cannot pass into the receiver without compression.

[0006] For example, the patent document with publication number CN114866051A specifically discloses a VHF band limiter and a limiting method thereof, including a first-stage limiting circuit, a second-stage limiting circuit, and a third-stage limiting circuit electrically connected in sequence through a delay line, and the delay phase of the delay line between the first-stage limiting circuit and the second-stage limiting circuit is 90°, which can ensure impedance matching between the power signal input end and the load end of the first-stage limiting circuit, so that most of the power of the high-power input signal flows into the load end, thereby realizing the limiting function; limiting the length of the delay line can reduce the influence of the delay line on high-power standing waves and power leakage; limiting the thickness of the delay line and the distance from the cavity to ensure the power capacity of the limiter and reduce insertion loss; the delay line with limited length, thickness and distance from the cavity can make the power signal delayed by the delay line to achieve delay and frequency band matching in the very high frequency band.

[0007] In summary, the existing technology still cannot completely solve the above technical defects, and the adopted technical solutions are relatively complex, with high requirements for operation, and cannot meet the requirements of large-capacity, fast-response, and high-power electromagnetic protection limiting. Therefore, it is necessary to design an electromagnetic protection limiter that can overcome the above technical defects and meet the requirements of large-capacity, fast-response, and high-power electromagnetic protection limiting. Summary of the invention

[0008] To solve the above technical problems, the present application provides an electromagnetic protection limiter, comprising: a waveguide plasma limiter, a solid-state PIN tube limiter and a third-stage limiting component, the waveguide plasma limiter is connected in series with the solid-state PIN tube limiter, the solid-state PIN tube limiter is connected in series with the third-stage limiting component, the third-stage limiting component comprises a microwave switch A, a low-noise amplifier, a fixed attenuator and a microwave switch B, the low-noise amplifier and the fixed attenuator are connected in parallel, the microwave switch A is connected in series with the input ends of the low-noise amplifier and the fixed attenuator, and the microwave switch B is connected in series with the output ends of the low-noise amplifier and the fixed attenuator.

[0009] Furthermore, the waveguide plasma limiter includes a resonant window, an inductive diaphragm, an upper electrode, a lower electrode and a sealing medium, wherein the upper electrode is arranged above the lower electrode and two groups are arranged in parallel, the inductive diaphragm is arranged on the left and right sides of the upper electrode and the lower electrode, the resonant window is parallel to the inductive diaphragm and arranged in front of the first group of inductive diaphragms, and the sealing medium is parallel to the inductive diaphragm and arranged behind the second group of inductive diaphragms.

[0010] Furthermore, the solid-state PIN tube limiter includes a shell ground, a choke inductor, a dielectric block, a PIN tube core, a DC blocking capacitor, a microstrip and a coaxial core. Three dielectric blocks are arranged side by side and spaced apart on the shell ground. Microstrips are arranged on the dielectric blocks. The PIN tube core is arranged in the gap between the dielectric blocks. DC blocking capacitors are arranged on the left microstrip and the right microstrip. The PIN tube core is connected to the microstrip through a gold wire. A coaxial core is arranged at the left end of the left microstrip, a coaxial core is arranged at the right end of the right microstrip, and the choke inductor is arranged on the middle microstrip.

[0011] Furthermore, the waveguide plasma limiter attenuates the HPM electromagnetic interference signal of 63dBm-73dBm.

[0012] Furthermore, the solid-state PIN tube limiter attenuates the peak leakage and the flat-top leakage of the waveguide plasma limiter, and attenuates the HPM electromagnetic interference signal that is lower than the start threshold of the solid-state PIN tube limiter.

[0013] Furthermore, the threshold lower than the solid-state PIN tube limiter start-up threshold is 63 dBm.

[0014] Furthermore, the low noise amplifier amplifies the HPM electromagnetic interference signal below 0 dBm, thereby ensuring the noise coefficient, dynamic range and stable output of the minimum detectable signal of the receiving system.

[0015] Furthermore, the fixed attenuator attenuates electromagnetic interference signals greater than 0dBmHPM, with an attenuation of 30dB.

[0016] Furthermore, the microwave switch A implements channel switching of the HPM electromagnetic interference signal according to the synchronously input wave gate signal.

[0017] Another object of the present invention is to provide a limiting method for the electromagnetic protection limiter, comprising the following steps:

[0018] After the HPM electromagnetic pulse interference signal enters the receiver RF front end, the waveguide plasma limiter determines whether the HPM electromagnetic pulse interference signal needs to be attenuated. The specific determination method is as follows:

[0019] When the HPM electromagnetic interference signal is less than 63 dBm, the waveguide plasma limiter has no attenuation on the signal, and the HPM electromagnetic interference signal directly enters the solid-state PIN tube limiter;

[0020] When the HPM electromagnetic interference signal is greater than 63 dBm, the waveguide plasma limiter attenuates the signal to make the HPM electromagnetic interference signal less than 63 dBm, so that the signal enters the solid-state PIN tube limiter for further attenuation;

[0021] After the HPM electromagnetic pulse interference signal is attenuated by the solid-state PIN tube limiter, the microwave switch A determines and switches the next processing channel of the HPM electromagnetic pulse interference signal. The specific switching method is as follows:

[0022] When the output signal power of the solid-state PIN tube limiter is greater than 0 dBm, the microwave switch A opens the fixed attenuator channel to attenuate the HPM electromagnetic pulse interference signal again, and after attenuation by 30 dB, the signal is finally output through the microwave switch B;

[0023] When the output signal power of the solid-state PIN tube limiter is below 0 dBm, the microwave switch A turns on the low-noise amplifier to amplify the HPM electromagnetic pulse interference signal to ensure the stability of the noise coefficient, dynamic range and minimum detectable signal index of the HPM electromagnetic pulse interference signal, and finally outputs it through the microwave switch B.

[0024] The beneficial effects of the present invention are:

[0025] 1. By connecting the waveguide plasma limiter and the solid-state PIN tube limiter in series, the high power capacity of the waveguide plasma limiter is used to protect the 73dBm HPM electromagnetic interference signal. The short response time of the solid-state PIN tube limiter is used to solve the problems of long response time and high peak leakage power of the plasma limiter. The limiter power capacity reaches 73dBm (20kW), the response time is less than 5ns, the threshold is higher than 16dBm, and the insertion loss is less than 2dB.

[0026] 2. The solid-state PIN tube limiter is designed with a high 1dB compression point, so that the strong echo signal can pass through the protection circuit without loss, ensuring the signal quality;

[0027] 3. By adopting the series-parallel structure design of the microwave switch, when the system is not powered on, the microwave switch has a large isolation degree, ensuring that the limiting level will not cause damage to the low-noise amplifier or the subsequent circuit;

[0028] 4. The radar detection equipment receiver can effectively suppress short-pulse high-power electromagnetic interference signals with a pulse width of more than ten nanoseconds, while being able to normally receive the strong echo signal reflected by the target irradiated by the signal, solving the problems of the traditional front door protection limiter such as long response time, large peak leakage, small power capacity, and too low threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a block diagram of the composition of an electromagnetic protection limiter provided according to an embodiment of the present invention;

[0030] Figure 2 is a schematic structural diagram of a waveguide plasma limiter simulation model provided in an embodiment of the present invention;

[0031] Figure 3 It is a structural schematic diagram of a simulation model of a solid-state PIN tube limiter provided in an embodiment of the present invention;

[0032] Figure 4 is a diagram of insertion loss simulation results of a waveguide plasma limiter provided in an embodiment of the present invention;

[0033] Figure 5 is a comparison diagram of the activated and non-activated states of the response test results of the waveguide plasma limiter provided by an embodiment of the present invention;

[0034] Figure 6 is a diagram of the insertion loss simulation result of the solid-state PIN tube limiter provided in an embodiment of the present invention;

[0035] Figure 7 2 is a schematic diagram of a peak leakage characteristic of a parameter characteristic test result of a solid-state PIN tube limiter provided in an embodiment of the present invention;

[0036] Figure 8 It is a schematic diagram of the recovery time characteristics of the parameter characteristic test results of the solid-state PIN tube limiter provided according to an embodiment of the present invention.

[0037] Explanation of the accompanying drawings: 1-waveguide plasma limiter, 2-solid-state PIN tube limiter, 3-microwave switch A, 4-low noise amplifier, 5-fixed attenuator, 6-microwave switch B, 7-resonance window, 8-inductor diaphragm, 9-upper electrode, 10-lower electrode, 11-sealing medium, 12-shell ground, 13-choke inductor, 14-dielectric block, 15-PIN tube core, 16-DC blocking capacitor, 17-microstrip, 18-coaxial core, 19-gold wire. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0039] The embodiment of the present invention provides an electromagnetic protection limiter and a limiting method thereof. A waveguide plasma limiter 1 and a solid-state PIN tube limiter 2 are connected in series, and the high power capacity characteristic of the waveguide plasma limiter is utilized to protect against a 73dBm HPM electromagnetic interference signal. The short response time characteristic of the solid-state PIN tube limiter is utilized to solve the problems of long response time and large peak leakage power of the plasma limiter. A microwave switch A3, a low-noise amplifier 4, a fixed attenuator 5 and a microwave switch B6 are designed in a series-parallel structure to ensure that the limiting level will not cause damage to the low-noise amplifier or a subsequent circuit.

[0040] The following is attached to the instruction manual Figure 1-8 The specific implementation of the present invention is described in detail.

[0041] An embodiment of the present invention provides an electromagnetic protection limiter, comprising: a waveguide plasma limiter 1, a solid-state PIN tube limiter 2 and a third-stage limiting component, wherein the waveguide plasma limiter 1 is connected in series with the solid-state PIN tube limiter 2, the solid-state PIN tube limiter 2 is connected in series with the third-stage limiting component, the third-stage limiting component comprises a microwave switch A3, a low-noise amplifier 4, a fixed attenuator 5 and a microwave switch B6, the low-noise amplifier 4 and the fixed attenuator 5 are connected in parallel, the microwave switch A3 is connected in series with the input ends of the low-noise amplifier 4 and the fixed attenuator 5, and the microwave switch B6 is connected in series with the output ends of the low-noise amplifier 4 and the fixed attenuator 5. The waveguide plasma limiter 1 and the solid-state PIN tube limiter 2 are connected in series and the high power capacity characteristic of the waveguide plasma limiter is utilized to protect against the HPM electromagnetic interference signal of 73dBm. The short response time characteristic of the solid-state PIN tube limiter is utilized to solve the problems of long response time and large peak leakage power of the plasma limiter. The microwave switch A3, the low noise amplifier 4, the fixed attenuator 5 and the microwave switch B6 are designed with a series-parallel structure. When the system is not powered on, the microwave switch has a large isolation degree to ensure that the limiting level will not cause damage to the low noise amplifier or the subsequent circuit. The microwave switch A3 is exactly the same as the microwave switch B6.

[0042] In this embodiment, the waveguide plasma limiter 1 includes a resonant window 7, an inductor diaphragm 8, an upper electrode 9, a lower electrode 10 and a sealing medium 11. The upper electrode 9 is arranged above the lower electrode 10 and two groups are arranged in parallel. The inductor diaphragm 8 is arranged on the left and right sides of the upper electrode 9 and the lower electrode 10. The resonant window 7 is parallel to the inductor diaphragm 8 and is arranged in front of the first group of inductor diaphragms 8. The sealing medium 11 is parallel to the inductor diaphragm 8 and is arranged behind the second group of inductor diaphragms 8. The waveguide plasma limiter 1 mainly attenuates the HPM electromagnetic interference signal above 63dBm and below 73dBm to protect the subsequent circuit from being burned. Its simulation model is shown in the attached figure. Figure 2 shown.

[0043] In the embodiment of the present invention, two waveguide plasma limiters 1, a resonant window 7 and a resonant gap with a cross-sectional size of 19.2mm×3mm are used. The resonant elements are separated by 1 / 4 of the waveguide wavelength, i.e., 9.75mm. The sealing window is made of high-frequency ceramic with a dielectric constant of 9.2, the discharge electrode material is tungsten, and the remaining materials are copper.

[0044] In the embodiment of the present invention, the simulation verification of the waveguide plasma limiter 1 is completed, and the insertion loss simulation result is as follows: Figure 4As shown in the figure, it can be seen that the insertion loss S21 of the waveguide plasma limiter 1 is less than 0.3dB within the working frequency range. At the same time, the response state of the waveguide plasma limiter 1 in the unactivated and activated states is tested. The comparison of the test results in the unactivated and activated states is shown in the figure below. Figure 5 shown.

[0045] In this embodiment, the solid-state PIN tube limiter 2 includes a shell ground 12, a choke inductor 13, a dielectric block 14, a PIN tube core 15, a DC blocking capacitor 16, a microstrip 17 and a coaxial core 18. The dielectric blocks 14 are arranged three side by side on the shell ground 12, and a microstrip 17 is arranged on the dielectric block 14. The PIN tube core 15 is arranged in the gap between the dielectric blocks 14. The DC blocking capacitor 16 is arranged on the left microstrip 17 and the right microstrip 17. The PIN tube core 15 is connected to the microstrip 17 through a gold wire 19. The coaxial core 18 is arranged at the left end of the left microstrip 17, and the coaxial core 18 is arranged at the right end of the right microstrip 17. The choke inductor 13 is arranged on the middle microstrip 17. Its simulation model is shown in the attached figure. Figure 3 As shown, the peak leakage and the flat-top leakage of the waveguide plasma limiter 1 are mainly attenuated, and the HPM electromagnetic interference signal below the start threshold is attenuated to protect the subsequent circuit from being burned.

[0046] In the embodiment of the present invention, the front-stage PIN tube adopts LA4607-000, whose maximum peak power is 67dBm, peak leakage power is 47dBm, and response time is less than 10ns; the rear-stage PIN tube adopts CLA4603-000, whose maximum peak power is 50dBm, no peak leakage power, response time is less than 5ns, and output flat-top power is 22dBm.

[0047] The embodiment of the present invention completes the simulation verification of the solid-state PIN tube limiter 2, and the insertion loss simulation result is as follows: Figure 6 As shown. Through simulation analysis, it is found that the insertion loss S21 of the solid-state PIN tube limiter 2 is less than 0.86dB within the working frequency band. At the same time, the parameters of the solid-state PIN tube limiter 2 are tested, and its peak leakage characteristics are shown in Figure 7 As shown, the recovery time characteristics are as follows Figure 8 shown.

[0048] In this embodiment, the waveguide plasma limiter 1 attenuates the HPM electromagnetic interference signal of 63dBm-73dBm.

[0049] In this embodiment, the solid-state PIN tube limiter 2 attenuates the peak leakage and the flat-top leakage of the waveguide plasma limiter 1 , and attenuates the HPM electromagnetic interference signal that is lower than the start threshold of the solid-state PIN tube limiter 2 .

[0050] In this embodiment, the value lower than the start threshold of the solid-state PIN tube limiter 2 is 63 dBm.

[0051] In this embodiment, the low noise amplifier 4 amplifies the HPM electromagnetic interference signal below 0 dBm to ensure the noise coefficient, dynamic range and stable output of the minimum detectable signal of the receiving system.

[0052] In this embodiment, the fixed attenuator 5 attenuates electromagnetic interference signals greater than 0dBmHPM with an attenuation of 30dB. The fixed attenuator 5 is composed of a resistor attenuation network, which mainly attenuates the limiting level power output by the solid-state PIN tube limiter 2 to ensure the safety of the subsequent circuit, and at the same time attenuates the high-power strong echo signal to ensure that the subsequent circuit operates in a linear state.

[0053] In this embodiment, the microwave switch A3 realizes channel switching of the HPM electromagnetic interference signal according to the synchronously input wave gate signal; the microwave switch A3 is composed of series-parallel PIN tubes. When receiving a high-power microwave electromagnetic interference signal or an echo signal power greater than 0dBm, the microwave switch selects the fixed attenuator channel to protect the subsequent circuit from saturation or damage; when receiving a weak signal, the microwave switch selects the low-noise amplifier channel, which has the characteristics of low noise coefficient and high sensitivity.

[0054] The limiting method for the electromagnetic protection limiter provided in the embodiment of the present invention comprises the following steps:

[0055] After the HPM electromagnetic pulse interference signal enters the RF front end of the receiver, the waveguide plasma limiter 1 determines whether the HPM electromagnetic pulse interference signal needs to be attenuated. The specific determination method is as follows:

[0056] When the HPM electromagnetic interference signal is less than 63dBm, the waveguide plasma limiter 1 has no attenuation on the signal, and the HPM electromagnetic interference signal directly enters the solid-state PIN tube limiter 2; at this time, when the input power is less than the 1dB compression point of the solid-state PIN tube limiter 16dBm, the signal energy will not cause damage to the subsequent circuit. As the input power increases, the solid-state PIN tube limiter starts to limit, and the output limit level is 20dBm. After the signal is attenuated by 30dB by the fixed attenuator 5, the output power -8dBm signal enters the subsequent circuit of the receiving system to protect the subsequent circuit from being burned.

[0057] When the HPM electromagnetic interference signal is greater than 63dBm, the waveguide plasma limiter 1 attenuates the signal to make the HPM electromagnetic interference signal less than 63dBm, thereby entering the solid-state PIN tube limiter 2 for further attenuation; at this time, the waveguide plasma limiter 1 activates the limiter to attenuate the signal, and the solid-state PIN tube limiter 2 attenuates the peak leakage power and the flat-top leakage power output by the waveguide plasma limiter 1, and enters the subsequent circuit after passing through the fixed attenuator 5.

[0058] After the HPM electromagnetic pulse interference signal is attenuated by the solid-state PIN tube limiter 2, the microwave switch A3 determines to switch the next processing channel of the HPM electromagnetic pulse interference signal. The specific switching method is as follows:

[0059] When the output signal power of the solid-state PIN tube limiter 2 is greater than 0 dBm, the microwave switch A3 opens the fixed attenuator 5 channel to attenuate the HPM electromagnetic pulse interference signal again, and after attenuation by 30 dB, it is finally output through the microwave switch B6;

[0060] When the output signal power of the solid-state PIN tube limiter 2 is below 0 dBm, the microwave switch A3 turns on the low noise amplifier 4 to amplify the HPM electromagnetic pulse interference signal to ensure the stability of the noise coefficient, dynamic range and minimum detectable signal index of the HPM electromagnetic pulse interference signal, and finally outputs it through the microwave switch B6.

[0061] When the system is not powered on, microwave switch A3 is connected to the fixed attenuator 5 channel, and the HPM electromagnetic interference signal enters the fixed attenuator 5 after being attenuated by the waveguide plasma limiter 1 and the solid-state PIN tube limiter 2. At the same time, the open end of microwave switch A3 has an isolation of 15dB, and the signal with a limit level of 20dBm is attenuated by microwave switch A3, and the signal power input to the low noise amplifier 4 is 7dBm, which can ensure that the low noise amplifier 4 will not be damaged.

[0062] The above disclosure is only a specific embodiment of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An electromagnetic protection limiter, characterized in that: include: A waveguide plasma limiter (1), a solid-state PIN tube limiter (2) and a third-stage limiting component, wherein the waveguide plasma limiter (1) is connected in series with the solid-state PIN tube limiter (2), the solid-state PIN tube limiter (2) is connected in series with the third-stage limiting component, the third-stage limiting component comprises a microwave switch A (3), a low-noise amplifier (4), a fixed attenuator (5) and a microwave switch B (6), the low-noise amplifier (4) and the fixed attenuator (5) are connected in parallel, the microwave switch A (3) is connected in series with the input ends of the low-noise amplifier (4) and the fixed attenuator (5), and the microwave switch B (6) is connected in series with the output ends of the low-noise amplifier (4) and the fixed attenuator (5).

2. The electromagnetic protection limiter according to claim 1, characterized in that: The waveguide plasma limiter (1) comprises a resonant window (7), an inductor diaphragm (8), an upper electrode (9), a lower electrode (10) and a sealing medium (11); the upper electrode (9) is arranged above the lower electrode (10) and is arranged in two parallel groups; the inductor diaphragm (8) is arranged on the left and right sides of the upper electrode (9) and the lower electrode (10); the resonant window (7) is parallel to the inductor diaphragm (8) and is arranged in front of the first group of inductor diaphragms (8); the sealing medium (11) is parallel to the inductor diaphragm (8) and is arranged behind the second group of inductor diaphragms (8).

3. The electromagnetic protection limiter according to claim 1, characterized in that: The solid-state PIN tube limiter (2) comprises a housing ground (12), a choke inductor (13), a dielectric block (14), a PIN tube core (15), a DC blocking capacitor (16), a microstrip (17) and a coaxial core (18); three dielectric blocks (14) are arranged side by side and spaced apart on the housing ground (12); a microstrip (17) is arranged on the dielectric block (14); a PIN tube core (15) is arranged in the gap between the dielectric blocks (14); a DC blocking capacitor (16) is arranged on both the left microstrip (17) and the right microstrip (17); the PIN tube core (15) is connected to the microstrip (17) via a gold wire (19); a coaxial core (18) is arranged at the left end of the left microstrip (17); a coaxial core (18) is arranged at the right end of the right microstrip (17); and the choke inductor (13) is arranged on the middle microstrip (17).

4. The electromagnetic protection limiter according to claim 2, characterized in that: The waveguide plasma limiter (1) attenuates the HPM electromagnetic interference signal of 63dBm-73dBm.

5. The electromagnetic protection limiter according to claim 3, characterized in that: The solid-state PIN tube limiter (2) attenuates the peak leakage and the flat-top leakage of the waveguide plasma limiter (1), and attenuates the HPM electromagnetic interference signal that is lower than the start threshold of the solid-state PIN tube limiter (2).

6. The electromagnetic protection limiter according to claim 5, characterized in that: The value lower than the start threshold of the solid-state PIN tube limiter (2) is 63dBm.

7. The electromagnetic protection limiter according to claim 1, characterized in that: The low noise amplifier (4) amplifies the HPM electromagnetic interference signal below 0 dBm, thereby ensuring the stable output of the noise coefficient, dynamic range and minimum detectable signal of the receiving system.

8. The electromagnetic protection limiter according to claim 1, characterized in that: The fixed attenuator (5) attenuates electromagnetic interference signals greater than 0 dBmHPM, with an attenuation of 30 dB.

9. The electromagnetic protection limiter according to claim 1, characterized in that: The microwave switch A (3) switches the channel of the HPM electromagnetic interference signal according to the synchronously input wave gate signal.

10. A limiting method for the electromagnetic protection limiter according to any one of claims 1 to 9, characterized in that: The following steps are involved: After the HPM electromagnetic pulse interference signal enters the RF front end of the receiver, the waveguide plasma limiter (1) determines whether the HPM electromagnetic pulse interference signal needs to be attenuated. The specific determination method is as follows: When the HPM electromagnetic interference signal is less than 63 dBm, the waveguide plasma limiter (1) has no attenuation on the signal, and the HPM electromagnetic interference signal directly enters the solid-state PIN tube limiter (2); When the HPM electromagnetic interference signal is greater than 63 dBm, the waveguide plasma limiter (1) attenuates the signal to make the HPM electromagnetic interference signal less than 63 dBm, thereby entering the solid-state PIN tube limiter (2) for further attenuation; After the HPM electromagnetic pulse interference signal is attenuated by the solid-state PIN tube limiter (2), the microwave switch A (3) determines to switch the next processing channel of the HPM electromagnetic pulse interference signal. The specific switching method is as follows: When the output signal power of the solid-state PIN tube limiter (2) is greater than 0 dBm, the microwave switch A (3) opens the fixed attenuator (5) channel to attenuate the HPM electromagnetic pulse interference signal again, and after attenuation by 30 dB, the signal is finally output via the microwave switch B (6); When the output signal power of the solid-state PIN tube limiter (2) is below 0 dBm, the microwave switch A (3) turns on the low noise amplifier (4) to amplify the HPM electromagnetic pulse interference signal, thereby ensuring the stability of the noise coefficient, dynamic range and minimum detectable signal index of the HPM electromagnetic pulse interference signal, and finally outputs it via the microwave switch B (6).

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