Antenna protection efficiency test system and method based on reciprocity principle

Abstract

The invention provides an antenna protection efficiency testing system and method based on a reciprocity principle, and belongs to the technical field of antenna testing. According to the invention, the reciprocity characteristic of the energy selection protection antenna is utilized, the microwave source signal is directly injected into the energy selection protection antenna to be tested, the power of the microwave source signal is gradually increased, the electromagnetic wave radiated by the energy selection protection antenna is received through the standard receiving antenna, and the change of the radiation capability of the energy selection protection antenna is observed. When the radiation capability of the energy selection protection antenna is reduced, the energy selection protection antenna enters a protection state, and the accurate protection efficiency can be calculated through the comparison of the radiation capability. As the antenna is a reciprocal device, the change of the receiving capability can be reversely deduced through the change of the radiation capability, namely, the protection efficiency of the energy selection protection antenna is calculated.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna testing, and particularly relates to an antenna protection effectiveness testing system and method based on the reciprocity principle. Background Art

[0002] With the rapid development of wireless communication technology, the electromagnetic environment is becoming increasingly complex, and electronic information devices are facing the threat of high-power microwave irradiation fields. How to achieve electromagnetic protection for electronic information systems while ensuring their normal operation has become an urgent problem to be solved. Currently, the energy domain protection means for electronic information systems mainly include energy-selective protective shields, ESPA (Energy Selective Protective Antenna), and circuit-level energy-selective protective devices. And for SE testing, it is a key link to verify the protection ability of the energy-selective protection structure. Achieving accurate SE (Shielding Effectiveness) testing is extremely crucial.

[0003] The energy-selective surface technology is an effective method applied to the electromagnetic protection of the radio frequency front end. It can achieve spatial non-linear transmission characteristics according to the strength change of the incident wave field intensity, and obtain a transient adaptive protection effect of strong field reflection and weak field wave transmission. Traditional SE testing methods for energy-selective surfaces include the irradiation method, waveguide injection method, etc., that is, a high-power irradiation source or a high-power injection source is used for input, and the input power is gradually increased to obtain the corresponding relationship between the input power and the received power, so as to obtain the SE of the energy-selective surface.

[0004] ESPA is to load non-linear devices and design the structure on the original antenna structure, so as to realize the integration of the protection function and the original antenna function. Currently, similar to the energy-selective surface technology, the SE testing for ESPA generally also directly uses the high-power irradiation method.

[0005] For example, when testing ESPA using the high-power irradiation method, a high-power microwave is irradiated by directly connecting a high-power signal source to a transmitting antenna. The antenna under test is used as a receiving antenna to receive the irradiated electromagnetic wave. After the received signal is attenuated by an attenuator, it is detected by a peak envelope detector. Finally, the detected voltage is displayed by an oscilloscope. During the experiment, the output power of the high-power signal source is gradually increased, and the SE of ESPA is obtained by detecting the change of the voltage through the oscilloscope. However, the high-power irradiation method has high requirements for the output power of the high-power signal source, and it is difficult for ordinary high-power sources to form high-power irradiation field conditions under irradiation conditions. Therefore, this method has high experimental requirements and poor flexibility.

[0006] For another example, the signal source is directly connected to the power amplifier, and is connected to one port of the isolator through a directional coupler. The second port of the isolator is connected to the ESPA under test, and the third port is connected to an attenuator and finally to a spectrum analyzer. Gradually increase the output power of the signal source, and evaluate the protection ability of the antenna by observing the reflected power of the ESPA under test, that is, the input power of the spectrum analyzer. This method has low requirements for high-power signal sources. However, this method can only measure the reflection coefficients of the ESPA in the normal working state and the protection state. It can simply evaluate the protection ability of the ESPA, but due to the lack of relevant information about the antenna such as the radiation pattern and gain, accurate SE cannot be obtained from the existing experimental data.

[0007] Therefore, to accurately obtain the SE of the ESPA, simplify the requirements of the experimental setup, and improve the completeness of the experiment, a more operable and flexible ESPA SE test method is needed.

[0008] Currently, there are mainly two methods for testing the protection ability of the ESPA: the direct irradiation method with a high-power microwave source and the reflection coefficient test method.

[0009] The direct irradiation method with a high-power microwave source is applicable to the SE test of the energy selection surface and the ESPA. It irradiates high-power microwaves by directly connecting a high-power signal source to the transmitting antenna to form a high-power microwave irradiation environment. The ESPA under test acts as a receiving antenna to receive the irradiated electromagnetic waves. After the received signal is attenuated by the attenuator, it is detected by a peak envelope detector. Finally, the detected voltage is displayed by an oscilloscope. During the experiment, the output power of the high-power signal source is gradually increased. When the irradiation field intensity reaches the threshold for activating the protection structure of the ESPA, the ESPA starts to produce a protection effect, and the SE of the ESPA is obtained by the change in the detected voltage.

[0010] In the reflection coefficient test method, an isolator device is used. First, the signal source is directly connected to the power amplifier, and is connected to one port of the isolator through a directional coupler. The second port of the isolator is connected to the ESPA under test, and the third port is connected to an attenuator and finally to a spectrum analyzer. Gradually increase the output power of the signal source, and evaluate the protection ability of the antenna by observing the reflected power of the ESPA under test, that is, the input power of the spectrum analyzer.

[0011] The direct irradiation method with a high-power microwave source introduced above requires the generation of high-power irradiation field conditions, which has high requirements for high-power signal sources or power amplifiers, high experimental requirements and poor flexibility. The reflection coefficient test method has low requirements for high-power signal sources, but it can only obtain the reflection coefficient of the ESPA and lacks information such as the radiation pattern and gain of the antenna, so accurate SE cannot be obtained.

[0012] The direct irradiation method of high-power microwave sources has been widely accepted and recognized. However, it has extremely high requirements for experimental equipment, requiring high-power microwave sources or power amplifiers with excellent performance, and it is impossible to set up this experimental scenario under conventional experimental conditions.

[0013] The reflection coefficient test method is a new test method. It can simply evaluate the protection ability by detecting the change in the reflected power of the ESPA, and has low requirements for experimental equipment. This experimental scenario can be set up under conventional experimental conditions. However, due to the lack of antenna-related information such as the antenna pattern and gain, this method cannot accurately obtain the SE of the ESPA. Summary of the Invention

[0014] To solve the above technical problems, the present invention proposes an antenna protection effectiveness test scheme based on the reciprocity principle.

[0015] In the first aspect of the present invention, an antenna protection effectiveness test system based on the reciprocity principle is proposed. The system includes a transmitting link and a receiving link. The transmitting link includes a microwave signal source, a power amplifier, an isolator, and an energy selection and protection antenna to be tested. The receiving link includes a standard receiving antenna, an attenuator, and a spectrum analyzer. Among them:

[0016] Taking the energy selection and protection antenna to be tested as the transmitting antenna, the protection ability of the energy selection and protection antenna to be tested is determined by observing the change in the antenna transmitting performance. The energy selection and protection antenna to be tested is a reciprocal microwave device. Its receiving performance and transmitting performance are equivalently analyzed, so as to test its protection effectiveness.

[0017] In the transmitting link, the microwave signal source generates a microwave signal, which is amplified by the power amplifier to generate a high-power microwave signal, and is connected to the energy selection and protection antenna to be tested after passing through the isolator. Among them, the isolator is used to protect the power amplifier and prevent the high-power signal reflected by the energy selection and protection antenna to be tested from damaging the sensitive components in the power amplifier.

[0018] In the receiving link, the standard receiving antenna is used to receive the radiation signal of the energy selection and protection antenna to be tested, the received signal is attenuated by the attenuator, and is connected to the spectrum analyzer, and the size of the received signal is observed through the spectrum analyzer.

[0019] According to the system of the first aspect of the present invention, the protection effectiveness of the energy selection and protection antenna to be tested is tested, where: the microwave signal source generates a microwave signal with a frequency of and a power of , which falls within the working frequency band of the energy selection and protection antenna to be tested; the microwave signal is amplified by the power amplifier, and the gain of the power amplifier at the frequency point is , and the energy selection and protection antenna to be tested at the The gain at the frequency point is , the loss in the transmitting link is ; the free space loss from the transmitting link to the receiving link is , the gain of the receiving antenna in the receiving link at the frequency point is , the attenuation coefficient of the attenuator is , the loss in the receiving link is ; the operating frequency band of the standard receiving antenna covers the operating frequency band of the energy-selective protection antenna under test, and the power of the signal received by the spectrum analyzer is , then ; takes different values in the normal operating state and the protection state, and are variables, and the others are constants.

[0020] According to the system of the first aspect of the present invention, the system tests the protection effectiveness of the energy-selective protection antenna under test, wherein:

[0021] Linearly increase the output power of the microwave signal source from small to large ;

[0022] When it is within the first range, the microwave signal is normally radiated through the energy-selective protection antenna under test, and the received signal power and increase linearly; as the output power increases, when the field strength at the feeding port of the energy-selective protection antenna under test increases to the first threshold, the protection structure is activated, and the gain of the energy-selective protection antenna under test decreases, and the received signal power decreases. At this time, the degree of decrease of the gain is used as the protection effectiveness of the energy-selective protection antenna under test;

[0023] As increases to the second range, the received signal power returns to the original linearly increasing level, and the protection structure of the energy-selective protection antenna under test is damaged and does not have the protection ability.

[0024] According to the system of the first aspect of the present invention, the system tests the protection effectiveness of the energy-selective protection antenna under test, wherein:

[0025] Analyze the curves of and . When the power starts to increase non-linearly, the injection power of the energy-selective protection antenna under test is the activation threshold of the protection structure. When When the power resumes its original linear increase level, the injection power of the protection antenna for the energy to be measured is the maximum tolerable power threshold; Coaxial electric field distribution It is expressed as:

[0026]

[0027] Among them, V is the voltage between the inner conductor and the outer conductor, is the coaxial radius, and the range is , is the inner diameter, is the outer diameter, the injection power and the characteristic impedance of the coaxial cable are respectively:

[0028]

[0029]

[0030] Among them, is the dielectric constant of the dielectric part of the coaxial cable;

[0031] Then the maximum electric field strength at the feeding position is:

[0032]

[0033] According to the injection power Calculate the starting field strength and damage field strength of the protection structure at the feeding port.

[0034] The second aspect of the present invention proposes a method for testing the protection efficiency of an antenna based on the reciprocity principle. In the transmitting link of the method, a microwave signal source, a power amplifier, an isolator, and a protection antenna for selecting the energy to be measured are configured. In the receiving link, a standard receiving antenna, an attenuator, and a spectrum analyzer are configured; In the method:

[0035] Take the protection antenna for selecting the energy to be measured as the transmitting antenna, and determine the protection ability of the protection antenna for selecting the energy to be measured by observing the change in the transmitting performance of the antenna; The protection antenna for selecting the energy to be measured is a reciprocal microwave device, and its receiving performance and transmitting performance are equivalently analyzed, so as to test its protection efficiency;

[0036] In the transmitting link, the microwave signal source generates a microwave signal, which is amplified by the power amplifier to generate a high-power microwave signal, and is connected to the protection antenna for selecting the energy to be measured after passing through the isolator; Among them, the isolator is used to protect the power amplifier and prevent the high-power signal reflected by the protection antenna for selecting the energy to be measured from damaging the sensitive components in the power amplifier;

[0037] In the receiving link, a standard receiving antenna is used to receive the radiation signal of the energy-selective protection antenna under test. The received signal is attenuated by an attenuator and then connected to a spectrum analyzer, and the size of the received signal is observed through the spectrum analyzer.

[0038] According to the method of the second aspect of the present invention, the protection effectiveness of the energy-selective protection antenna under test is tested, specifically including: a microwave signal source generates a microwave signal with a frequency of and a power of , which falls within the operating frequency band of the energy-selective protection antenna under test; the microwave signal is amplified by a power amplifier, and the gain of the power amplifier at the frequency point is , the gain of the energy-selective protection antenna under test at the frequency point is , the loss in the transmitting link is ; the free space loss from the transmitting link to the receiving link is , the gain of the receiving antenna in the receiving link at the frequency point is , the attenuation coefficient of the attenuator is , the loss in the receiving link is ; the operating frequency band of the standard receiving antenna covers the operating frequency band of the energy-selective protection antenna under test, the power of the signal received by the spectrum analyzer is , then ; takes different values in the normal operating state and the protection state, and are variables, and the others are constants.

[0039] According to the method of the second aspect of the present invention, the protection effectiveness of the energy-selective protection antenna under test is tested, specifically including:

[0040] Linearly increase the output power of the microwave signal source from small to large;

[0041] When it is within the first range, the microwave signal is normally radiated through the energy-selective protection antenna under test, and the received signal power increases linearly with ; as the output power increases, when the field strength at the feed port of the energy-selective protection antenna under test increases to the first threshold, the protection structure is activated, and the gain of the energy-selective protection antenna under test decreases, and the received signal power decreases. At this time, the degree of decrease in the gain is used as the protection effectiveness of the energy-selective protection antenna under test;

[0042] As Increased to the second range, received signal power Restored to the original linear increase level. The protection structure of the protection antenna for the energy to be measured is damaged and does not have protection ability.

[0043] According to the method of the second aspect of the present invention, the protection effectiveness of the protection antenna for the energy to be measured is tested, specifically including:

[0044] For And The curve of is analyzed. When The power starts to increase non-linearly, the injection power of the protection antenna for the energy to be measured is the protection structure activation threshold. When The power restores to the original linear increase level, the injection power of the protection antenna for the energy to be measured is the maximum tolerance power threshold; Coaxial line electric field distribution Is expressed as:

[0045]

[0046] Wherein, V is the voltage between the inner conductor and the outer conductor, Is the coaxial radius, and the range is , Is the inner diameter, Is the outer diameter, injection power And the characteristic impedance of the coaxial line Are respectively:

[0047]

[0048]

[0049] Wherein, Is the dielectric constant of the dielectric part of the coaxial line;

[0050] Then the maximum field strength At the feeding position is:

[0051]

[0052] According to the injection power Calculate the protection structure activation field strength and damage field strength at the feeding port.

[0053] From the perspectives of the test requirements of the antenna SE and its practical applications, the present invention proposes an antenna protection effectiveness test system and method based on the reciprocity principle. The present invention mainly utilizes the reciprocity characteristics of the energy-selective protection antenna, directly injects the microwave source signal into the ESPA to be tested, gradually increases the power of the microwave source signal, receives the electromagnetic waves radiated by the ESPA through a standard receiving antenna, observes the change in the radiation ability of the ESPA. When the radiation ability of the ESPA decreases, it indicates that the ESPA enters the protection state. At this time, the accurate SE can be calculated through the comparison of the radiation ability before and after. Since the antenna is a reciprocal device, the change in the receiving ability can be inferred from the change in the radiation ability, that is, the SE of the ESPA can be calculated. The traditional direct irradiation method with a high-power microwave source has high requirements for experimental equipment conditions, while the reflection coefficient test method cannot obtain the accurate SE. The method designed in this application has low requirements for experimental equipment, is relatively easy to carry out the experiment, does not require a microwave signal source with high power, only needs an ordinary microwave signal source plus a power amplifier. And this method can directly measure the accurate SE without complex mathematical operations. Description of the Drawings

[0054] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0055] Figure 1 It is a structural diagram of an antenna protection effectiveness test system based on the reciprocity principle.

[0056] Figure 2 It is a schematic diagram of the measured protection effectiveness of the energy-selective protection antenna. Detailed Embodiments

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0058] Abbreviation and Definition of Key Terms:

[0059] ESPA: Energy Selective Protective Antenna, which mainly protects against high-power microwaves.

[0060] SE: Shielding Effectiveness, which refers to the suppression ability of a protection antenna relative to its original gain reception under high-power microwave irradiation.

[0061] Existing electronic information systems urgently need to solve the problem of electromagnetic hardening, improve electromagnetic protection capabilities, and contain the threat of high-power microwaves to electronic information equipment. And SE is a key indicator for evaluating the electromagnetic protection capabilities of ESPA, and generally the SE of electronic information equipment is obtained through experimental testing methods. The traditional direct irradiation method with a high-power microwave source has high requirements for experimental equipment and poor experimental flexibility. The reflection coefficient test method evaluates the protection ability by comparing the reflection coefficients of ESPA in the normal working state and the protection state, and can only measure the reflection coefficient and cannot obtain the accurate SE.

[0062] Therefore, based on the experimental testing requirements of the protection antenna SE, the present invention proposes a convenient testing system and method for the SE of ESPA.

[0063] First Embodiment

[0064] This embodiment relates to a SE testing system and method for an energy-selective protection antenna, which is mainly based on the reciprocity characteristic of the antenna itself. By directly injecting a high-power microwave signal into the ESPA and observing the change in the radiation ability of the ESPA, the change in the reception ability of the ESPA under high-power microwave signal irradiation can be deduced, that is, the SE of the ESPA is obtained. As Figure 1 shown, the testing system includes a transmitting link and a receiving link. The transmitting link includes a microwave signal source, a power amplifier, an isolator, and the ESPA to be tested. The receiving link includes a standard receiving antenna, an attenuator, and a spectrum analyzer.

[0065] The traditional direct irradiation method with a high-power microwave source uses the ESPA to be tested as a receiving antenna and evaluates the protection ability of the ESPA by observing the change in reception performance. In the present invention, the experimental system is different from the former. It uses the ESPA to be tested as a transmitting antenna and infers the protection ability of the ESPA by observing the change in the transmitting performance of the antenna. Since the antenna is a reciprocal microwave device, its receiving performance and transmitting performance can be equivalently analyzed. Therefore, it is effective to test the SE of the ESPA through the method of this application.

[0066] In the transmitting link, first, a microwave signal is generated by the microwave signal source, amplified by the power amplifier to generate a high-power microwave signal, and connected to the isolator and finally to the ESPA to be tested. The role of the isolator is to protect the power amplifier and prevent the high-power signal reflected by the ESPA to be tested from damaging the sensitive components in the power amplifier.

[0067] In the receiving link, a standard receiving antenna is used to receive the radiation signal of the ESPA under test, and after attenuating the received signal through an attenuator, it is connected to a spectrum analyzer to observe the magnitude of the received signal.

[0068] The microwave signal source generates a microwave signal with a frequency of , and a power of , which falls within the operating frequency band of the ESPA under test. The microwave signal is amplified by a power amplifier, and the gain of the power amplifier at the frequency point is . The gain of the ESPA under test at the frequency point is . The loss in the transmitting link is . The free space loss from the transmitting link to the receiving link is . The gain of the receiving antenna in the receiving link at the frequency point is . The attenuation coefficient of the attenuator is . The loss in the receiving link is . During the experimental setup process, the operating frequency band of the standard receiving antenna should cover the operating frequency band of the ESPA under test, and the magnitude of the gain can be clearly determined.

[0069] Therefore, through calculation, the power of the signal received by the spectrum analyzer can be obtained, and its magnitude is:

[0070]

[0071] In the above formula, since the ESPA is a protective antenna, its gain is different in the normal operating state and the protective state. Generally speaking, and are variables, and other parameters are all constants.

[0072] During the experiment, first connect all the experimental equipment according to the experimental scheme proposed in the application. Then, linearly increase the output power of the microwave signal source from small to large. At first, is small, the microwave signal can be normally radiated through the ESPA, and the received signal power increases linearly with . When the output power increases to a certain extent, the field strength at the feeding port of the ESPA is large enough, causing the protection structure to start, and the gain of the ESPA decreases, and the received signal power decreases. At this time, the degree of gain decrease is the SE of the ESPA. When continues to increase, the received signal power It may return to the original linearly increasing level. At this time, the protection structure of the ESPA antenna is damaged and does not have the protection ability. In summary, the solution of the present invention uses the conversion method to cleverly characterize the change in the radiation ability of the ESPA through the received signal power to characterize, according to The change can effectively judge the SE size of the ESPA. This experiment has high reliability, and the experimental equipment requirements are low, which is convenient to carry out operations in the laboratory.

[0073] For and When analyzing the curves, when The power starts to increase non-linearly. At this time, the injection power of the ESPA is the protection structure activation threshold. When The power returns to the original linearly increasing level. At this time, the injection power of the ESPA is the maximum tolerance power threshold.

[0074] In addition, the coaxial electric field distribution formula is as follows:

[0075]

[0076] V is the voltage between the inner conductor and the outer conductor, is a variable representing the coaxial radius, with a range of , representing the inner diameter and the outer diameter respectively, and the input power and the characteristic impedance of the coaxial cable The magnitudes are as shown in the following formula:

[0077]

[0078]

[0079] Among them, is the dielectric constant of the coaxial cable dielectric part.

[0080] Combining the above formulas, the maximum field strength at the feeding position can be obtained as:

[0081]

[0082] It can be seen that according to the injection power The magnitudes of the protection structure activation field strength and the damage field strength at the feeding port can be calculated.

[0083] Second Embodiment (SE Test of Patch-Type ESPA)

[0084] The front of the patch-type ESPA is a metal radiation patch structure, and the back is a ground plane. The feeding port uses an SMA-type connector and is welded at the ground plane position. The feeding probe inside it penetrates the dielectric substrate and is connected to the radiation patch for power supply.

[0085] According to the internal protection structure at the ESPA feeding structure, it is modified on the basis of the feeding structure of the original patch antenna and a diode is loaded, thus completing the ESPA design with the ability of energy-selective electromagnetic protection. This type of antenna is a coaxial-fed patch antenna, and there is not enough space in the existing structure to be modified to integrate the energy-selective electromagnetic protection ability. Therefore, the method of upper and lower stratification of the antenna dielectric substrate and hollowing out the center of the upper dielectric substrate is adopted, and a protection structure is designed at the coaxial probe structure to achieve the protection ability. After that, the upper and lower dielectric substrates are laminated and fixed with Nylon screws at the endpoints. In addition, the hollowed-out part of the dielectric substrate has enough height to protect the diode and avoid damaging the diode due to the mechanical strength generated by the lamination of the laminates.

[0086] As Figure 2 shown, it is the SE experimental test result of the patch-type ESPA. First of all, each experimental device in the experimental scheme should be selected. The microwave signal source is selected as the model with a large adjustable range of output signal power, a large frequency band range, and the maximum output power of the signal source should be above 20 dBm; the power amplifier is selected as the model with high gain and stable amplification factor, and before the experiment starts, the amplification factor of the power amplifier at the working frequency point should be tested through relevant experiments. The isolation degree of the isolator should be above 20 dB to ensure the safety and stability of the sensitive components inside the power amplifier. The working frequency band of the standard receiving antenna should cover the actual working frequency band of the ESPA. The working frequency band of the spectrum analyzer should cover the actual working frequency band of the ESPA.

[0087] After the experimental system is built, gradually increase the output power of the microwave signal source, that is, increase the injection power of the ESPA, and observe the received power situation of the spectrum analyzer in the receiving link. Through conversion, the injection power-received power corresponding curve is obtained, and the SE of the ESPA can be analyzed according to this curve.

[0088] First of all, the injection power is gradually increased from -10 dBm, and the received power increases linearly with the increase of the injection power. At this time, the antenna is in a normal working state, and the injected signal can be normally radiated to the external free space through the antenna. When the injection power increases to 22 dBm, the received power no longer increases linearly with the increase of the injection power. At this time, the protection structure has been activated, the radiation ability of the antenna is weakened, and the degree of reduction of the antenna gain coefficient is the size of the SE, that is, the difference between the linear output power and the actual output power is the size of the SE. When the injection power increases to 48 dBm, the size of the received power returns to the size of the original linearly increasing power. At this time, due to the high field strength at the feeding port, the protection structure is damaged and the ESPA no longer has the protection ability.

[0089] It can be seen that the activation threshold of the protection structure of this type of ESPA is 22 dBm, the damage threshold is 48 dBm, and the maximum protection efficiency can reach 26 dB.

[0090] In summary, compared with the prior art, the present invention can avoid the need for high-power microwave sources and high-gain power amplifiers in the traditional irradiation method, and there is no need to provide large-sized high-power microwave sources or power amplifiers. The experimental method designed by the present invention is simple, has higher operability, and lower cost. In addition, the present invention can avoid the drawback that the reflection coefficient test method can only obtain the reflection coefficient of ESPA under different working states. The experimental data obtained by the experimental system involved in the present invention already includes information such as antenna pattern and gain, and accurate SE data can be deduced, and the experimental results are more accurate.

[0091] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. The above embodiments only represent several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An antenna protection effectiveness test system based on the reciprocity principle, characterized in that, The system includes a transmitting link and a receiving link. The transmitting link includes a microwave signal source, a power amplifier, an isolator, and an energy-selective protection antenna under test. The receiving link includes a standard receiving antenna, an attenuator, and a spectrum analyzer. Among them: The energy-selective protection antenna under test is used as a transmitting antenna, and the protection ability of the energy-selective protection antenna under test is determined by observing the change in the transmitting performance of the antenna. The energy-selective protection antenna under test is a reciprocal microwave device, and its receiving performance and transmitting performance are equivalently analyzed to test its protection effectiveness. In the transmitting link, the microwave signal source generates a microwave signal, which is amplified by the power amplifier to generate a high-power microwave signal and is connected to the energy-selective protection antenna under test after passing through the isolator. Among them, the isolator is used to protect the power amplifier and prevent the high-power signal reflected by the energy-selective protection antenna under test from damaging the sensitive components in the power amplifier. In the receiving link, the standard receiving antenna is used to receive the radiation signal of the energy-selective protection antenna under test, the received signal is attenuated by the attenuator, and is connected to the spectrum analyzer, and the size of the received signal is observed through the spectrum analyzer.

2. The antenna protection effectiveness test system based on the reciprocity principle according to claim 1, characterized in that The system tests the protection effectiveness of the protection antenna for the energy to be measured, where: The microwave signal source generates a microwave signal with a frequency of and a power of , which falls within the operating frequency band of the protection antenna for the energy to be measured; The microwave signal is amplified by a power amplifier, and the gain of the power amplifier at the frequency point is , the gain of the protection antenna for the energy to be measured at the frequency point is , and the loss in the transmitting link is ; The free space loss from the transmitting link to the receiving link is , the gain of the receiving antenna in the receiving link at the frequency point is , the attenuation coefficient of the attenuator is , and the loss in the receiving link is ; The operating frequency band of the standard receiving antenna covers the operating frequency band of the protection antenna for the energy to be measured, the power of the signal received by the spectrum analyzer is , then ; takes different values in the normal operating state and the protection state, and are variables, and the others are constants.

3. The antenna protection effectiveness test system based on the reciprocity principle according to claim 2, characterized in that, The system tests the protection effectiveness of the energy-selective protection antenna under test, among which: Linearly increase the output power of the microwave signal source from small to large ; When within the first range, The microwave signal is normally radiated through the energy selection protection antenna under test, and the received signal power and increases linearly; as the output power increases, when the field strength at the feeding port of the energy selection protection antenna under test increases to the first threshold, the protection structure is activated, and the gain of the energy selection protection antenna under test decreases, and the received signal power decreases. At this time, the degree of decrease in the gain is taken as the protection effectiveness of the energy selection protection antenna under test; As increases to the second range, the received signal power returns to the original linearly increasing level, and the protection structure of the protection antenna for the energy to be measured is damaged and does not have the protection ability.

4. The antenna protection effectiveness test system based on the reciprocity principle according to claim 3, characterized in that The system tests the protection effectiveness of the energy-selective protection antenna under test, among which: For and the curve is analyzed. When the power starts to increase non-linearly, the injection power of the protection antenna for the energy to be measured is the protection structure activation threshold. When the power resumes its original linearly increasing level, the injection power of the protection antenna for the energy to be measured is the maximum tolerance power threshold; the coaxial cable electric field distribution is expressed as: ， where V is the voltage between the inner conductor and the outer conductor, is the coaxial radius, with the range of , is the inner diameter, is the outer diameter, the injected power and the characteristic impedance of the coaxial line are respectively: ， ， Among them, is the dielectric constant of the dielectric part of the coaxial line; The maximum field strength at the feeding position is as follows: ， According to the injection power Calculate the starting field strength and damage field strength of the protection structure at the feed port.

5. A method for testing the protection effectiveness of an antenna based on the reciprocity principle, characterized in that, In the method, a microwave signal source, a power amplifier, an isolator, and an energy-selective protection antenna under test are configured on the transmitting link, and a standard receiving antenna, an attenuator, and a spectrum analyzer are configured on the receiving link. In the method: The energy-selective protection antenna under test is used as a transmitting antenna, and the protection ability of the energy-selective protection antenna under test is determined by observing the change in the transmitting performance of the antenna. The energy-selective protection antenna under test is a reciprocal microwave device, and its receiving performance and transmitting performance are equivalently analyzed to test its protection effectiveness. In the transmitting link, the microwave signal source generates a microwave signal, which is amplified by the power amplifier to generate a high-power microwave signal and is connected to the energy-selective protection antenna under test after passing through the isolator. Among them, the isolator is used to protect the power amplifier and prevent the high-power signal reflected by the energy-selective protection antenna under test from damaging the sensitive components in the power amplifier. In the receiving link, the standard receiving antenna is used to receive the radiation signal of the energy-selective protection antenna under test, the received signal is attenuated by the attenuator, and is connected to the spectrum analyzer, and the size of the received signal is observed through the spectrum analyzer.

6. The method for testing the antenna protection effectiveness based on the reciprocity principle according to claim 5, wherein Test the protection effectiveness of the protection antenna for the energy to be measured, specifically including: The microwave signal source generates a microwave signal with a frequency of and a power of , which falls within the operating frequency band of the protection antenna for the energy to be measured; The microwave signal is amplified by a power amplifier, and the gain of the power amplifier at the frequency point is , the gain of the protection antenna for the energy to be measured at the frequency point is , and the loss in the transmitting link is ; The free space loss from the transmitting link to the receiving link is , the gain of the receiving antenna in the receiving link at the frequency point is , the attenuation coefficient of the attenuator is , and the loss in the receiving link is ; The operating frequency band of the standard receiving antenna covers the operating frequency band of the protection antenna for the energy to be measured, the power of the signal received by the spectrum analyzer is , then ; takes different values in the normal operating state and the protection state, and are variables, and the others are constants.

7. A method for testing the antenna protection effectiveness based on the reciprocity principle according to claim 6, characterized in that, Testing the protection effectiveness of the energy-selective protection antenna under test specifically includes: Linearly increase the output power of the microwave signal source from small to large ; When within the first range, The microwave signal is normally radiated through the energy selection protection antenna under test, and the received signal power increases linearly with As the output power increases, when the field strength at the feed port of the energy selection protection antenna under test increases to the first threshold, the protection structure is activated, and the gain of the energy selection protection antenna under test decreases, and the received signal power decreases. At this time, the degree of decrease in the gain is used as the protection effectiveness of the energy selection protection antenna under test; As increases to the second range, the received signal power returns to the original linearly increasing level, and the protection structure of the protection antenna for the energy to be measured is damaged and does not have the protection ability.

8. A method for testing the antenna protection effectiveness based on the reciprocity principle according to claim 7, characterized in that, Testing the protection effectiveness of the energy-selective protection antenna under test specifically includes: For and of the curves, when the power starts to increase non-linearly, the injection power of the protection antenna for the energy to be measured is the protection structure activation threshold. When the power resumes its original linearly increasing level, the injection power of the protection antenna for the energy to be measured is the maximum tolerance power threshold; the coaxial cable electric field distribution is expressed as: ， where V is the voltage between the inner conductor and the outer conductor, is the coaxial radius, with the range of , is the inner diameter, is the outer diameter, the injected power and the characteristic impedance of the coaxial line are respectively: ， ， Among them, is the dielectric constant of the dielectric part of the coaxial line; The maximum field strength at the power feeding position is ， According to the injection power Calculate the starting field strength and damage field strength of the protection structure at the feed port.

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