Active phased-array antenna EIRP test method based on planar near field
By combining gain and loss calculations of horn antennas and active phased array antennas in planar near-field testing, the problem of insufficient accuracy in EIRP testing of active phased array antennas is solved, realizing an efficient and economical testing method applicable to multi-polarization active phased array antennas.
Patent Information
- Application Number
- CN202411618274.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-01-07
AI Technical Summary
Traditional EIRP testing methods for active phased array antennas lack accuracy in planar near-field testing, and the high cost of compact field testing limits their application.
An EIRP test method for active phased array antennas based on planar near-field is adopted. By connecting the horn antenna with a vector network analyzer and a near-field probe antenna, planar near-field scanning is performed. The EIRP value of the active phased array antenna is obtained by combining the gain and loss calculations of the horn antenna and the active phased array antenna.
It improves the accuracy of planar near-field testing, reduces the investment in testing instruments, is applicable to linearly polarized and circularly polarized active phased array antennas, reduces testing costs, and enhances the economy and applicability of testing.
Smart Images
Figure CN119269897A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of active phased array antenna testing, and in particular to an active phased array antenna EIRP testing method based on planar near field. Background Art
[0002] In the design and application of active phased array antennas, EIRP is a crucial radiation performance parameter. It is equal to the product of the phased array antenna input power and the antenna gain. The EIRP performance parameter represents the ability of the active phased array to transmit strong signals, which directly affects the wireless communication or target detection capability of the active phased array system.
[0003] Traditionally, EIRP testing of active phased array antennas mostly uses direct far-field methods or quasi-far-field compact field methods. Direct far-field testing requires that the test distance satisfy the condition of R ≥ 2D2 / λ, where R is the far-field distance, D is the maximum aperture size of the antenna, and λ is the operating wavelength. For large-aperture, high-frequency antennas, this means that an extremely large test site is required, which is often difficult to achieve in actual operations. Although compact field testing can simulate far-field environments at a relatively close distance, its high cost and limited utilization efficiency of the reflective surface also restrict its application to a certain extent.
[0004] With the rapid development of active phased array antenna technology, the aperture size of antennas continues to increase to meet the growing application needs. This has prompted planar near-field testing technology to gradually become an important means of testing the performance of active phased array antennas. However, the traditional far-field-based EIRP test method faces significant problems when applied to planar near-field testing. Since the planar near-field test is performed within a range of 3 to 10 wavelengths from the antenna, the antenna is still in the radiation near-field area at this time, and the main lobe of its radiation pattern has not yet been fully formed, which will cause the measured radiation power value to be too small. At the same time, the actual gain of the standard gain horn used to receive the antenna radiation signal in the near-field area will also be lower than the gain calibrated in the far field, further exacerbating the deviation of the test results. Summary of the invention
[0005] In view of the problem that the near-field test accuracy of the EIRP test of the active phased array antenna in the prior art is insufficient, the present invention provides an active phased array antenna EIRP test method based on planar near field, which overcomes the limitations of the planar near field test in EIRP evaluation and improves the accuracy of the test.
[0006] To achieve the above technical objectives, the present invention provides a technical solution, which is an active phased array antenna EIRP test method based on planar near field, comprising the following steps: A1, connect the horn antenna to the vector network analyzer and the near-field probe antenna, adjust the antenna alignment and polarization direction, measure the S21 amplitude of the near field of the horn antenna, perform a planar near-field scan of the horn antenna, and obtain amplitude and phase data; A2, remove the horn antenna, test the RF cable loss between the output port of the vector network analyzer and the horn antenna, calculate the horn antenna gain and the total loss from the horn antenna to the input port of the vector network analyzer; A3, connect the active phased array antenna to the vector network analyzer and the near-field probe antenna, adjust the antenna alignment and polarization direction, set the active phased array antenna to the transmit beam state, measure the S21 amplitude of the active phased array antenna near field, and record the output power of the vector network analyzer; A4, gradually increase the power output of the vector network analyzer. When the S21 amplitude drops to a value greater than the set value, record the S21 amplitude and the output power of the vector network analyzer, readjust the output power of the vector network analyzer to the output power in A3, perform a planar near-field scan of the active phased array antenna, and obtain the near-field amplitude and phase data of the active phased array antenna. A5, perform near-field to far-field conversion on the planar near-field amplitude and phase data of the horn antenna and the active phased array antenna, obtain the gain of the active phased array antenna based on the gain of the horn antenna, calculate the total loss from the active phased array antenna to the input of the vector network analysis, and calculate the EIRP value of the active phased array antenna.
[0007] In this technical solution, first, by firmly mounting the horn antenna on a turntable and connecting the vector network analyzer and the near-field probe antenna, ensure that the antenna is accurately aligned and the polarization direction is consistent. Subsequently, the S21 amplitude of the near field of the horn antenna is measured, and a comprehensive planar near-field scan is performed to collect key amplitude and phase data. Next, after removing the horn antenna, the RF cable loss connected between the output port of the vector network analyzer and the horn antenna is tested, and then the gain of the horn antenna and its total loss to the input of the vector network analysis are calculated. Subsequently, the active phased array antenna is installed on the turntable, and the vector network analyzer and the near-field probe antenna are also connected, and adjusted to the optimal alignment and polarization state. Set the antenna to the transmitting beam mode, measure the S21 amplitude of its near field, and record the output power of the vector network analyzer at this time. In the process of gradually increasing the power output of the vector network analyzer, when the S21 amplitude drops beyond the preset threshold, accurately record the S21 amplitude and the corresponding output power. Subsequently, the output power is restored to the level in step A3, and the active phased array antenna is scanned in the planar near field again to obtain the amplitude and phase data of its near field. Finally, by performing near-field to far-field conversion on the planar near-field amplitude and phase data of the horn antenna and the active phased array antenna, combined with the known horn antenna gain, the gain of the active phased array antenna is derived. Then the total loss from the active phased array antenna to the input of the vector network analysis is calculated, and finally the EIRP value of the active phased array antenna is obtained, thus ensuring the accuracy and reliability of the EIRP test of the active phased array antenna.
[0008] The present invention is further configured as: an active phased array antenna EIRP test method based on planar near field according to claim 1, characterized in that, in step A1 or A3, the connection between the vector network analyzer and the near-field probe antenna includes: the output port of the vector network analyzer is connected to the horn antenna through a radio frequency cable, and the input port of the vector network analyzer is connected to the near-field probe antenna through a radio frequency cable.
[0009] In this technical solution, the docking process not only requires that the impedance, loss and other parameters of the cable perfectly match the test requirements, but also ensures that the connection is stable and reliable to avoid any signal leakage or interference.
[0010] The present invention is further configured as follows: in step A1 or A3, adjusting the antenna alignment and polarization direction includes: setting the operating frequency of the vector network analyzer, adjusting the near-field probe antenna to align with the center of the horn antenna, and keeping the polarization direction consistent, and maintaining the distance between the apertures between 3 and 10 times the wavelength of the near-field test distance.
[0011] In this technical solution, first, in order to ensure the accuracy and effectiveness of the test, the operating frequency of the vector network analyzer is set. Next, adjust the near-field probe antenna and the center alignment of the horn antenna, which not only requires visual alignment, but also ensures that the signal transmission path between the two is unobstructed to minimize signal loss and interference. At the same time, ensure that the polarization direction of the near-field probe antenna is completely matched with the antenna to be tested to ensure accurate reception and measurement of the signal. In addition, keep the distance between the mouth surfaces at the near-field test distance, that is, between 3 and 10 times the wavelength. Adjusting the appropriate near-field distance helps reduce the impact of the coupling effect on the test results and ensures the accuracy and reliability of the test.
[0012] The present invention is further configured as follows: the polarization direction being kept consistent comprises: When the horn antenna is linearly polarized, adjust the linear polarization direction of the near-field probe antenna to be consistent with the linear polarization direction of the horn antenna; When the horn antenna is circularly polarized, adjust the circular polarization direction of the near-field probe antenna to be consistent with the circular polarization direction of the horn antenna.
[0013] In this technical solution, whether it is linear polarization or circular polarization, the polarization direction of the near-field probe antenna will be accurately adjusted according to the polarization mode of the horn antenna to ensure that the polarization characteristics of the two are completely matched. This not only reflects the professionalism and rigor of the test method, but also provides a solid foundation for subsequent near-field scanning, data acquisition and EIRP value calculation, thereby ensuring the accuracy and credibility of the entire test method.
[0014] The present invention is further configured that: the distance between the apertures is maintained between 3 and 10 times the wavelength of the near-field test distance and must be consistent with the aperture distance during the horn antenna test.
[0015] In this technical solution, by maintaining strict consistency of the mouth-to-face distance, the error introduced by the distance change can be effectively reduced, thereby further improving the accuracy and reliability of the test.
[0016] The present invention is further configured such that: when the active phased array antenna is in a transmitting beam state, the beam pointing is between 0° and 70°.
[0017] This technical solution not only reflects the professionalism and rigor of the test method, but also ensures the accuracy and practicality of the test results. By controlling the beam pointing within the range of 0° to 70°, it can effectively simulate the beam coverage in actual use scenarios, thereby more accurately evaluating the performance of the antenna. In addition, it also helps to reduce the errors introduced by improper beam pointing, further improving the accuracy and reliability of the test.
[0018] The present invention is further configured as follows: the formula for calculating the horn antenna gain and the total loss from the horn antenna to the vector network analysis input end is: L_ant=S21_ant-G_ant-L l ; Where L_ant is the total loss from the horn antenna to the input of the vector network analysis, S21_ant is the S21 amplitude of the horn antenna near field, L l is the RF cable loss connecting the output port of the vector network analyzer and the horn antenna.
[0019] In this technical solution, through this formula, the loss of the horn antenna in the entire test link can be systematically calculated, thereby making a more accurate and comprehensive evaluation of the antenna performance, thereby improving the accuracy and efficiency of the test.
[0020] The present invention is further configured as follows: the formula for calculating the total loss from the active phased array antenna to the vector network analysis input terminal is: L_apr=L_ant+S21_p1-S21_ant+G_ant-G_apr; Among them, L_apr is the total loss from the active phased array antenna to the input of the vector network analysis, L_ant is the total loss from the horn antenna to the input of the vector network analysis, S21_p1 is the S21 amplitude in A4, S21_ant is the S21 amplitude in the near field of the horn antenna, G_ant is the gain of the horn antenna, and G_apr is the gain of the active phased array antenna.
[0021] In this technical solution, the difference between the two S21 amplitudes reflects the change of the signal between different test points, and the difference between the gain of the horn antenna and the active phased array antenna takes into account the influence of different antenna gains on the loss calculation. It can accurately quantify the loss of the active phased array antenna in the entire test link, and then make a more accurate and comprehensive evaluation of its performance, thereby improving the accuracy and efficiency of the test.
[0022] The present invention is further configured as follows: the formula for calculating the EIRP value of the active phased array antenna is: EIRP=P_1+S21_p1-L_apr+S21_p1-S21_p0; Among them, EIRP is the EIRP value of the active phased array antenna, P_1 is the output power of the vector network analyzer in A4, S21_p1 is the S21 amplitude in A4, L_apr is the total loss from the active phased array antenna to the input of the vector network analysis, and S21_p0 is the S21 amplitude in the near field of the active phased array antenna.
[0023] In this formula, P_1 is the output power of the vector network analyzer in A4, which indicates the initial signal strength received by the active phased array antenna, S21_p1 is the S21 amplitude in A4, which reflects the transmission characteristics of the signal at this point, and S21_p0 is the S21 amplitude in the near field of the active phased array antenna, which is used to correct the signal changes in the near field test. This allows the radiation performance of the active phased array antenna to be fully evaluated and its EIRP value to be accurately obtained.
[0024] The present invention is further configured as follows: in step A5, the power output of the vector network analyzer is gradually increased by controlling the power output to be gradually increased in steps of 0.5 dB to 2 dB.
[0025] In this technical solution, a smooth change in signal strength is ensured during the test, so that the performance of the antenna at different power levels can be captured and analyzed more accurately, test errors caused by power mutations are avoided, and the accuracy and reliability of the test are improved.
[0026] The beneficial effects of the present invention are as follows: (1) the limitations of planar near-field testing in EIRP evaluation are overcome, and the accuracy of the test is improved; (2) the loss of near-field gain is taken into account, and the gain loss of the horn antenna and the active phased array antenna near field is regarded as the overall loss of reception and substituted into the EIRP calculation, thereby ensuring the test accuracy of the EIRP value of the active phased array antenna in the planar near field; (3) the test instrument only needs a vector network analyzer, and does not need a signal source and a spectrum analyzer, so that the instruments for passive testing and active EIRP testing can be shared, reducing the investment in test instruments, simplifying the test circuit, and improving economy; (4) the applicability is wide, and it is applicable to the planar near-field EIRP test of all current linearly polarized and circularly polarized active phased array antennas. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 It is a schematic diagram of the structure of the horn antenna erected in the plane near field; Figure 3 It is a schematic diagram of the structure of the active phased array antenna installed in the plane near field; Figure 4 The EIRP test results of the embodiment of the present invention are compared with those of the compact field direct test method. DETAILED DESCRIPTION
[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation method described herein is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0029] like Figures 1 to 4 As shown in the figure, as the first embodiment of the present invention, a method for testing EIRP of an active phased array antenna based on a planar near field is characterized in that it comprises the following steps: Step A1: Install the horn antenna stand on the turntable. Figure 2 As shown, the output port of the vector network analyzer is connected to the horn antenna through an RF cable, and the input port of the vector network analyzer is connected to the near-field probe antenna through an RF cable. The near-field probe antenna is adjusted to align with the center of the standard horn antenna, and the linear polarization method of the near-field probe antenna and the horn antenna is adjusted to ensure consistency, and the distance between the mouth surfaces is maintained at a near-field test distance of 3 times the wavelength. At this time, the RF output of the vector network analyzer is turned on, and the amplitude of the near field of the horn antenna is measured to be S21_ant.
[0030] The operating frequency of the active phased array antenna in the present invention is 27.5 GHz to 29.5 GHz, so the operating frequency of the vector network analyzer is set to 27.5 GHz to 29.5 GHz, and the near-field test distance of three times the wavelength is 30.5 mm.
[0031] The horn antenna is scanned in the planar near field and the amplitude and phase data of the horn antenna in the planar near field are measured.
[0032] Step A2: Remove the horn antenna from the turntable and use a vector network analyzer to test the RF cable loss between the output port of the vector network analyzer and the horn antenna, recorded as L l According to the data of the horn antenna, the gain of the horn antenna is G_ant, so the total loss from the horn antenna to the input of the vector network analysis can be obtained as L_ant = S21_ant-G_ant-L l .
[0033] Step A3: Install the active phased array antenna rack on the turntable, such as Figure 3As shown, the output port of the vector network analyzer is connected to the horn antenna through an RF cable, and the input port of the vector network analyzer is connected to the near-field probe antenna through an RF cable. The near-field probe antenna is adjusted to be aligned with the center of the standard horn antenna. The active phased array antenna is linearly polarized. The linear polarization direction of the near-field probe antenna is adjusted to be consistent with the linear polarization direction of the active phased array antenna, and the distance between the apertures is maintained at 3 times the wavelength of the near-field test distance. At this time, the RF output of the vector network analyzer is turned on, and the active phased array antenna is set to be in the transmitting beam state with the beam pointing at 0°. The amplitude of the near field of the active phased array antenna is measured to be S21_p0, and the output power of the vector network analyzer at this time is recorded as P_0.
[0034] Step A4: gradually increase the power output of the vector network analyzer in 1 dB steps. When the S21 value decreases by more than 1 dB compared with S21_p0, record the S21 amplitude at this time as S21_p1, and record the output power of the vector network analyzer at this time as P_1.
[0035] The output power of the vector network analyzer is readjusted to P_0, and the planar near-field scanning of the active phased array antenna is performed to measure the planar near-field amplitude and phase data of the active phased array antenna.
[0036] Step A5: Perform near-field to far-field conversion on the planar near-field amplitude and phase data of the horn antenna and the planar near-field amplitude and phase data of the active phased array antenna, respectively. The gain of the horn antenna is G_ant, and the gain of the active phased array antenna can be obtained from the gain of the horn antenna as G_apr. Therefore, the total loss from the active phased array antenna to the input end of the vector network analysis can be obtained as L_apr = L_ant + S21_p1 - S21_ant + G_ant - G_apr.
[0037] The test data is processed and the EIRP value of the active phased array antenna is calculated by the following formula: EIRP = P_1 + S21_p1 - L_apr + S21_p1 - S21_p0.
[0038] Figure 4 The EIRP test results of the test method of the present invention are compared with those of the direct test method in a compact field. EIRP tests are performed on the five frequency points in the middle of the active phased array antenna under test operating in the frequency range of 27.5 GHz to 29.5 GHz. The difference with the test result of the compact field is less than 0.3 dB, and the planar near-field EIRP test result and the compact field EIRP test result are within the error range.
[0039] In this embodiment, first, by firmly mounting the horn antenna on a turntable and connecting the vector network analyzer and the near-field probe antenna, ensure that the antenna is accurately aligned and the polarization direction is consistent. Subsequently, the S21 amplitude of the near field of the horn antenna is measured, and a comprehensive planar near-field scan is performed to collect key amplitude and phase data. Next, after removing the horn antenna, the RF cable loss connected between the output port of the vector network analyzer and the horn antenna is tested, and then the gain of the horn antenna and its total loss to the input of the vector network analysis are calculated. Subsequently, the active phased array antenna is installed on the turntable, and the vector network analyzer and the near-field probe antenna are also connected, and adjusted to the optimal alignment and polarization state. The antenna is set to the transmitting beam mode, the S21 amplitude of its near field is measured, and the output power of the vector network analyzer at this time is recorded. In the process of gradually increasing the power output of the vector network analyzer, when the S21 amplitude drops beyond the preset threshold, the S21 amplitude and the corresponding output power are accurately recorded. Subsequently, the output power is restored to the level in step A3, and the active phased array antenna is scanned in the planar near field again to obtain the amplitude and phase data of its near field. Finally, by performing near-field to far-field conversion on the planar near-field amplitude and phase data of the horn antenna and the active phased array antenna, combined with the known horn antenna gain, the gain of the active phased array antenna is derived. Then the total loss from the active phased array antenna to the input of the vector network analysis is calculated, and finally the EIRP value of the active phased array antenna is obtained, thereby ensuring the accuracy and reliability of the EIRP test of the active phased array antenna. P_1 is the output power of the vector network analyzer in A4, which indicates the initial signal strength received by the active phased array antenna. S21_p1 is the S21 amplitude in A4, which reflects the transmission characteristics of the signal at this point. S21_p0 is the S21 amplitude of the near field of the active phased array antenna, which is used to correct the signal changes in the near field test. In this way, the radiation performance of the active phased array antenna can be comprehensively evaluated and its EIRP value can be accurately obtained.
[0040] It can be understood that the calculation of the horn antenna gain is obtained by looking up a table, such as looking up a gain calibration report.
[0041] Preferably, in step A1 or A3, connecting the vector network analyzer and the near-field probe antenna includes: the output port of the vector network analyzer is connected to the horn antenna through a radio frequency cable, and the input port of the vector network analyzer is connected to the near-field probe antenna through a radio frequency cable.
[0042] In this technical solution, the docking process not only requires that the impedance, loss and other parameters of the cable perfectly match the test requirements, but also ensures that the connection is stable and reliable to avoid any signal leakage or interference.
[0043] It can be understood that the polarization direction remains consistent including: When the horn antenna is linearly polarized, adjust the linear polarization direction of the near-field probe antenna to be consistent with the linear polarization direction of the horn antenna; When the horn antenna is circularly polarized, adjust the circular polarization direction of the near-field probe antenna to be consistent with the circular polarization direction of the horn antenna.
[0044] In this technical solution, whether it is linear polarization or circular polarization, the polarization direction of the near-field probe antenna will be accurately adjusted according to the polarization mode of the horn antenna to ensure that the polarization characteristics of the two are completely matched. This not only reflects the professionalism and rigor of the test method, but also provides a solid foundation for subsequent near-field scanning, data acquisition and EIRP value calculation, thereby ensuring the accuracy and credibility of the entire test method.
[0045] Preferably, the wavelength is the wavelength at the maximum operating frequency.
[0046] The specific description of the present invention in the above embodiments is only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical engineers in this field may make some non-essential improvements and adjustments to the present invention based on the contents of the above invention, which fall within the scope of protection of the present invention.
Claims
1. An active phased array antenna EIRP test method based on planar near field, characterized in that: The following steps are involved: A1, connect the horn antenna to the vector network analyzer and the near-field probe antenna, adjust the antenna alignment and polarization direction, measure the S21 amplitude of the near field of the horn antenna, perform a planar near-field scan of the horn antenna, and obtain amplitude and phase data; A2, remove the horn antenna, test the RF cable loss between the output port of the vector network analyzer and the horn antenna, calculate the horn antenna gain and the total loss from the horn antenna to the input port of the vector network analyzer; A3, connect the active phased array antenna to the vector network analyzer and the near-field probe antenna, adjust the antenna alignment and polarization direction, set the active phased array antenna to the transmit beam state, measure the S21 amplitude of the active phased array antenna near field, and record the output power of the vector network analyzer; A4, gradually increase the power output of the vector network analyzer. When the S21 amplitude drops to a value greater than the set value, record the S21 amplitude and the output power of the vector network analyzer, readjust the output power of the vector network analyzer to the output power in A3, perform a planar near-field scan of the active phased array antenna, and obtain the near-field amplitude and phase data of the active phased array antenna. A5, perform near-field to far-field conversion on the planar near-field amplitude and phase data of the horn antenna and the active phased array antenna, obtain the gain of the active phased array antenna based on the gain of the horn antenna, calculate the total loss from the active phased array antenna to the input of the vector network analysis, and calculate the EIRP value of the active phased array antenna.
2. According to claim 1, the method for testing EIRP of an active phased array antenna based on planar near field is characterized in that: In step A1 or A3, connecting the vector network analyzer and the near-field probe antenna includes: connecting the output port of the vector network analyzer to the horn antenna through a radio frequency cable, and connecting the input port of the vector network analyzer to the near-field probe antenna through a radio frequency cable.
3. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 1, characterized in that: In step A1 or A3, adjusting the antenna alignment and polarization direction includes: Set the operating frequency of the vector network analyzer, adjust the near-field probe antenna to align with the center of the horn antenna, keep the polarization direction consistent, and keep the distance between the apertures between 3 and 10 times the wavelength of the near-field test distance.
4. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 3, characterized in that: The polarization direction being consistent includes: When the horn antenna is linearly polarized, adjust the linear polarization direction of the near-field probe antenna to be consistent with the linear polarization direction of the horn antenna; When the horn antenna is circularly polarized, adjust the circular polarization direction of the near-field probe antenna to be consistent with the circular polarization direction of the horn antenna.
5. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 3, characterized in that: The distance between the apertures is maintained between 3 and 10 times the wavelength of the near-field test distance and must be consistent with the aperture distance during the horn antenna test.
6. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 1, characterized in that: When the active phased array antenna is in a transmitting beam state, the beam pointing is between 0° and 70°.
7. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 1, 2 or 3, characterized in that: The formula for calculating the horn antenna gain and the total loss from the horn antenna to the vector network analysis input is: <h2 style=";text-align:left;direction:ltr">L_ant=S21_ant-G_ant-L<h2 style=";text-align:left;direction:ltr"> l <h2 style=";text-align:left;direction:ltr"> ; Where L_ant is the total loss from the horn antenna to the input of the vector network analysis, S21_ant is the S21 amplitude of the horn antenna near field, L l is the RF cable loss connecting the output port of the vector network analyzer and the horn antenna.
8. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 7, characterized in that: The formula for calculating the total loss from the active phased array antenna to the vector network analysis input is: L_apr=L_ant+S21_p1-S21_ant+G_ant-G_apr; Among them, L_apr is the total loss from the active phased array antenna to the input of the vector network analysis, L_ant is the total loss from the horn antenna to the input of the vector network analysis, S21_p1 is the S21 amplitude in A4, S21_ant is the S21 amplitude in the near field of the horn antenna, G_ant is the gain of the horn antenna, and G_apr is the gain of the active phased array antenna.
9. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 8, characterized in that: The formula for calculating the EIRP value of the active phased array antenna is: EIRP=P_1+S21_p1-L_apr+S21_p1-S21_p0; Among them, EIRP is the EIRP value of the active phased array antenna, P_1 is the output power of the vector network analyzer in A4, S21_p1 is the S21 amplitude in A4, L_apr is the total loss from the active phased array antenna to the input of the vector network analysis, and S21_p0 is the S21 amplitude in the near field of the active phased array antenna.
10. The method for testing EIRP of an active phased array antenna based on planar near field according to claim 1, characterized in that: In step A5, the power output of the vector network analyzer is gradually increased by controlling the power output to be gradually increased in steps of 0.5 dB to 2 dB.