A phased array antenna multi-beam channel calibration system

Abstract

The application discloses a kind of phased array antenna multi-beam channel calibration systems, comprising: fixed probe, it is set to the antenna to be measured and receives direction perpendicular to the plane where antenna to be measured is located, for receiving the signal that antenna to be measured emits and conversion is calibration signal;Upper computer, for outputting frequency control instruction to vector network analyzer, outputting beam control instruction to wave control time sequence controller, receiving each group calibration signal sent by vector network analyzer, the initial test amplitude and initial phase value obtained by calculating to all calibration signals, according to the initial test amplitude and initial phase value of antenna each channel coordinate relationship and frequency size are compensated to obtain the amplitude data and phase data after compensation.The application keeps probe stationary, so that the quick calibration test of each channel under each frequency point, each beam can be quickly completed, to ensure the quick calibration efficiency of phased array antenna.

Description

Technical Field

[0001] The present invention relates to the field of antenna measurement, and in particular to a multi-beam channel calibration system for a phased array antenna. Background Art

[0002] With the continuous development of wireless communication application demand, the large-scale and widespread application of active phased array antennas, especially with the rapid development of multi-beam phased array antennas, batch production and testing of phased array antennas, a convenient and efficient device has become more urgent. A fast testing method and algorithm will greatly improve test efficiency and save enterprise costs.

[0003] In current industry technology, channel calibration testing for phased array antennas often utilizes traditional planar near-field calibration methods. This involves using a mechanical device such as a scanning gantry to carry a probe antenna through physical movement to collect amplitude and phase data for the current channel, thereby completing calibration. For example, prior art (patent application number CN202110902101.8) discloses a rapid calibration and testing system and method for phased array antennas. This system, which falls within the field of antenna measurement technology and relates to a near-field testing system, specifically to rapid calibration and pattern testing of phased array antennas. The system includes a host computer module, a switch module, a synchronization control module, a signal source module, a power amplifier module, a low-noise amplifier module, a phased array antenna to be tested, a power supply module, a calibration control module, a scanning module, a signal conditioning module, and a vector network module. The scanning module receives configuration information from the switch module via an Ethernet interface, moves the scanning probe, and then transmits the scanning probe's position information to the switch module via the Ethernet interface.

[0004] This approach has the following disadvantages: Calibration of multi-beam channels takes significantly more time. For example, if the antenna under test is a multi-beam phased array antenna with 8 beams, a 1024-channel array, and 6 frequencies, calibration tests must be performed for each frequency and each beam's 1024 channels. This results in a total of 6 * 8 * 1024 = 49,152 calibration tests, requiring calibration of each channel at each frequency and each beam. Using conventional calibration methods, which rely on the physical movement of the scanning probe carried by the gantry, would be extremely time-consuming and labor-intensive. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a phased array antenna multi-beam channel calibration system.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] A first aspect of the present invention provides a phased array antenna multi-beam channel calibration system, comprising:

[0008] A fixed probe is set toward the antenna to be tested and its receiving direction is perpendicular to the plane where the antenna to be tested is located, and is used to receive the signal transmitted by the antenna to be tested and convert it into a calibration signal;

[0009] The host computer is used to output frequency control instructions to the vector network analyzer, output beam control instructions to the beam control timing controller, receive each set of calibration signals sent by the vector network analyzer, calculate all calibration signals to obtain initial test amplitude and initial phase values, and compensate the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency of each channel of the antenna to obtain compensated amplitude data and phase data;

[0010] The vector network analyzer is used to generate a specified frequency signal according to the received frequency control command and input it to the antenna under test, and transmit the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal;

[0011] The beam control timing controller is used to generate a beam control signal with a control sequence of "frequency-beam-channel" in sequence according to the received beam control instruction, input it to the antenna under test, and generate a trigger acquisition signal after outputting the beam control signal to the vector network analyzer.

[0012] Furthermore, the calibration signal includes real signal data and imaginary signal data.

[0013] Furthermore, the “frequency-beam-channel” is replaced by “frequency-beam-channel-phase”, where each channel corresponds to two phases, p1 and p1+180°, where p1 represents any value between 0 and 360°.

[0014] For the calibration signals corresponding to the two phase values ​​of the same frequency, the same beam and the same channel, the real part data of the signals are subtracted and then divided by two, and the imaginary part data of the signals are subtracted and then divided by two to obtain the calibration signal with interference removed.

[0015] Furthermore, the "frequency-beam-channel" is replaced by "frequency-beam-channel-phase", where each channel corresponds to four phases, namely p1, p2, p1+180°, and p2+180°, where p1 represents any value in the range of 0-360°, and p2 represents any value in the range of 0-360° except p1;

[0016] For the calibration signals with phase values ​​of p1 and p1+180° at the same frequency, beam, and channel, the real part of the signals is subtracted and then divided by two, and the imaginary part of the signals is subtracted and then divided by two to obtain the first calibration signal with interference removed.

[0017] For the calibration signals with phase values ​​of p2 and p2+180° at the same frequency, beam, and channel, subtract the real part of the signals and divide by two, and subtract the imaginary part of the signals and divide by two, respectively, to obtain a second calibration signal with interference removed.

[0018] The first calibration signal is used to calculate the first initial test amplitude and the first initial phase value, and the second calibration signal is used to calculate the second initial test amplitude and the second initial phase value. The average value of the first initial test amplitude and the second initial test amplitude is taken as the initial test amplitude, and the average value of the first initial phase value and the second initial phase value is taken as the initial phase value.

[0019] Furthermore, the vector network analyzer transmits the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal, and outputs a transmission completion signal to the beam control timing controller after the transmission is completed; the beam control timing controller generates the next beam control signal after receiving the transmission completion signal; or:

[0020] The beam control timing controller generates the next beam control signal at a fixed time.

[0021] Furthermore, the calibration system further comprises:

[0022] The switch is connected between the host computer and the vector network analyzer, and between the host computer and the wave control timing controller for data transmission.

[0023] Furthermore, the initial test amplitude and initial phase values ​​are compensated according to the coordinate relationship and frequency of each channel of the antenna to obtain the compensated amplitude data and phase data, specifically including:

[0024] Using the channel coordinate relationship and wavelength, the wave path difference △phase between the corresponding channel and the physical distance difference C is calculated;

[0025] Using the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f, the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel is calculated;

[0026] The initial test amplitude is superimposed on the wave path difference △phase to obtain the calibrated amplitude data, and the initial phase value is superimposed on the signal attenuation difference △mag to obtain the calibrated phase data.

[0027] Furthermore, the calculation of the wavelength difference Δphase between the corresponding channel and the physical distance difference C using the channel coordinate relationship and the wavelength includes:

[0028] Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel;

[0029] The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k;

[0030] The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h;

[0031] The path difference △phase is calculated based on the physical distance difference C and the wavelength λ.

[0032] Furthermore, the calculation of the signal attenuation difference Δmag during electromagnetic wave transmission of the corresponding channel using the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f includes:

[0033] Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel;

[0034] The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k;

[0035] The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h;

[0036] Substitute the physical distance difference C and the electromagnetic wave transmission frequency f into the electromagnetic wave spatial transmission attenuation formula to calculate the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel.

[0037] Furthermore, the calibration system further comprises:

[0038] DC power supply, used to supply power to the beam control timing controller and the antenna under test.

[0039] The beneficial effects of the present invention are:

[0040] (1) In an exemplary embodiment of the present invention, the system can keep the scanning probe stationary, so that it can quickly complete the rapid calibration test of each channel under each frequency point and each beam, and complete the final test through mathematical algorithm analysis data processing to ensure the rapid calibration efficiency of the phased array antenna (that is, during the test, the probe and the antenna under test remain stationary, and the rapid beam state switching and channel state switching of the wave control timing controller and the use of triggered communication with the vector network analyzer are used to complete the rapid channel calibration test). Its test efficiency is 30-50 times that of the traditional calibration test method, which greatly improves the efficiency.

[0041] No scanning frame control or motion is required, significantly reducing scanning frame costs, labor, and equipment costs in traditional testing processes. Furthermore, the test environment is extremely simple to set up, with low requirements, eliminating the high-precision scanning frame control and scanning plane requirements required in traditional testing methods.

[0042] It can perform multi-beam phased array antenna testing as well as conventional phased array antenna testing (i.e., the beam value can be 1), and has wide applicability.

[0043] (2) In an exemplary embodiment of the present invention, two calibration signals with a phase difference of 180° are collected for the same channel. The real part data of the two calibration signals are subtracted and then divided by two, and the imaginary part data of the two calibration signals are subtracted and then divided by two to obtain a calibration signal with interference removed. The test mode with coupling removal algorithm is adopted, which can not only meet the phased array calibration test with single channel switching, but also the test mode with all antenna array channels open, so that the device can use calibration tests with different antenna power-on states.

[0044] (3) In an exemplary embodiment of the present invention, the signal with a phase difference of 180° is subtracted. Since the two sets of data are inverse signals, the subtraction of the two can quickly filter out the relevant useless signals. At the same time, the average value of the two correlation tests is taken to make the final result closer to the true value.

[0045] (4) In one exemplary embodiment of the present invention, the beam control timing controller and the vector network analyzer use external trigger handshake signals for communication throughout the entire calibration test, making the entire calibration test faster. In another exemplary embodiment, the beam control timing controller generates the next beam control signal at a fixed time, which makes the data acquisition process stable and controllable.

[0046] (5) In an exemplary embodiment of the present invention, the switch is mainly used for network port communication, and the settings are mainly dependent on the host computer. The switch plays the role of data forwarding and network communication.

[0047] (6) In an exemplary embodiment of the present invention, a specific implementation method of calibration data is disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a structural block diagram of a phased array antenna multi-beam channel calibration system provided in an exemplary embodiment of the present invention;

[0049] Figure 2 This is a structural block diagram of a phased array antenna multi-beam channel calibration system provided in yet another exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is described clearly and completely below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0051] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "up," "down," "left," "right," "vertical," "horizontal," "inside," and "outside" are based on the directions or positional relationships described in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0053] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0054] See also Figure 1 , Figure 1 The structure block diagram of a phased array antenna multi-beam channel calibration system provided by an exemplary embodiment of the present invention is shown, including:

[0055] A fixed probe is set toward the antenna to be tested and its receiving direction is perpendicular to the plane where the antenna to be tested is located, and is used to receive the signal transmitted by the antenna to be tested and convert it into a calibration signal;

[0056] The host computer is used to output frequency control instructions to the vector network analyzer, output beam control instructions to the beam control timing controller, receive each set of calibration signals sent by the vector network analyzer, calculate all calibration signals to obtain initial test amplitude and initial phase values, and compensate the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency of each channel of the antenna to obtain compensated amplitude data and phase data;

[0057] The vector network analyzer is used to generate a specified frequency signal according to the received frequency control command and input it to the antenna under test, and transmit the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal;

[0058] The beam control timing controller is used to generate a beam control signal with a control sequence of "frequency-beam-channel" in sequence according to the received beam control instruction, input it to the antenna under test, and generate a trigger acquisition signal after outputting the beam control signal to the vector network analyzer.

[0059] Specifically, in this exemplary embodiment, the entire calibration process includes a radio frequency control part and a calibration control part, wherein:

[0060] The RF control section includes: a host computer outputs frequency control commands to the vector network analyzer. The vector network analyzer generates a specified frequency signal based on the received frequency control commands and inputs it to the antenna under test. A fixed probe receives the antenna's transmitted signal and converts it into a calibration signal, which is then input to the vector network analyzer, thus completing the closed-loop RF link. The fixed probe is positioned toward the antenna under test, with the receiving direction perpendicular to the plane of the antenna under test, and remains stationary throughout the entire process.

[0061] The calibration control part includes: the host computer outputs beam control instructions to the wave control timing controller, and the wave control timing controller generates beam control signals with a control sequence of "frequency-beam-channel" in sequence according to the received beam control instructions, and inputs them into the antenna to be tested, thereby changing the broadcast control state of the antenna, that is, placing the antenna in different frequency points, different beams, and different channels in sequence to meet the needs of fast calibration testing; at the same time, the wave control timing controller generates a trigger acquisition signal after outputting the beam control signal and outputs it to the vector network analyzer. After receiving the trigger acquisition signal, the vector network analyzer triggers the vector network acquisition, that is, transmits the calibration signal output by the fixed probe to the host computer until the test of all frequencies, all beams, and all channels is completed. At this time, the wave control timing controller also stops the output of the beam control signal; finally, the host computer receives all the calibration signals, and compensates the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency size of each channel of the antenna to obtain the compensated amplitude data and phase data.

[0062] Taking a multi-beam phased array antenna with 8 beams, an array size of 1024 channels, and a total of 6 frequencies as an example, the beam control signal of "frequency-beam-channel" has a frequency value of 1-6, a beam value of 1-8, and a channel value of 1-1024. In one exemplary embodiment, the above-mentioned "frequency-beam-channel" generated in sequence can be "1-1-1", "1-1-2", ..., "3-2-248", "3-2-249", ... "6-8-1023", "6-8-1024", that is, after the data collection of all channels of the same beam at the same frequency is completed, the data collection of all channels of the next beam at the same frequency is carried out. After the data collection of all channels of all beams at the same frequency is completed, the data collection of all channels of the same beam at the next frequency is carried out. In another exemplary embodiment, after the data collection of all channels of the same beam at the same frequency is completed, the data collection of all channels of the same beam at the next frequency is carried out, and so on. As long as the data collection of all channels of all beams at all frequencies can be achieved,

[0063] In summary, the advantages of this exemplary embodiment are as follows:

[0064] (1) The system using this exemplary embodiment can keep the scanning probe stationary, so that it can quickly complete the rapid calibration test of each channel under each frequency point and each beam, and complete the final test through mathematical algorithm analysis data processing to ensure the rapid calibration efficiency of the phased array antenna (that is, during the test, the probe and the antenna under test remain stationary, and the rapid beam state switching and channel state switching of the wave control timing controller and the use of triggered communication with the vector network analyzer are used to complete the rapid channel calibration test). Its test efficiency is 30-50 times that of the traditional calibration test method, which greatly improves the efficiency.

[0065] (2) The system using this exemplary embodiment does not require scanning frame control and movement, which greatly reduces the scanning frame cost in traditional testing processes, saving manpower and equipment costs. At the same time, the test environment is extremely simple to set up and has low requirements, omitting the high-precision control scanning frame requirements and scanning plane requirements in traditional testing methods. More specifically, not using a high-precision scanning frame can reduce construction costs by one-third.

[0066] (3) The system using this exemplary embodiment can perform multi-beam phased array antenna testing as well as conventional phased array antenna testing (i.e., the beam value can be 1), and has wide applicability.

[0067] It should be noted that when the calibration data / compensated amplitude data and phase data acquired by the host computer are consistent with the number of channels (or corresponding multiples as described in the preferred exemplary embodiment below), it can be determined that the calibration is completed.

[0068] The fixed probe can be located at a near-field, mid-field, or far-field distance from the antenna, with the mid-field distance providing the best performance. The mid-field distance falls between the near-field and far-field distances. In one exemplary embodiment, the near-field distance can be defined as the distance from the antenna to one wavelength (λ). The far-field distance can be defined as 2λ, 3λ, or 10λ, or as 5λ / 2π. In another exemplary embodiment, the mid-field, near-field, and far-field distances are calculated based on the antenna's maximum dimension D. For example, the far-field distance is ≥2D² / λ, the near-field distance is λ / 2π, and the mid-field distance lies between the two, preferably (2D² / λ) / 2. The choice can be made based on actual needs.

[0069] More preferably, in an exemplary embodiment, the calibration signal includes real signal data and imaginary signal data.

[0070] Specifically, in this exemplary embodiment, a beam-controlled timing controller triggers the acquisition signal output to a vector network analyzer. For a specific frequency, beam, and channel, the calibration signal acquired by the vector network analyzer is a complex number, rA+iA, where r represents the real signal data, i represents the imaginary signal data, and A represents the channel number. The complex number is used because it is directional.

[0071] More preferably, in an exemplary embodiment, the “frequency-beam-channel” is replaced by “frequency-beam-channel-phase”, where each channel corresponds to two phases, p1 and p1+180°, where p1 represents any value between 0-360°.

[0072] For the calibration signals corresponding to the two phase values ​​of the same frequency, the same beam and the same channel, the real part data of the signals are subtracted and then divided by two, and the imaginary part data of the signals are subtracted and then divided by two to obtain the calibration signal with interference removed.

[0073] Specifically, in this exemplary embodiment, the phase of the control channel cn is in the p1 state, where p1 is a constant and can be any value in the range of (0-360°). The channel phase states of all phased array antennas can be set to the p1 value.

[0074] For a certain frequency point, a certain beam, and a certain channel, two acquisition signals are triggered in sequence by the beam control timing controller and output to the vector network analyzer. The phases of the two "frequency point-beam-channel-phase" beam control signals are p1 and p1+180° respectively. At this time, the two calibration signals collected by the vector network analyzer are the complex number rA1+iA1 and the complex number rA2+iA2 respectively. The "1" in the "complex number rA1+iA1" represents the first data acquisition of the channel, and the "2" in the "complex number rA2+iA2" represents the second data acquisition of the channel.

[0075] Here, rA1, rA2, iA1, and iA2 represent signals in different states and are vector data. Each data point represents the sum of the true signal and the interference signal. Since the interval between acquisitions is very short, it can be assumed that the interference signal remains constant throughout the test. rA1 and rA2 are 180° apart and have an inverse relationship, and iA1 and iA2 are similarly 180° apart and have an inverse relationship. Therefore, when subtracting rA1 from rA2 and iA1 from iA2, the interference signals in the same direction can be subtracted. Due to their inverse nature, the result of the subtraction is twice the true signal. Therefore, the calibration signal (i.e., a complex number) calculated using this method is the real and imaginary components of the true signal in the same direction. Specifically, rA1 = (rA1 - rA2) / 2, and iA1 = (iA1 - iA2) / 2.

[0076] Therefore, by adopting this method, the interference signal can be filtered out, making the data collection more accurate.

[0077] Furthermore, mathematical algorithms are used to remove coupled signals, allowing calibration tests to be performed even with all channels of the antenna under test fully powered. Specifically, if the antenna under test is fully powered, the test data will be less reliable. If the antenna under test is fully powered without decoupling noise technology, the collected signal will be impure, incorporating spatial noise and signals radiated from other channels, resulting in an inaccurate signal.

[0078] More specifically, in this exemplary embodiment, by collecting vector data, reverse data A and data B can be obtained, and A and B are equal-energy signals. Assuming C is the coupling noise and spatial interference information, the following relationship is obtained:

[0079] A=A1+C; and B=B1+C;

[0080] Among them, A1 and B1 are two real reverse signals, then AB=2A1, so C has been eliminated through the implementation of the algorithm, so the measured data will be more accurate and real, improving the accuracy of system testing.

[0081] Therefore, the test mode with the coupling removal algorithm can not only meet the phased array calibration test with single channel switching, but also test the test mode with all antenna array channels open. Therefore, the device can perform calibration tests with different antenna power-on states.

[0082] More preferably, in an exemplary embodiment, the “frequency-beam-channel” is replaced by “frequency-beam-channel-phase”, where each channel corresponds to four phases, namely p1, p2, p1+180°, and p2+180°, where p1 represents any value in the range of 0-360°, and p2 represents any value in the range of 0-360° except p1.

[0083] For the calibration signals with phase values ​​of p1 and p1+180° at the same frequency, beam, and channel, the real part of the signals is subtracted and then divided by two, and the imaginary part of the signals is subtracted and then divided by two to obtain the first calibration signal with interference removed.

[0084] For the calibration signals with phase values ​​of p2 and p2+180° at the same frequency, beam, and channel, subtract the real part of the signals and divide by two, and subtract the imaginary part of the signals and divide by two, respectively, to obtain a second calibration signal with interference removed.

[0085] The first calibration signal is used to calculate the first initial test amplitude and the first initial phase value, and the second calibration signal is used to calculate the second initial test amplitude and the second initial phase value. The average value of the first initial test amplitude and the second initial test amplitude is taken as the initial test amplitude, and the average value of the first initial phase value and the second initial phase value is taken as the initial phase value.

[0086] Specifically, similar to the above exemplary embodiment, interference signals can be filtered out by subtracting 180° opposite data, making data acquisition more accurate; and in this exemplary embodiment, two sets of calibration data are also used to calculate the initial test amplitude and initial phase value respectively and take the average value. The purpose of taking the average value is mainly to avoid the spatial interference signal from being completely filtered out during a certain test process, and the two average values ​​are used to minimize the impact on the data results in the event of an accident.

[0087] For example, if the channel is broken, the final result will be a noise signal that is infinitesimal. If the result is inaccurate due to a large noise influence, it will be a value much smaller than the normal theoretical value. First, the final result can be quickly observed to confirm that the measured channel has been damaged. Second, it can quickly confirm that the channel is not damaged, but the coupling or noise signal is too large.

[0088] The initial test amplitude and initial phase values ​​are calculated for all calibration signals:

[0089] (1) Taking an exemplary embodiment in which only one set of calibration signals is collected or an exemplary embodiment in which only interference signals are filtered out as an example, the calibration signal or the calibration signal after interference removal is rA1+iA1. Then, the method for calculating the initial test amplitude and initial phase value is:

[0090] The initial test amplitude mag={Log10[(rA1^2)+iA1^2)]^0.5}*20, and the initial phase value phase=tan(rA1 / iA1).

[0091] (2) For an exemplary embodiment with two sets of calibration signals, the first calibration signal is rA1+iA1 and the second calibration signal is rA2+iA2, then the initial test amplitude and initial phase values ​​are calculated as follows:

[0092] The first calibration signal is used to calculate and obtain a first initial test amplitude and a first initial phase value:

[0093] The first initial test amplitude mag1={Log10[(rA1^2)+iA1^2)]^0.5}*20, the initial phase value phase1=tan(rA1 / iA1);

[0094] The second calibration signal is used to calculate the second initial test amplitude and the second initial phase value:

[0095] The second initial test amplitude mag2={Log10[(rA2^2)+iA2^2)]^0.5}*20, the initial phase value phase2=tan(rA2 / iA2);

[0096] Take the average of the first initial test amplitude and the second initial test amplitude as the initial test amplitude:

[0097] Initial test amplitude mag=(mag1+mag2) / 2;

[0098] Take the average of the first initial phase value and the second initial phase value as the initial phase value:

[0099] The initial phase value phase = (phase1 + phase2) / 2.

[0100] More preferably, in an exemplary embodiment, the vector network analyzer transmits the calibration signal output by the fixed probe to a host computer after receiving the trigger acquisition signal, and outputs a transmission completion signal to the beam control timing controller after the transmission is completed; the beam control timing controller generates a next beam control signal after receiving the transmission completion signal; or:

[0101] The beam control timing controller generates the next beam control signal at a fixed time.

[0102] Specifically, in one embodiment of this exemplary embodiment, the beamforming timing controller and the vector network analyzer communicate entirely using external trigger handshake signals. During signal transmission, the beamforming timing controller generates a trigger acquisition signal after outputting a beam steering signal and outputs it to the vector network analyzer. Upon receiving the trigger acquisition signal, the vector network analyzer transmits the calibration signal output by the fixed probe to the host computer. During signal reception, the vector network analyzer transmits the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal. Upon completion of the transmission, the vector network analyzer outputs a transmission completion signal to the beamforming timing controller. Upon receiving the transmission completion signal, the beamforming timing controller generates the next beam steering signal. This approach speeds up the entire calibration test.

[0103] More specifically, if Figure 2 As shown, the TCP / IP module of the beam control timing controller is connected to the host computer (in a preferred exemplary embodiment, the connection is made to the host computer via a switch) to obtain the beam control instructions of the host computer and transmit them to the FPGA of the beam control timing controller; the FPGA generates a beam control signal according to the beam control instruction and sends it to the antenna under test through the J30J connector. When the beam control signal is sent (i.e., the corresponding state of the antenna under test is controlled), the FPGA generates a trigger acquisition signal and outputs it to the TriggerIn interface of the vector network analyzer through the BNC OUT interface, triggering the vector network analyzer to acquire the signal; after the vector network analyzer completes acquiring the calibration signal, the ReadyForTrigger of the vector network analyzer will output a high-level signal (i.e., a transmission completion signal) to the BNC IN interface of the beam control timing controller. After receiving the transmission completion signal, the FPGA of the beam control timing controller generates the next beam control signal.

[0104] In another embodiment of the present invention, the beam control timing controller generates the next beam control signal at a fixed time. This method makes the data acquisition process stable and controllable.

[0105] More preferably, in an exemplary embodiment, Figure 2 As shown, the calibration system further includes:

[0106] The switch is connected between the host computer and the vector network analyzer, and between the host computer and the wave control timing controller for data transmission.

[0107] Specifically, in this exemplary embodiment, the switch is mainly used for network port communication, and the settings are mainly dependent on the host computer. The switch plays the role of data forwarding and network communication.

[0108] In addition, optionally, in an exemplary embodiment, the host computer may also be connected to the antenna under test via a switch (not shown in the figure). The host computer mainly controls the antenna under test, forwards the protocol via the switch, and performs network communication.

[0109] More preferably, in an exemplary embodiment, compensating the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency of each channel of the antenna to obtain the compensated amplitude data and phase data specifically includes:

[0110] Using the channel coordinate relationship and wavelength, the wave path difference △phase between the corresponding channel and the physical distance difference C is calculated;

[0111] Using the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f, the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel is calculated;

[0112] The initial test amplitude is superimposed on the wave path difference △phase to obtain the calibrated amplitude data, and the initial phase value is superimposed on the signal attenuation difference △mag to obtain the calibrated phase data.

[0113] Specifically, in this exemplary embodiment, a specific implementation of calibration data is disclosed.

[0114] The calibrated amplitude data is obtained by superimposing the initial test amplitude on the wave path difference Δphase, and the calibrated phase data is obtained by superimposing the initial phase value on the signal attenuation difference Δmag. Specifically, the following steps can be performed:

[0115] The calibrated amplitude data Mag = initial test amplitude mag + signal attenuation difference △mag;

[0116] The calibrated phase data Phase = initial phase value phase + path difference △phase.

[0117] More preferably, in an exemplary embodiment, the calculating the wavelength difference Δphase between the corresponding channel and the physical distance difference C using the channel coordinate relationship and the wavelength includes:

[0118] Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel;

[0119] The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k;

[0120] The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h;

[0121] The path difference △phase is calculated based on the physical distance difference C and the wavelength λ.

[0122] Specifically, in this exemplary embodiment, unlike traditional near-field calibration tests, since there is no motion control of the scanning frame, the physical distance between each channel of the phased array antenna under test and the fixed probe is different. Therefore, during the electromagnetic wave transmission process, due to the different transmission distances, the period it takes for the electromagnetic wave emitted from the phased array channel under test (the corresponding channel) to reach the probe that receives the signal is also different.

[0123] Available known data include: wavelength λ = V / f, where V is the speed of light (3*10^8 m / s), f is the electromagnetic wave transmission frequency, and h is the test distance (i.e., the distance between the fixed probe and the plane of the antenna under test). The origin is the point of direct light from the fixed probe perpendicular to the plane of the antenna under test, or any point on the plane of the antenna under test. In one exemplary embodiment, for the majority of cases where the antenna under test is a planar antenna, (dx, dy) are the coordinates of each channel. In another exemplary embodiment, for the minority of cases where the antenna under test is a conformal antenna, (dx, dy, dz) are the coordinates of each channel. The following uses the planar antenna as an example. For conformal antennas, dz can be added to the calculation.

[0124] The process for calculating the wave path difference △phase can include:

[0125] (1) As shown above, (dx, dy) is the relative coordinate of the reference point. According to the Pythagorean theorem, its hypotenuse is K=(dx^2+dy^2)^0.5, which is also the first distance K between the corresponding channel and the origin.

[0126] (2) h is the test distance. According to the Pythagorean theorem, the second distance between the tested phased array channel (corresponding channel) and the fixed probe is L=(K^2+h^2)^0.5.

[0127] (3) If the test distance is known to be h, then the difference between the distance of the tested phased array channel (corresponding channel) from the fixed probe and the test distance is the physical distance difference C = Lh, where C is the physical distance difference.

[0128] (4) Since the wavelength of the test frequency is λ, the path difference between the frequency channels is △phase = C %λ, where C is the physical distance difference and λ is the wavelength. The modulo C and λ is the path difference △phase between the tested phased array channel and the test distance.

[0129] More preferably, in an exemplary embodiment, the calculation of the signal attenuation difference Δmag during electromagnetic wave transmission of the corresponding channel using the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f includes:

[0130] Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel;

[0131] The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k;

[0132] The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h;

[0133] Substitute the physical distance difference C and the electromagnetic wave transmission frequency f into the electromagnetic wave spatial transmission attenuation formula to calculate the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel.

[0134] Specifically, unlike traditional near-field calibration tests, this exemplary embodiment lacks motion control of the scanning gantry. Consequently, each channel of the phased array antenna under test is physically located at a different distance from the fixed probe. Therefore, during electromagnetic wave transmission, the electromagnetic waves emitted from the tested channels (corresponding channels) experience varying atmospheric attenuation upon reaching the fixed probe receiving the signal due to varying transmission distances. The formula for electromagnetic wave spatial transmission attenuation is known to be: S = 32.45 + 20*LOG(f) + 20*LOG(L), where 32.45 is the free-space dissipation formula (i.e., the Friis constant -32.44 dB), f is the electromagnetic wave transmission frequency, and L is the transmission distance.

[0135] The process of calculating the signal attenuation difference △mag based on the wave path difference △phase may include (wherein, the available known data that are the same as those for calculating the wave path difference △phase are not described in detail):

[0136] (1) As shown above, (dx, dy) is the relative coordinate of the reference point. According to the Pythagorean theorem, its hypotenuse is K=(dx^2+dy^2)^0.5, which is also the first distance K between the corresponding channel and the origin.

[0137] (2) h is the test distance. According to the Pythagorean theorem, the distance between the tested phased array channel (corresponding channel) and the fixed probe is L = (K^2 + h^2)^0.5.

[0138] (3) If the test distance is known to be h, then the difference between the distance of the tested phased array channel (corresponding channel) from the fixed probe and the test distance is C=Lh, that is, the physical distance difference C.

[0139] (4) The signal attenuation difference during the electromagnetic wave transmission of the corresponding phased array channel is: △mag=32.45+20*LOG(f)+20*LOG(C).

[0140] More preferably, in an exemplary embodiment, Figure 2 As shown, the calibration system further includes:

[0141] DC power supply, used to supply power to the beam control timing controller and the antenna under test.

[0142] The wave-controlled timing controller has a DC-DC module inside to complete the power conversion. The vector network analyzer can be directly powered by 220V AC.

[0143] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications can be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications derived therefrom remain within the scope of protection of the present invention.

Claims

1. A phased array antenna multi-beam channel calibration system, characterized by: include: A fixed probe is set toward the antenna under test with the receiving direction perpendicular to the plane where the antenna under test is located, and is used to receive the signal transmitted by the antenna under test and convert it into a calibration signal; the distance between the fixed probe and the antenna under test is a near-field distance, a mid-field distance, or a far-field distance, and the mid-field distance is between the near-field distance and the far-field distance; The host computer is used to output frequency control instructions to the vector network analyzer, output beam control instructions to the beam control timing controller, receive each set of calibration signals sent by the vector network analyzer, calculate all calibration signals to obtain initial test amplitude and initial phase values, and compensate the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency of each channel of the antenna to obtain compensated amplitude data and phase data; The vector network analyzer is used to generate a specified frequency signal according to the received frequency control command and input it to the antenna under test, and transmit the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal; The beam control timing controller is used to generate a beam control signal in the order of "frequency-beam-channel" according to the received beam control instruction, input it to the antenna under test, and generate a trigger acquisition signal after outputting the beam control signal to the vector network analyzer; The switch is connected between the host computer and the vector network analyzer, and between the host computer and the wave control timing controller for data transmission; DC power supply, used to supply power to the beam control timing controller and the antenna under test; The compensating the initial test amplitude and initial phase values ​​according to the coordinate relationship and frequency of each channel of the antenna to obtain the compensated amplitude data and phase data specifically includes: Using the channel coordinate relationship and wavelength, the path difference △phase between the measured phased array channel and the test distance is calculated; Using the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f, the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel is calculated; The initial test amplitude is superimposed on the wave path difference △phase to obtain the calibrated amplitude data, and the initial phase value is superimposed on the signal attenuation difference △mag to obtain the calibrated phase data; The TCP / IP module of the beam control timing controller is connected to the host computer to obtain the beam control instructions from the host computer and transmit them to the FPGA of the beam control timing controller; the FPGA generates a beam control signal according to the beam control instruction and sends it to the antenna under test through the J30J connector. When the beam control signal is sent, the FPGA generates a trigger acquisition signal and outputs it to the TriggerIn interface of the vector network analyzer through the BNC OUT interface, triggering the vector network analyzer to acquire the signal; after the vector network analyzer completes the acquisition of the calibration signal, the ReadyForTrigger of the vector network analyzer will output a high-level signal, that is, a transmission completion signal, to the BNC IN interface of the beam control timing controller. After receiving the transmission completion signal, the FPGA of the beam control timing controller generates the next beam control signal.

2. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The near-field distance is the distance from the antenna to be measured to one wavelength λ, and the far-field distance is beyond 2λ, 3λ, 10λ or 5λ / 2π.

3. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The mid-field distance, near-field distance, and far-field distance are calculated based on the maximum dimension D of the antenna. The far-field distance is ≥2D² / λ, the near-field distance is λ / 2π, and the mid-field distance lies in between, where λ represents the wavelength.

4. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The calibration signal includes real signal data and imaginary signal data.

5. The phased array antenna multi-beam channel calibration system according to claim 4, characterized in that: The "frequency-beam-channel" is replaced by "frequency-beam-channel-phase", where each channel corresponds to two phases, p1 and p1+180°, where p1 represents any value from 0 to 360°; For the calibration signals corresponding to the two phase values ​​of the same frequency, the same beam and the same channel, the real part data of the signals are subtracted and then divided by two, and the imaginary part data of the signals are subtracted and then divided by two to obtain the calibration signal with interference removed.

6. The phased array antenna multi-beam channel calibration system according to claim 4, characterized in that: The "frequency-beam-channel" is replaced by "frequency-beam-channel-phase", where each channel corresponds to four phases, namely p1, p2, p1+180°, and p2+180°, where p1 represents any value in the range of 0-360°, and p2 represents any value in the range of 0-360° except p1; For the calibration signals with phase values ​​of p1 and p1+180° at the same frequency, beam, and channel, the real part of the signals is subtracted and then divided by two, and the imaginary part of the signals is subtracted and then divided by two to obtain the first calibration signal with interference removed. For the calibration signals with phase values ​​of p2 and p2+180° at the same frequency, beam, and channel, subtract the real part of the signals and divide by two, and subtract the imaginary part of the signals and divide by two, respectively, to obtain a second calibration signal with interference removed. The first calibration signal is used to calculate the first initial test amplitude and the first initial phase value, and the second calibration signal is used to calculate the second initial test amplitude and the second initial phase value. The average value of the first initial test amplitude and the second initial test amplitude is taken as the initial test amplitude, and the average value of the first initial phase value and the second initial phase value is taken as the initial phase value.

7. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The vector network analyzer transmits the calibration signal output by the fixed probe to the host computer after receiving the trigger acquisition signal, and outputs a transmission completion signal to the beam control timing controller after the transmission is completed; the beam control timing controller generates the next beam control signal after receiving the transmission completion signal; or: The beam control timing controller generates the next beam control signal at a fixed time.

8. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The calculation of the wavelength difference Δphase between the corresponding channel and the physical distance difference C using the channel coordinate relationship and the wavelength includes: Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel; The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k; The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h; The path difference △phase is calculated based on the physical distance difference C and the wavelength λ.

9. The phased array antenna multi-beam channel calibration system according to claim 1, characterized in that: The method uses the electromagnetic wave spatial transmission attenuation formula, the physical distance difference C between the corresponding channel and the fixed probe, and the electromagnetic wave transmission frequency f to calculate the signal attenuation difference Δmag during the electromagnetic wave transmission process of the corresponding channel, including: Taking the center of the antenna front as the origin, calculate the first distance K between the corresponding channel and the origin according to the coordinates of each channel; The second distance L between the corresponding channel and the fixed probe is calculated according to the test distance h and the first distance k; The physical distance difference C between the corresponding channel and the fixed probe is calculated based on the second distance L and the test distance h; Substitute the physical distance difference C and the electromagnetic wave transmission frequency f into the electromagnetic wave spatial transmission attenuation formula to calculate the signal attenuation difference △mag during the electromagnetic wave transmission process of the corresponding channel.

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