Radio frequency wire testing apparatus for digital multi-beamforming patterns

Abstract

The application discloses a kind of digital multi-beam forming directivity diagram radio frequency wired testing device, the application first builds directivity diagram radio frequency wired test environment, equipment to be measured mainly includes: digital array component, beam forming unit and beam control unit, auxiliary test equipment mainly includes: signal source, spectrum analyzer, power divider, radio frequency cable, digital-to-analog conversion equipment etc., with equal length and in-phase radio frequency cable is connected to the channel in digital array component and the arrangement direction of the azimuth angle to be scanned is consistent, fix two typical azimuths perpendicular to each other, respectively to scan elevation direction, obtain two-dimensional cross-section directivity diagram by spectrum analyzer.The application proposes a kind of method for directivity diagram test under laboratory desktop environment under the background of digital multi-beam verification demand, solves the directivity diagram convenient verification problem of multi-beam system, and can be applied to phased array antenna field.

Description

Technical Field

[0001] This invention relates to the field of phased array antennas, and in particular to a wired radio frequency test apparatus for digital multi-beamforming patterns. Background Technology

[0002] Phased array antennas, with their flexible beam scanning capabilities, are widely used in fields such as communication, telemetry, and radar. After the array antenna beam is formed, its radiation pattern usually needs to be scanned and tested, which is an important means of verifying the array antenna's synthesized gain and beamforming algorithm.

[0003] Methods for testing the radiation pattern of phased array antennas can be categorized by far-field conditions (far-field method and near-field method) and by auxiliary equipment type (turntable method and calibration antenna movement method). The turntable method typically involves selecting a microwave anechoic chamber equipped with a turntable, mounting the antenna under test (DUT) on the turntable, and performing near-field phase shift compensation or no far-field compensation based on the distance relationship between each element of the DUT and the calibration antenna. The DUT is then rotated using the turntable to measure the phased array antenna radiation pattern. The turntable method requires a turntable and servo system. For situations where a turntable is unavailable or inconvenient, the calibration antenna can be mounted on a mobile platform (vehicle-mounted, ship-mounted, airborne, etc.) to scan the array radiation pattern. The calibration antenna movement method requires mounting the antenna on a mobile platform, recording its trajectory, and combining the results with ground system test data to obtain the radiation pattern. This method is relatively cumbersome, costly, and has limited engineering applicability.

[0004] In recent years, digital array antennas have gained increasing popularity due to their advantages of flexible multi-beamforming and easy reconfiguration. After the multi-beamforming algorithm is injected into a digital array, verification and testing of the radiation pattern for each beam and at different frequencies are required. Even after the multi-beam algorithm is reconfigured, further testing is necessary. This involves a large workload, tight deadlines, and limited verification sites. Traditional radiation pattern testing methods can no longer meet the batch verification requirements of digital multi-beam systems. Therefore, a flexible and convenient radiation pattern testing and verification method needs to be designed for digital multi-beam systems. Summary of the Invention

[0005] In view of this, the present invention proposes a wired radio frequency test device for digital multi-beamforming pattern to solve the problems in the background art.

[0006] The technical solution adopted in this invention is as follows:

[0007] A wired test apparatus for digital multi-beamforming pattern radio frequency includes a signal source, a power divider, radio frequency cables, a digital array assembly, a beamforming unit, a beam control unit, a digital-to-analog converter, and a spectrum analyzer.

[0008] The signal source is used to generate a test reference signal, which is then output to the power divider.

[0009] A power divider is used to split a single signal output from a signal source into multiple signals and output them to a digital array component via radio frequency cables;

[0010] The digital array component is used to amplify, frequency convert, and convert the corresponding input signals into digital signals through multiple receiving channels, and output digital signals to the beamforming unit.

[0011] The beam control unit is used to fix an azimuth angle and set the elevation angle scanning parameters each time, calculate the amplitude and phase weights of different receiving channels in the digital array component under different azimuth and elevation angles, and output them to the beamforming unit.

[0012] The beamforming unit is used to perform phase weighting and beamforming on the digital signals of each receiving channel according to the amplitude and phase weights issued by the beam control unit, and output the signal to the digital-to-analog converter.

[0013] Digital-to-analog converters are used to convert the digital signals from beamforming into analog signals, which are then output to a spectrum analyzer.

[0014] A spectrum analyzer is used to derive the test pattern.

[0015] Furthermore, a high-level single-tone signal is output from the signal source and used as a reference signal for the radiation pattern test.

[0016] Furthermore, the RF cables connecting each output port of the power divider to each input port of the digital array component are of equal length and in phase.

[0017] Furthermore, the radio frequency cable is connected to a channel in the digital array assembly that is aligned with the azimuth angle of the area to be scanned.

[0018] Furthermore, the pitch angle scanning parameters set in the beam control unit include: pitch scan start angle, pitch scan end angle, pitch scan step angle, and pitch scan time interval, wherein the pitch scan step angle is related to the beamwidth.

[0019] Furthermore, the azimuth angle changed in the beam control unit satisfies the following constraints:

[0020]

[0021] In the formula, θ p and θ q Indicates azimuth angles of two different orientations or directions;

[0022] The formulas for calculating the amplitude and phase weights of different receiving channels are as follows:

[0023]

[0024] In the formula, (x nm,y nm ) represents the coordinate position of the receiving channel element in the nth row and mth column, λ is the wavelength, and A nm The value is the amplitude weighting value of the receiving channel in the nth row and mth column, where θ is the azimuth angle. This refers to the pitch angle.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (i) The present invention proposes a wired test method for digital multi-beamforming radiation patterns, which does not require complex environments or equipment such as microwave anechoic chambers, turntables and servo systems, calibration towers or drones. It can complete the test and verification with the assistance of common equipment such as signal sources, spectrum analyzers, power dividers and RF cables, and has simple requirements for test sites and test instruments.

[0027] (ii) The present invention proposes a wired RF test method for digital multi-beamforming pattern, which can automatically complete multi-beam batch testing with a simple and efficient test process. Attached Figure Description

[0028] Figure 1 This is a flowchart of the process of the present invention.

[0029] Figure 2 This is a diagram illustrating the device composition and signal flow of the present invention.

[0030] Figure 3 This is an example of the 8×8 digital array component to be tested in this invention.

[0031] Figure 4 To ensure that the scanning orientation is fixed at 0° in this invention, the radio frequency cable is connected to the receiving channel parallel to the 0° orientation.

[0032] Figure 5 To ensure that the scanning orientation is fixed at 90°, the radio frequency cable is connected to the receiving channel that is parallel to the 90° orientation. Detailed Implementation

[0033] The present invention will be further described below with reference to specific implementation steps:

[0034] This invention discloses a wired radio frequency testing method for digital multi-beamforming patterns. The composition and connection diagram of the device under test (DUT) and auxiliary testing equipment are shown below. Figure 2 This includes signal sources, power dividers, RF cables, digital array components, beamforming units, beam control units, digital-to-analog converters, and spectrum analyzers;

[0035] The signal source is used to generate a test reference signal, which is then output to the power divider.

[0036] A power divider is used to split a single signal output from a signal source into multiple signals and output them to a digital array component via radio frequency cables;

[0037] The digital array assembly is used to amplify, frequency convert, and convert the corresponding input signals into digital signals through multiple receiving channels, and output digital signals to the beamforming unit; wherein, the digital array assembly does not contain an antenna unit;

[0038] The beam control unit is used to fix an azimuth angle and set the elevation angle scanning parameters each time, calculate the amplitude and phase weights of different receiving channels in the digital array component under different azimuth and elevation angles, and output them to the beamforming unit.

[0039] The beamforming unit is used to perform phase weighting and beamforming on the digital signals of each receiving channel according to the amplitude and phase weights issued by the beam control unit, and output the signal to the digital-to-analog converter.

[0040] Digital-to-analog converters are used to convert the digital signals from beamforming into analog signals, which are then output to a spectrum analyzer.

[0041] A spectrum analyzer is used to derive the test pattern.

[0042] Test steps refer to Figure 1 Specifically, it includes:

[0043] (1) Prepare the device to be tested, which mainly includes: digital array components, beamforming units and beam control units;

[0044] (2) Prepare auxiliary testing equipment, mainly including: signal source, power divider, RF cable, digital-to-analog converter and spectrum analyzer;

[0045] (3) Set the test signal output by the signal source to a medium-strong level single-tone signal, and connect the RF cable from the output port of the power divider to the input port of the digital array component. The RF cables should be of equal length and in phase, and connected to the channel in the digital array component that is aligned with the direction of the azimuth angle of the position to be scanned.

[0046] (4) Fix the azimuth angle as θ in the beam control unit. n n = 1, ..., N s N s To determine the number of azimuth scans, set the elevation angle scan parameters, including: the elevation scan start angle. End angle of pitch scan Pitch scan step angle Pitch scan interval The pitch scanning step angle is related to the beamwidth, and is generally 1 / 10 of the beamwidth;

[0047] (5) The beam control unit calculates the azimuth angle θ and elevation angle. Below, the amplitude and phase weights of the nth row and mth column channel of the component are calculated using the following formula:

[0048]

[0049] And the weights are sent to the beamforming unit;

[0050] (6) The beamforming unit performs phase weighting and beamforming on the digital signals of each receiving channel according to the amplitude and phase weights issued by the beam control unit. The beamforming calculation formula is as follows:

[0051]

[0052] In the formula, N and M represent the number of horizontal and vertical elements of the rectangular subarray, respectively;

[0053] (7) Set the total scan time T on the spectrum analyzer. total The calculation formula is:

[0054]

[0055] (8) Simultaneously click the scan start button on both the spectrum analyzer and the beam control unit to obtain the test pattern in the spectrum analyzer;

[0056] (9) Change the azimuth angle and repeat steps (4) to (8), wherein the changed azimuth angle satisfies the following constraints:

[0057] mod(θ p -θ q ,180°)≠0

[0058] In the formula, θ p and θ q This indicates two different azimuth angles or opposite directions. The scan ends after the desired effect is achieved.

[0059] Implementation Example: First, set up a wired RF test environment for the radiation pattern. The device under test mainly includes: digital array components, beamforming units, and beam control units. The auxiliary test equipment mainly includes: signal source, spectrum analyzer, power divider, RF cables, digital-to-analog converter, etc. Connect the RF cables of equal length and in phase to the channel in the digital array components that is aligned with the azimuth angle of the direction to be scanned. Fix two typical azimuth directions that are perpendicular to each other, and scan the elevation direction in turn. Obtain the two-dimensional cross-sectional radiation pattern through the spectrum analyzer.

[0060] Reference Figure 3The digital array component under test is an 8x8 rectangular array, the power divider is 1 to 8, and there are 8 RF cables of equal length and in phase. The pitch scan start angle is set to -60°, the pitch scan end angle to +60°, the pitch scan step angle to 1°, and the pitch scan time interval to 1 second, with a total scan duration of 121 seconds. The azimuth direction is scanned at least twice, with the first scan referring to... Figure 4 During scanning, the azimuth angle is fixed at a typical angle of 0°. Eight RF cables are connected to eight channels in the array assembly that are parallel to the azimuth angle of 0°. The second reference... Figure 5 During scanning, the azimuth angle was fixed at a typical angle of 90°, and eight RF cables were connected to eight channels in the array assembly parallel to the 90° azimuth. Two typical angle scans were performed to obtain a two-dimensional cross-sectional radiation pattern test curve, which was compared with the theoretical radiation pattern curve. Once the expected effect was achieved, the scan ended.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A wired radio frequency testing device for digital multi-beamforming pattern generation, characterized in that, This includes signal sources, power dividers, RF cables, digital array components, beamforming units, beam control units, digital-to-analog converters, and spectrum analyzers; The signal source is used to generate a test reference signal, which is then output to the power divider. A power divider is used to split a single signal output from a signal source into multiple signals and output them to a digital array component via radio frequency cables; The digital array component is used to amplify, frequency convert, and convert the corresponding input signals into digital signals through multiple receiving channels, and output digital signals to the beamforming unit. The beam control unit is used to fix an azimuth angle and set the elevation angle scanning parameters each time, calculate the amplitude and phase weights of different receiving channels in the digital array component under different azimuth and elevation angles, and output them to the beamforming unit. The beamforming unit is used to perform phase weighting and beamforming on the digital signals of each receiving channel according to the amplitude and phase weights issued by the beam control unit, and output the signal to the digital-to-analog converter. Digital-to-analog converters are used to convert the digital signals from beamforming into analog signals, which are then output to a spectrum analyzer. A spectrum analyzer is used to derive the test pattern.

2. The RF wired test apparatus for digital multi-beamforming pattern generation according to claim 1, characterized in that, A high-level single-tone signal is output from the signal source and used as a reference signal for the radiation pattern test.

3. The RF wired test apparatus for digital multi-beamforming pattern generation according to claim 1, characterized in that, The RF cables connecting each output port of the power divider to each input port of the digital array component are of equal length and in phase.

4. The RF wired test apparatus for digital multi-beamforming pattern generation according to claim 1, characterized in that, The radio frequency cable is connected to a channel in the digital array assembly that is aligned with the azimuth angle of the area to be scanned.

5. The RF wired test apparatus for digital multi-beamforming pattern generation according to claim 1, characterized in that, The pitch angle scanning parameters set in the beam control unit include: pitch scan start angle, pitch scan end angle, pitch scan step angle, and pitch scan time interval, where the pitch scan step angle is related to the beamwidth.

6. The RF wired test apparatus for digital multi-beamforming pattern generation according to claim 1, characterized in that, The azimuth angle changed in the beam control unit satisfies the following constraints: mod(θ p -θ q ,180°)≠0 In the formula, θ p and θ q Indicates azimuth angles of two different orientations or directions; The formulas for calculating the amplitude and phase weights of different receiving channels are as follows: In the formula, (x nm ,y nm ) represents the coordinate position of the receiving channel element in the nth row and mth column, λ is the wavelength, and A nm The value is the amplitude weighting value of the receiving channel in the nth row and mth column, where θ is the azimuth angle. This refers to the pitch angle.

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