Rapid detection and estimation method for reflection phase of multi-beam microwave reflection array antenna unit

Abstract

The technical scheme of the invention discloses a rapid detection and estimation method for a reflection phase of a multi-beam microwave reflection array antenna unit. The rapid detection and estimation method is suitable for a to-be-tested sample with any size. The test method provided by the invention has lower requirements on the size of the to-be-tested sample and does not need to be used according to a test environment. The test method provided by the invention is faster, and a complex test environment does not need to be built. According to the test method provided by the invention, the to-be-tested piece is more easily biased during test, and the test environment is not damaged.

Description

Technical Field

[0001] This invention relates to a rapid detection and prediction technology for the reflection phase of a multi-beam microwave reflective array antenna element. Background Technology

[0002] Multi-beam reconfigurable microwave reflector array antennas (MRIs) achieve beamforming by loading tuning devices or tuning materials onto the antenna elements, thereby altering the reflection phase of each element and thus changing the direction and shape of the emitted beam. They offer advantages such as low cost, low loss, low power consumption, and ease of manufacturing, making them important for applications in wireless communication, radar, remote sensing, and military detection. Compared to traditional phased arrays, MRIs can achieve multi-beam shaping using high-power, high-cost TR components, significantly reducing costs. Typical tuning devices include switching diodes, varactor diodes, and microelectromechanical switches, while typical tuning materials include liquid crystals and vanadium dioxide.

[0003] As frequencies rise to 10GHz and above 20GHz, large reflector arrays manufactured solely through simulation or analytical estimation often fail to achieve the required performance. A significant reason for this error is manufacturing error; even a 10-micrometer-level manufacturing error can cause a significant change in the phase of the reflected elements, exhibiting considerable randomness and fluctuation. Typical errors in printed circuit fabrication are at least 0.02mm, or approximately 20 micrometers. Therefore, rapid testing, measurement, and prediction of the phase of small-scale tunable antenna elements before mass production of large reflector arrays are crucial for ensuring a high success rate and yield in design and manufacturing.

[0004] At present, the main methods for testing and measuring the phase of reflective array elements include waveguide method [1], parallel plate waveguide method [2], resonant cavity method [3], absorbing screen window [4], and bow-shaped [5]. These methods are limited by the testing principle and site requirements, and have the following three problems: a. The need for highly customized sample dimensions based on the testing platform limits the design of array units and the types of testable samples, making it impossible to measure highly customized, high-performance array units. Taking the waveguide method as an example, assuming a side length of a standard rectangular waveguide cross-section is 10 cm, and the number of periodic units that can be accommodated within its interval is an integer N, then the periodic dimension of the unit must be a discrete value of 10 / N, and cannot be arbitrarily chosen, thus limiting the unit design. The same applies to the absorbing screen / window method.

[0005] b. The testing environment requires a large footprint and has high construction costs, resulting in high testing costs and long testing times. For example, the bow-shaped method requires the construction of a low-reflectivity microwave anechoic chamber environment.

[0006] c. Difficulty in biasing the sample under test. Tuning devices and materials requires external cables to power them and alter their properties; the introduction of this bias circuitry disrupts the testing environment. For example, in the resonant cavity method, the sample material size needs to perfectly fit and fill the closed cavity. The introduction of a bias circuitry not only disrupts the cavity mode but also causes incomplete cavity closure, leading to decreased testing accuracy or unreliability. Furthermore, the cavity method limits the periodicity of the cells to finite discrete values.

[0007] References [1] H. Rajagopalan and Y. Rahmat-Samii, "On the ReflectionCharacteristics of a Reflectarray Element with Low-Loss and High-LossSubstrates," in IEEE Antennas and Propagation Magazine, vol. 52, no. 4, pp.73-89, Aug. 2010. [2] M. Yarleque and A. Miranda, "Permittivity Measuring TechniqueBased on a Parallel-Plate Waveguide Concept," 2012 VI Andean RegionInternational Conference, Cuenca, Ecuador, 2012, pp. 67-70. [3] ASTM D2520-13, Standard Test Methods for Complex Permittivity(Dielectric Constant) of Solid Electrical Insulating Materials at MicrowaveFrequencies and Temperatures to 1650°C, ASTM International, 2013. [4] DK Ghodgaonkar, VV Varadan and VK Varadan, "Free-spacemeasurement of complex permittivity and complex permeability of magneticmaterials at microwave frequencies," in IEEE Transactions on Instrumentationand Measurement, vol. 39, no. 2, pp. 387-394, April 1990. [5] Radar absorbing material reflectivity GJB 2038A-2011, National Military Standard of the People's Republic of China, 2011. Summary of the Invention

[0008] The technical problem this invention aims to solve is that current methods for testing and measuring the phase of reflective array elements have the following limitations: (1) The periodic size of the constrained unit must be a finite discrete value, which restricts the degree of freedom of the design; (2) Circuit biasing is difficult, construction and cost are high.

[0009] To address the aforementioned technical problems, the present invention discloses a rapid detection and prediction method for the reflection phase of a multi-beam microwave reflective array antenna element, applicable to samples of any size to be tested, characterized by comprising the following steps: Step 1: Set up a test system including a transmitting antenna, a receiving antenna, and a vector network analyzer. Connect the transmitting antenna and the receiving antenna to the vector network analyzer. There are no requirements for the test environment in which the test system is located. Step 2: Place the sample to be tested directly in front of the transmitting and receiving antennas. The sample is connected to an external control unit, which controls different states of the unit loading devices or materials on the sample, wherein: The dimensions of the sample to be tested do not need to be aligned with the testing system; The distance between the sample to be tested and the transmitting and receiving antennas does not need to strictly meet the far-field conditions of the device under test; Step 3: Align the transmitting or receiving antenna with the sample to be tested; Step 4: Measure the phase of the transmission coefficients of the transmitting and receiving antennas and record it as Φ1; Step 5: Change the unit state of the sample to be tested through the control unit, and measure the phase of the transmission coefficient of the transmitting antenna and the receiving antenna again, and record it as Φ2; Step 6: Calculate ΔΦ=Φ1-Φ2 to obtain the phase difference of the unit on the sample to be tested under different states.

[0010] Preferably, in step 1, the transmitting antenna and the receiving antenna are placed on a non-metallic base, and the non-metallic base does not need to be covered with absorbing material.

[0011] Preferably, in step 2, the sample to be tested is placed on a non-metallic base, and the non-metallic base does not need to be covered with absorbing material.

[0012] Preferably, in step 2, the distance between the sample to be tested and the transmitting and receiving antennas is 2D. 2 / λ±30%, where D is the larger of the aperture size of the transmitting or receiving antenna, and λ is the wavelength corresponding to the test frequency.

[0013] Preferably, in step 2, the angle between the central axis of the receiving antenna and the sample normal, and the angle between the central axis of the transmitting antenna and the sample normal, are both less than 20 degrees.

[0014] Compared to existing testing methods for the reflection phase of reflective array antenna elements, the method proposed in this invention has the following advantages: First, the testing method proposed in this invention has lower requirements for the size of the sample under test. It is no longer necessary to customize the size of the sample under test according to the test environment, such as waveguide size, resonant cavity size, etc. It only needs to be a plane or curved surface with a certain area.

[0015] Secondly, the testing method proposed in this invention is faster and does not require the construction of a complex testing environment. This invention only requires a small area to place the device under test and the speaker, eliminating the need for a large-scale darkroom, thus requiring less space and allowing for rapid setup.

[0016] Third, the testing method proposed in this invention makes it easier to bias the device under test (DUT) without damaging the testing environment. The testing method does not require a sealed testing space and can be placed in an open space. Therefore, the biasing device and circuitry are easy to place without damaging the testing environment or reducing the accuracy of the final test results. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system used in this invention; Figure 2 This is a physical schematic diagram of the system used in the embodiment; Figure 3 This illustrates the phase difference between the test and simulation.

[0018] In the attached diagram, 1 is the receiving antenna, 2 is the transmitting antenna, and 3 is the array under test. Detailed Implementation The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0019] Multi-beam microwave reflective array antenna elements typically employ 1-bit or 2-bit phase shifting. Their element reflection phase does not require precise measurement down to a few degrees to achieve functionality. By relaxing the requirements for testing accuracy, the freedom of element design, the convenience of testing, the freedom of offset design, and the speed of testing can be improved, thereby reducing overall R&D costs and development cycle, and increasing the success rate of R&D.

[0020] Therefore, the rapid detection and prediction method for the reflection phase of a unit in a multi-beam microwave reflective array antenna disclosed in this invention is applicable to samples of any size and has no requirements on sample size (most existing solutions require the sample size to be aligned with the test system), and includes the following steps: Step 1: Set up a test system. The test system includes a transmitting antenna 2, a receiving antenna 1, and a vector network analyzer. The transmitting antenna 2 and the receiving antenna 1 are connected to the two ports of the network analyzer via microwave cables to measure the transmission coefficients of the transmitting and receiving antennas.

[0021] Step 2: Place the array 3 (i.e., the sample) composed of the units under test directly in front of the transmitting antenna 2 and the receiving antenna 1. A controller is connected to the back of array 3 to control the different states of the devices or materials loaded on the units of array 3 (in this embodiment, switching diodes are loaded on the surface of array 3, and a voltage source is connected behind them to control the on / off state of the diodes on the surface of array 3). This invention has no requirements for the testing environment; it does not require array 3 to be placed in a microwave anechoic chamber together with the transmitting antenna 2 and the receiving antenna 1. They only need to be placed on a non-metallic base (the non-metallic base does not require the placement of absorbing materials), thereby reducing the requirements for the testing environment and lowering testing costs.

[0022] In a preferred embodiment of the present invention, the distance between the array 3 and the transmitting antenna 2 and the receiving antenna 1 is 2D. 2 / λ±30%, where D is the larger of the aperture size of transmitting antenna 2 or receiving antenna 1, and λ is the wavelength corresponding to the test frequency. This invention does not require the distance between the sample and array 3 and the transmitting antenna 2 and receiving antenna 1 to strictly satisfy the "far-field condition of the device under test," but only requires 2D of the "transmitting and receiving antennas" (rather than the sample size). 2The value is estimated as / λ ± 30%, which greatly alleviates the problem of excessive test space occupation caused by the requirement that the sample must be strictly located in the far field region of the transmitting and receiving antennas. In this embodiment of the invention, the distance between the transmitting antenna 2 and the receiving antenna 1 is 80 mm from the surface of the array 3.

[0023] In a preferred embodiment of the present invention, the angle θ between the central axis of the receiving antenna 1 and the normal of the array 3 is... r The angle θ between the central axis of transmitting antenna 2 and the normal of array 3 is less than 20 degrees. t Less than 20 degrees. In this embodiment of the invention, it is not necessary to place and adhere the sample to a closed space (such as a waveguide, parallel plate waveguide, absorbing screen, etc.). The central axes of the transmitting antenna 2 and the receiving antenna 1 are placed directly in front of the array 3 at an angle of less than 20 degrees, thereby greatly reducing the stringent requirements on sample size and installation method and improving the adaptability of the test. In this embodiment of the invention, the included angle θ t =θ r =10°.

[0024] Step 3: Align the transmitting antenna 2 or the receiving antenna 1 with the array 3.

[0025] Step 4: Power supply 2V, control all the switching diodes on the surface of array 3 to be in the conducting state, test the transmission coefficient S21 of transmitting antenna 2 and receiving antenna 1, and record it as Φon.

[0026] Step 5: Power supply 0V, control all switching diodes on the surface of array 3 to be in the off state, test the phase of the transmission coefficient S21 of transmitting antenna 2 and receiving antenna 1, and record it as Φoff.

[0027] Step 6: Calculate ΔΦ = Φon - Φoff to obtain the phase difference in different cell states on array 3, such as... Figure 3 As shown. By Figure 3 As can be seen, in the 26-28 GHz range, the method of this invention can be used to quickly predict the phase difference caused by the state switching of the reflector array elements.

Claims

1. A rapid detection and prediction method for the reflection phase of a multi-beam microwave reflective array antenna element, applicable to samples of any size, characterized in that... Includes the following steps: Step 1: Set up a test system including a transmitting antenna, a receiving antenna, and a vector network analyzer. Connect the transmitting and receiving antennas to the vector network analyzer. There are no requirements for the test environment of the test system. Step 2: Place the sample to be tested directly in front of the transmitting and receiving antennas. Connect the sample to an external control unit. Control the different states of the loaded devices or materials on the sample. Note that: the size of the sample to be tested does not need to be aligned with the test system; the distance between the sample to be tested and the transmitting and receiving antennas does not need to strictly meet the far-field conditions of the device under test. Step 3: Align the transmitting antenna or receiving antenna with the sample to be tested; Step 4: Measure the phase of the transmission coefficient of the transmitting antenna and the receiving antenna, and record it as Φ1; Step 5: Change the unit state of the sample to be tested through the control unit, and measure the phase of the transmission coefficient of the transmitting antenna and the receiving antenna again, and record it as Φ2; Step 6: Calculate ΔΦ=Φ1-Φ2 to obtain the phase difference of the unit on the sample to be tested under different states.

2. The method for rapid detection and prediction of the reflection phase of a multi-beam microwave reflective array antenna element as described in claim 1, characterized in that, In step 1, the transmitting antenna and the receiving antenna are placed on a non-metallic base, which does not require the application of absorbing material.

3. The method for rapid detection and prediction of the reflection phase of a multi-beam microwave reflective array antenna element as described in claim 1, characterized in that, In step 2, the sample to be tested is placed on a non-metallic base, which does not require the placement of absorbing material.

4. The method for rapid detection and prediction of the reflection phase of a multi-beam microwave reflective array antenna element as described in claim 1, characterized in that, In step 2, the distance between the sample to be tested and the transmitting and receiving antennas is 2D. 2 / λ±30%, where D is the larger of the aperture size of the transmitting or receiving antenna, and λ is the wavelength corresponding to the test frequency.

5. The method for rapid detection and prediction of the reflection phase of a multi-beam microwave reflective array antenna element as described in claim 1, characterized in that, In step 2, the angle between the central axis of the receiving antenna and the sample normal, and the angle between the central axis of the transmitting antenna and the sample normal, are both less than 20 degrees.

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