A large antenna power distribution test method

Abstract

The present invention discloses a large-scale antenna power distribution test method. The RFID tag grid carried by the drone simplifies the measurement equipment and operation. Compared with the directional pattern measurement technology in the prior art, the present invention reduces the need for professional operating skills, making the setting and adjustment of the measurement equipment faster and more flexible, and greatly improving the speed of data collection; at the same time, the present invention uses relatively low-cost drones and RFID systems, which reduces the dependence on fixed facilities compared to traditional far-field and near-field measurement methods, thereby significantly reducing the overall cost of antenna measurement. In addition, the present invention utilizes the high maneuverability of drones and the wireless characteristics of RFID technology, and can deploy and perform measurement tasks in various geographical environments and different weather conditions, with minimal impact on the environment, which not only reduces interference with the environment, but also makes measurement in ecologically sensitive areas possible.

Description

Technical Field

[0001] The present invention belongs to the technical field of test and measurement, and particularly relates to a method for testing the power distribution of a large antenna. Background Art

[0002] With the rapid development of wireless communication technology, accurate antenna performance evaluation has become increasingly important. Especially for large fixed antennas, such as broadcast, communication, and astronomical observation antennas, the measurement of their radiation patterns and power distribution is crucial for ensuring signal coverage and reception quality. As Figure 1 shown, traditional antenna radiation pattern measurement methods usually rely on physically rotating the antenna to obtain its radiation performance in different directions.

[0003] Far-field measurement and Compact Antenna Test Range (CATR) are the most commonly used methods in traditional antenna measurement. Far-field measurement is mainly used to evaluate the radiation characteristics and radiation patterns of antennas. As Figure 2 shown, the antenna under test emits electromagnetic waves at a sufficient distance (far-field region), and the receiving antenna measures the intensity and phase of these waves. The far-field distance is usually defined as greater than 2D2 / λ (D is the maximum size of the antenna, and λ is the wavelength). In the far-field region, the electromagnetic waves are approximately plane waves, which is convenient for analyzing the directivity and gain of the antenna. However, far-field measurement requires a large open space to form a sufficient measurement distance, which is difficult to achieve in urban or space-constrained environments. Establishing and maintaining a far-field measurement range requires significant investment, including land, equipment, and maintenance costs. In addition, due to the limitation of the measurement distance, it may take a long time to complete a full antenna measurement, especially during the process of adjusting and calibrating the antenna.

[0004] Compact Antenna Test Range (CATR) uses a special reflector to convert the spherical wavefront emitted by the source antenna into a plane wavefront, thereby simulating far-field conditions at a shorter distance. This technology allows for far-field measurement of antenna performance in a smaller space, especially in space-constrained environments. CATR usually uses special parabolic or hyperbolic reflectors to ensure the correct transformation and uniformity of the wavefront. As Figure 3 shown, the compact antenna test range adopts a three-reflector setup, but still has problems of high equipment cost and sensitivity to alignment accuracy. The construction of CATR requires expensive reflectors and precise mechanical equipment, with high initial investment and maintenance costs; at the same time, the system is very sensitive to alignment problems. The precise alignment of the reflector is crucial; any misalignment may lead to significant errors in the measurement.

[0005] Although the above two existing technologies have their respective advantages, they also have many limitations and challenges. Traditional antenna measurement methods, especially far-field and CATR, require a large amount of initial investment and maintenance costs, including purchasing land, building facilities, purchasing and maintaining high-cost equipment, etc. In areas with limited geographical locations or complex environmental conditions, such as mountainous areas or urban environments, it is very difficult to conduct effective antenna measurements. At the same time, in the measurement of large antennas, physical rotation may be impractical or infeasible. The existence of these problems has prompted us to explore new solutions to improve the efficiency of large antenna measurements. Therefore, developing a technology that can evaluate the radiation pattern of an antenna without rotating the antenna is of great significance for improving measurement efficiency and reducing operation complexity. This need has prompted the research and development of new technology solutions aimed at accurately measuring antenna performance through innovative methods without changing the physical position of the antenna. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for testing the power distribution of a large antenna.

[0007] The present invention provides a method for testing the power distribution of a large antenna. The testing device used in this testing method includes a control host, a flexible net, and multiple carrying devices; RFID readers and microcontrollers are installed on some or all of the carrying devices. Testing elements are provided at multiple nodes of the flexible net; the testing elements receive the signals emitted by the antenna under test and transmit the received information to the control host through the RFID reader. The testing element is provided with an RFID antenna, a broadband antenna, and an RFID chip. The broadband antenna is used to receive the power signal emitted by the antenna under test; each RFID chip can receive the radio frequency signal emitted by the RFID reader through the RFID antenna.

[0008] During the working process, multiple carrying devices jointly hang and unfold the flexible net and make the unfolded flexible net face the antenna under test. The carrying device drives the unfolded flexible net to move relative to the antenna under test. The RFID reader wirelessly powers the RFID chip through the RFID antenna; the RFID chip sends the power signal received by the broadband antenna to the RFID reader through the RFID antenna.

[0009] This testing method includes the following steps:

[0010] Step 1: Fix different corners or edges of the flexible net on different carrying devices; each carrying device drives the unfolded flexible net to fly to the target position so that the flexible net faces the antenna under test directly.

[0011] Step 2: The RFID reader sends a query instruction to all test components. The RFID chips in the test components receive the query instruction and are self-powered by the energy wirelessly transmitted by the RFID reader. The broadband antennas in the test components receive the signals emitted by the antenna under test. After the RFID chips collect enough energy, they transmit the power signals measured by the broadband antennas back to the RFID reader.

[0012] Step 3: The RFID reader transmits the signals of the antenna under test sent by each test component to the microcontroller. The microcontroller generates the power distribution of the transmitted signals of the antenna under test according to the positions of the test components relative to the antenna under test and the measured antenna power.

[0013] Preferably, the size of the flexible net is 5m×5m; the distance between adjacent nodes is 25cm.

[0014] Preferably, multiple detection points surrounding the antenna under test are set; each carrying device drives the deployed flexible net to fly to each detection point in turn and executes Step 2 and Step 3 to obtain the power distribution in different directions of the antenna under test.

[0015] Preferably, the angle θ between the connecting lines of two adjacent detection points to the antenna under test, the width P of the flexible net, and the distance L from the detection point to the antenna under test satisfy the following relationship: tan(θ / 2) = P / (2L); so that the edges of the flexible net at the two detection points are fitted to ensure that all directions around the antenna under test are detected.

[0016] Preferably, the signal intensities measured by each test component at the same height on the flexible net at each detection point are extracted to obtain the amplitude of the transmitted signal of the antenna under test in the circumferential direction, and the radiation pattern of the antenna under test is drawn.

[0017] Preferably, in Step 3, the method for obtaining the positions of the test components relative to the antenna under test is: measuring the positions of the test components relative to the microcontroller before the test, and combining the movement paths of the carrying devices to obtain the positions of the test components relative to the antenna under test.

[0018] Preferably, the carrying device is a drone. In Step 1, the two corners at the top of the flexible net are respectively fixed to the bottoms of two drones.

[0019] Preferably, the test component includes a microstrip reflection layer, a GND layer, and a signal receiving layer stacked. The broadband antenna is arranged on the microstrip reflection layer; the RFID antenna and the RFID chip are arranged on the signal receiving layer; a broadband detector is also arranged on the microstrip reflection layer; the broadband detector is used to convert the received power signal into an analog voltage signal. An analog-to-digital converter is also arranged on the signal receiving layer. The analog-to-digital converter is used to receive the signal sent by the broadband detector, convert the received analog signal into a digital signal and then send it to the RFID chip.

[0020] Preferably, the method for converting the antenna signal under test into a digital signal is as follows: The broadband detector receives the signal emitted by the antenna under test through the broadband antenna, converts the received signal into an analog voltage signal, and then inputs it into the analog-to-digital converter. The analog-to-digital converter converts the received analog voltage signal into a digital voltage signal.

[0021] Preferably, the test element uses a flexible printed circuit board as the circuit substrate.

[0022] Preferably, after completing data transmission, the broadband detector and the analog-to-digital converter enter the sleep mode and stop working.

[0023] Preferably, an energy storage capacitor is connected in the circuit to ensure stable power supply. During the working process, the RFID chip charges the energy storage capacitor; the energy storage capacitor maintains the stable power supply of the broadband detector and the analog-to-digital converter.

[0024] Preferably, the model of the broadband detector is AD8317; the model of the analog-to-digital converter is ADS7042.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. The present invention simplifies the measurement equipment and operation through the RFID tag grid carried by the unmanned aerial vehicle. Compared with the pattern measurement technology in the prior art, the present invention reduces the requirement for professional operation skills while making the setting and adjustment of the measurement equipment faster and more flexible; in addition, by using the relatively low-cost unmanned aerial vehicle and RFID system, the present invention reduces the dependence on fixed facilities compared with the traditional far-field and near-field measurement methods, thus significantly reducing the overall cost of antenna measurement.

[0027] 2. By utilizing the high mobility of the unmanned aerial vehicle and the wireless characteristics of the RFID technology, the present invention can deploy and execute measurement tasks in various geographical environments and different weather conditions, improving the adaptability of the measurement. At the same time, compared with the traditional methods that require large-scale measurement facilities, the unmanned aerial vehicle and RFID system of the present invention have minimal impact on the environment. This not only reduces the interference to the environment but also makes it possible to conduct measurements in ecologically sensitive areas.

[0028] 3. By utilizing the ability of the unmanned aerial vehicle to quickly deploy and collect data, the present invention greatly improves the speed of data collection. Just input a predetermined route into the MCU carried on the unmanned aerial vehicle, and the unmanned aerial vehicle can quickly move on the predetermined flight path while automatically collecting the required measurement data, greatly shortening the time of the entire measurement process, and is suitable for measuring the pattern of the antenna in time-sensitive or applications that require quick response scenarios.

[0029] 4. Through precise flight control and advanced data processing technologies, the present invention enables the feedback information provided by the test element to be accurately recorded and processed in real time, ensuring that the collected data has high precision and reliability. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the measurement pattern of a traditional rotating antenna.

[0031] Figure 2 It is a schematic diagram of measuring the antenna pattern using the far-field measurement method.

[0032] Figure 3 It is a schematic diagram of measuring the antenna pattern using the compact antenna test range method.

[0033] Figure 4 It is a schematic diagram of the test device of the present invention.

[0034] Figure 5 It is a schematic diagram of the structure of the test element in the present invention.

[0035] Figure 6 It is a cross-sectional schematic diagram of the test element in the present invention.

[0036] Figure 7 It is a schematic diagram of the data communication method of the test element in the present invention.

[0037] Figure 8 It is a flowchart of measuring the pattern and power distribution of the antenna under test in the present invention.

[0038] Figure 9 It is a flowchart of the RFID reader / writer controlling the test element in the present invention.

[0039] In the figure: 1. Mounting device; 2. Test element; 3. Flexible net; 2-1. Microstrip reflection layer; 2-2. Signal receiving layer; 2-3. RFID antenna; 2-4 Broadband antenna; 2-5. RFID chip; 2-6. Broadband detector; 2-7. Through-hole; 2-8. Analog-to-digital converter. Detailed Embodiments

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] As Figure 4As shown in the figure, a large antenna pattern and power distribution test device includes a control host, a plurality of carrier devices 1, a flexible net 3, an RFID reader / writer, and a microcontroller mounted on the carrier device 1. The flexible net 3 is jointly structured by a plurality of carrier devices 1, and test elements 2 are provided at all nodes (i.e., grid intersections) of the flexible net 3; the test elements 2 are used to receive the signals emitted by the antenna under test and transmit the signals to the RFID reader / writer; the test elements 2 use flexible printed circuit boards as circuit substrates to reduce their own weight and improve the overall flexibility and portability of the flexible net 3; the RFID reader / writer is used to provide power for the test elements 2 and transmit the received information to the control host through the microcontroller to obtain the antenna power distribution; the microcontroller is used to control the movement path of the carrier device 1 according to preset instructions.

[0042] In this embodiment, the size of the flexible net 3 is 5m×5m; the spacing between adjacent nodes is 25cm.

[0043] In some embodiments, a wireless transmission technology including Bluetooth, Wi-Fi, and NFC is used to replace the RFID technology to transmit the signals emitted by the antenna under test to the microcontroller.

[0044] As Figure 5 , 6 , as shown in FIG. 7, the test element 2 includes a microstrip reflection layer 2-1, a GND layer, and a signal receiving layer 2-2 which are stacked. The microstrip reflection layer 2-1 includes a broadband antenna 2-4 and a broadband detector 2-6; the broadband antenna 2-4 is used to receive the power signal emitted by the antenna under test and transmit it to the broadband detector 2-6; the broadband detector 2-6 is used to convert the received signal into an analog voltage signal. The signal receiving layer 2-2 includes an RFID antenna 2-3, an RFID chip 2-5, and an analog-to-digital converter 2-8. The RFID chip 2-5 uses the radio frequency signal emitted by the RFID reader / writer for self-power supply and supplies power to the microstrip reflection layer 2-1 through the power supply control output interface. At the same time, a 200uF energy storage capacitor is connected to the circuit to ensure stable power supply; the RFID antenna 2-3 is connected to the signal input interface of the RFID chip 2-5 and is used to collect the radio frequency signal emitted by the RFID reader / writer to activate the RFID chip 2-5, and each RFID chip 2-5 can receive the radio frequency signal emitted by the RFID reader / writer; the analog-to-digital converter 2-8 is used to receive the signal sent by the broadband detector 2-6 and convert the received analog signal into a digital signal corresponding one-to-one to the power emitted by the antenna under test. Through holes 2-7 are provided on the media of the GND layer, the microstrip reflection layer 2-1, and the signal receiving layer 2-2; the wires between the RFID chip 2-5 and the broadband antenna 2-4 and the broadband detector 2-6, and between the broadband detector 2-6 and the analog-to-digital converter 2-8 respectively pass through the corresponding through holes 2-7.

[0045] AsFigure 8 As shown in the figure, the working principle of the large antenna pattern and power distribution test device includes the following steps:

[0046] Step 1: Fix different corners or edges of the flexible net 3 on different carrying devices 1; each carrying device 1 drives the deployed flexible net 3 to fly to the target position, so that the flexible net 3 faces the antenna under test.

[0047] In this embodiment, the carrying device 1 is selected as a drone, and two corners at the top of the flexible net 3 are respectively fixed to the bottoms of two drones. This enables the flexible net 3 to easily cover the antenna under test and measure data around the antenna under test at 360°.

[0048] Step 2: As Figure 9 shown in the figure, the RFID reader sends a query command to all test components 2. The RFID chip 2-5 in the test component 2 receives the query instruction, and uses the RFID antenna 2-3 to collect the instruction sent by the RFID reader for self-power supply, thereby ensuring the normal operation of the test component 2. After the test component 2 collects enough energy, the RFID chip 2-5 in the test component 2 provides the working voltage required for the broadband detector 2-6 and the analog-to-digital converter 2-8.

[0049] Step 3: The broadband detector 2-6 receives the signal emitted by the large antenna under test through the broadband antenna 2-4, converts the received power signal into an analog voltage signal and inputs it into the analog-to-digital converter 2-8. The analog-to-digital converter 2-8 converts the received analog voltage signal into a digital voltage signal, and then transmits it to the RFID chip 2-5 through the SPI bus. The RFID chip 2-5 receives the signal from the analog-to-digital converter 2-8, and after packing and processing the received signal, it transmits the digital signal back to the RFID reader through the RFID antenna 2-3. After the data transmission is completed, the broadband detector 2-6 and the analog-to-digital converter 2-8 enter the sleep mode to save energy and wait for the next operation.

[0050] In this embodiment, the model of the broadband detector 2-6 is AD8317; the model of the analog-to-digital converter 2-8 is ADS7042.

[0051] Step 4: The RFID reader transmits the signals of the antenna under test sent by each test component 2 to the microcontroller. Since the relative positions of the test components 2 and the carrying device 1 are fixed; according to the positions of the test components 2 relative to the microcontroller measured before the test, combined with the movement path of the carrying device 1, the positions of the test components 2 relative to the antenna under test are obtained; the power of the antenna under test is obtained according to the received digital voltage signal; the microcontroller generates the power distribution of the signal emitted by the antenna under test according to the positions of the test components 2 relative to the antenna under test and the power of the antenna under test, and transmits it back to the control host.

[0052] The received power P corresponding to any test element 2 r has the following expression:

[0053]

[0054] where P t is the transmitted power of the antenna under test; G t is the gain of the antenna under test; G r is the gain of the broadband antennas 2-4; λ is the wavelength of the wireless signal; R is the distance between the antenna under test and the broadband antennas 2-4.

[0055] The received power P of the test element 2 through the broadband antennas 2-4 r , from which the gain G of the antenna under test in different directions can be calculated t .

[0056] In some embodiments, by extracting the signal intensities measured by each test element 2 at the same height on the flexible mesh 3 at each detection point, the amplitude of the transmitted signal of the antenna under test in the circumferential direction is obtained, and the radiation pattern of the antenna under test is plotted.

[0057] Step Five: Set a plurality of detection points around the antenna under test; the included angle θ between the connecting lines of adjacent two detection points to the antenna under test, the width P of the flexible mesh 3, and the distance L from the detection point to the antenna under test satisfy the following relationship: tan(θ / 2) = P / (2L); make the edges of the flexible mesh 3 at the two detection points fit, ensuring that all directions around the antenna under test are detected. Each carrying device 1 drives the unfolded flexible mesh 3 to fly to each detection point in turn and executes Steps Two to Four to obtain the power distribution of the antenna under test in different directions.

Claims

1. A large antenna power distribution test method, characterized in that: The test device used in the test method comprises a control host, a flexible net (3) and a plurality of carrying devices (1); an RFID reader / writer and a microcontroller are installed on some or all of the carrying devices (1); test elements (2) are arranged at a plurality of nodes of the flexible net (3); the test element (2) receives a signal emitted by the antenna under test and transmits the received information to the control host through the RFID reader / writer; the test element (2) is provided with an RFID antenna (2-3), a broadband antenna (2-4) and an RFID chip (2-5); the broadband antenna (2-4) is used to receive a power signal emitted by the antenna under test; each RFID chip (2-5) can receive a radio frequency signal emitted by the RFID reader / writer through the RFID antenna (2-3); The test method includes the following steps: Step 1: fix different corners or edges of the flexible net (3) on different carrying devices (1); each carrying device (1) drives the unfolded flexible net (3) to fly to a target position, so that the flexible net (3) faces the antenna to be tested; Step 2: The RFID reader sends a query command to all test elements (2); the RFID chip (2-5) in the test element (2) receives the query command and uses the energy wirelessly sent by the RFID reader to power itself; the broadband antenna (2-4) in the test element (2) receives the signal sent by the antenna under test; the RFID chip (2-5) transmits the power signal received by the broadband antenna (2-4) back to the RFID reader; Step 3: The RFID reader transmits the antenna signals under test sent by each test element (2) to the microcontroller; the microcontroller generates a power distribution of the signal transmitted by the antenna under test according to the position of each test element (2) relative to the antenna under test and the measured antenna power.

2. A large antenna power distribution test method according to claim 1, characterized in that: A plurality of detection points surrounding the antenna under test are set; each carrying device (1) drives the unfolded flexible net (3) to fly to each detection point in sequence and execute steps two and three to obtain the power distribution of the antenna under test in different directions.

3. A large antenna power distribution test method according to claim 2, characterized in that: The angle between the lines connecting two adjacent detection points to the antenna under test θ , Width of the flexible mesh (3) P , the distance from the detection point to the antenna under test L Satisfies the following relationship: tan( θ / 2)= P / (2 L ).

4. A large antenna power distribution test method according to claim 2, characterized in that: The signal strengths of the test elements (2) at the same height on the flexible net (3) at each detection point are extracted to obtain the amplitude of the signal transmitted by the antenna under test in a circumferential direction, and the directional diagram of the antenna under test is drawn.

5. A large antenna power distribution test method according to claim 1, characterized in that: In the step three, the method for obtaining the position of each test element (2) relative to the antenna under test is as follows: before the test, the position of each test element (2) relative to the microcontroller is measured, and the position of each test element (2) relative to the antenna under test is obtained in combination with the moving path of the carrying device (1).

6. A large antenna power distribution test method according to claim 1, characterized in that: The carrying device (1) is a drone; in step 1, the two corners of the top of the flexible net (3) are respectively fixed to the bottom of the two drones.

7. A large antenna power distribution test method according to claim 1, characterized in that: The test element (2) comprises a stacked microstrip reflection layer (2-1), a GND layer and a signal receiving layer (2-2); a broadband antenna (2-4) is arranged on the microstrip reflection layer (2-1); an RFID antenna (2-3) and an RFID chip (2-5) are arranged on the signal receiving layer (2-2); a broadband detector (2-6) is also arranged on the microstrip reflection layer (2-1); the broadband detector (2-6) is used to convert a received power signal into an analog voltage signal; an analog-to-digital converter (2-8) is also arranged on the signal receiving layer (2-2); the analog-to-digital converter (2-8) is used to receive a signal sent by the broadband detector (2-6), and convert the received analog signal into a digital signal and then send it to the RFID chip (2-5).

8. A large antenna power distribution test method according to claim 7, characterized in that: The method for converting the measured antenna signal into a digital signal is as follows: a broadband detector (2-6) receives the signal sent by the measured antenna through a broadband antenna (2-4), converts the received signal into an analog voltage signal, and then inputs the received signal into an analog-to-digital converter (2-8), and the analog-to-digital converter (2-8) converts the received analog voltage signal into a digital signal.

9. A large antenna power distribution test method according to claim 8, characterized in that: The broadband detector (2-6) and the analog-to-digital converter (2-8) enter a sleep mode and stop working after completing data transmission.

10. A large antenna power distribution test method according to claim 1, characterized in that: The test element (2) uses a flexible circuit board as a circuit substrate.

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