Phased-array antenna test system and calibration method based on reference antenna temperature compensation

Abstract

The invention relates to a phased-array antenna test system and correction method based on reference antenna temperature compensation, and belongs to the technical field of antenna housing electrical performance test. When a phased-array antenna is used as a receiving antenna to test a radome, a tester needs to frequently mount or dismount the radome in a short time. The invention provides a phased-array antenna test system based on reference antenna temperature compensation, an industrial personal computer of the test system is respectively connected with a transmitting source, a local oscillator source, a liquid cooling source and a receiver, the transmitting source is connected with a transmitting antenna, and the local oscillator source and the receiver are respectively connected with an intermediate frequency / local oscillator unit; a receiving antenna and a reference antenna are arranged on a rotary table, patch temperatures are arranged on the surfaces of the receiving antenna and the reference antenna, and the receiving antenna and the reference antenna are connected with an intermediate frequency / local oscillator unit through independent frequency mixers respectively; the receiving antenna is a phased-array antenna, the reference antenna is arranged in the water tank, and cooling liquid is injected into the phased-array antenna and the water tank at the same time through the liquid cooling source; by changing the temperature and the test frequency value of the cooling liquid and recording the sampling value, a gain and temperature comparison table of the antenna is established in the industrial personal computer, and the gain of the antenna is compensated and corrected during the external field test based on the comparison table, so that the amplitudes of two paths of receiving signals are obtained, and the electrical performance of the radome is calculated. The signal stability of the receiving antenna and the reference antenna can be improved, the signal accuracy is ensured, the influence of environment temperature change on the test accuracy is reduced, and the test efficiency is improved.

Description

Technical Field

[0001] This invention relates to a phased array antenna testing system and calibration method based on reference antenna temperature compensation, belonging to the field of radome electrical performance testing technology. Background Technology

[0002] Phased array antennas typically generate significant heat and utilize constant-temperature sources, such as liquid coolers, to maintain a relatively constant temperature of liquid or gas. During operation, the constant-temperature source heats or cools the liquid or gas used for cooling, continuously supplying it to the phased array antenna. Therefore, if a phased array antenna is used as a receiving antenna in field testing, its temperature will remain unchanged when the ambient temperature remains relatively stable, meaning its gain and transmission phase will not change. When the ambient temperature changes significantly, the antenna temperature will only change slightly. However, if the temperature of the liquid or gas supplied by the constant-temperature source changes, the phased array antenna temperature will also change, consequently altering its gain and transmission phase.

[0003] Similarly, when using a parabolic antenna as a reference antenna, its gain and transmission phase change significantly with temperature. Furthermore, it's impossible to establish an accurate temperature-dependent correlation table for the transmission phase of the antenna and RF components through experimentation. In practical applications, the gain performance of the antenna and RF components will change due to temperature. In field testing, the test system is susceptible to factors such as sunlight, rain, snow, and ambient temperature. Especially during winter and summer, field test systems using a phased array antenna as the receiving antenna and a parabolic antenna as the reference antenna are significantly affected by ambient temperature. Changes in the gain and transmission phase of the reference antenna and RF components in the system significantly impact the accuracy of the test results.

[0004] Currently, when the test site is outdoors, the ambient temperature fluctuates significantly. To ensure that the ambient temperature does not change drastically during the test, when using a phased array antenna as the receiving antenna to test the radome, test personnel need to frequently install or remove the radome in a short period of time. This consumes a lot of manpower and greatly reduces test efficiency. Summary of the Invention

[0005] This invention addresses the testing of phased array antennas in outdoor environments by proposing a phased array antenna testing system and calibration method based on reference antenna temperature compensation. A correlation table between the gain of the receiving antenna and the temperature of the reference antenna is established through experimental measurements, providing data for backend signal amplitude correction.

[0006] This invention proposes a phased array antenna testing system based on reference antenna temperature compensation. The system's industrial control computer is connected to a transmitter, a local oscillator, a liquid cooler, and a receiver. The transmitter is connected to a transmitting antenna, and the local oscillator and receiver are connected to an intermediate frequency (IF) / local oscillator unit, respectively. A receiving antenna and a reference antenna are arranged on a turntable, both with surface-mount temperature sensors. Each antenna is connected to the IF / local oscillator unit via a separate mixer. The receiving antenna is a phased array antenna, and the reference antenna is placed in a water tank. Coolant is simultaneously injected into both the phased array antenna and the water tank via the liquid cooler. By changing the coolant temperature and the test frequency and recording the sampled values, a gain-temperature comparison table for the antenna is established in the industrial control computer. Based on this table, the antenna gain is compensated and corrected during field testing to obtain the amplitude of the two received signals, thereby calculating the electrical performance of the radome.

[0007] Advantageously, the reference antenna is a parabolic antenna.

[0008] Advantageously, the signal is transmitted to the transmitting antenna through the transmitting source.

[0009] Advantageously, microwave signals are transmitted via the transmitting antenna.

[0010] Advantageously, the local oscillator source transmits a local oscillator signal to the intermediate frequency / local oscillator unit, which then transmits the signal to the receiver.

[0011] Advantageously, the radio frequency components or cables of the phased array antenna and the reference antenna are set to be of equal length or with a length difference of no more than 2 meters.

[0012] This invention also proposes a calibration method for a phased array antenna test system based on reference antenna temperature compensation. This method is used in the aforementioned antenna test system and includes the following steps: S1. Before testing, a constant temperature source is used to supply the phased array antenna, the reference antenna, and the radio frequency components connected to them with a gradually changing coolant. The amplitude values ​​of the surface temperature under electromagnetic wave signals at different frequencies are measured and recorded, and a gain-temperature comparison table is established. S2. During testing, a constant temperature source is used to control the phased array antenna, the reference antenna, and their respective connected RF components to a certain temperature. The surface temperature measured at this time is θ. m ; S3. Set the frequency of the transmitter to f, use a phased array antenna to measure, and calculate the sampling gain A of the test system at this frequency. fθm a With transmission phase φ fθm a ; S4. Install the radome onto the phased array antenna and measure the temperature θ on the surface of the phased array antenna. nWhile maintaining a constant temperature and keeping the frequency of the emission source at f, calculate the sampling gain A of the test system at this frequency. fθn r With transmission phase φ fθn r ; S5. Obtain θ by referring to the gain and temperature comparison table. m With θ n The antenna gain is K. fθm With K fθn , for A fθn r After correction, the temperature θ is obtained. m The correction value below is: A fθm r =A fθn r -(K fθm -K fθn ) φ fθm r =φ fθn r ; S6. Based on the A obtained above fθm a φ fθm a A fθm r φ fθm r The sampled values ​​from the test system are used for subsequent indicator calculations.

[0013] Advantageously, the amplitude comparison method is used to obtain the relative gain values ​​at various temperatures and frequencies, and a gain-temperature comparison table is established.

[0014] Advantageously, the sampling gain A of the test system at this frequency is calculated using the two-channel ratio method. fθm a With transmission phase φ fθm a .

[0015] Beneficial effects: It can improve the signal stability of the receiving antenna and the reference antenna, ensure the accuracy of the signal, reduce the impact of ambient temperature changes on test accuracy, and improve test efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the test system with liquid cooling source of the present invention. Detailed Implementation

[0017] Figure 1The testing system uses an industrial control computer to control the transmitter, local oscillator, and liquid cooling source, and receives signals from the receiver. The transmitter sends signals to the transmitting antenna, and the local oscillator sends local oscillator signals to the intermediate frequency / local oscillator unit. A receiving antenna and a reference antenna are arranged on a turntable, with a radar radome mounted on the receiving antenna. The receiving and reference antennas are connected to the intermediate frequency / local oscillator unit via mixers, and the intermediate frequency / local oscillator unit is connected to the receiver. A phased array antenna is used as the receiving antenna, and a parabolic antenna is used as the reference antenna. A water tank is constructed, and the reference antenna is placed inside. Coolant is simultaneously injected into both the phased array antenna and the water tank using the liquid cooling source.

[0018] Before field testing, a constant-temperature coolant was supplied to the phased array antenna and the reference antenna using a liquid cooling source. The surface temperature of both antennas was measured using a patch thermometer. A microwave signal was then emitted by the transmitting antenna, and the sampled values ​​from both antennas were recorded. The sampled values ​​were recorded using the same method after changing the coolant temperature. A gain-temperature correlation table for the phased array antenna and the reference antenna was established using the above method and input into the industrial control computer.

[0019] During field testing, a liquid cooling source was used to supply coolant at a suitable temperature to the phased array antenna and the receiving antenna. A patch thermometer was used to measure the temperature of both antennas, and the temperature was recorded in the test computer. Referring to the gain-temperature comparison table established before the test, the gain of the two antennas was compensated and corrected to obtain two received signals at the same temperature. The electrical performance of the radome was then calculated.

[0020] The method is as follows: 1) Set the radio frequency components or cables connecting the phased array antenna and the reference antenna to be of equal length or with a length difference of no more than 2 meters; 2) A constant temperature source is used to continuously supply coolant at a certain temperature to the phased array antenna, the reference antenna, and their respective connected RF components. A patch thermometer is used to measure the temperature θ1 of the two antennas, and the different frequency points F1, F2, F3, ..., F2 of the two antennas at temperature θ1 are recorded. N The amplitude value of the electromagnetic wave signal is A F1θ1 A F2θ1 A F3θ1 A FNθ1 ; 3) Change the supply temperature of the constant temperature source, and use a patch thermometer to measure the temperature of the two antennas as θ2. Record the different frequency points F1, F2, F3, ..., F2 of the two antennas at temperature θ2. N The amplitude value of the electromagnetic wave signal is A F1θ2 A F2θ2 A F3θ2 A FNθ2 ; 4) Measure the temperature of the two antennas at temperatures θ1, θ2, θ3…θ using the same method.N Amplitude values ​​at different frequencies {A FNθN}; 5) Use the amplitude comparison method to obtain the relative gain values ​​{K} of the two antennas at various temperatures and frequencies. FNθN Establish a gain vs. temperature comparison table; 6) Use a constant temperature source to control the phased array antenna, the reference antenna, and their respective connected RF components to the same temperature to ensure that the transmission phase of the components to the test channel and the reference channel of the receiver is the same. 7) The temperature θ on the surfaces of the two antennas was measured using a patch thermometer. m The system was kept at a constant temperature, and the frequency of the transmitter was set to f. A phased array antenna was used for measurement, and the sampling gain A of the test system at that frequency was calculated using the two-channel ratio method. fθm a With transmission phase φ fθm a ; 8) The radome was installed on the phased array antenna, and the surface temperature of the phased array antenna was measured as θ. n The system was kept at a constant temperature, and the frequency of the transmitter was set to f. The sampling gain A of the test system at this frequency was calculated using the two-channel ratio method. fθn r With transmission phase φ fθn r ; 9) Obtain θ by looking up the table m With θ n The antenna gain is K. fθm With K fθn , for A fθn r After correction, the temperature θ is obtained. m The correction value below A fθm r =A fθn r -(K fθm -K fθn ) φ fθm r =φ fθn r ; 10) Based on the A obtained above fθm a φ fθm a A fθm r φ fθm r The sampled values ​​from the test system are used for subsequent indicator calculations.

Claims

1. A phased array antenna testing system based on reference antenna temperature compensation, characterized in that: The industrial control computer of the test system is connected to the transmitter, local oscillator, liquid cooling source, and receiver. The transmitter is connected to the transmitting antenna, and the local oscillator and receiver are connected to the intermediate frequency / local oscillator unit, respectively. A receiving antenna and a reference antenna are arranged on a turntable, both with surface temperature patches. The receiving antenna and the reference antenna are each connected to the intermediate frequency / local oscillator unit via their own mixers. The receiving antenna is a phased array antenna, and the reference antenna is placed in a water tank. Coolant is injected into both the phased array antenna and the water tank simultaneously through the liquid cooling source. By changing the temperature of the coolant and the test frequency value and recording the sampled values, a gain-temperature comparison table for the antenna is established in the industrial control computer. Based on this comparison table, the antenna gain is compensated and corrected during field testing to obtain the amplitude of the two received signals, thereby calculating the electrical performance of the radome.

2. The phased array antenna testing system according to claim 1, characterized in that: The reference antenna is a parabolic antenna.

3. The phased array antenna testing system according to claim 1, characterized in that: The transmitter sends a signal to the transmitting antenna.

4. The phased array antenna testing system according to claim 3, characterized in that: Microwave signals are transmitted through the transmitting antenna.

5. The phased array antenna testing system according to claim 1, characterized in that: The local oscillator source sends a local oscillator signal to the intermediate frequency / local oscillator unit, which then sends the signal to the receiver.

6. The phased array antenna testing system according to claim 1, characterized in that: The radio frequency components or cables of the phased array antenna and the reference antenna are set to be of equal length or with a length difference of no more than 2 meters.

7. A calibration method for a phased array antenna test system based on reference antenna temperature compensation, the method being used in the antenna test system according to any one of claims 1-6, characterized in that, The method includes the following steps: S1. Before testing, a constant temperature source is used to supply the phased array antenna, the reference antenna, and the radio frequency components connected to them with a gradually changing coolant. The amplitude values ​​of the surface temperature under electromagnetic wave signals at different frequencies are measured and recorded, and a gain-temperature comparison table is established. S2. During testing, a constant temperature source is used to control the phased array antenna, the reference antenna, and their respective connected RF components to a certain temperature. The surface temperature measured at this time is θ. m ; S3. Set the frequency of the transmitter to f, use a phased array antenna to measure, and calculate the sampling gain A of the test system at this frequency. fθm a With transmission phase φ fθm a ; S4. Install the radome onto the phased array antenna and measure the temperature θ on the surface of the phased array antenna. n While maintaining a constant temperature and keeping the frequency of the emission source at f, calculate the sampling gain A of the test system at this frequency. fθn r With transmission phase φ fθn r ; S5. Obtain θ by referring to the gain and temperature comparison table. m With θ n The antenna gain is K. fθm With K fθn , for A fθn r After correction, the temperature θ is obtained. m The correction value below is: A fθm r =A fθn r -(K fθm -K fθn ) f fθm r =φ fθn r ; S6. Based on the A obtained above fθm a φ fθm a A fθm r φ fθm r The sampled values ​​from the test system are used for subsequent indicator calculations.

8. The calibration method for the phased array antenna test system according to claim 7, characterized in that: The relative gain values ​​at various temperatures and frequencies were obtained using the amplitude comparison method, and a gain-temperature comparison table was established.

9. The calibration method for the phased array antenna test system according to claim 7, characterized in that: The sampling gain A of the test system at this frequency was calculated using the two-channel ratio method. fθm a With transmission phase φ fθm a .

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