| Active phased array antenna is an antenna that uses electronic scanning technology to achieve beam steering.The heat emitted by its active devices will increase the temperature of the substrate and the array,which will directly affect the electrical performance.In addition,the increase in temperature will lead to changes in device characteristics,indirectly affect electrical performance.With the improvement of the working frequency and integration of the antenna,the thermoelectric coupling effect becomes increasingly prominent and becomes a key problem restricting the improvement of electrical performance.Aiming at the problem that traditional methods are difficult to accurately analyze the thermoelectric coupling effect and implement accurate dynamic compensation,the following study are carried out.(1)Based on the field-circuit coupling method,the thermoelectric coupling model of the active phased array antenna is established to analyze the effect of temperature on the radiation performance of the antenna.First,according to the measured data,the equivalent circuit temperature drift characteristic model of the active RF chip is established to characterize the effect of temperature on the chip performance.Secondly,according to the temperature drift characteristic model,the thermoelectric coupling model of the T/R module is constructed based on the field-circuit coupling method,which is used to analyze the influence of temperature on the transmission current of the module.On this basis,according to the superposition principle of the antenna pattern,the thermoelectric coupling model of the active phased array antenna is established.(2)An optimal design method for the temperature self-compensation circuit of the T/R module is proposed to automatically compensate the electrical performance of the active phased array antenna.Based on the thermoelectric coupling model of the T/R module,the thermal and electromagnetic performance of the T/R module and the temperature selfcompensation circuit structure are co-simulated and analyzed,in order to optimize and design the structural parameters of the temperature self-compensation circuit.It realizes the stability of electrical performance of the active phased array antenna under actual working conditions,and overcomes the defect of limited accuracy of active temperature compensation caused by the quantization error of digital chips.(3)Using the optimal design method of temperature self-compensation circuit,a temperature compensation circuit module and an X-band four-channel T/R module with temperature selfcompensation function are designed respectively.The measured results show that the temperature drift of the transmission phase of the feeder link of the T/R module is reduced by about 67%.The simulation results of the X-band active phased array antenna show that when the operating temperature reaches 65°C,the beam pointing deviation is reduced by about 70%,and the gain loss is reduced by about 69%.This verifies the effectiveness of the self-compensation method in this paper. |
