Influence Mechanism And Compensation Method Of Temperature On Electrical Performance Of Active Phased Array Antenna

With the development of active phased array antenna towards high-density and high-power,the coupling between its temperature field and electromagnetic field becomes more and more significant,which leads to the decrease of gain,the elevation of the side lobe and the increase of the pointing deviation,that is,there is a significant electrical-thermal couple effect.Therefore,compensation is generally made according to the results of simulation analysis in engineering.However,the simulation model often ignores the error between the theoretical model and the real model and the influence of the non-uniform front temperature on the electrical performance of the antenna,which leads to the inaccuracy of the modeling.Furthermore,it is impossible to effectively compensate the electrical performance of the antenna.Aiming at the electrical-thermal couple problem of active phased array antenna,this thesis focuses on the electrical-thermal couple modeling of antenna and the temperature compensation of electrical performance.The main work of the thesis includes:(1)A temperature drift characteristics modeling method of active devices based on extreme learning machine is proposed.Based on the measured data,the mathematical model of the ambient temperature and the temperature drift characteristics of active devices are established by the ultimate learning machine,which effectively improves the efficiency and accuracy of the electrical-thermal couple analysis.(2)A temperature drift characteristics modeling method of active devices based on extreme-transfer learning is proposed.According to the affine transform,the complete data is transplanted to the incomplete data model training.The final temperature drift characteristic model is generated by adaptive weighting.The method solves the problem that the active device samples are not complete and the prediction accuracy of the model generated by the extreme learning machine has low prediction accuracy and is difficult to be generalized.(3)The electrical-thermal couple model of T/R components is derived based on the temperature drift characteristic model of active devices.Then,combining with the active phased array antenna field intensity direction diagram,the influence of temperature on excitation current amplitude,phase and other factors is considered,and the antenna electrical-thermal couple model is constructed.The influence of temperature inhomogeneity on active phased array antenna is studied by electrical-thermal couple analysis.(4)To solve the problem of electric performance loss of active phased array antenna caused by temperature,a phase compensation method based on multi-objective optimization is proposed.The phase of all elements of the array is used as the optimization vector through this method,and the real and imaginary parts of the excitation current are used as the objective optimization functions respectively,then the multi-objective optimization model is constructed and solved,so that the antenna array pattern approximates the ideal value as a whole.This method is applied to the temperature compensation simulation.The experimental results show that the beam direction compensation is 95.68%,the gain compensation is 84.85%and the maximum compensation of the side lobe is 88.69%.It shows that the extreme-learning machine based electrical-thermal couple model of antenna has high prediction accuracy,and the array phase compensation method can effectively compensate the loss of antenna electrical performance caused by temperature.