Research On Near Far Field Measurement Technology Of Airborne Horn Antenna

Accurate antenna measurement technology is a necessary means to optimize antenna performance and design high-performance antenna.Based on the basic theory of antenna near-field measurement technology,the near-field and far-field transformation technology of an airborne horn antenna is studied.The plane wave expansion formula of the antenna and the near-field and far-field antenna coupling formula under the condition of probe compensation are derived by using the mode expansion method.This paper focuses on the probe error in the near-field measurement,uses the hybrid formula method to compensate the probe error,and carries on the simulation analysis of the test probe,compares the simulation results with the calculation results of the formula method,and carries on the error calculation.In view of the low efficiency of the existing airborne antenna gain and phase center measurement,the gain measurement is carried out by using the comparison method,and the relationship between the antenna phase center and the position coordinate is obtained by moving the reference point.The random error of near-field data is eliminated by using the leiinda criterion.Through the optimization and selection of hardware equipment in the test system,the problem of low efficiency of near-field data acquisition is solved.According to the above analysis,a set of near-field test system for airborne horn antenna is designed.The test system can realize the control of vector network and scanning frame through the control of upper computer software,complete the antenna near-field data acquisition,and finally obtain the radiation phase information such as antenna far-field pattern,gain and phase center,so as to realize the near-field and far-field transformation of airborne horn antenna.Finally,the near-field test system is used to measure the airborne horn antenna,and the error between the measured far-field pattern and gain and the simulation results is analyzed.The experimental results show that the measurement system can improve the calculation accuracy of antenna pattern and gain,and improve the efficiency of phase center and near-field acquisition.This method of airborne horn antenna near-field and far-field transformation is feasible and meets the design requirements.