通道幅相误差对数字阵列天线性能影响及校准

摘要

为实现低副瓣数字阵列天线性能，需要对阵面通道幅相误差进行校准。针对此问题，定性分析了通道幅相误差、阵面通道数与数字阵列天线主要性能(副瓣电平、波束指向、增益)的相对关系，分析结果表明：通道间幅相误差越大，副瓣电平、波束指向、增益越差；通道数越多，副瓣电平、波束指向受通道误差影响越小，而增益受通道幅相误差的影响与阵面通道数无关。结合数字阵雷达实际使用中阵面通道幅相误差修调问题，重点研究了通道误差测量方法。给出了利用内监测法和中场测量法进行通道误差测量的原理、实现方法及适用条件，该2种通道误差测量方法可以作为互补手段使用。最后，给出了一种基于多次测量取平均值的数字阵列幅相误差校准方法，仿真结果表明：校准前后，通道幅相误差分别由2 dB和20°变为0.4 dB和2°，满足指标要求。%The calibration of channel amplitude/phase errors is necessarily required in order to achieve the performance of low side-lobe digital array. The relationships among channel amplitude/phase errors, array channels and the main performance (side-lobe level, beam direction, gain) of digital array are analyzed. Analysis results show that, the side-lobe, gain and beam direction would deteriorate as the amplitude/phase errors increase; the influence degree of amplitude/phase errors on the side-lobe level and beam direction would decrease as the number of the array channels increase; the influence of amplitude/phase errors on gain is independent on the number of the array channels. According to the adjustment problem of channel amplitude/phase errors in digital array application, as a complementary method of measuring the channel amplitude/phase errors, the principle, implementation methods and application conditions of internal-monitor and mid-field measurement are studied in detail. A calibration method of channel amplitude/phase errors is put forward. Simulation results show that after calibration, the channel amplitude/phase errors decrease from 2 dB and 20° to 0.4dB and 2° respectively,which meets the expected specification.