Study Of The Keytechniques Ofamplitude-phase Consistency Test For DBF System

Beamforming for satellite-borne communications systems has attracted intensive attention in the past decade as it enables frequency reuse among the areas covered by different beams, and hence greatly improves bandwidth efficiency. But in the realization of beamforming,because of the inherent error of components circuit aging and temperature and other environmental factors,the amplitude and phase of each channel mismatch, which affect the pointing accuracy of beam forming network. So it is necessary to measure the inconsistency of the beam forming network. Then, the effect of channel mismatch could be eliminated by compensating the measurement results to the multiple beam forming network.The paper firstly introduces the measurement platform of power and phase of DBF systems, establishes the mathematical model of the DBF amplitude and phase consistency by the description of the multi beam forming network, and gives 4 indicators for the measuration of the platform’s performance. It introduces a beamforming network weights matrix test method on DS-CDMA, and then performs the theoretical derivation. It alsoexhibits the analysis of the frequency offset between the feedback signal and the local oscillator frequency and the two stage frequency offset estimation algorithm and simulation results are given.In view of the factors that cause the inconsistency of the transmitting channel and receiving channel of the platform, designs the sender online self-check, the sender offline calibration and the receiver offline calibration to calibrate the platform.At last, the stability of the whole system is tested and the performance analysis is given,which includes the intermediate frequency test and the radio frequency test. The test results show that the accuracy of measurement platform meets the requirements(relative power is less than 0.1dB, relative phase is less than 1°). And in the long time test the measurement platform works stability.