Study On The Effects Of Signal Amplitude And Phase Errors On The Performance Of Phased Array Antennas

As a new kind of electronic sanning antenna developed in1960’s, phased array antennashave received more and more attentions and been widely used in practical engineering fieldssuch as radar and communnication systems because of its huge advantages overanti-interference capability, highly beam pointing accuracy and the ability of fast beamforming and scanning. But side lobe levels, beam pointing accuracy and null depth will beinfluenced by various factors,such as the torlence of fabrication, assembly errors, distortionscaused by high temprature etc.All of which can result in the deviation of signal amplitude andphase and further make an impact on the performance of antenna system. Thus, the researchon the effects of amplitude and phase errors has great theoretical and practical significance.Firstly, this paper introduces several types of amplitude and phase errors,and utilizingthe theory of probablity, analysis have been made on the bad effects of which on sidelobelevels of sum patterns,null depth and beam pointing accuracy of sum and difference patternsfrom theoreical aspects.Computer simulations verify the validity of the analytical results.Then,according to the requirements of plannar phased array antenna system,simulations are carriedout to retrieve the tolerance of the sysytem.Finally,five kinds of methods to eliminate the badeffects of amplitude and phase errors have been detailed.The wok has been done are as follows:(1) The effects caused by amplitude and phase errors on antenna gain, peak sidelobe levels,null depth and beam pointing accuracy of both sum and difference patterns are presentedincluding the associated analytical equations plus the derivation process.Several concretecases have been studied and the estimation results have been given. Its validity are proven bycomputer simulations.(2) According to the requirements of planar phased array antenna, system tolerance hasbeen retrieved by computer simulations, which showed that in order to meet the requirementsof the system, the correlated amplitude and phase errors of feeding network, randomamplitude and phase errors as well as the number of failture array element must be controlledin a certain level.(3) Five kinds of methods to reduce amplitude and phase errors have been presented, forexample, creating an amp-pha table to realize joint adjustment, adopting random phasingtechniques to minimizing phase errors,using near field and far field measurement for thepurpose of test and diagnosis and employing monitoring techniques. Studies and practiceshowed that these methods can reduce amplitude and phase errors effectively.