MICROWAVE SWITCHED BEAMFORMER FOR RECEIVER FRONT END.pdf

Abstract

In this thesis ,we propose a microwave switched beamformer (MSBF) receiver design, which is a Microwave Beamforming technique, where the antenna elements signals are switched and corresponding phase shift is controlled. A prototype of the MSBF structure consisting of a four-element microstrip patch antenna array with phase shifter is implemented and verified experimentally. In the design process of antenna array the first step in our work is to design a feed network consisting of a power combiner and the switched control phase shifter. The Wilkinson power combiner is implemented as it minimizes the reflection of electromagnetic waves from each output arm of the combiner network. In its basic form, Wilkinson power combiner combines the input signals from each branch of antenna array to give a single output signal with equal phase or 180 degree phase shift in any branch. In this thesis, MSBF structure is implemented with p-i-n diode based switched phase shifter. Since the cost of the phase shifters increases the price tag of the array antenna, low cost and conformal phase shifters are always on demand. A new switch design, which is more compact in size, cost effective and superior in performance is presented. The structure scattering parameters are measured for different switching states. An integrated simulation of complete switched beamformer structure for all switching combination is presented. One of the switching combination structure for the microwave switched beamformer (MSBF) receiver is fabricated and tested.