Analysis of Slot and Microstrip Radiators backed by Cylindrical Cavity

Abstract

This thesis proposes and extends work on two new kinds of waveguide fed anten-nas.The rst is an aperture-coupled microstrip patch antenna excited from a waveg-uide shunt-slot. Oering the slot from the waveguide centerline provides a means ofmodifying the patch excitation.The second is a variety of cylindrical cavity-backed slot radiators employing singleand multiple radiating elements. Initially, a coupling module for a cylindrical cavityis used to investigate the behavior of the cavity relating to coupling of energy to andfrom it. The input and output are taken by a rectangular waveguide using a slot asa coupling element. Subsequently, the upper side of the cavity is used to realize aradiating slot- single element. The inuence of the ground plane size on the radiationof the cavity backed slot radiator is investigated. Subsequently, a cavity with a largecross section is used to realize three-slot and ve-slot radiating arrays fed from asingle cylindrical cavity.The various structures proposed in this thesis work were analyzed and optimizedusing the FEM-based EM simulation tool, Ansoft HFSS. Based on the designs carriedout, the realized hardware was tested to validate the simulations.The investigation of all geometries in the thesis was successfully completed. Thus,the ecacy of waveguide shunt-slot feeding for a microstrip patch and the use of acylindrical cavity for feeding an array of slots was established. This latter methodeliminates a beamformer that is conventionally necessary to excite radiating slot ar-rays.