Analysis and design of artificial surfaces based planar antennas

Abstract

Future and Modern applications of Satellite, Radars and wireless systems require directive antennas operating on multiple or wide range of frequencies and compact antenna structures. New microwave antennas with compact structure, wide bandwidth and directive radiation characteristics have been explored in this thesis. These antennas are designed by applying partially reflecting surfaces (PRS) in the planar antenna structures. Partially reflecting surfaces are used to improve the performance of planar antennas. PRSs are used as superstrate above the planar antennas and this composite structure is known in the literature as Resonant Cavity Antenna (RCA) Configuration. Planar antennas are used as the primary feed of RCA configuration. These antennas are mainly designed for Radar applications but can also be utilized for next generation of mobile networks (5G) and other emerging applications such as vehicular satellite communication, high-speed wireless Local Area Networks, various point-to-point radio link communication. The analysis of novel antenna structures using double sided square newlineloop PRS with complementary layers has been presented in the research work. The structure is of compact profile and with directive radiation. The performance of the PRS has been proved with two types of feed antennas i.e. square microstrip patch and microstrip fed slot antenna. Same performance of the PRS proves the behavior of the PRS structure. newline newlineTwo structures of Low Profile Resonant Cavity antennas are designed and analysed. First, with probe fed patch antenna as primary feed loaded with double sided complementary PRS. The PRS is formed by printing periodic array of complementary metallic square loops on the opposite sides of the dielectric material. This PRS acts as newlinea dual band matching section between the microstrip patch and free space, hence resulting in dual resonance. The proposed structure has been analyzed using equivalent circuit model. Parametric analysis of the sensitive structural parameters has also been analysed.