A RECONFIGURABLE PATCH ANTENNA WITH EBG STRUCTURE

Abstract

Microstrip antennas are widely used in wireless communications because of their compatibility, low profile, low power consumption and low cost. The capability to select the frequency is essential for diverse missions and this is achieved by a Reconfigurable Antenna. Resonant frequency of an antenna is changed by reconfiguring its geometrical structure. To achieve reconfigurability RF switching devices such as PIN diodes , photoconductive switches, micro-electromechanical system (MEMS) switches and FETs can be used.

Electromagnetic Bandgap (EBG) Structures that are those structures in which each element follows periodicity. Hence using EBG structures in a conventional patch antenna increase bandwidth and provide better suppression of harmonics .

This major project combines these two structures designing a reconfigurable patch antenna with EBG structure in which PIN diodes are used as switch as they provide fast switching speeds, reasonably high current handling capabilities, reliability and ease of modelling.

First of all the phase reflection diagram for a unit cell of proposed EBG is shown, after that bandgap of full EBG structure is shown using suspended transmission line method. Different EBG structures’ bandgaps are also compared. Then the EBG structure is combined with a reconfigurable patch antenna and simulation results are presented in terms of return loss, VSWR and radiation pattern. A comparison between simulated results for reconfigurable antenna with and without EBG structures for return loss and radiation pattern is also provided. All the above simulations are carried out by CST STUDIO SUITE 2014.