Hybrid Microstrip Patch Antenna Design for Broad Band Operations

Abstract

newlineIn this thesis a number of hybrid microstrip patch antennas with large impedance bandwidth and enhanced gain have been reported. It also covers the study of fundamentals of microstrip patch antenna and basics of broadband antenna. A series of parametric studies newlinehave been done for finding the dependency of reflection coefficient and gain of the antenna newlineon various design parameters of the patch and ground plane and also to achieve the desired newlineresults and performance. This parametric analysis is completely a simulation based study using CST Microwave Software. Six hybrid microstrip patch antennas have been designed by combining different conventional shaped patches and incorporating open end slots into newlinethe reduced ground plane. Out of these six antennas; two antennas are for broadband, one newlineantenna is for ultrawideband, two antennas are for super wideband and one antenna is for high gain wideband applications. Also an FSS structure has been designed to improve the gain of a wideband microstrip antenna. All the antennas and FSS have been developed on newlinelow cost and reliable FR-4 substrate having dielectric constant 4.4, loss tangent 0.02 and thickness 1.6 mm and simulated by using CST microwave studio software which is based on Finite Element Method (FEM). In addition, focus is also given to model the microstrip patch antenna to its equivalent lumped RLC circuit using commercially available ADS software. In the first work, a hybrid broadband antenna is designed, fabricated and tested. newlineThe radiating plane consists of three circular patches among which two circles are identical and they are placed in such a way that the composite radiating structure looks like a HEART . Two rectangular slots are loaded in the reduced width ground plane to get broadband characteristics. The antenna having dimension of 29 mm × 32 mm × 1.6 mm exhibits an impedance bandwidth of 5 GHz (from 2.5 GHz to 7.5 GHz) and a fractional bandwidth of 100%. Also a peak gain of 3.6 dBi at 5.5 GHz and 6.9 GHz with enough