Comparative study on different feeding techniques of rectangular patch antenna

Abstract

A microstrip patch antenna is a planar directional antenna in which a metal patch is placed on top of a dielectric substrate which in turn is placed on top of a metal ground plane. The power transfer between a source and antenna is done through a feed line. In general, the characteristic impedance of a transmission line is 50 ohms. By maximum power transfer theorem, the patch antenna should be fed at a point where input impedance is 50 ohms for maximum input power. There are several feeding techniques for patch antenna to match this condition. In this paper, a comparative study between inset feed, co-axial feed, aperture feed and proximity feed of a rectangular micro-strip patch antenna is done on the basis of S11 parameter, VSWR, directivity, beamwidth, bandwidth and radiation pattern. Design for each feeding technique is simulated and studied using the CST microwave studio software. The resonant frequency of the four antennas studied in this paper is 2 GHz. The fabricated inset fed patch antenna has been tested. It has acceptable return loss and comparable radiation performance with that of the simulated antenna.