Fractal boundary circularly polarised single feed microstrip antenna

Abstract

A Koch fractal boundary circularly polarised single feed microstrip antenna is presented. The proposed antenna gives very good circular polarisation with axial ratio close to 0 dB at the centre frequency of 2510 MHz, 3 dB axial ratio bandwidth of about 1.6% and impedance bandwidth of 6.2%. It is established that it is easy to obtain circular polarisation using the fractal curve as the boundary. The antenna provides about 6 dB gain over the frequency band of operation.