Compact single feed circularly polarized fractal boundary microstrip antenna

Compact circularly polarized single feed microstrip antenna is presented. The proposed CP antenna uses Koch curve as boundary. It is shown that by using fractal curve as boundary to the square patch the size can be reduced by more than 35% without much reduction in gain of the antenna. The antenna gives a very good circular polarization with minimum axial ratio very close to 0 dB at the center frequency of 2220 MHz. The antenna provides almost constant gain of about 5.6 dBi over the frequency band of operation.