Poly Fractal Boundary Circularly Polarised Microstrip Antenna for WLAN/Wi-MAX Wireless Applications

Abstract

The design of circularly polarised multiband poly fractal boundary microstrip antenna is proposed and experimentally studied. Initially the two orthogonal sides of the square patch are replaced with different fractal curves for circular polarisation (CP) radiation. Along the x and y axes, Minkowski and Koch fractal curves are employed. A 45° rotated poly fractal slot is embedded at the center of the fractal patch for triband CP operation. The indentation depths and indentation angles of the Minkowski and Koch fractal curves are optimised for better CP emission. The inserted fractal slot redistributes the current elements on the patch for tri band CP radiation. The measured 3-dB axial ratio bandwidths of the proposed antenna at 2.4 GHz, 3.4 GHz, and 5.8 GHz are 1.53 per cent, 0.81 per cent, and 1.62 per cent respectively, making it an able candidate for WLAN and Wi-MAX wireless applications.