Design of inscribed square circular fractal antenna with adjustable notch-band characteristics

This paper presents the design of an inscribed square circular fractal antenna with notch having adjustable frequency characteristics. The position and width of the notch band can be adjusted in the entire operating band. A prototype of the antenna has been designed on FR4 substrate dielectric constant 4.3 and thickness h = 1.53 mm with a U-shape slot in coplanar waveguide feed of length L = 11 mm and slot width W = 0.4 mm. The experimental result of this antenna exhibits ultra wide band characteristics from frequency 3.1 GHz to 15.0 GHz. The notch in operating band helps to reduce the interference with the frequency bands of Worldwide Interoperability for microwave access (WiMAX). The simulated and experimental return loss are found in good agreement. The experimental radiation of this antenna in azimuth plane is nearly omni-directional. This proposed inscribed square circular fractal antenna with notch can thus be used for Ultra wide band (UWB) system, microwave imaging and precision position system.