Design Of Compact Monopole Ultra Wide Band Antenna Structure For Cognitive Radio Applications
A novel antenna structure is proposed by incorporating the PIN diodes within the slots of a octagonal patch
antenna structure for achieving the reconfigurability. This technique is employed to achieve multiband operation of the
antenna and the reconfigurability is achieved through switching. The octagonal patch is of compact size and is fed through a
50Ω microstrip. The antenna parameters have been investigated through simulation using CST software and the relative
parametric analysisis presented. It has been demonstrated that the proposed antenna provides an ultra-wideband width
(UWB) from 3GHz to 10.6 GHz completely covering the range set by the Federal Communication Commision (FCC) for UWB
applications also in cognitive radio (CR) applications. The slots at suitable size and position are intended for operating the
antenna at multiple frequencies i.e Ultra Wide Band operation (UWB) and the switching has been employed for achieving the
desired frequency ranges. This operation is better utilized for communicating with the spectrum which is the primitive
requirement of the CR. The combination of PIN diode switches in the slots provided along with the antenna changes the
frequency by dynamic operation of the switching state to either on or off mode. The electrical lengths are varied by operational
switches on and off. By the proper activation/deactivation of the switches alters the present flow and changes resonance
frequency. This paper presents a simulated compact, low cost, high gain, good radiating properties monopole octagonal
shaped frequency reconfigurable antenna for multiband operation together with the results.
Index Terms— Monoploe Octagonal shaped, Slots, switching, Reconfigurability, Cognitive Radio, Ultra Wide Band, CST.