Design tunable filter-antennas for cognitive radio applications

In this paper, we designed frequency-tunable microstrip antennas for Cognitive Radio (CR) applications. First we investigated an Open Loop Resonator (OLR) based on the band stop filter, and its transformation into a bandpass filter. Then incorporation of the bandpass filter with a wideband antenna was investigated. A comparison between the proposed and existing designs was obtained. All of these designs are modified in dimension to the existing designs. The modification is made by reducing the dimensions by 0.2 mm. The simulation is done by using HFSS simulation.