A polarization diverse tunable filtenna for cognitive radio applications

In this paper, the design of a polarization diversity tunable filtenna (filter-antenna) for overlay cognitive radio applications is presented. The frequency tuning technique is based on integrating a tunable bandpass filter into the feed line of a wideband printed antenna. The proposed structure is able to tune its operating frequency, as well as, radiate right handed and left handed circularly polarized (RHCP/LHCP) waves in the (φ=0°, θ=±45°) radiation directions at the same operating frequency. A prototype of the proposed tunable filtenna is fabricated and measured. A good agreement between simulated and measured results is witnessed.