TUNABLE FILTER-ANTENNAS FOR COGNITIVE RADIO APPLICATIONS

Abstract

In this paper, frequency-tunable microstrip antennas, for cognitive radio applications, are proposed. The approach is based on electrically tuning the antenna's operating frequency by integrating reconflgurable band pass fllters into wideband antenna structures. The design of an open loop resonator (OLR)-based bandstop fllter, and its transformation to a bandpass fllter, are investigated flrst. Then, the incorporation of the bandpass fllter, with a wideband antenna, is detailed. The same methodology is employed to design cognitive radio pattern and polarization diversity tunable fllter-antennas. A good agreement between the simulated and measured results for the difierent fabricated prototypes is attained.