The need for efficient spectrum management continues to grow as the number of users of wireless technologies continues to increase. Solutions to this problem include cognitive radio systems, which aim to adaptively reduce interference by seeking less-crowded frequency bands, and smart antenna systems, which attempt to reduce interference by directing energy toward desired users and placing nulls in the directions of interferers.

While seeking to adapt to the challenges posed by frequency spectrum crowding, designers are also tasked with minimizing the size, weight, power consumption, and cost of components. Minimizing these parameters helps manufacturers to reduce their costs and provide more capable systems to their users, which is important in both the consumer and military domains.

This work investigates the design of a tunable filtering antenna for interference mitigation applications. The filtering antenna concept offers several benefits over traditional antennas, such as increased impedance bandwidth, the elimination of reflections at device ports, and reduced size. The design methods for filtering antennas presented in the literature are reviewed and used. A new filtering antenna is developed which achieves center frequency tuning in the S-band, making it a candidate for integration into cognitive radio systems. The realized filtering antenna provides increased impedance bandwidth and aids in maintaining input impedance matching across the tuning range when compared to the reference antenna.