An integrated narrowband-wideband antenna

In this paper, we proposed an integrated ultra-wideband (UWB) and narrowband (NB) antenna for cognitive radio applications. The UWB antenna was achieved using a fat monopole with a microstrip type feed-line. The antenna can be reconfigured to a switchable NB antenna by the use of cascaded complementary split ring resonators within the feed-line. The reconfigurability was based on a frequency-switchable filter embedded in the feed-line. Simulations and measurements demonstrated that the UWB mode operated from 2 to 10 GHz, while being able to switch to multiple NB frequencies.