Dual Tunable Multifunctional Reconfigurable Vivaldi Antenna for Cognitive/Multi-Standard Radio Applications

A novel tunable triple band-notch vivaldi antenna which can also be reconfigured as a tunable narrow band antenna is proposed in this paper. The triple band notch characteristic is obtained by placing three split ring resonators (SRR) on the slotline and tuning it using a varactor diode. A tuning range from 800 MHz-1.1 GHz is contributed by each of the three varactor loaded SRRs yielding an overall tuning range of 3.5 GHz. The gain of the standalone Vivaldi is around 6-7 dBi in the entire Ultra wide Band (UWB) spectrum. The same antenna is reconfigured into narrowband antenna by introducing switches on the slotline above the SRR. This reconfigurable antenna is suitable for both underlay and interweave spectrum access in Cognitive Radio.