Compact UWB Antenna With Tunable Band-Notched Characteristic Based on Microstrip Open-Loop Resonator

A compact ultrawideband (UWB) antenna with an electronically tunable notched band is proposed for UWB communication applications. The proposed antenna utilized a C-shaped ground to realize miniaturization and a pair of open-loop resonators (OLRs) to create notched band. The center frequency of the notched band can be electronically tuned by changing the effective electrical length of the OLRs, which is achieved by employing varactor diodes. A prototype with an overall size of 24 × 28 mm2was constructed, and good agreement has been obtained between simulation and measurement. The experimental results show that, for a varactor diode capacitance approximately ranging from 0.63-2.67 pF, a continuous tuning notched band range from 5.1 to 5.9 GHz is achieved.