Compact UWB antenna with sharp band-notched characteristics for lower WLAN band

A compact ultra-wideband (UWB) antenna with sharp band-notched characteristics is presented. The sharp band-notched characteristic is realised by inserting a half wavelength C-shaped slot in the patch and adding two half wavelength stepped impedance resonators around the feed-line. Simulated and experimental results show that the designed antenna, with compact size of 30 × 36 mm², has an impedance bandwidth of 3.1-10.6 GHz for return loss less than -10, except the lower WLAN band of 5.15-5.35 GHz (return loss >; -5 dB). The ratio of -5 dB notched bandwidth to -10 dB notched bandwidth is 0.79. Moreover, the antenna has good omnidirectional radiation patterns in the H-plane.