Compact trapezoidal antenna for ultra-wideband applications with band-notch filter

A novel compact trapezoidal ulra-wideband (UWB) antenna with frequency notch characteristic which is fed by a 50 microstrip line is proposed and investigated. Details of the antenna design and simulation results on the return loss, voltage standing wave ratio (VSWR) and the E-and H-plane radiation patterns of the proposed antenna are presented. The antenna is very small in size, only 0.15λ square at 3GHz. By etching a complementary split ring resonator (CSRR) in the radiating patch near the feeding point, a very sharp notched band of 4.8GHz–5.4GHz with return loss larger than −7dB at which the wireless LAN service is assigned is obtained. The −10dB return loss bandwidth of the proposed antenna is 3GHz–12.4GHz covering the entire band assigned for the UWB application, which is about 122% with respect to the center frequency of 7.7GHz. The radiation patterns of the proposed antenna are not deteriorated by the inclusion of the CSRR and are relatively stable over its operating band.