Compact ultra-wideband printed monopole antenna with a trapezoidal radiator

A compact ultra-wideband (UWB) printed monopole antenna with a trapezoidal radiator is proposed and investigated. The size of the antenna is 15×15mm², only 0.15λ square at 3GHz. The conducting ground is defected to achieve better impedance matching over the entire UWB frequency band. The proposed antenna is fed by a 50 microstrip line. The parameters which affect the performance of the antenna are investigated and optimized values are obtained. The frequency band of the proposed antenna is 2.2GHzߝ18.4GHz for voltage standing wave ratio (VSWR) less than 2, which is about 157% with respect to the center frequency of 10.3GHz. The radiation patterns of the proposed antenna are relatively stable over its operating band and the H-plane patterns are all omnidirectional.