UWB Circular Monopole Ominidirectional Antenna with a Slot for Radiation Pattern Improvement

An ultra wideband (UWB) circular monopole antenna consisting of a ground plane, a radiating element and a feed member is proposed in this paper. The radiating element comprises a simple circular metal patch, with a slot on one side of the patch. This slot can decrease the gain variation in the y-z plane of the radiation pattern and increase the impedance bandwidth. The whole size of the antenna is 30 × 30 × 0.813 mm
³
. The measured -10 dB impedance bandwidth of the circular monopole antenna is from 2.3 GHz to 6.1 GHz. The gain variation is less than or around 15 dB in the y-z plane and below 7 dB in the x-z plane over the operating bandwidth.