An UWB Monopole Antenna for Partial Discharge Detection

An ultra-wideband (UWB) monopole antenna for partial discharge detection is proposed in this paper. The antenna is composed of a stepped monopole, a circular metal sleeve, an annular slot, a metal cap and a metal reflector. By using a 50 Ω coaxial cable to excite the monopole, good vertically polarized omnidirectional radiation performance is achieved for the monopole antenna. To improve the impedance matching, widen the impedance bandwidth and improve the gain of the proposed antenna, load a circular sleeve with a metal cap around the monopole. To further improve the impedance bandwidth of middle and low frequency bands, the monopole radiator is changed into a stepped monopole, and an annular slot is etched on the metal reflector. The simulated results show that the proposed antenna has an ultrawide impedance bandwidth of 102.6% for reflection coefficient S11 ≤ -10 dB, ranging from 1.69 GHz to 5.25 GHz. In addition, the antenna also has good omnidirectional radiation performance, and a gain range of 0.91 to 6.2 dBi. These performances show that the proposed antenna is highly competitive in partial discharge detection.