Wideband Vertically Polarized Omnidirectional Antenna with low profile for Partial Discharge Detection

This paper introduces a design method for a patch antenna that achieves a broad bandwidth, good omni-directivity, and a low-profile configuration. The antenna's design leverages a circular patch coupled with four feeding loops to facilitate multi-band resonance, thereby expanding the bandwidth. Following design optimization, the antenna has good impedance matching and maintains excellent omnidirectional performance. The prototype was tested. The antenna has accomplished an ultra-wide bandwidth ranging from 1.65 to 3.26 GHz, alongside maintaining its omnidirectional radiation pattern and a very low profile (0.07 times the free-space wavelength λo at the lower edge of the operational frequency band).