Planar Ultrawideband Circularly Polarized Cosine Slot Archimedean Spiral Antenna for Partial Discharge Detection

Design and experimental verification of an ultrawideband planar circularly polarized ultrahigh frequency (UHF) sensor is presented for detection partial discharge (PD) activities in high voltage (HV) equipment. The proposed cavity-backed cosine slot Archimedean spiral (CSAS) antenna with electromagnetic (EM) transparent radome. dual-arm was meandered as wave size reduction optimized broadband operation circular polarization (CP) over 0.5-5 GHz. Unidirectional radiation pattern CP achieved GHz using cavity loaded EM absorber. fabricated UHF CSAS has the widest operating bandwidth smallest aperture $0.26\lambda {}_{L}$ when compared to existing PD sensors, where notation="LaTeX">$\lambda wavelength at lowest frequency. Time domain incipient signals phase resolved patterns gathered three commonly occurring defects test cells mimicking gas insulated switchgear (GIS) indicate better sensitivity capability than reference sensor. signal measurements comparison other sensors that could be used HV