Novel multiband/broadband horizontally polarized omnidirectional antennas

Novel multiband/broadband horizontally polarized omnidirectional antennas (HPOAs) are proposed in this paper. The HPOAs are made up of a metallic cavity and a bent feedline. By shaping the cavity and the feedline, the HPOAs can achieve multiband or broadband performances. A dual-band HPOA, a broadband HPOA, and a compact tri-band HPOA are developed. The impedance bandwidths of the dual-band HPOA for return loss (RL) >10 dB are 8.8% (2.37-2.59 GHz) for the lower band and 21.5% (4.85-6.02 GHz) for the upper band. The broadband HPOA achieves a bandwidth of about 50.2%. The tri-band HPOA covers the Chinese Unmanned Aircraft System (CUAS) bands (840.5-845 MHz, 1430-1444 MHz and 2408-2440 MHz). Good omnidirectional radiation patterns are obtained for all these HPOAs.