Low-Loss Dual-Wideband Circularly-Polarized Antenna With Using Loading Technology

A millimeter-wave novel loading method to realize dual-wideband circularly-polarized (CP) performance based on a low-loss waveguide radiating antenna is proposed in this paper. The band-notching and CP characteristics can be achieved respectively by the simple loadings of non-radiating grooves and radiating stubs, while good impedance-matching is also achieved in a wide range. It can be seen from the simulated results that the proposed dual-wideband circularly-polarized antenna has the impedance bandwidths of 37% (25.3~34GHz) and 7.8% (37.49~39.77 GHz), and 3 dB axial ratio (AR) bandwidths of 29.6% and 5.95% in the lower- and higher-bands. Since the position of the introduced notch can be independently controlled by adjustable parameters, the bandwidth of the two frequency bands can be adjusted according to different applications. Besides, the simulated gains at 28 GHz and 38 GHz are 7.6 dBi and 6.9 dBi, respectively.