A Wideband Differential Dual Circularly Polarized Laminated Resonator Antenna

Abstract

A wideband differential dual circularly polarized (CP) laminated resonator antenna (LRA) is reported in this letter for the first time. Two 90° hybrid couplers and four rotationally symmetrical L-probes are adopted as the feeding of the dual CP LRA. The four input ports of the 90° hybrid couplers form two pairs of differential ports for dual CP operations. When each pair of differential ports is supplied with differential signals, the proposed LRA works in its degenerate dominant modes, ${\rm TE}^{y}_{101}$ and ${\rm TE}^{x}_{011}$ modes, with a −90°/+90° phase difference, which radiates left-handed circular polarization (LHCP) or right-handed circular polarization (RHCP) waves, respectively. For demonstration, an antenna prototype is simulated, manufactured, and experimented. The differential dual CP LRA in a low profile of 0.119λ₀ shows a broad measured effective bandwidth of 28.6% confined by the −10 dB differential impedance, 3 dB axial ratio (AR), and −15 dB LHCP-to-RHCP isolation bandwidths. Besides, the radiation patterns are stable and symmetric. The in-band gain varies within 1 dB. The proposed LRA is a promising candidate for applications in differential wireless communication systems of multiple circular polarization.