Search

A broadband low-profile, circularly polarized metasurface antenna with a nonuniform aperture is proposed for L band satellite communications. By optimizing the nonuniform geometry, antenna size is minimized and bandwidth is expanded. Characteristic mode analysis (CMA) clearly reveals the dominant modes and stimulated modes for wideband operation. The feeding structure employs a quadrature phase quarter-power divider to excite a collection of orthogonal modes, generating stable circular polarization (CP) radiation and a phase center. Numerous feeds and crossing slots, in conjunction with the metasurface, produce multiple resonances and minimum axial ratio (AR) locations when excited, resulting in a broad impedance and AR response. The low profile nonuniform metasurface CP antenna achieves a 40% −10 dB impedance bandwidth, a 47% 3 dB AR bandwidth, and a peak gain of 8.7 dBic with a compact dimension of 0.67 × 0.67 × 0.06 λ 3. [ABSTRACT FROM AUTHOR]

This paper presents a dual-band circular polarized (CP) hybrid dielectric resonator antenna (HDRA) with gain enhancement. The fundamental TE 111 mode and high-order TE 113 mode are excited by the orthogonal CPs in the two frequency bands. This is achieved by cutting four corners along the DRA diagonal and adding a metal strip on the corner. The DRA design procedure is presented to verify its operations. The gain improvement is achieved by loading the water on the top of DRA. This leads to a 1.32 dB improvement on the upper band and have no impact on the lower band. The proposed DRA is fabricated and measured. The results verify its dual-band CP operation at 1.58 GHz (left-hand) and 2.40 GHz (right-band). Two bandwidths of the lower band and upper bands are 20.52% and 21.72%, respectively. The gain improvement is verified from the measurement on both states. The proposed HDRA can be applied for the dual-function communications such as GPS and WLAN. [ABSTRACT FROM AUTHOR]