Dual Circularly Polarized Substrate Integrated Waveguide Cavity-Backed Antenna With Enhanced Bandwidth and Reduced Size for Wideband Wireless Applications

Abstract

A dual circularly polarized (CP) substrate integrated waveguide (SIW) cavity-backed antenna with the feasibility of obtaining a wider bandwidth and relatively smaller size than other homogeneous referenced antennas is proposed and demonstrated. Fed by a quadrature hybrid coupler, the proposed double-layered stacked antenna, consisting of a perturbed circular SIW cavity and an improved circular patch radiator, is designed, analyzed, and fabricated. Good agreement between simulated and measured results is observed. Simulation and measurement results reveal that the proposed antenna can provide impedance bandwidths of 45.7% (4.74-7.55 GHz) and 46.2% (4.75-7.6 GHz), as well as 3-dB axial ratio (AR) bandwidths of 37.5% (4.74-6.93 GHz) and 37.2% (4.75-6.92 GHz) for RHCP and LHCP, respectively. Meanwhile, within the effective RHCP/LHCP bandwidths, the proposed antenna has gains from 4.8 dBic to 7.6 dBic with an average gain of 6.4 dBic for RHCP, and gains from 4.9 dBic to 7.5 dBic with an average gain of 6.3 dBic for LHCP, respectively. Additionally, the measured effective dual CP bandwidth of 37.2% (4.75-6.92 GHz) not only meets the need for certain or WiMAX (5.5 GHz) band communication application, but also provides the potential to implement multiservice transmission.