AR bandwidth and gain enhancements of patch antenna using single dielectric superstrate

摘要

A single-feed circularly polarised (CP) patch antenna loaded with a single dielectric superstrate for a wideband high-gain CP radiation is presented. Along with the gain enhancement, the emphasis is on extra CP radiation of the antenna caused by the superstrate, which broadens the axial-ratio (AR) bandwidth significantly. A prototype antenna was fabricated and measured at a frequency of 11 GHz. The antenna with overall size of 40 × 40 × 17.45 mm has a voltage standing wave ratio <;2 bandwidth of 24.35% (10.1-12.9 GHz), a 3 dB AR bandwidth of 13.6% (10.3-11.8 GHz), a peak gain of 13.17 dBic, a 3 dB gain bandwidth of >26% (10.0-13.0 GHz), and a radiation efficiency of >90%. The presence of superstrate produces a ~350% increase in 3 dB AR bandwidth and a ~7 dB increase in the broadside gain relative to the conventional CP patch antenna.