Gap-coupled designs of slit cut circular microstrip antenna for circular polarization

摘要

Design of circularly polarized circular microstrip antenna using narrow slit is proposed on thinner glass epoxy substrate. In 1000 MHz frequency range, a single patch yields axial ratio bandwidth of 10 MHz with VSWR bandwidth of 46 MHz. To enhance the bandwidth of a single patch, its gap-coupled sequentially rotated designs, namely, gap-coupled configuration either along x or y-axis, gap-coupled along both the axes and 3 × 3 gap-coupled array designs, are proposed. The 3 × 3 gap-coupled array design yields axial ratio and VSWR bandwidth of 27 MHz (2.6%) and 63 MHz (6.1%), respectively. All the designs exhibit pattern maxima in the bore-sight direction. On thinner glass epoxy substrate, proposed 3 × 3 array designs gives peak bore-sight gain of nearly 1 dBi. Thus proposed low cost design of 3 × 3 array with given axial ratio and VSWR bandwidth and bore-sight gain can be used in personal communication applications in 1000 MHz frequency range.