Design of Compact Circularly Polarized Microstrip Antennas using Meta-surfaces

The designs of compact circularly polarized (CP) microstrip antennas over the meta-surfaces (reactive impedance surfaces) are described in this paper. A conventional truncated corner square microstrip patch is used to design CP microstrip antenna over different reflection phases of the meta-surfaces. First the reflection phase diagram of meta-surface is studied and then CP microstrip antennas are designed over different meta-surface reflection phase regions with fixed overall antenna size. The largest microstrip patch size reduction and best CP bandwidth is achieved for the CP antenna over the meta-surface with +45 degrees reflection phase as compared to CP microstrip antenna without meta-surface. The size reduction of the CP microstrip patch is achieved around 40% at +45 degrees reflection phase.