Improvement in circularly polarized square patch design by double-layered ground structure

Abstract

Radiation performance of a circularly polarized (CP) truncated corner square patch on a conventional ground plane (GP) has been enhanced by using a simple and novel configuration of stacked dual GP. The proposed configuration employs a single fed truncated corner square patch etched onto a substrate grounded with a patch shaped small GP and having second square shaped GP of standard size separated from the first one with an air gap at an optimized distance. This configuration is ideal for many wireless and satellite communication applications. Simulated results indicate the best achievable axial ratio (AR) of about 0.4 dB for a stacked dual GP CP antenna compared to an AR of 2.7 dB for a conventional single GP CP antenna, indicating an improvement in cross polarized (XP) isolation of about 18 dB. AR bandwidth has also been improved by almost 100% with the stacked dual GP configuration when compared with conventional CP antenna. Improved radiation performance has been achieved without affecting impedance bandwidth and peak gain of the patch. Analysis based on GP size variation of the conventional CP antenna and stacked dual GP antenna reveals that stacked dual GP configuration results in compact CP antenna with good radiation performance.