Analysis of Dual Band Circularly Polarized Microstrip Hexagonal Patch Antenna by Tuning the Feed Position

Analysis of a single-feed arrangement of hexagonal patch is proposed, which is capable of pro viding circular polarization along low return loss. An antenna is designed on a glass epoxy FR-4 substrate with overall thickness of the structure less than 1.6 mm or 0.11A0. Reflection coefficient is better than -22 dB at 5.7 GHz; -32dB at 8.2GHz and impedance better than 50Ω may be achieved with the proposed geometry. Measured S11 (dB) and VSWR bandwidth percentage variations of the pro posed antenna with frequency and feed position are compared to simulated results for better understanding. The measured Eand H-plane radiation patterns in the entire impedance bandwidth are identical in shape, and the direction of maximum radiations is normal to the patch geometry. In the entire axial ratio bandwidth range of the pro posed antenna, the E-plane left circularly polarized patterns are nearly 15 dB higher than the corresponding right circularly polar ized patterns.