A Novel Unidirectional Dual-Band Circularly-Polarized Patch Antenna

A novel unidirectional dual-band circularly -polarized (CP) patch antenna is proposed in this communication. By loading a pair of L-shaped stubs outside the truncated patch, an outer mode and an inner mode are excited respectively. Therefore, dual-band CP operations are generated. The dual CP bandwidths are 3% and 4%. Because the meandering probe feed technique is used, the proposed antenna enjoys the wide impedance bandwidths of 8% for the lower band and 19% for the upper band. The peak gains within the dual bands are 9 dBic and 8.2 dBic and its height is 0.086λ. Besides, the front-to-back ratios are about 20 dB.