Dual-frequency dual circularly-polarised patch antenna with wide beamwidth
X.L. Bao, M.J. Ammann
Volume: 44, Issue: 21, 9. October 2008
A dual-frequency dual-circularly polarised patch antenna with wide beamwidth is proposed. The two-layer structure comprises circular patches with offset circular slots connected to rectangular slots. They provide orthogonal perturbations realising RHCP and LHCP for the lower and upper bands, respectively. The wide beamwidth is realised by extending the substrate beyond the groundplane. Measurements
show a maximum beamwidth of 1808 and gains of 3.9 and 0.5 dBic for zenith and 108 elevation, respectively, for the upper band. The measured beamwidth for the low band is 1308 with a maximum gain of 3.9 and 20.7 dBic for zenith and 108 elevation, respectively. The axial-ratio is less than 3 dB in the hemisphere for elevations greater than 108 for both bands.
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