Wideband Circularly Polarized Microstrip Antenna With Wide Beamwidth

A novel wideband circularly polarized antenna for S-band satellite communications with wide beamwidth is presented. The wide impedance bandwidth is achieved by using the modified inverted-L feeds and stacked patches. The wide beamwidth is obtained by the semi-open metal cavity. A prototype of the antenna is implemented, and the measured bandwidth is 30.1% with the reflection coefficient $\leq \hbox {-}10~\hbox {dB}$ , axial ratio $\leq 3~\hbox {dB}$ , half-power beamwidth (HPBW) $\geq 100^\circ$ , and gain $\geq 3~\hbox {dBic}$ . Experimental results show that the proposed antenna has good impedance matching, circular polarization, and wide beamwidth characteristics.