A Wideband Circularly Polarized H-Shaped Patch Antenna

A wideband H-shaped patch antenna for circular polarization is described. By incorporating a long probe inside a substantial high cavity (~ 0.26λ), a circularly polarized (CP) antenna in broadside direction is achieved. The horizontal arm of the probe is implemented by means of a printed monopole that is diagonally coupled to a small H-shaped copper plate. The CP antenna features a wide operational bandwidth of 19.4%. The maximum gain and the efficiency of this small antenna are recorded as >5 dBic and >80%, respectively, across the bandwidth. The dimension of the H-shaped patch is 0.3λ × 0.3λ whereas the ground plane size is 1.8λ × 1.8λ.