Dual-band dual-polarised square patch antennas using shorting metallic cylinder

A single-feed microstrip patch antenna with a shorting metallic cylinder, that can be operated at two distinct resonant modes is proposed. The two resonant modes can radiate a monopole-like pattern with vertical polarisation and a broadside pattern with circular polarisation, respectively. In addition, the effects of the metallic cylinder size on the frequency ratio of the two operating frequency bands are studied. Measured results support the simulation analyses.