Single-layer partially reflective surface for an orthogonally-polarised dual-band high-gain resonant cavity antenna

This study presents a novel dual-band resonant cavity antenna (RCA) with orthogonal linear polarisations. The proposed RCA utilises one single-sided slotted-patch partially reflective surface (PRS) excited by a microstrip patch antenna. The two operating frequencies can be arbitrarily and independently controlled and the polarisation of each band is orthogonal to the other. A prototype is designed, fabricated and tested. The measured results show a dual broad-side beam with lower-band gain of 18.06 dBi at 10.25 GHz with vertical polarisation (V-pol) and the upper-band gain of 19.41 dBi at 11.05 GHz with horizontal polarisation (H-pol). Besides, the proposed RCA has the capability of independent beam-forming. By applying progressive phase gradient using variable slot length over PRS, the V-pol lower-band beam is tilted off broadside up to 29°, whereas the H-pol upper-band beam is fixed at broadside.