This research presents a new, highly compact, polarisation-agile slotted-waveguide array antenna. The proposed antenna can electronically switch among Horizontal linear, vertical linear, right-handed circular, and left-handed circular polarisation states. Such polarisation-agile antenna design is achieved by employing a hybrid sequential–corporate feed topology for the active polariser plate, resulting in a 37.9% reduction in size compared to a previous design. A fabricated 4-element linear array of the antenna, operated at 2.5 GHz, exhibits peak realised gains of 12.91 dBi, 13.53 dBi, 12.55 dBi and 12.89 dBi across the four polarisation states, respectively. In circular polarisation modes, the axial ratio is 1.2 dB with cross-polarisation isolation exceeding 45 dB. The antenna offers an impedance bandwidth of approximately 55 MHz. Designed for scalability within a compact form factor, this antenna is a viable solution for cutting-edge radar and remote sensing systems with stringent size constraints.
Chakrabarti et al. (Mon,) studied this question.