Wideband circularly polarized horn antenna with large aspect ratio for terahertz applications

This Letter proposes a circularly polarised horn antenna with large side length ratio. In virtue of 45° deflection structure and rectangular aperture with large aspect ratio, the proposed antenna achieves wideband circular polarisation radiation in small dimension. The fabrication is made on the prototype of the proposed antenna operating in the range of 220–320 GHz. Both of the measured circular polarisation bandwidth and impedance bandwidth of the designed antenna are 37% (220–320 GHz). This compact wideband circularly polarised antenna can be widely used in terahertz applications.