Ring-loaded coaxial groove horn antenna for 12/14/20/30 GHz bands

In order to achieve rotationally symmetric beam, low cross-polarization component, and small size in a wide frequency band, a new quad-band horn is proposed in this paper by using a coaxial groove structure loading a ring structure. As a design example, a compact horn antenna with a cross-polarization level of less than -30 dB in a specific quad-band, Ku/Ka-band, is presented.