A Dielectric Rod Loaded Feed Horn Antenna for Dual-Band Dual-Polarized Backhaul Reflectors

Journal article, 2026

This paper presents a dual-band dual-polarized feed horn that operates in both the 18GHz band (17.7−19.7 GHz) and the E band (71−76 GHz & 81−86 GHz) for backhaul communications. The feed is innovatively designed using a horn loaded with a double-layer dielectric rod to maintain a constant beamwidth across dual-band operation with a frequency ratio of 4.2:1 while also achieving over 30 dB isolation between the bands without the use of any filters. The feed horn is excited by a dual-band orthomode transducer (OMT) to enable dual polarization in both frequency bands, where the gap waveguide technology is employed to relax the manufacturing constraints. The fabricated feed exhibits nearly constant 10dB beamwidths of 68.0°±5.0° over the 18GHz and the E bands, below −30dB mutual coupling without additional filters and a measured reflector gain of 37–39 dBi and 47.5–49.1 dBi in the two bands.