Design of a 118 GHz Corrugated Horn Based on the Modal Analysis

This paper presents a 118 GHz tanh-linear profile corrugated feedhorn with high Gaussian coupling efficiency and ultra-low sidelobes for quasi-optical systems. By optimizing the amplitude and phase of the HE11, HE12 and HE13 modes at the aperture of the feedhorn, we have acquired high beam symmetry, low sidelobe levels about −43 dB and 99.47% coupling to the fundamental Gaussian mode in the CHAMP simulation. A comparative analysis of linear, sin2-parallel and tanh-linear profile corrugated feedhorns has been done, which shows the tanh-linear profile feedhorn has the best performance of the three.