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 HE 11 , HE 12 and HE 13 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, sin ² -parallel and tanh-linear profile corrugated feedhorns has been done, which shows the tanh-linear profile feedhorn has the best performance of the three.