Design of a tanh profiled compact Gaussian corrugated horn for Cassegrain antenna application
A design method of a tanh profiled corrugated horn coupling to the fundamental Gaussian beam mode with low sidelobe levels and symmetry radiation pattern is presented working at Terahertz(THz) frequency. The calculation of slot depth of feedhorn has a variable-pitch-to-width-slot mode converter in order to produce the HE11 hybrid mode, whilst increasing a linear phase stability section reaches the purpose of coincidence stationary phase in the aperture of horn. This feedhorn design methodology has been validated experimentally in CHAMP and GRASP having obtaining -40dB side-lobe levels and -58dB cross polarization levels at 322GHz At last, the designed tanh profiled corrugated horn is applied into a Cassegrain antenna with a very stable output phase which reveals a good accuracy and superior performance comparing the far-field patterns with ideal Gaussian feed and sin-profiled feed.