Design of a Dual-band Feed System for S/X-band VLBI Observations

The design of the dual-band feed system for 22-m geodetic VLBI radio telescope is described. The developed dual-band feed system allows simultaneous operation at S/X-band with dual-circular polarization. The dual-band feed horn comprises a coaxial waveguide horn for S-band and a dual-mode horn for X-band. A novel device for S-band circular polarizer was designed and manufactured for the dual-band feedhorn.