Frequency re-use in GTE earth stations with beam waveguide feed

Frequency reuse by orthogonal linear polarization in the AT&T-GTE domestic satellite system is an essential element in conserving limited orbital and spectrum allocations in the 4/6-GHz frequency bands. To achieve acceptable end-to-end system noise performance, a dual-polarized beam-waveguide feed system has been designed and built for earth stations. Extensive 1/3-scale model tests were used to verify the initial horn, diplexer, and mirror designs; full-scale system tests have shown that all cross-polarization performance goals are exceeded by comfortable margins when polarization ellipticity is corrected by simple waveguide squeeze-sections.