Analysis And Design Of High-performance Dual-band Feed

In recent years, the Ku-band and Ka-band is used more and more in satellite communication and some new design requirements of the antennas in satellite ground stations, such as wideband or multiband, low cross-polarization, multi-beam and multi-polarization, is proposed.With the development of satellite communication,the trend for satellite terminals is shifting away from large ground stations to small, mobile terminals that can operate on the move. This trend makes the interest in design of high performance, low cost and compact feed increase. The feed is the core of the antenna systems. Designing the compact feed with low cost, wideband or multiband, low cross-polarization and multi-polarization in Ku and Ka band is the main study purpose in this paper.In this paper, the dual-band linear polarization feed working in Ku band and the dual-band circular polarization feed working in Ka band are designed. They are compact and easy fabricating. Good radiation characteristic is gained when they are applied in reflector antenna and Luneberg lens antenna systems.In Ku band, two vertical waveguide to coaxial converter are introduced to get the dual-band linear polarization in quadrature, and the reflect-cylinder structure is used to increase the transceiver isolation. The dielectric rod horn with excellent main beam circularity, low cross-polarization is introduced as the radiation aperture.The dual-band circular polarization feed with relative bandwidth of 45% working in Ka band is composed of dual band branching orthomode transducer(OMT), dual-band polarizer and dual-band corrugated horn. Compared with the traditional dual-band circular polarization feed, the design in this paper simplifies the feed structure and reduces the subassembly of the feed, and good standing-wave ratio, hign transceiver isolation, excellent main beam circularity and good axial ratio characteristic is gaind.