Reconfigurable antenna options for the Canadian broadcast satellite system

One of the options for the Canadian broadcast satellite system involves an ultimate system consisting of six satellites each broadcasting 16 channels of Ku-band programming to an associated time zone. The time zones correspond to the six 'service areas' across Canada, including the Pacific, Prairie, Manitoba, Ontario, Quebec, and Atlantic areas. An interim system would employ only two satellites at different orbit locations each with a dedicated antenna optimized for three of the time zones. The design of the reconfigurable antenna poses certain problems with respect to the requirements for high gain, low cross-polarization, and low sidelobe levels. The considered antennas are discussed, taking into account dual-mode antennas, single-mode antennas, and elliptical-beam antennas.