A DUAL MODE K-BAND ANTENNA
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2002-Feb-28
This publication describes a dual mode K-Band antenna for use on spacecraft communications links. A constellation of Low Earth Orbit (LEO) satel- lites is being developed for the Iridium7M'SM program which uses communication links between satellites (SV) and Earth stations in the 30/20 GHz commu- nications band. Each SV contains four high data rate K-Band links using gimbaled spot beam anten- nas and one omnidirectional low data rate link. Due to the small size ofthe SV nadir pointing panel, it is difficult to obtain a clear 180" field of view for the omni antennas without interfering with the movea- ble spot beam antennas. Antenna towers are required for the omni antennas to raise them above the spot beam antennas to give the required field of view. For certain combinations of spot beam azimuth and elevation angles, the spot beam antennas point directly at the omni antennas, causing degradat,ion ofboth the omni and spot beam patterns.