An alternative feed design for the MRO antenna

NASA's Mars Reconnaissance Orbiter (MRO), scheduled for launch in 2005, will study the history of water on Mars. The current feed design for the 3-meter reflector antenna uses a dielectrically supported disk-on-rod Kaband (32 GHz) feed in the center of an X-band (7.2, 8.4 GHz) corrugated horn. As a potential backup design in case of problems, an alternate feed design for the MRO antenna that does not use any dielectric materials or a disc-on-rod was developed. The design uses a Ka-band Potter Horn in the center of the current Xband MRO corrugated horn. Using the same High-gain reflector assembly, the new feed provides virtually the same X-band gain (within 0.1 db) and more than 1 dB improvement at Ka-band.