High Performance 30/20 GHz Transponder System Using Suspended Substrate MIC Down and Upconverters

In order to fully realize the operating potential of millimeter-wave communications systems, a 20/30 GHz spacecraft transponder system has been designed around the use of subharmonically pumped down and up converters. These converters, exhibiting the lowest commercially available system noise figures, provide a reliable nucleus for use in multichannel transponder architecture. SSB receiver noise temperatures of less than 1250/spl deg/K including the 250/spl deg/K contribution from an 8 GHz IF amplifier have been achieved for the subharmonically pumped down-converter operating between 30.2 and 31.2 GHz.