This paper describes the engineering verification of the active RF equipment that consists of the Ka band satellite transponder for the COMS(Communication, Ocean and Meteorological Satellite). The COMS communications transponder receives 30 GHz signals and down-converts to 3 GHz for beam switching and then up-converts to 20 GHz for transmitting to ground. Therefore a 30 GHz LNA, 30/3 GHz Downconverter, 3GHz Switch matrix 3/20 GHz Upconverter and Channel amplifier have been developed for the performance verification. These are designed by using MMIC technology to reduce size and mass, and to secure high stable performances. The LNA shows 2.0 dB noise figure with the compact size of 50 mm $ imes$ 35 mm $ imes$ 20 mm. The Downconverter triplicates the 8 GHz from DRVCO type LO for downconverting 30 GHz signal to 3 GHz and the Upconverter doubles the 8 GHz signals for upconverting 3 GHz signals to 20 GHz. Each frequency converter has a redundant chain in one housing. The Switch matrix has 4 $ imes$ 4 arrays composed by pin-diode switches and power combiners/dividers. The Channel amplifier has a32dB commandable gain control range and 20 dB automatic level control range to use transponders at optimum operating condition. In addition to engineering verification of the RF active equipment, Thermal/Mechanical analysis and the oyher environmental analysis shall be performed to secure successful development of the flight model equipment.