A Compact K-Band High Data Rate Upconverter / Solid State Power Amplifier (SSPA) Downlink Engineering Model for LEO Missions

An engineering model of a Ka-Band transmitter downlink module for LEO satellites has been developed. The module consists of a custom MMIC chipset, LO circuit module, RF filtering and associated module control electronics. The MMIC chipset consists of an IF attenuator, up-converter, driver MPA and HPA. The HPA exhibits a peak output power of approximately 41dBm with an associated PAE of 25% in the 25.5-27GHz band. The MPA has a small-signal gain of greater than 27dB with an output power > 31dBm. The up-converter MMIC has a conversion gain of approximately 25dB with compliant spurious performance and the attenuator MMIC provides 6-bit control. The MMICs are mounted onto a 4-layer RF substrate and copper inserts provide a low thermal resistance between the package and module baseplate. The output from the MMIC PCA feeds a PCBWR34 transition mounted underneath the PCA, this in turn feeds the waveguide filter. The DC power consumption is 55W from 28V.