Ka-band tone generator for the ISARA Cubesat

This paper describes the design and fabrication of a 26GHz tone generator for the ISARA Cubesat. The tone generator uses a phase locked loop (PLL) frequency multiplier to get to 26GHz from an on board temperature compensated crystal oscillator (TCXO). The output of the PLL feeds a solid state power amplifier (SSPA) that puts out approximately 27dBm of RF power. The SSPA output then feeds a monolithic microwave integrated circuit (MMIC) switch which toggles between a high gain and low gain antenna as part of the ISARA experiment. The microwave electronics is packaged in an aluminum chassis and utilizes hybrid assembly technology. There are bare die with ribbon and wire interconnects in addition to printed circuit boards (PCB) which use surface mount technology (SMT) for assembly. Custom distributed circuits were designed for implementing the 26GHz filters, couplers and power detectors. A key aspect of this module's performance is its overall thermal stability which is highly dependent upon its assembly technology. The order of operations of each assembly phase, attachment materials, contamination control and reliability of interconnects all determine how well the hardware performs in flight.