60-GHZ MONOLITHIC DOWN-CONVERTER AND UP-CONVERTER UTILIZING A SOURCE-INJECTION CONCEPT

This paper deals with the design considerations, fabrication process, and performance of coplanar waveguide (CPW) heterojunction FET (HJFET) down- and up-converter monolithic microwave integrated circuits (MMIC 's) for V-band wireless system applications. To realize a mixer featur ing a simple structure with inherently isolated ports, and yet permitt ing independent port matching and low local oscillator (LO) power oper ation, a ''source-injection'' concept is utilized by treating the HJFE T as a three-port device in which the LO signal is injected through th e source terminal, the RF (or IF) signal through the gate terminal, an d the IF (or RF) signal is extracted from the drain terminal. The down -converter chip incorporates an image-rejection filter and a source-in jection mixer. The up-converter chip incorporates a source-injection m ixer and an output RF filter. With an LO power and frequency of 7 dBm and 60.4 GHz, both converters can operate at any IF frequency within 0 .5-2 GHz, with a corresponding conversion gain within -7 to -12 dB, pr imarily dominated by the related filter's insertion loss. Chip size is 3.3 mm x 2 mm for the down-converter, and 3.5 mm x 1.8 mm for the up- converter.