Monolithic Up / Down Converters for Millimeter-wave Wireless Networks

This paper describes CPW heterojunction FET (HJFET) down- and up- converter MMICs for millimeter-wave wireless networks. To realize a mixer featuring a simple structure with inherently isolated ports, and yet permitting independent port matching and low LO power operation, a "source injection" concept is utilized by treating the HJFET as a three-port device in which the LO signal is injected through the source terminal, the RF (or IF) signal, through the gate terminal, and the IF (or RF) signal is extracted from the drain terminal. With an LO power and frequency of 7dBm and 60.4GHz, both converters can operate for any IF frequency within 0.5 to 2GHz, with a corresponding conversion gain within ¿7 to ¿12dB. Chip size is 3.3mm × 2mm for the downconverter, and 3.5mm × 1.8mm for the upconverter.