Design of double-balanced MMIC mixer for Ka-band satellite communications

A MMIC (monolithic microwave integrated circuit) mixer chip using the Schottky diode of an InGaAs/GaAs p-HEMT process has been developed to act as the receiver down converter of a Ka-band satellite transponder. A different approach to the MMIC mixer structure is applied for reducing the chip size by the exchange of ports between IF and LO. This MMIC covers with RF (30.6-31.0 GHz) and IF (20.8-21.2 GHz). According to the on-wafer measurement, the miniature (3.0 x 1.5 mm) MMIC mixer demonstrates conversion loss below 7.8 dB, LO-to-RF isolation above 27 dB, LO-to-IF isolation above 19 dB, and RF-to-IF isolation above 40 dB, respectively. (C) 2002 Wiley Periodicals, Inc.