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 × 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. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 401–403, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10475