Characteristics of a 60 GHz MMIC mixer with an open stub microstrip line

In this article, 60 GHz MMIC down-conversion mixers for a 60 GHz communication system are designed and fabricated on-chip using a 0.12 μm GaAs PHEMT process technology with an fT of 78 GHz and fmax of 190 GHz.The characteristics of a 60 GHz monolithic cascode mixer with an open stub microstrip line are compared with those of a 60 GHz monolithic cascode mixer without an open stub microstrip line, which are integrated on-chip including matching and bias circuits. The 60 GHz monolithic cascode mixer with an open stub microstrip line measured at RF 60 GHz show a conversion gain of −16 dB, LO to RF isolation of 21.5 dB, and LO to IF isolation of 40.5 dB. Especially in the case of the mixer, the LO to IF isolation characteristic is much better than that of the 60 GHz monolithic cascode mixer without an open stub microstrip line. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1341–1345, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25191