A fully integrated 5.2 GHz GaInP/GaAs HBT upconversion micromixer with output LC current combiner and oscillator

A 5.2 GHz upconversion micromixer with output LC current combiner and integrated oscillator is demonstrated in 2 /spl mu/m GaInP/GaAs HBT technology in this paper. The micromixer has a single-ended input and a passive LC current combiner is used to convert the mixer differential output into a single-ended output. A cross-coupled LC oscillator with oscillation frequency of 4.3 GHz and a cascode buffer amplifier are also integrated in the same chip. The die size is 1 mm/sup 2/. The fully integrated upconversion micromixer has a conversion gain of -2.5 dB, OP/sub 1dB/ of -12.5 dBm and 40 dB RF-IF isolation when the input IF=0.9 GHz and thus the output RF=5.2 GHz. The IF input return loss is better than 25 dB for frequencies up to 6 GHz while RF output return loss is better than 12 dB for frequencies from 5.15 GHz to 5.35 GHz.