Highly linear 20 GHz-micromixer in SiGe bipolar technology

An active mixer operating at 20 GHz based on the Gilbert micromixer topology was designed and fabricated in SiGe technology. High performances are measured and especially an excellent linearity for moderate current consumption is demonstrated. The circuit shows an Output IP3 of +12 dBm and a conversion gain Gc of +7.7 dB for an optimum LO power of only -2 dBm. The bias current in the entire circuit is only 25 mA for a chip size of 1.8 /spl times/ 2 mm/sup 2/.