A packaged SiGe x2 sub-harmonic mixer for U-NII band applications

This paper describes a packaged SiGe x2 sub-harmonic mixer (SHM) for use in the Unlicensed National Information Infrastructure (U-NII) bands. The SHM is an active, double-balanced mixer that achieves x2 sub-harmonic mixing through two quadrature (I/Q) driven, stacked Gilbert-cell switching stages. Single-ended-to-differential conversion, buffering and I/Q phase separation of the LO signal are integrated on-chip. The SHM has a measured conversion gain of 9.3 dB, a P1-dB of -15.7 dBm and an 2LO/RF isolation greater than 35 dB at 5.25 GHz. At 5.775 GHz, the conversion gain is 7.7 dB, the P1-dB is -15.0 dBm, and the isolation is greater than 35 dB. The mixer core consumes 9.5 mA from a 5.0 V supply voltage.