A Broadband Low-Power Millimeter-Wave CMOS Downconversion Mixer With Improved Linearity

This brief presents a broadband, low-local-oscillator (LO)-power, and low-dc-power millimeter-wave (MMW) downconversion mixer with improved linearity using TSMC 90-nm CMOS low-power (LP) process. By employing an active load in the bias network, the linearity of the mixer can be improved effectively. In addition, the conversion gain (CG) of the mixer at high LO power is also improved, whereas the CG at low LO power is not appreciable degraded. The operation principle of the added active load and the impacts on mixer's linearity and CG are analyzed in detail. With a 1.2-V supply voltage and a 0-dBm LO drive power, the proposed mixer with the active load exhibits CG of 0 dB with flatness of ±2 dB from 20 to 50 GHz, input P1 dB (IP1 dB) of -1 dBm, and IIP3 of 9.5 dBm with RF at 43 GHz. The measured IIP3 is 5.6 dB higher than the conventional approach without the active load, and the dc power consumption of the proposed design is 6 mW, including the IF buffers, which is only 1.8 mW higher than the conventional approach.