Design of a Ku-band Gilbert mixer with gain, noise figure and linearity enhancement

This paper presents the first Ku-band (12–18 GHz) mixer employs a Post Distortion Cancellation (PDC) technique to absorb the Third Order Intermodulation Distortion (IMD3) generated by transconductance stage. As the parasitic capacitances degrade the gain, noise figure and linearity of the circuit, an extra inductor is added between source nodes of switching transistors to enhance all the above three features. Simulations in a 0.18-μm CMOS technology demonstrate 4.1 dB IIP3 improvement compared to conventional Gilbert mixer. The gain and noise figure are also improved by approximately 0.6 dB and 1 dB in the entire band, respectively. The proposed circuit draws only 3-mA from a 1.8-V supply, which appears to be the same power as that in conventional mixer.