An Ultra-Wideband Distributed Active Mixer MMIC in 0.18- $\mu$ m CMOS Technology

In this paper, a distributed circuit topology for active mixers suitable for ultra-wideband operations is presented. By employing nonuniform artificial transmission lines with the complementary transconductance stages in the Gilbert-cell multiplier, the proposed mixer demonstrates broadband characteristics at microwave frequencies while maintaining a high conversion gain (CG) with improved gain flatness. Using a 0.18-mum CMOS process, the proposed circuit is implemented, exhibiting a -3-dB bandwidth of 28 GHz. With a local-oscillator power of 3 dBm and an IF frequency of 10 MHz, the fabricated circuit has a CG of 12.5plusmn1 dB and an average input third-order intercept point (IIP₃) of 0 dBm within the entire frequency range. The fully integrated wideband mixer occupies a chip area of 0.87times0.82 mm² and consumes a dc power of 20 mW from a 2-V supply voltage