Ka-band ultra low voltage miniature sub-harmonic resistive mixer with a new broadside coupled Marchand balun in 0.18-μm CMOS technology

A Ka-band sub-harmonically pumped resistive mixer (SHPRM) was designed and fabricated using the standard 0.18-mu m complementary metal-oxide-semiconductor (CMOS) technology. An area-effective asymmetric broadside coupled spiral Marchand balance-to-unbalance (balun) with magnitude and phase imbalance compensation is used in the mixer to transform local oscillation (LO) signal from single to differential mode. The results showed that the SHPRM achieves the conversion gain of -15--12.5 dB at fixed f (IF)=0.5 GHz with 8 dBm LO input power for the radio frequency (RF) bandwidth of 28-35 GHz. The in-band LO-intermediate freqency (IF), RF-IF, and LO-RF isolations are better than 31, 34, and 36 dB, respectively. Besides, the 2LO-IF and 2LO-RF isolations are better than 60 and 45 dB, respectively. The measured input referred P1dB and 3rd-order inter-modulation intercept point (IIP3) are 0.5 and 10.5 dBm, respectively. The measurement is performed under a gate bias voltage as low as 0.1 V and the whole chip only occupies an area of 0.33 mm(2) including pads.