A V-Band Ultra Low Power Sub-Harmonic I/Q Down-Conversion Mixer Using Current Re-Used Technique

In this brief, we present a low power sub-harmonic I/Q mixer using the current re-used technique for WiGig at 60 GHz. A transformer integrates the RF trans-conductance stage and LO switching stage by the current re-used technique to save dc power. We only adopt a single transistor at RF stage to replace differential RF amplifier to save die area as only half of the RF matching network is required. The trans-conductance of the RF stage is increased by the gm-boost technique. In addition, since the current re-used technique gathering the dc current from both I and Q mixer cores, the transconductance of the RF stage is also increased. In order to reduce the die area of passive components, we use mutually coupled inductors to implement lumped element Wilkinson power divider. We also add extra capacitors on all ports of the coupler to improve return loss. The measured peak gain is -7.9 dB at 61 GHz under LO power of 5 dBm at 30 GHz. The measured IP1dB is better than -9.5 dBm in four channels. The measured 3-dB RF bandwidth is from 56.5-67 GHz and 3-dB IF bandwidth is 1.5 GHz. Total dc power consumption is only 3.45 mW and each mixer consumes 1.73 mW for 1.1 V supplied voltage. To our best knowledge, this current re-used I/Q mixer has the lowest dc power and good conversion gain among active I/Q mixers at V-band.