Low Voltage High Linearity Ultra-wideband Folded Mixer for Direct Conversion Receivers

This paper presents a low voltage high linearity ultra-wideband folded mixer for direct conversion receivers. There are four parts in this mixer, a transconductance stage, a switching stage, a load stage, and buffer stages. The transconductance stage uses self-bias technology, and direct superposition method to improve supply voltage and linearity. A forward-body-bias technique is utilized in the switching stage to reduce the supply voltage. The load stage adopts common mode feedback structure to improve both conversion gain (CG) and linearity. The buffer stages uses common source amplifiers to raise conversion gain and output power. Advanced Design System simulator is the verification tool. Within full band operation from 3.1CHz to 10.6CHz, the proposed mixer exhibits simulation results of conversion gain from 5.1 to 6.6 dB. Noise figure (NF) from 16 to 16.7dB, and a input third order intercept point (11P3) from 1.1 to 3.3dBm.