Achieving high linearity and conversion gain in double balanced mixer with cascoded RF and LO stage

Abstract

A simple Cascaded double balanced mixer working at 2.4 GHz, for WLAN application was designed and using 90 nm CMOS technology. The proposed mixer incorprates minimum number of transistors in comparing with the gilbercell mixer. Staking LO stage just above the RF stage reducing the voltage headroom of mixer. Differential combination of RF stage has a common source node and the Differential combination of LO stage has common drain node. Differential combination for both RF and LO stage cancels the feed through error of higher order harmonic signals, improving the linearity of the mixer.Both RF and LO stage contributes to the overall transconductance of the mixer, improving the conversion gain of the mixer. The simulated response of the proposed mixer shows a Conversion gain of 12 dB, IIP3 point of 8.3 dBm and one dB compression point of 8.5 dBm.