A 2.4 GHz High Performance CMOS Sub-Harmonic Mixer

In this paper a low power CMOS sub-harmonic mixer based on the Gilbert cell for 2.4 GHz ISM band application is presented, in which the position of the switching and transconductance stages of mixer has been exchanged. A tuning out inductor has been used between the RF and LO switching stages to improve the linearity and noise figure, and also to enhance the conversion gain of the Mixer. The utilized tuning out inductor results to higher LO voltage swing at the source terminal of RF transconductance stage transistors which provides higher conversion gain and also improves the linearity and noise performance of the mixer by tuning out the parasitic capacitances of the RF and LO stages. Simulation results performed by Advanced Design System (ADS) in TSMC 0.18 μm CMOS process at 1.8 V supply voltage show that the proposed mixer has exhibited high performance after a FOM-based comparison, without increasing the power consumption of 5 mw.