Design and Analysis of Active RF Mixer for Wideband Communication System

Abstract

"This work presents active RF double-balanced down converter mixer with some modification and new techniques. Gilbert topology provides overall good gain and LO-RF isolation. It has poor noise figure performance. It is a narrow band in terms of Conversion Gain (CG), input matching and Noise Figure (NF). So noise cancelling transconductor is presented which lower noise figure of the first stage. With this technique, noise from input matching network can be eliminated and noise figure from rest of circuit can be minimized. To provide current requirement of the trans-conductor stage and to increase overall gain of mixer circuit current-bleeding circuit is used. This technique is used to make active mixer wideband in terms of parameters i.e. noisefigure, conversion gain, input-reflection coefficient, third order input-intercept point, and isolation. This circuit is implemented using MOSFET 0.18 ?m technology. It achieves conversion gain of 13.0 to 17.3 dB, the noise figure of 4 to 7.5 dB, third order inputintercept point is -3.78 dBm over a frequency range 1 GHz to 3 GHz. LO-RF isolation is good and input-reflection coefficient is also given better result in the entire frequency range. Active Mixer consumes 10.2 mA current from 1.6 V supply."