Conversion gain and linearity enhancement of active CMOS mixer for wireless applications

This paper presents an improved circuit of CMOS based Gilbert double balanced mixer. Proposed mixer design technique is aimed to achieve high conversion gain and linearity with low power consumption. Modified inductive source degeneration technique is used for the linearity improvement and multiple transconductance stage technique is used to improve the conversion gain of the mixer. The range of RF frequency is 500 MHz to 2700 MHz, LO frequency varies from 650 MHz to 2095 MHz and intermediate frequency (IF) varies from 150 MHz to 605 MHz. The circuit provides an Input Third Order Intercept point (IIP3) of 14.365 dBm at 2.7 GHz RF frequency. The conversion gain of 10.575 is achieved. The proposed mixer is implemented using 0.18μm CMOS process using 2.2V supply.