A CMOS low loss/high linearity passive mixer for 2.45 GHz low power applications

A fully integrated passive mixer suitable for 2.45 GHz low consumption and low cost applications is proposed and demonstrated in a 90 nm CMOS technology. An original operating principle is adopted which is based on the use of a local oscillator square signal exhibiting a duty cycle less than 1/4. By using such a LO driving, the mixer operates as a sampler and can theoretically achieve a voltage conversion gain of 0 dB. This mixer has been integrated in a complete monolithic receiver. According to simulations, measurements demonstrate improvements of 5 dB on gain and 3 dB on noise figure without any linearity degradation and any additional cost, when compared to a common LO driving of 1/2 duty cycle.