Design of high linearity low flicker noise 5.2 GHz down-conversion mixer for direct conversion receiver

A design of high linearity (IIP3), low flicker noise (NF), high conversion gain (CG) double-balanced Gilbert-cell mixer (DBGCM) is presented. Since the performance of a direct conversion receiver (DCR) is strongly affected by linearity and flicker noise (1/f) of a mixer in receiving side, a hybrid technique of dynamic current injection (DCI), a tuned inductor in switching pair and direct superposition method are employed to improve the flicker noise corner frequency, conversion gain and IIP3 of a DBGCM without affecting the other parameters. The mixer is designed and implemented on 0.18 µm CMOS technology and a few of the measured results were presented. The proposed mixer has a simulated conversion gain of 14dB, while the IIP3 at +13 dBm, single side band (SSB) noise figure is 8.4dB (@ 100kHz).