An LO phase mismatch compensation technique for noise reduction in active mixers

A detection and compensation technique for LO phase mismatches is presented to reduce noise in the mixer. Based on theoretical analysis and simulation, this work shows that the LO phase mismatch degrades the noise figure, gain, and linearity of the mixer. To compensate the LO phase mismatch, a new concept of the mixer is proposed, and its prototype is fabricated in 0.18-μm CMOS technology. In addition, a current bleeding mixer, which is known for low flicker noise topology, is also fabricated for comparative purposes. From the measured results, the proposed mixer reduces the flicker noise corner frequency by almost half when it is compared to the current bleeding mixer. Moreover, the proposed mixer improves gain and linearity without additional power consumption.