A 39-GHz down-conversion mixer with a compact and broadband transformer-based image-rejection filter in 65-nm CMOS.

This paper presents a 39-GHz broadband image-rejection down-conversion mixer for 5G millimeter-wave (mmWave) communication. To achieve a broadband image rejection, this paper proposes an on-chip compact transformer-based image-rejection filter, which exhibits the ability to track the pole and zero frequencies simultaneously. Moreover, the working mechanism and design guideline of the transformer-based image-rejection filter are illustrated with theoretical analysis, simulations and measurements. To enhance the mixer linearity performance, the transconductance stage of the conventional Gilbert mixer is utilized as a current source, and the radio frequency (RF) signal is directly fed into the switching stage. Fabricated in a 65-nm CMOS process, using a single-stage image-rejection filter with a compact area of only 0.013 mm2, the measurement results show that the proposed down-conversion mixer achieves a gain of 0 dB, a 3-dB RF bandwidth from 34 to 42 GHz, an input 1-dB compression point (IP 1dB) of 5.6 dBm, and an image rejection ratio (IRR) of about 25 dBc. [ABSTRACT FROM AUTHOR]