28-GHz CMOS Up-Conversion Mixer With Improved LO Second-Harmonic Leakage Signal Suppression for 5G Applications

• Published in: IEEE access Vol. 10; pp. 57003 - 57011
• Main Authors: Lee, Suyeon, Jeon, Yangji, Yoon, Dae-Young, Lee, Ockgoo, Im, Donggu, Nam, Ilku
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G mobile communication; Baluns; Buffers; CMOS; CMOS technology; Gain; Intermediate frequencies; intermediate frequency amplifier; Intermediate frequency amplifiers; Leakage; local oscillator buffer; Millimeter waves; millimeter-wave; Mixers; Noise levels; Quadratures; Radio frequency; Rejection; System-on-chip; Transceivers; Transformers; up-conversion mixer; Upconversion
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2022.3178440

A CMOS up-conversion mixer with an intermediate frequency (IF) amplifier and local oscillator (LO) buffer is presented for mobile 28-GHz-band 5G dual-conversion transceivers. A balun transformer with improved common-mode rejection ratio characteristics is proposed to improve the LO second-harmonic signal suppression, which is a problem in the up-conversion mixer of the 5G dual-conversion architecture. By applying the proposed balun transformer instead of the conventional one, a common-mode rejection ratio greater than 10 dB can be achieved at the frequencies of the LO second-harmonic leakage signal. An up-conversion mixer with an IF amplifier and LO buffer incorporating the proposed balun transformer was implemented in a 65-nm CMOS process, and it draws a current of 31.4 mA from a 1-V supply voltage. It provides a gain larger than 22.2 dB, a noise figure less than 4.1 dB, a third-order output intercept point higher than 4.6 dBm, and an LO second-harmonic leakage signal lower than −55.5 dBm in frequencies ranging from 26.5 GHz to 29.5 GHz. It also exhibits a suppression improvement of the LO second-harmonic leakage signal of approximately 14 dB with respect to an up-conversion mixer with IF amplifier and LO buffer using the conventional balun transformer. The proposed up-mixer with IF amplifier and LO buffer is the first one reported that addresses the 2LO leakage issue and the first demonstration of 2LO leakage signal suppression improvement for a 5G mmWave dual-conversion single-quadrature transmitter.