Down-Conversion Gilbert Cell Mixer Design for 5G Wireless Communications Systems

This paper presents a down-conversion Gilbert Cell mixer design operating in the 28 GHz millimeter-wave (mmWave) frequency band in 5G applications. The current bleeding technique is used to increase the conversion gain (CG) in the down-conversion mixer circuit, which leads to high linearity (IIP3) and low noise Figure (NF) performance. An intermediate frequency (IF) buffer has been coupled to the mixer outputs to improve linearity performance and facilitate impedance matching. The proposed mixer circuit is designed using a commercial 40 nm low-power CMOS technology. The mixer core and the IF buffer draw 43.61 mA from a 1.1 V supply voltage. According to post-layout simulation results, the mixer performs with a conversion gain of -2.32 dB, a noise Figure of 9.482 dB, and IIP3 of 12.667 dBm in the 28 GHz millimeter-Wave (mmWave) frequency band, including the current bleeding structure and the output buffers. Finally, high isolation between ports has been established, with LO-RF isolation below -50 dB, LO-IF isolation below -40 dB, and RF-IF isolation below -40 dB.