A tunable passive mixer for SAW-less front-end with reconfigurable voltage conversion gain and intermediate frequency bandwidth

An adjustable mixer for surface acoustic wave (SAW)-less radio frequency (RF) front-end is presented in this paper. Through changing the bias voltage, the presented mixer with reconfigurable voltage conversion gain (VCG) is suitable for multi-mode multi-standard (MMMS) applications. An equivalent local oscillator (LO) frequency-tunable high-Q band-pass filter (BPF) at low noise amplifier (LNA) output is used to reject the out-of-band interference signals. Base-band (BB) capacitor of the mixer is variable to obtain 15 kinds of intermediate frequency (IF) bandwidth (BW). The proposed passive mixer with LNA is implemented in TSMC 0.18μm RF CMOS process and operates from 0.5 to 2.5GHz with measured maximum out-of-band rejection larger than 40dB. The measured VCG of the front-end can be changed from 5 to 17dB; the maximum input intercept point (IIP3) is 0dBm and the minimum noise figure (NF) is 3.7dB. The chip occupies an area of 0.44mm2 including pads. Copyright © by HIGH TECHNOLOGY LETTERS PRESS.