An N-path bandpass filter with a tuning range of 0.1–12 GHz and stopband rejection > 20 dB in 32 nm SOI CMOS

This paper presents an N-path bandpass filter with a tuning range of 0.1-12 GHz, a constant 3-dB bandwidth of 150 MHz (1-dB bandwidth of 80 MHz), and a stopband rejection greater than 20 dB. The filter includes two sets of 4-path mixers to remove the dependence of the rejection on the switch resistance, and also a clock (LO) divider which operates at 0.2-24 GHz. The passband insertion loss is 3-7.4 dB from 0.1-12 GHz with a power consumption of 20-130 mW. The measured in-band IIP3 is 21-6 dBm and the measured out-of-band IIP3 is 29-15 dBm at 120 MHz offset for 0.1-12 GHz, respectively. To the best of the authors' knowledge, this is the widest tuning range demonstrated for an N-path bandpass filter of any kind.