A Noise-Cancelling Harmonic Selection Receiver Using an N-Path Filter for 5G Applications

Abstract

A wideband noise-cancelling harmonic rejection (NC-HR) RF receiver using two separate N-path filter-based down-conversion paths is presented to avoid amplification at harmonic blocker frequencies. The proposed harmonic blocker-tolerant architecture suppresses blockers placed at or around integer multiples of the local oscillator (LO) frequency. Moreover, the differential HR N-path switching system with resistive coefficients used in the main down-conversion path allows for the 3rd harmonic of the LO frequency to be selected, helping to reduce the dynamic power consumption of the multi-phase LO generator by a factor of three. Post-layout simulation results show that the 3.6 −7.2 GHz receiver implemented in a 65 nm CMOS process achieves a harmonic-rejection ratio (HRR) of 56 dB, a noise figure (NF) of less than 2.6 dB at a 130 MHz baseband frequency for a 7.2 GHz RF signal, with a power consumption of 12.6 mW including the LO current.