A 6 GHz 130 nm CMOS Harmonic Recombination RF Receiver Front-End Using N-Path Filtering

An RF receiver front-end using two feedforward N-path switching filters and harmonic-recombination configuration is presented. As the time-variant nature of the N-path filter introduces multiple frequency translations, third harmonic selection of the switching frequency rather than the fundamental helps to reduce the input frequency of the multiphase clock generator by a factor of three. The proposed 5.9-7.1 GHz RF receiver operates at the third harmonic of the local oscillator, thanks to the combination of an N-Path switching filter and a harmonic recombination architecture. The receiver is implemented in a 130 nm CMOS technology and operates from a 1.2 V supply. Post-layout simulation results show that, for a 6 GHz RF input, the receiver provides a harmonic rejection of 45 and 55 dB for the first and second harmonics, respectively. A noise figure of 5.5 dB at a 16 MHz baseband frequency is achieved, and an input matching of less than -15 dB is attained over the desired frequency band.