The N-path filter is widely used in the front end of radio frequency receivers due to its adjustable center frequency and good linearity

but it also has the defect of weak anti-harmonic folding ability. A differential 8-path band-pass filter based on prefiltering technology with anti-harmonic folding is designed. The filter consists of two pre-LC band-stop filters and a series inductor single-ended to double-ended differential 8-channel band-pass filter. The former is used to suppress the 7th and 9th harmonics with the strongest folding

and the latter is used to suppress even harmonics. Basedon TSMC 40nm process

Cadence Spectre RF simulation results show that the center frequency fs of the filter can be tuned in the range of 600 M~1.6 GHz

the out-of-band suppression at fs=1 GHz is 30 dB

and the harmonic folding suppression at 7fs and 9fs is greater than 90 dB

even harmonic maximum suppression is 120 dB

and gain is greater than 5dB

noise figure (NF) is less than 5 dB

insertion loss (S11) is less than -10 dB

and in-band IIP3 is between 6 dB~17 dB.