Wideband Tunable N-Path Mixer With Calibrated Harmonic Rejection Including the 7th LO Harmonic

In this study, a harmonic-rejection N-path mixer is designed, implemented, calibrated, and measured. The proposed mixer features a wide bandwidth suitable for low-power multi-standard RF front-end receivers while keeping low complexity by opting for only 5 paths rather than 10 and only one stage to perform harmonic rejection up to the
$7^{th}$
local oscillator (LO) harmonic. This work employs a calibration strategy to prevent mismatches due to the fabrication process from affecting the system performance. The 0.17-1.2-GHz RF front-end mixer is fabricated in a 28-nm FDSOI technology. Measurements show a harmonic rejection higher than 45 dB for the
$3^{rd}$
,
$5^{th}$
, and
$7^{th}$
LO harmonics, 13 dB gain, 13.3 dB NF, −3.5 dBm in-band IIP3. The total power consumption is only 22 mW for a surface area of
$0.62\times 0.22~mm^{2}$
.