A Quadrature Balanced N-Path Receiver for Frequency Division Duplex With Thermal and Phase Noise Cancellation Under Antenna VSWR

In this work, we propose a frequency division duplexing (FDD) transceiver front-end (TFE) capable of canceling both the transmitter (TX) noise and reciprocal mixing (RM), under antenna voltage standing wave ratio (VSWR) variations. The TFE is composed of a quadrature balanced N -path receiver (QBNR) with the addition of a coupled auxiliary path to cancel reflected RM from the antenna. A discrete implementation incorporating two-port N -path (TPNP) filters manufactured in TSMC CMOS 65 nm is shown. Measurements of the proposed TFE show more than 27-dB TX noise cancellation, with NF of 6-7 dB in the presence of a 5-dBm modulated TX blocker, under VSWR of 2:1 and equal thermal and RM noise floors of −147 dBm/Hz, with power consumption of 57 mW at a 1.5-GHz local oscillator (LO) frequency.