High-Power Tunable FDD Front-End Employing A Balanced CMOS N-Path Receiver and Evanescent-Mode Cavity Filters

A single-antenna, frequency-tunable FDD front-end supporting simultaneous transmit (TX) and receive (RX) operation with high power handling capabilities and low TX and RX losses is presented. The system comprises a balanced CMOS N-path mixer-first receiver in series with tunable evanescent-mode filters, and leverages frequency-selective reflectivity and matching for quadrature signal construction, destruction, and noise cancellation at corresponding ports of interest. A measured 65~nm CMOS receiver prototype with manufactured cavity filters demonstrated 38~dBm blocker tolerance (B1dB) at 1~GHz at 100~MHz TX/RX spacing with no RX EVM degradation, <~0.4~dB TX insertion loss and 3.5$-$4.5~dB RX NF over 0.9$-$1.8~GHz tunable frequency range.