A 2.8-4.3 GHz Simultaneous Dual-Carrier Transformer-Coupled Passive Mixer-First Receiver Front-End Supporting Blocker Suppression

One long-term goal of software-defined radios is to create RF receivers capable of operating in any band over a wide frequency range. In addition, many radio systems today require access to multiple bands simultaneously. Conventional N-path passive mixer-first receivers do not support this capability without experiencing significant performance degradation due to channel cross-loading. This work presents a high dynamic range N-path passive mixer-first receiver architecture capable of simultaneously down-converting two arbitrary bands through a single RF port. The architecture consists of two passive mixers arranged in a series configuration with a transformer front-end to minimize cross-loading between mixers while still providing impedance transparency and associated interference suppression for both bands. When operating within a single band, the architecture offers the added advantage of enhanced blocker suppression. This is achieved by utilizing one of the mixers, driven at the blocker frequency, to redirect blocker power away from the protected mixer.