Concept for a novel low-complexity QAM transceiver architecture suitable for operation close to transition frequency

The implementation of ultra-high speed mm-wave and THz transceivers based on homodyne concepts suffers from severe scaling issues with respect to system complexity, circuit size and power consumption as such transceivers nowadays typically need to operate close to the transition frequency of the underlying semiconductor process. In order to mitigate these severe issues, we propose a novel regenerative sampling concept based on a simple positive feedback low-gain amplifier stage. We show for the first time a concept that allows to regenerate quadrature modulated signals with minimal effort based on a simultaneous phase and amplitude regenerative sampling (SPARS) process. This concept enables attractive alternatives to the homodyne approach, e.g., a synthesizer-free self-mixing receiver, which significantly reduces the complexity of the receiver circuit. This paper provides the proof-of-concept of the novel approach by simulations and by measurements with a lumped element 22 GHz 16-QAM feasibility demonstrator.