A digital mm-Wave PA architecture with Simultaneous Frequency and back-off Reconfigurability

Abstract

Spectrally-efficient operation with high power and high efficiency at deep back-off will be critical for the next-generation mm-Wave transmitters for 5G and beyond. In addition, as larger non-contiguous chunks of the mm-Wave spectrum open up, dynamic frequency reconfiguration while ensuring high spectral and energy efficiency can become key towards optimal utilization of spectral resources. In this paper, we present a generalized asymmetrical multi-port combiner based network synthesis approach that enables both frequency and back-off reconfigurability in a mm-Wave power amplifier (PA) architecture to maintain high-efficiency operation with spectrally efficient codes across a wide frequency range. As a proof of concept, a silicon-based PA is presented which operates between 30–55 GHz with peak Psat of 23.7 dBm at 40 GHz and output collector efficiency (ηout) of 34.5 % and 22% at the 0 and −6 dB back-off respectively. The PA maintains ηout > 16% at −6 dB back-off across the range. Non-constant modulation is demonstrated with pulse shaping and with data rates upto 4 Gbps across the frequencies from 30–50 GHz.