Millimeter-Wave Reconfigurable Power Amplifier and Transmitter Architectures with Antenna Interfaces

Abstract

Wireless communication is undergoing a fundamental transformation as the new spectrum in the millimeter-wave (mm-Wave) frequencies (30-300 GHz) opens up to serve as the backbone for the next-generation wireless infrastructure. The application range is expected to be extremely heterogeneous ranging from extremely high-speed cellular connectivity, automotive-to-anything (V2x), augmented reality (AR), virtual reality (VR) to wireless backhaul and last mile connectivity. In this, mm-Wave phased arrays, and massive multiple-input-multiple-output (MIMO) systems will serve as the wireless front-end elements to allow adaptive beamforming, tracking and spatial multiplexing for high-spectral efficiency. However, as multiple spectral regions across 20-100 GHz become available, it will be essential to move from current frequency-specific designs that operate at known frequencies to dynamic spectrally-adaptive architectures that learn from the available spectral information. At the hardware level, such reconfigurability is hugely challenging to achieve in the mm-Wave transceiver. Specifically, for the transmitter (Tx) architecture, there is a substantial trade-off between output power, energy efficiency, spectral reconfigurability and spectral efficiency (linearity). This thesis presents a generalized multi-port network synthesis approach to enable active impedance synthesis for simultaneously broadband operation with high peak and back-off efficiency in an mm-Wave power amplifier (PA) architecture. We base the approach on generalized active load-pulling across a series of interacting mm-Wave digital-to-analog (DAC) cells where we can map the optimal operation across frequency and back-off into a set of asymmetric codes. Multiple proof-of-concept architectures are presented to enable back-off efficient wide-band operation across 25-105 GHz. Additionally, we present an extension of this architecture to overcome load-impedance mismatch events at the output of the transmitter and wide-band antenna interfaces for reconfigurable transmitter front-ends.