Advances in Efficient and Resilient Radio Frequency Transceiver Circuits

Abstract

Nowadays, society relies primarily on services provided by critical infrastructures, such
as health, transportation, and public safety. Such services rely on wireless connectivity that
is susceptible to blocking signals. In addition to blocking signals coming from surrounding
devices, the transmitter of an individual device may leak power into its own receiver. The
leakage is a major challenge that leads the receiver to compress since it has higher power than
the received signal. Concurrently, the transceiver radio unit requires high power to operate,
which adds further challenges in achieving net-zero goals. The transmitter chain consumes most
of the power of the radio unit due to the power-hungry power amplifier. The main challenges in
designing power amplifiers are efficiency and linearity. Power amplifiers consume a significant
amount of power during signal amplification before transmission, and their nonlinearity can
cause spectral regrowth, which can impact adjacent channels and interfere with other devices.
In addition, inefficient power amplifiers dissipate more power, which can produce heat that
might affect the circuitry. This thesis focuses on receiver resilience and transmitter efficiency
in wireless communications radio frequency (RF) transceiver systems. A low-noise amplifier
(LNA) analysis and design are presented to implement high dynamic range receivers that would
avoid being overloaded by high input power. The proposed LNA topology achieves a wideband
linearity improvement without compromising the noise figure and gain. In addition to the LNAs,
self-interference cancellation techniques add another protection layer to the receiver from the
transmitter, enabling simultaneous transmission and reception. On the transmitter chain, a design
and implementation of a sequential power amplifier have been presented to increase the power
back-off efficiency of the power amplifier. The amplifier topology achieves back-off efficiency
without the use of load modulation. The benefit of this approach is that it allows wideband
operation of the amplifier and facilitates modular design.

Date of Award	23 Jan 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Mark A Beach (Supervisor) & Tommaso Cappello (Supervisor)