RF-IV waveform engineering inspired MMIC design

The research work presented in this thesis sets out to investigate improvements to the power amplifier (PA) design cycle through the use of Waveform Engineering techniques. This is approached using alternative simulation methods with strong links to the data available from time domain based radio frequency waveform measurement and characterisation systems. One key objective of this work is to improve the overall efficiency of the radiofrequency power amplifier stage by focusing on circuit design. More specifically, the direct utilisation of waveform-engineering techniques in the development of multi-stage amplifiers to improve power added efficiency was targeted. In developing these power amplifier design methodologies, the techniques are demonstrated and validated using monolithic microwave integrated circuit (MMIC) implementation. This work has also led to an increase in understanding of the operation of the device terminal waveforms which is used to drive an alternative simulation approach. Through the use of standard computer-aided design (CAD) device models and measured waveform data, a 2-stage MMIC Gallium Nitride power amplifier has been detailed. This amplifier also uses internal node probe points in the interstage matching network, along with a new application of the waveform measurement system, to allow investigation of the terminal waveforms to validate the performance. This direct implementation of these waveform measurements provides valuable information on the design of the interstage networks to reduce the number of design iterations resulting in a more efficient design process. Waveform-engineering-based designs completed in this research have been demonstrated with test circuits and the time domain measurement system to demonstrate new modes of operation, as well as complete designs realised as prototype MMIC power amplifiers