Use this URL to cite or link to this record in EThOS:
Title: Input harmonic and mixing behavioural model analysis
Author: Bell, James Joseph
ISNI:       0000 0004 5358 7968
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2014
Availability of Full Text:
Access from EThOS:
Access from Institution:
This thesis details the necessary evolutions to Cardiff University's HF measurement system and current CAD model implementation to allow for input second harmonic and mixing models to be measured, generated, and simulated. A coherent carrier distribution system was built to allow four Agilent PSGs to be trigger linked, thus enabling for the first time three harmonic active source- and load-pull measurements at X-band. Outdated CAD implementations of the Cardiff Model were made dynamic with the use of ADS' AEL. The move to a program controlled schematic population for the model allows for any type of model to be generated and input into ADS for simulation. The investigations into isolated input second harmonic models have yielded an optimal formulation augmentation that describes a quadratic magnitude and phase dependency. Furthermore, augmentations to the model formulation have to comprise of a model coefficient and its complex conjugate in order to maintain real port DC components. Any additional terms that describe higher than a cubic phase dependency are not recommended as average model accuracy plateaus, at 0.89%, from the quartic terms onwards. Further model investigations into input and output harmonic mixing of coefficients has been detailed and shows that model coefficient mixing achieves better model accuracy, however, coefficient filtering is suggested to minimize model file sizes. Finally, exercising the modelling process from measurement to design, a generated source- and load-pull mixing model was used to simulate an extrinsic input second harmonic short circuit, an intrinsic input second harmonic short circuit, and input second harmonic impedance that half-rectified the input voltage waveform with Class-B output impedances. The tests were set up to see the impact of input second harmonic tuning on drain efficiency. Efficiencies of 77.31%, 78.72%, and 73.35% were observed for the respective cases, which are approximately a 10% efficiency improvement from measurements with no input second harmonic tuning. These results indicate that to obtain performances at X-band close to theory or comparable to performance at lower frequencies input waveform engineering is required.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)