Developing a multi-tone load-pull system for the direct extraction of Cardiff behavioural model coefficients

Al-Rawachy, Azam 2019. Developing a multi-tone load-pull system for the direct extraction of Cardiff behavioural model coefficients. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The main objective of this thesis is to develop and utilize a high-speed measurement system based on PXIe modules for multi-tone measurements. This thesis addresses challenges that have been tackled during developing an accurate LabVIEW software to measure the multi-tone signal. Having solved these problems, the system's functionality was demonstrated by using it to extract some useful data such as stability and gain information for RF designers in, ‘real time’ during active load-pull measurements. In the final part of the thesis, the system was used to aid the development of the Cardiff behavioural model. One of the main challenges in the development of the Cardiff behavioural model is to correctly select the required mixing terms to have an accurate model. Initial work has been focused on determining the correct, phase polynomial coefficients of the Cardiff Model. The first technique presented in this thesis utilises two-tone measurements and the Fast Fourier Transform (FFT) to observe the mixing order from the resultant intermodulation (IMD) products, which are directly associated with the Cardiff Model coefficients. Employing the IFFT, the selected tones have been transferred to the time-domain travelling-wave. This allowed for b-wave analysis and load modulation coverage to be seen on the Smith Chart. The resultant load-modulation from the two-tone measurements has been used as a target for CW impedance measurements to verify whether the identification holds for the CW domain. The result shows there is an VII offset between the CW measurements and the two-tone measurements for larger annuli as the

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Engineering
Uncontrolled Keywords:	Behavioural Model; Multi-Tone Stimulus; Device Nonlinear Model; Load-Pull Measurements; Stability Analysis; Gain Figure Calculations.
Date of First Compliant Deposit:	25 October 2019
Last Modified:	28 Jul 2020 01:29
URI:	https://orca.cardiff.ac.uk/id/eprint/126294

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