This research project has developed a high power RF Measurement system in the Centre for High Frequency Engineering, Cardiff University. There are two main contributions of this thesis. The first contribution is the implementation of step attenuators in the RF high power measurement system, incorporated with the approach of using the Sparameter model for correction measured waveform in measurement software processing. The step attenuator is situated between the broadband directional couplers (which obtains the incident and reflected signal from the DUT) and signal receivers (such as a sampling oscilloscope or MTA). The aim of this implementation is to extend the dynamic range of the measurement system and to develop a technique for reducing the recalibration process while the measurement system needs more attenuation in the signal condition part of the measurement system. These benefits allow the quick and convenient characterisation of the DUT under large signal excited environment. The second contribution is the further development of the Harmonic Bypass Structure (HBS), which is used instead of the step attenuator. The advantage of a HBS is that it can overcome the harmonic distortion drawback of the step attenuator approach. This drawback is caused by choosing improper high attenuation which is unsuitable for the measured signal condition. There is, therefore, a trade-off between the fundamental and harmonic frequencies. The advantage of an HBS is that it is capable of selecting the frequency band to attenuate while other frequencies can pass through to the receiver. In the meantime, the S-parameter model and modified measurement software are well suited similar to the step attenuator approach.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:575694 |
| Date | January 2012 |
| Creators | Russamee, Nilaped |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/48483/ |
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