The evolution of high power transistors has ultimately increased the complexity of their design, interaction and incorporation within microwave frequency power amplifiers. The requirement for high efficiency and high linearity for a wide band frequency by the consumer has put pressure on designers. Due to unexpected and unpredictable failures, device characterisation of the transistor in operational conditions is a highly valuable advantage. The proposed work will describe a non-intrusive, ultra-miniaturised, high resolution electric field probe system; with the capability of measuring relative voltage and waveforms distribution of complex active devices within their operating conditions. The design, construction and evolution of the probing system will be described displaying a resolution of better than 100μm, with a flat frequency response of up to 8GHz. Due to the miniaturised size and the flexibility in positioning, the probe has the ability to measure on-chip, at the device plane, across the device periphery. Results will show direct observation of device plane voltages in high power RFPAs, where the device can exhibit variation in the voltage distribution across the periphery. Such variation will be a function of the internal behaviour and not evident in the output characteristics of the device. This work will also describe a novel method for absolute calibration of the probing system which can be implemented with every movement of the measurement plane. Therefore presenting a successful and calibrated EFP system capable of device characterisation and diagnostics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:646309 |
| Date | January 2014 |
| Creators | Dehghan, Nelo |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/73139/ |
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