High Power, Pulsed, RF Generation from Nonlinear Lumped Element Transmission Lines (NLETLs)
Final rept. 19 Jul 2009-19 Jul 2010
OXFORD UNIV (UNITED KINGDOM) DEPT OF ENGINEERING SCIENCE
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This research project studies the generation of high power bursts of solitonsnonlinear oscillations at radio frequencies from nonlinear lumped element transmission lines NLETLs where the nonlinear elements are ferroelectric capacitors or metallised tiles of ferroelectric ceramic. This work leads on from an existing programme where nonlinear tuning diodes or varactors have been used in NLETLs to study and model these phenomena. Earlier work in our laboratories has already demonstrated the feasibility of constructing NLETLs using both strontium and bariumstrontium titanates to generate soliton bursts at power levels of tens of MW at frequencies up to 50MHz. This project will study the feasibility of increasing this power to 500MW and above at frequencies of 500 MHz. The main difficulty with this technology has been one of coupling the RF soliton burst efficiently into a resistive load. Several ways of addressing this problem have been identified using experimental, low power NLETLs constructed using varactor diodes and also from a comprehensive computer model of the behaviour of such lines. This model has been exhaustively tested by comparison with experimental results. This project draws on these results to move to high voltage NLETLs built mainly using nonlinear ferroelectric ceramics in the form of capacitors or metallised blocks which should be able to deliver high power RF bursts efficiently into resistive loads and antennas.
- Radiofrequency Wave Propagation