"The project has successfully achieved most of the objectives that were set in the proposal.
In a first phase, the clipping contour method has been extended to the third harmonic using a numerical approach, in Matlab. The results have been presented at the European Microwave Conference 2016, London, in the paper:
- R. Quaglia and S. Cripps, ""Harmonic clipping contours: Numerical computation and extension to higher harmonics,"" 2016 46th European Microwave Conference (EuMC), London, 2016, pp. 405-408. doi: 10.1109/EuMC.2016.7824365
In a second phase, Roberto has been able to re-write the closed form equations of the clipping contours in a novel formulations that allows to insert an arbitrary number of harmonics, thus fulfilling the objectives of WP1. This result, plus the measurements that validate the extended theory, have been published in:
- R. Quaglia, J. J. Bell and S. Cripps, ""New General Formulation and Experimental Verification of Harmonic Clipping Contours in High-Frequency Power Devices,"" in IEEE Transactions on Microwave Theory and Techniques, in printing. doi: 10.1109/TMTT.2017.2687900
Roberto has also collaborated with other members of the Centre for High Frequency Engineering in the work published in:
R. Quaglia, D. J. Shepphard and S. Cripps, ""A Reappraisal of Optimum Output Matching Conditions in Microwave Power Transistors,"" in IEEE Transactions on Microwave Theory and Techniques, vol. 65, no. 3, pp. 838-845, March 2017. doi: 10.1109/TMTT.2016.2627557
The objectives of WP2, WP3 and WP4 have been also achieved in large part. Roberto has embedded the Clipping Contour design tool in ADS and MWO, two of the most diffused CAD software among PA designers. The tool has been useful in designing a number of prototypes, in particular to estimate, during the design, the amount of clipping that the active device was experiencing during its operation. The most prominent result has been the design of an integrated Doherty PA, in collaboration with the US foundry Qorvo Inc. The state-of-the art performance of the fabricated device have been presented at the International Microwave Symposium 2017, Honolulu, US, in the paper:
R. Quaglia, M.D. Greene, M.J. Poulton and S.C. Cripps, ""Design and characterization of a 1.7–2.7GHz quasi-MMIC Doherty power amplifier,"" International Microwave Symposium 2017.
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