PhD Alumni

Traina Daniele

Present position: Project Manager at Thales-e-Transactions

Thesis title:  Cauchy Method Modeling applied to the Computer-Aided Tuning of Microwave Filters and Duplexers
Advisor:  Giuseppe Macchiarella
Research area:  Communications
Thesis abstract:  
In this work, a novel formulation of the Cauchy method is presented, which can be applied in the extraction of circuit models from measured (lossy) response of microwave filters. The application of the proposed formulation has been verified using measurements from a test filter for GSM base stations.
The presented extrapolating technique is integrated into a novel computer-aided tuning procedure for microwave filters exploited in base stations for mobile communications. This procedure uses also a synthesis technique analytically performed (no optimization required). The suitable combination of these techniques furnish a very fast algorithm which can be adopted for a real-time tuning process. Experimental examples on different base-station filters employed in GSM and UMTS communication systems has confirmed its effectiveness. The presented procedure can also be used in the diagnosis of the fabricated base-station filter, due to the good agreement between the test filter and the extracted model.
The duplexer modeling using the Cauchy method has also been considered. A Vandermonde matrix generates an ill-conditioned system matrix when applied with finite numerical precision. This deficiency affects the Cauchy method by restricting its application to only lower order systems. Therefore, this work presents innovative, accurate, and robust formulations of the Cauchy method to rectify this limitation and make the Cauchy method suitable for the extraction of a high order microwave duplexer polynomial model. Finally, an innovative and accurate general formulation of the Cauchy method to rectify the Vandermonde matrix's limitation and make the Cauchy method suitable for the model extraction of a higher order microwave systems is presented. Each of these procedures has been successfully verified by numerical application examples.