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Analyse et optimisation de lignes de transmission à variation continue d'impédance : application au filtrage

Abstract : Sometimes electromagnetic approach can not be directly used to design microwave circuits. So, finding new techniques based on circuit theory is still of interest to analyse and design microwave systems. To keep the accuracy of these techniques as far as possible while increasing frequency, a minimisation of several spurious effects must be done. These effects may be brought by discontinuities. That's why, nonuniform transmission lines can be used to avoid discontinuity effects, particularly in microwave filters. An original approach to analyse and optimise Continuously Varying Transmission Lines (CVTL) is used to design planar microwave filters. The method is based on exact solutions of the telegrapher's relations of non-uniform transmission lines. The CVTL scattering parameters are investigated in detail in the frequency domain. In order to validate the method, several different CVTL are built using microstrip and coplanar waveguide technology. Measured data are presented and compared with theory over a wide frequency range. Then, the technique based on CVTL is used to accurately analyse arbitrary coupled nonuniform transmission lines. This approach sounds interesting to design band-pass filters. For several examples, measurements are compared to simulation results. By comparison to usual techniques our method brings additional degrees of freedom. They are used to control the out-of-band responses of coupled band-pass filter. Handling capability and method accuracy are validated by comparing simulation and experimental results.
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Contributor : Marc Le Roy Connect in order to contact the contributor
Submitted on : Wednesday, March 31, 2010 - 10:44:19 AM
Last modification on : Wednesday, November 10, 2021 - 1:54:05 PM


  • HAL Id : tel-00468594, version 1


Marc Le Roy. Analyse et optimisation de lignes de transmission à variation continue d'impédance : application au filtrage. Sciences de l'ingénieur [physics]. Université de Bretagne occidentale - Brest, 1999. Français. ⟨tel-00468594⟩



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