The work presented in this thesis is divided into two parts. The first part is devoted to the development of a computational electromagnetic code based on the TLM method (Transmission Line Matrix) to simulate structures with multi-scale aspects, requiring multigrids-subgrids locally refined. This leads to solve a simultaneous spatial and time domain coupling problem. As it was proved to be very effective for spatial domain coupling, the technique using transformers introduced by Wlodarczyk is implemented. Actual work is focussed on the time domain coupling to allow using the maximum time step in each sub grid. Interpolation techniques such as Taylor second order and cubic Spline and also a prediction technique inspired from the Prony-Pisarenko method for power spectral density estimation were implemented and evaluated. The second part is devoted to the design of rectennas. Such non-linear and multi-scale structures, integrating Schottky diodes, are key elements of wireless power transmission or energy harvesting systems. It is demonstrated that modelling rectennas with a global circuit-electromagnetic simulation tool in time domain as with TLM provides a substantial advantage compared to commercial simulation softwares that requires various experimental adjustments, rendering complex the design process. It becomes then possible to accurately predict the conversion efficiency of an entire rectenna. The design and complete experimental characterization of two compact rectennas operating at 2.45GHz are finally presented.
