Souhil Megherbi

Experimental characterization and numerical simulation of a dielectric tuning technique dedicated to miniature monolithic NMR coils

The use of monolithic transmission line design allows developing miniature Radio Frequency (RF) resonators with high sensitivity for Nuclear Magnetic Resonance (NMR) applications. This design has allowed great improvement in NMR micro imaging achieving large Signal to Noise Ratio (SNR) but requires a dedicated tuning technique.

Behavioral VHDL-AMS modeling of nuclear magnetic resonance sensor

This paper describes the development of a model of a nuclear magnetic resonance (NMR) spiral coil sensor, using an analog hardware description. Our procedure implies several steps, with emphasis on model complexity reduction, identification of critical parameters and validation of experimental measurements. The proposed macro-model permits extremely fast simulation while providing nearly FEM accuracy. As a tool for coding the description of system level modelling, we use the analog hardware description language VHDL-AMS. For achieving the behavioural computation results, the SYSTEM VISION simulation environment from Mentor Graphics/spl reg/ was employed. In our proposed modelling, the different parts of the sensor and the different effects involved (electrical parameters, physical and magnetic coupling, loss effects) can be modelled within the same tool, together with the sensor environment: electrical command and detection circuit, time dependent magnetic field, and so on.

RF MEMS: Silicon micro-mechanical capacitive structures

The general study is dedicated to Wireless Sensor Networks. The idea is to associate micro-mechanical and microwave communication functions to exchange information between a remote sensor and a base station [1]. A specific part of this project concerns the conception, realisation, and characterisation of a passive microwave frequency shifter used for back-modulation around 2 GHz. The interesting point was to develop this function with an integrated silicon micro-mechanical rotating structure. The paper describes the prototype of the RF MEMS already developed in ESIEE laboratory. And we insist on the microwave measurements performed and the associated equivalent models.