Optimisation and realisation of a portable NMR apparatus and Micro Antenna for NMR

International audienceThis paper is focused on two designs and realizations. The first one concerns a prototype of a portable NMR (nuclear magnetic resonance) apparatus. The second one concerns NMR micro antenna realization. For the first part, our goal is the NMR magnetic field homogeneity and the signal-to-noise ratio (SNR) improvement. Since de the volume of the sample to analyse is around 1 cm 3 , the design is optimized to obtain a good SNR. Particularly, the magnet is chosen to obtain a high magnetic field with limited inhomogeneities. The receiver antenna is designed and optimized to have high feeling factor and then more sensitivity. A mixer and a low-pass filter are used in order to limit the bandwidth and reduce the thermal noise. The FID is digitized and addressed to a FPGA which averages successive acquisitions in order to increase the SNR. The final acquisition is processed for determining the FID spectrum. In the second part, a new concept of micro coil is presented in order to measure the small volumes and small concentrations samples by NMR spectroscopy at 4.7 T (200 MHz proton frequency resonance). This micro sensor would offer the possibility of new investigation techniques based on micro coils' implantation used for in vivo study of local cerebral metabolites of animals models

Design and Simulation of Microstrip Patch Antenna for Early Breast Cancer Detection

International audienc

Development of New RF sensor for Early Diagnosis of Breast Cance

National audienc

Optimisation and realisation of a portable NMR apparatus and Micro Antenna for NMR

International audienceThis paper is focused on two designs and realizations. The first one concerns a prototype of a portable NMR (nuclear magnetic resonance) apparatus. The second one concerns NMR micro antenna realization. For the first part, our goal is the NMR magnetic field homogeneity and the signal-to-noise ratio (SNR) improvement. Since de the volume of the sample to analyse is around 1 cm 3 , the design is optimized to obtain a good SNR. Particularly, the magnet is chosen to obtain a high magnetic field with limited inhomogeneities. The receiver antenna is designed and optimized to have high feeling factor and then more sensitivity. A mixer and a low-pass filter are used in order to limit the bandwidth and reduce the thermal noise. The FID is digitized and addressed to a FPGA which averages successive acquisitions in order to increase the SNR. The final acquisition is processed for determining the FID spectrum. In the second part, a new concept of micro coil is presented in order to measure the small volumes and small concentrations samples by NMR spectroscopy at 4.7 T (200 MHz proton frequency resonance). This micro sensor would offer the possibility of new investigation techniques based on micro coils' implantation used for in vivo study of local cerebral metabolites of animals models

In situ Sensitivity Improvement of NMR Receiver Probes (Coils and Microcoils)

The sensitivity is a main problem for NMR experiments and it is laid down by the thermal noise of the receiver coil and its geometry. To improve the sensitivity of an NMR receiver coil, considering the postulate of Friis, the signal must be amplified as close as possible to the coil. Here we present a method to achieve optimum in situ low noise amplification for the sensitivity improvement of an NMR receiver coil or microcoil. In this paper we propose a realistic transducer model of an NMR coil and a reliable method to model an LNA. We introduce the requirements to achieve a low noise matching network for NMR receivers allowing an improvement of the sensitivity of the coil by a factor of 6. This sensitivity improvement has its interest in MRI by increasing the field of view with a higher SNR but also in MRS by reducing the limit of detection

3D FEM Simulation study of RF μCOILS For biomedical and environmental applications

International audienc

Plasmon induced transparency and waveguide mode based optical biosensor for self-referencing sensing

In this paper, we present and investigate a novel approach for self-referenced sensing using a multilayer structure in Kretschmann configuration. The obtained results show that the structure can support two modes, plasmon-induced transparency and waveguide mode. The sensing performance of the structure was evaluated by calculating the sensor Sensitivity, Quality Factor, and Figure of Merit. Moreover, to quantify the capability of our approach for self-referencing sensing we calculated the self-referencing figure of merit. We demonstrate that the PIT mode-based approach has the best simulation results in terms of Figure of Merit of 5950/RIU, Quality Factor of 292.5/RIU, and Self-Referencing Figure of Merit of 5.7. The designed biosensors can be used for accurate and reliable sensing applications