L'accueil de projets exogènes à l'IEMN dans le cadre du réseau RTB du CNRS

International audienc

Inkjet printed flexible transmission lines for high frequency applications up to 67 GHz

International audienceThis letter introduces radio frequency(RF) characterization of ink-jet printed coplanar waveguides (CPW) with and without strain. Kapton is selected as flexible substrate with different sintering temperature. With optimized inkjet printing parameters, well defined patterns with high resolution yield low attenuation constant even when operated up to 67GHz. Finally, we demonstrate that the RF performance of CPW is barely affected by bending

On-Wafer Broadband Microwave Measurement of High impedance Devices-CPW Test Structures with Integrated Metallic Nano-resistances

International audienceOn-wafer microwave characterization and uncertainty evaluation of two-port coplanar waveguide (CPW) high impedance nanodevices devices are proposed. The test vehicles are built up with resistive metallic nano-films integrated in tapered CPW structures. Microwave conductance in the range 100-500µS associated to parallel capacitances in the order of hundreds aF are exemplary shown up to 20GHz. In addition, the uncertainty related to the post-calibration residual errors terms together with a sensitivity study to the technological process variability using FEM-based EM modelling are considered

Gallium nitride MEMS resonators: how residual stress impacts design and performances

International audienceStarting from Gallium Nitride epitaxially grown on silicon, pre-stressed micro-resonators with integrated piezoelectric transducers have been designed, fabricated, and characterized. In clamped-clamped beams, it is well known that tensile stress can be used to increase the resonant frequency. Here we calculate the mode shape functions of out-of-plane flexural modes in pre-stressed beams and we derive a model to predict both the resonant frequency and the piezoelectric actuation factor. We show that a good agreement between theory and experimental results can be obtained and we derive the optimal design for the electromechanical transduction. Finally, our model predicts an increase of the quality factor due to the tensile stress, which is confirmed by experimental measurements under vacuum. This study demonstrates how to take advantage from the material quality and initial stress resulting of the epitaxial process