International audienceMicrowave switching devices based on the semiconductor-metal transition of VO2 thin films were developped on two types of substrates C-plane sapphire and SiO2 / Si, and in both shunt and series configurations. Under thermal activation, the switches achieved up to 30-40 dB average isolation of the radio-frequency rf signal on 500 MHz-35 GHz frequency band with weak insertion losses. These VO2-based switches can be electrically activated with commutation times less than 100 ns, which make them promising candidates for realizing efficient and simple rf switches

Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal-insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal-insulator transition in VO thin films. The devices were integrated in coplanar microwave waveguides (CPWs) in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO-based switching (more than 260 million cycles without failure) compared with the voltage-activated mode (breakdown at around 16 million activation cycles). The evolution of the electrical self-oscillations of a VO-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

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This paper introduces the first results of dielec-7 tric spectroscopy characterization of glioblastoma cells, measur-8 ing their crossover frequencies in the ultra-high-frequency range 9 (above 50 MHz) by dielectrophoresis (DEP) techniques. Exper-10 iments were performed on two glioblastoma lines U87-MG and 11 LN18 that were cultured following different conditions, in order 12 to achieve different phenotypic profiles. We demonstrate here that 13 the presented DEP electrokinetic method can be used to discrim-14 inate the undifferentiated from the differentiated cells. In this 15 study, microfluidic lab-on-chip systems implemented on bipolar-16 complementary oxide semiconductor technology are used allowing 17 single cell handling and analysis. Based on the characterizations 18 of their own intracellular features, both the selected glioblastoma 19 (GBM) cell lines cultured in distinct culture conditions have shown 20 clear differences of DEP crossover frequency signatures compared 21 to the differentiated cells cultured in a normal medium. These re-22 sults support the concept and validate the efficiency for cell char-23 acterization in glioblastoma pathology. 24 Index Terms-BiCMOS chip, biological cell manipulation, 25 glioblastoma cells, high frequency dielectrophoresis. 26 I. INTRODUCTION 27 G LIOBLASTOMA (GBM) is one of the most frequent and 28 the most aggressive tumors of the central nervous system.

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