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Giorgio DE ANGELIS, Andrea LUCIBELLO, Romolo MARCELLI, Simone CATONI, Antonio LANCIANO, Roberta BUTTIGLIONE, Massimiliano DISPENZA, Flavio GIACOMOZZI, Benno MARGESIN, Alfredo MAGLIONE, Mirko ERSPAN, Chantal COMBI

Single-Pole Double-Thru and True Time Delay Lines in Alumina Packaging Based on RF MEMS Switches in Silicon Technology
pp. 283–307

Abstract. Packaged MEMS devices for RF applications have been modelled, realized and tested. In particular, RF MEMS single ohmic series switches have been obtained on silicon high resistivity substrates and they have been integrated in alumina packages to get single-pole-double-thru (SPDT) and true-time-delay-line (TTDL) configurations. For this purpose, the individual switches have been considered as the building blocks of more complicated structures, and the alumina substrate has been properly tailored in order to get the best electrical performances considering all the technological steps necessary for the final hybrid device. Actually, several parameters and processes have been considered for such an optimization, involving the geometry, the wire bonding and the cover to be used. Test structures with technologically actuated switches have been also manufactured in order to have the best reference result for the proposed structures. After that, the same devices have been packaged for the final test.
As a result, TTDLs for wide band operation, specifically designed for the (6-18) GHz band, have been obtained, with insertion losses less than 2 dB up to 14 GHz for the short path and 3 dB for the long path (5 dB for the real device), and delay times in the order of 0.3–0.4 ns for the short path and 0.5–0.6 ns for the long path. The maximum differential delay time is in the order of 0.2 ns.

 

 

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Daniela DRAGOMAN, Adrian DINESCU, Raluca MULLER, Cristian KUSKO, Alex. HERGHELEGIU,  Mihai KUSKO

Waveguiding in PMMA photonic crystals
pp. 308–316

Abstract. The fabrication of two-dimensional photonic crystals (PCs) by using the electron-beam lithography (EBL) technique to directly pattern the positive PMMA electronoresist is presented. The design, simulation and fabrication of a channel waveguide in this PC is described in detail.  The actual fabrication of this passive structure useful in integrated optic applications is a challenge because the PC waveguide configuration is integrated with a taper optical waveguide on the same substrate. Simulations performed with the finite difference time domain (FDTD) method predict the optical behavior, and especially the band gap, of the structure under investigation.

 

 

 

 

 

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Daniel Foty

Nanoscale Electron Devices:  Difficulties, Granularities, and Applications
pp. 317–338

Abstract. Some critical (but little-recognized) aspects of nanoscale electron device technology are considered.  According to history, nanoscale electron devices will have to address some convergence of an abundance and a scarcity. A major impediment to progress is the emergence of a variety of granularities – a problem as much intellectual as material.

 

 

 

 

 

 

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Aubin Lecointre, Daniela Dragomirescu, Robert Plana

Channel Capacity Limitations versus Hardware Implementation for UWB Impulse Radio Communications
pp. 339–353

Abstract. Starting from the Shannon channel capacity, we propose an IR-UWB channel capacity based on the delay spread for multipath time variant channels. This IR-UWB channel capacity is obtained from the no ISI (Inter Symbol Interference) assumption and for binary modulations. The impact of the kind of implementation is considered on the IR-UWB channel capacity. This study is lead for mixed and mostly digital implementation. The key parameters and theirs impacts on the channel capacity are exposed in each case: the data converters for mostly digital implementations and the pulse generator capabilities for mixed implementations. Finally, these two implementations are compared from a data rate point of view. Their behaviors regarding an increase of the operating frequency are also studied.

 

 

 

 

 

 

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Ana-Maria LUCA, Ioan-Alexandru TRANCĂ, Andrei DANCHIV

Current Sensing Accuracy Improvement by Feedback Offset Cancelation
pp. 354–365

Abstract. This paper presents a precision over current protective function integrated in a high side power switch. The accuracy improvement is based on using a low offset, autozero amplifier for providing the same bias conditions for both the power and the sense transistors.

 

 

 

 

 

 

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Andrea Lucibello, Giorgio De Angelis, Emanuela Proietti, Romolo Marcelli, Giancarlo Bartolucci

Design, Technology and Test of Micro-Machined Coplanar Grounded Wave-Guides on Si Substrates
pp. 366–375

Abstract. Coplanar wave-guide grounded lines (CPWG) have been designed, realized by micro-machining of high resistivity silicon wafers and tested up to 40 GHz. Different configurations have been compared between them by changing the dimensions of the micro-machined via-holes used for the ground connection, as well as their number and separation, to get the optimal electrical matching conditions. Wide-band matching and losses as low as 0.1–0.2 dB/mm have been obtained within the 40 GHz range, in agreement with the predicted behaviour.

 

 

 

 

 

 

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Bogdan ŞERBAN, A. K. SARIN KUMAR, Ştefan COSTEA, Mihai MIHĂILĂ, Octavian BUIU, Mihai BREZEANU, Nicolae VARACHIU, Cornel COBIANU

Polymer-Amino Carbon Nanotube  Nanocomposites For Surface Acoustic Wave CO2 Detection
pp. 376–384

Abstract. The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA) and amino-carbon nanotubes (amino-CNTs), the second on polyethyleneimine (PEI) and amino-carbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, coated with the two nanocomposites, showed good sensitivity when varying the CO2 concentrations in the range (500–5000) ppm. The sensor sensitivity is larger when using polyethyleneimine amino-carbon nanotubes than in the case when only a pure polyethyleneimine layer is considered for coating. PAA-amino-CNTs films feature considerable frequency shifts under the influence of CO2 molecules.

 

 

 

 

 

 

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Monica SIMION, Lavinia RUTA, Irina KLEPS, Dana STAN, Adina BRAGARU, Mihaela MIU, Teodora IGNAT, Adrian DINESCU, Mihaela MATACHE

Porous/Gold surface Preparation for Protein Microarray Applications
pp. 385–393

Abstract. Surface chemistry is extremely important in microarray technology, since it determines the successful attachment of the molecules, spot morphology or signal intensity. This paper describes development of functionalised gold layer surfaces deposited onto porous silicon as substrates for microarray experiments. Two gold textures were studied in order to find the best ratio between signal intensity and spot morphology.  The experiments revealed: (i) that porous silicon substrate ensures spots uniformity and good response of the signal intensity with respect to concentration; (ii) saturation bands for high concentrations for both types of substrates.

 

 

 

 

 

 

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Ştefan SIMION, Romolo MARCELLI, Gheorghe SAJIN, Giancarlo BARTOLUCCI, Florea CRĂCIUNOIU

A Method for On-Wafer Experimental Characterization of a 4-Port Circuit, Using a 2-Port Vector Network Analyzer
pp. 394–401

Abstract. The paper presents an experimental method useful to characterize on-wafer a four-port circuit, using a two-port VNA (Vector Network Analyzer). As an example, the method is applied for a coupler. The results obtained by using this method and the expected results obtained by simulation are in good agreement.

 

 

 

 

 

 

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Rodica VOICU, Raluca MüLLER, Laura EFTIME, Cătălin TIBEICA

Design Study for An Electro-Thermally Actuator for Micromanipulation
pp. 402–409

Abstract. A new design for a polymeric microgripper was developed. Two microgrippers with different dimensions were considered. An evaluation between these models was performed using the simulation results. Finite-element analyses of the microgripper, using COVENTORWARE, are performed in order to evaluate the relation between the displacement, temperatures and the electrical current passing through the metallic layers.

 

 

 

 

 

 

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Ştefan Ioan VOICU, Nicoleta Doriana STANCIU, Aurelia Cristina NECHIFOR, Dănuţ Ionel VAIREANU, Gheorghe NECHIFOR

Synthesis and Characterisation of Ionic Conductive Polysulfone Composite Membranes
pp. 410–422

Abstract. In order to combine the advantages of polysulfone (PSf) as a membrane material and the requirements of an enhanced selectivity to that of polyaniline as a conductive polymer, this paper reports the results obtained for synthesis of polysulfone-polyaniline composite membranes by a new technique consisting in phase inversion by immersion precipitation accompanying by chemical reaction followed by the activation of polyaniline with sulfonated β- cyclodextrine and p-sulfocalix[4]arene. The above synthesized membranes were structurally characterized using Scanning Electron Microscopy, FT-IR spectroscopy, thermal analysis. The ionic conductivity and electrochemical characteristics were also determined by Electrochemical Impedance Spectroscopy.