|
Cristian RAVARIU, Adrian RUSU Abstract. Among the nanodevices, the vacuum nanotransistors are intensively studied in the last decade. A recent novel device was proposed as the NOI - Nothing On Insulator - nanotransistor, inspired from ultrathin SOI devices. Therefore, this new device preserves some properties from the SOI structures. Obviously, the NOI nanotransistor is a vacuum tunnel device among the vacuum field emission devices. But the main target, in this paper, is to prove that its particularity comes from affiliation to the FETs family, monitoring the gate-control on the drain current. The drain current is activated by the VDS voltage under tunneling conditions. But the gate terminal modulates the carriers concentration and consequently the drain current flow, accordingly with its inherent included SOI structure. Also, a new model parameter comes to complete the NOI theory. The third order derivative was used for the extraction of a threshold drain-source voltage that splits the work domain in two conduction regions. Read the pdf.
Alina CISMARU, Marius VOICU, Antonio RADOI, Adrian DINESCU, Dan NECULOIU, Mircea DRAGOMAN Abstract. The paper presents modeling, fabrication and measurements of microwave propagation in electromagnetic band gap (EMBG) CNTs based resonator for DNA detection. We report on sensing of DNA wrapped on multi walled carbon nanotubes (CNTs) deposited over a coupled lines area of two types of EMBG resonator structures. A new EMBG structure with coupled lines as a defect in the structure in order to obtain a EMBG resonator is proposed. Two types of EMBG resonator structures having the distance between the coupled lines 50 µm and 100 µm respectively have been used in order to find the best coupling with CNTs. The transmission magnitude and the phase for two types of EMBG resonators based on carbon nanotubes has been presented. Detection of DNA using EMBG resonators based on CNTs was demonstrated by a shift of the resonance frequency and an averaged phase shift of 20 degrees for a broadband frequency range of 6-20 GHz. Read the pdf
Bogdan ŞERBAN, A. K. SARIN KUMAR, Mihai BREZEANU, Cornel COBIANU, Octavian BUIU, Cazimir BOSTAN, Nicolae VARACHIU, Ştefan COSTEA Abstract. The CO2 sensing performance of several coating layers deposited on piezoelectric devices (Surface and Bulk Acoustic wave - SAW/BAW) are discussed and compared. The layers are amino groups-based polymers and their selection was based on two principles: Hard Soft Acid Bases (HSAB) and Bronsted-Lowry. Experimentally measured CO2 frequency shifts and sensitivities of emeraldine, 4-sulfocalix[4]arene-doped polyaniline, matrix based emeraldine and carbonic anhydrase (PACA) are compared to previously reported results obtained for coatings such as: polyallylamine (PAA), polyethyleneimine (PEI), nanocomposite matrix based on PAA-aminocarbon nanotubes and PEI-aminocarbon nanotubes. Read the pdf
Cristian NEACŞU, Valentin CHESARU, Claudius DAN, Mircea BODEA Abstract. This paper presents a continuous time chaos generator based on a simple oscillator structure. The developed mathematical model (based on dedicated software), Spice simulation and hardware implementation of the circuit demonstrate the strange attractor and chaotic behavior. Read the pdf
Alexandru RUSU, Dragoş DOBRESCU, Corneliu BURILEANU, Adrian RUSU Abstract. In this paper we present a unity-gain follower amplifier based on a gated diode operated in breakdown regime in common cathode configuration. The amplifier has only one stage and it provides power amplification, high input impedance and a low output one. The maximum frequency that can be applied on the entrance of the amplifier so that the output remains undistorted is dependent on the bias current therefore it can be used also as a programmable low pass filter. The diode is fully characterized in order to set the bias in the linear region where the amplification is very close to one. Read the pdf
Cornel STĂNESCU, Radu IACOB, Cristian DINCĂ, Ovidiu PROFIRESCU Abstract. This paper presents an adjustable LDO with external control technique for the current limit. Using an external resistor, the user can change the current limit within wide domain. This is possible by using a special block which generates the current reference for the current protection block. The block consumes between 5 and 25 µA, and uses the 1.25 V voltage reference. The proposed LDO has a fast transient response and can deliver up to 300 mA continuous load current. It consumes 100 µA and has a dropout voltage of 200 mV at 300 mA. Read the pdf
F. GIACOMOZZI, V. MULLONI, S. COLPO, J. IANNACCI, B. MARGESIN, A. FAES
Abstract. RF MEMS are assuming a great importance in the fast evolving telecommunication market and space applications. In the last years a flexible technology platform has been developed and continuously optimized at FBK (Italy) for the fabrication of RF MEMS basic components as well as complex RF circuits working in the frequency range from sub-GHz up to more than 100 GHz. The paper reports about the fabrication process and its capabilities. The most important process features are described together with some modifications required for the manufacturing of specific devices, like dielectric less RF MEMS switches. Examples of produced devices and their performances are briefly presented. Read the pdf
Alina-Cristina BUNEA, Dan NECULOIU, Alexandru MÜLLER Abstract. This paper investigates a series of membrane supported millimeter wave transmission lines up to 110 GHz. The structures were fabricated using high resistivity silicon micromachining (wet etching). Three approaches, based on full-wave electromagnetic simulations, analytic closed form equations and equivalent circuit were used in the investigation process. The results were validated by the experimental results for different test structures. The analytic equations were inserted in a Matlab routine and the effective permittivity and characteristic impedance were plotted for various geometries. These same geometries were then simulated electromagnetically in CST Microwave Studio. A comparison between the two approaches is made. The effective permittivity of a membrane supported coplanar waveguide (CPW) line was extracted from measurements and it is in very good agreement with the electromagnetically simulated data. Read the pdf.
Valentin BUICULESCU Abstract. A novel transition from microstrip and coplanar lines to the specific signal interfaces of usual surface assembled components is considered in this paper. It is aimed to improve the bandwidth of printed circuit board (PCB) based packages, provided by smaller values and better geometry controlled parasitic elements due to proposed structure. Moreover, the same interface model is compatible with surface assembly of substrate integrated waveguide components. Guidelines for component values preliminary calculation and optimization are presented. Microstrip test circuits were accordingly manufactured for design verification, with satisfactory results up to 8 GHz. The relative permittivity of FR-4 substrate material used in our experiments is considered the solely responsible for certain differences existing between simulated and experimental data, because they became effective after PCB manufacturer was replaced. Read the pdf
|