Global modeling approach to the design of an MMIC amplifier using Ohmic Electrode-Sharing Technology

An innovative technique for high--density, high-frequency integrated circuit design is proposed.The procedure exploits the potentialities of a global modeling approach,previously applied only at device level,enabling the circuit designer to explore flexible layout solutions imed at important reduction in chip size and cost.The new circuit design technique is presented by means of an example consisting of a wide-band amplifier,implemented with the recently proposed Ohmic Electrode-Sharing Technology (OEST).The good agreement between experimental and simulated results confirms the validity of the proposed MMIC design approach

Millimeter-wave FET modeling based on a frequency extrapolation approach

An empirical distributed model, based on electromagnetic analysis and standard S-parameter measurements up to microwave frequencies, is shown to be capable of accurate small-signal predictions up to the millimeter-wave range. The frequency-extrapolation approach takes advantage from a physically-expected, smooth behavior of suitably defined elementary active devices connected to a passive distributed network. On this basis, small-signal millimeter-wave FET modeling becomes an affordable task in any laboratory equipped with a standard microwave vector network analyzer and electromagnetic simulation capabilities. In the paper, wide experimental validation of the proposed model up to 110GHz is presented for PHEMT devices with different sizes and bias conditions

System Level Analysis of Millimetre-wave GaN-based MIMO Radar for Detection of Micro Unmanned Aerial Vehicles

The detection of Unmanned Aerial Vehicles (UAVs) of micro/nano dimensions, is becoming a hot topic, due to their large diffusion, and represents a challenging task from both the system architecture and components point of view. The Frequency Modulated Continuous Wave (FMCW) radar architecture in a Multi-Input Multi-Output configuration has been identified as the most suitable solution for this purpose, due to both its inherent short-range detection capability and compact implementation. This paper describes the operation and technology challenges inherent to the development of a millimeter-wave FMCW MIMO radar for small UAVs detection. In particular it analyzes the sub-systems specifications and the expected system performance with respect to a chip set designed and developed in GaN at 37.5 GHz applications

Comparison of four different colorimetric and fluorometric cytotoxicity assays in a zebrafish liver cell line

Background: A broad spectrum of cytotoxicity assays is currently used in the fields of (eco)toxicology and pharmacology. To choose an appropriate assay, different parameters like test compounds, detection mechanism, specificity, and sensitivity have to be considered. Furthermore, tissue or cell line can influence test performance. For zebrafish (Danio rerio), as emerging model organism, cell lines are now increasingly used, but few studies examined cytotoxicity in these cell systems. Therefore, we compared four cytotoxicity assays in the zebrafish liver cell line, ZFL, to test four differently acting model compounds. The tests comprised two colorimetric assays (MTT assay using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide, and the LDH assay detecting lactate dehydrogenase activity) and two fluorometric assays (alamarBlue® using resazurin, and CFDA-AM based on 5-carboxyfluorescein diacetate acetoxymethyl ester). Model compounds were the pharmaceutical Tamoxifen, its metabolite 4-Hydroxy-Tamoxifen, the fungicide Flusilazole and the polycyclic aromatic hydrocarbon Benzo[a]pyrene. Results: All four assays performed well in the ZFL cells and led to reproducible dose-response curves for all test compounds. Effective concentrations causing 10% or 50% loss of cell viability (EC10 and EC50 values) varied by a maximum factor of 7.0 for the EC10 values and a maximum factor of 1.8 for the EC50 values. The EC values were not statistically different between the four assays, which is due to the assessed unspecific effects of the compounds. However, most often, the MTT assay and LDH assay showed the highest and lowest EC values, respectively. Nevertheless, the LDH assay showed the highest intra- and inter-assay variabilities and the lowest signal-to-noise ratios. In contrast to MTT, the other three assays have the advantage of being non-destructive, easy to handle, and less time consuming. Furthermore, AB and CFDA-AM can be combined on the same set of cells without damaging the cells, allowing later on their use for the investigation of other endpoints. Conclusions: We recommend the alamarBlue and CFDA-AM assays for cytotoxicity assessment in ZFL cells, which can be applied either singly or combined.JRC.H.5-Rural, water and ecosystem resource

Enhanced transfection of cell lines from Atlantic salmon through nucoleofection and antibiotic selection

Background Cell lines from Atlantic salmon kidney have made it possible to culture and study infectious salmon anemia virus (ISAV), an aquatic orthomyxovirus affecting farmed Atlantic salmon. However, transfection of these cells using calcium phosphate precipitation or lipid-based reagents shows very low transfection efficiency. The Amaxa Nucleofector technology™ is an electroporation technique that has been shown to be efficient for gene transfer into primary cells and hard to transfect cell lines. Findings Here we demonstrate, enhanced transfection of the head kidney cell line, TO, from Atlantic salmon using nucleofection and subsequent flow cytometry. Depending on the plasmid promoter, TO cells could be transfected transiently with an efficiency ranging from 11.6% to 90.8% with good viability, using Amaxa's cell line nucleofector solution T and program T-20. A kill curve was performed to investigate the most potent antibiotic for selection of transformed cells, and we found that blasticidin and puromycin were the most efficient for selection of TO cells. Conclusions The results show that nucleofection is an efficient way of gene transfer into Atlantic salmon cells and that stably transfected cells can be selected with blasticidin or puromycin

A Scalable PHEMT Model Taking Into Account Electromagnetic and Electro-Thermal Effects

The paper proposes an approach to model a P-HEMT taking into account for the electrical-thermal- electromagnetic behavior in an effective way.The model is based on the integration of a distributed approach,which considers an intrinsic device for gate finger,each of them equipped with a thermal equivalent circuit.The latter considers also the mutual interacting between the adjacent intrinsic devices by means a voltage-controlled voltage- source that allows considering the thermal coupling by a series of coefficients determined in an analytical way.The electrical model has been extracted from a 2x150um PHEMT and then applied to predict the DC and RF characteristic of a 8x150um proving the model scalability capability

A Distributed Approach for the Characterisation of Parasitic Networks in Electron Device Modelling

A new modeling approach for electron devices up to millimeter-wave frequencies is proposed. It exploits a previously proposed distributed approach with the aim of deriving a more computationally efficient model still preserving good accuracy. In particular, a new electron device model based on a “single active device” and a “distributed description of the parasitic structure” is derived, which can easily be identified through conventional scattering parameter measurements and electromagnetic simulations. Preliminary validation results are provided in the paper

A MMIC lumped element directional coupler with arbitrary characteristic impedance and its application

In this paper the design technique for MMIC lumped element directional couplers, based on arbitrary termination impedance, is described. Arbitrary impedance terminations allow matching the linear and nonlinear elements to the coupler without the requirement of transformer networks. The technique’s capability is demonstrated through the design of a single balanced mixer prototype at 1.8GHz for which measured and simulated data are provided