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ABSTRACT: In this paper we present an improved model of the multilayered T-type electromagnetic interference chip LC filter for printed circuit board applications, and an improved measurement technique for characterization of such devices. Electrical parameters measurements of the same LC filter can vary for different measurement types. Because of that, we have developed new adaptation microstrip test fixture on printed circuit board for vector network analyzers' measurements of surface mount devices with three terminals. Two commercially available components, multilayer T-type LC filters, are measured and characterized using a vector network analyzer. The comparison of measurement data and simulation values of electrical equivalent circuit and electromagnetic model for two LC filters is further presented. The new improved model of T-type LC filters has provided better agreement between measurement and simulation.
IEEE Transactions on Magnetics 11/2011; · 1.36 Impact Factor
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ABSTRACT: A novel uniaxial anemometer was created using a NTC thick film segmented thermistor to measure wind speed and direction. The anemometer operated on the principle of heat loss caused by the air volume flow and air speed. A NTC segmented thermistor served as a wind sensor in the anemometer. It was self-heated by a DC constant voltage. The self-heated DC current through the thermistor was changed by heat loss due to resistivity changes. The wind speed was varied from 1 to 15 m/s for different input air temperatures in the range of -20 to +40degC. The wind direction was determined by measuring voltage differences on the inner electrodes of the NTC segmented thermistor. The air temperature was measure by a cold NTC thick film segmented thermistor calibrated in the claim chamber. Anemometar inertia was measured at room temperature (at 25degC) and normal room humidity (at 50%). The results obtained enable fast optimization and implementation of a uniaxial anemometer in a 3D anemometer.
Microelectronics, 2008. MIEL 2008. 26th International Conference on; 06/2008
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ABSTRACT: This paper describes the design, modeling, simulation, and fabrication of thick-film segmented thermistors. These thermistors were printed on alumina using negative temperature coefficient 3K3 paste, composed of nanometer powder. Their room temperature resistance was measured versus the number of segments and electrode surface value for the fixed layer thickness and electrode spacing. After that, very large thermistors were printed to serve as both the powerful self-heaters and the heat loss sensors in the thermistor volume air flow meter and anemometer. For an application in AC bridges, impedance Z(f) and insertion loss S21 [dB] of the same largest segmented thermistor were measured using network analyzer HP8752A. Impedance modeling was performed using simple equivalent electrical circuit with circuit parameters estimated by fitting procedure (traditional approach), as well as using a commercial electromagnetic simulation program microwave office (MWO, novel approach). This was followed by the modeling of electrical current distribution over a number of segments done within the MWO. The results obtained from simulations and measurements were mutually compared.
IEEE Sensors Journal 11/2007; · 1.52 Impact Factor
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ABSTRACT: Two planar NTC thick film thermistors were placed in a rectangular air guide with a large cross section area and connected to opposite branches of a Wheatstone bridge to form air flow sensor. Thick film sensors used in measurements were printed on alumina using of thermistor paste NTC 3K3 - 95/2 in EI Iritel. NTC thermistor paste was composed of submicronic powder (mixture of Mn, Co and Fe oxides), 4% B<sub>2</sub>O<sub>3</sub> and an organic vehicle. The most suitable planar NTC thermistor geometry for an air sensor was segmented type with an optimized surface value of 75×12×0.5 mm. It was used to cover part of an open air gauge and conduct a heat from flowing air. The resistivity difference obtained on the thermistors was compared with the volume velocity of air laminar flow at room ambient temperature and humidity.
Microelectronics, 2004. 24th International Conference on; 06/2004
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ABSTRACT: The paper describes the design, fabrication, and test of integrated LC filters in thick-film technology. The range of filters was electrically characterized using the HP 8566B network analyzer. We present a scalable analytical model for thick-film integrated LC filters that is suitable for design and circuit simulations. We also provide simple expressions for evaluating the optimum conductor thicknesses.
IEEE Transactions on Instrumentation and Measurement 09/2002; · 1.21 Impact Factor
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ABSTRACT: The paper describes the design, fabrication and test of integrated
LC filters in thick film technology. The range of filters was
electrically characterized using a HP 8566B network analyzer. We present
a scalable analytical model for thick film integrated LC filters that is
suitable for design and circuit simulations. We also provide simple
expressions for evaluating the optimum conductor thicknesses
Instrumentation and Measurement Technology Conference, 2001. IMTC 2001. Proceedings of the 18th IEEE; 02/2001
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ABSTRACT: Solenoid-bar type inductors and transformers with different turns
ratio are analyzed. In this paper in equivalent circuit models for
inductors and transformers are presented. Parasitic physical phenomena
important to prediciton of inductor quality factor Q are included in the
model, and special attention is paid to inductance calculations
Microelectronics, 2000. Proceedings. 2000 22nd International Conference on; 02/2000
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ABSTRACT: A new NTC thick film paste called 3K3-95/2 was composed of
submicron powder (a mixture of Mn, Co and Fe oxides), 4% Bi<sub>2</sub>O
<sub>3</sub> and an organic vehicle. The paste was screen printed on an
alumina substrata and sintered in a thick film conveyor furnace at
temperatures in the range 650 to 1000 °C. Thick film thermistor
layers were characterized by X-ray data, optical microscopy and SEM.
Electrical measurements were performed on the samples after printing Ag
epoxy electrodes on the top of the NTC layers. Then, new test NTC thick
film matrices with different planar thermistor geometries were
constructed and realized: “sandwich”,
“multilayer”, “segmented” and
“interdigitated” geometries. Their resistivity varied as a
function of layer thickness, electrode size and shape in the range of 10
Ω to 100 MΩ. The electrical resistivity of planar
thermistors was measured in the climate chamber in the range -30°C
to 120°C, when the thermistor temperature parameters B and Tc were
obtained (B=4200 K, Tmax=130°C). The main advantages of planar thick
film thermistor geometries over bulk types are faster temperature
response and custom design possibility for sensor applications
Microelectronics, 1997. Proceedings., 1997 21st International Conference on; 10/1997
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ABSTRACT: Different planar inductive structures were designed, simulated,
fabricated in multilayer thick film technology and measured. Analytical
analysis and computer simulations of design inductor parameters were
performed for optimization of thick film multilayer inductors in order
to achieve desired electrical characteristics. An original CAD has been
developed and can be useful generally in different design simulations.
Two prototype series were realized on an Al<sub>2</sub>O<sub>3</sub>
substrate using Pd/Ag conductive paste and Ni-ferrite paste for magnetic
layers: inductors on magnetic layers and “sandwich”
inductors
Microelectronics, 1997. Proceedings., 1997 21st International Conference on; 10/1997
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ABSTRACT: Ni-ferrite powder average grain size less than 0.9µm was used for the ferrite paste preparation. Ferrite paste was printed on Al2O3 substrate and fired 850°C/10min. After Ni-ferrite thick film characterization had been done, simple planar inductor geometry, such as square spirals, were printed on it. Measurements were done, using an HP 4194A impedance analyser. The experimental results were summarized and compared with theoretical predictions given by the electromagnetic analysis using the method of current images for the reason of accounting the effect of magnetic substrate. The computer program, developed here, allows determination of the required thickness of the substrate which will produce inductance enhancement of the given permeability of the substrate material. The same results can also be used to determine the permeability of magnetic film or substrate quickly and are directly applicable to the design of the planar inductors.
COMPEL International Journal of Computations and Mathematics in Electrical 12/1995; 14(4):291-295. · 0.30 Impact Factor
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ABSTRACT: A few types of thick film integrated LC cells were created based on planar inductors and capacitors. The planar thick film inductors such as meander and bispiral were integrated into the top electrodes of the planar thick film capacitors such as sandwich and interdigitated to form thick film LC cells. Thick film planar LC arrays were made by repeating the 3, 4 or 8 LC cells on the same substrate. The two dielectric pastes made in EI Iritel were used for planar cell arrays: BaTiO<sub>3</sub> for planar LC and ZnO for planar LCV cells (V varistor is built in capacitor). Electrodes were printed using PdAg paste. NiFe<sub>2</sub>O <sub>4</sub> paste made in EI Ferrites and EI Iritel was printed on the bottom and the top of LC cells to increase the inductivity L. These arrays were aimed to serve as planar EMI/RFI suppressors of radiative noise on I/O connections. The main advantages of these cell arrays over the classical ones are: custom design, new geometries with distributed L/C/V, built in planar varistors, easy reproduction, DIL package etc
Microelectronics, 1995. Proceedings., 1995 20th International Conference on; 10/1995
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ABSTRACT: Various thick film varistor constructions were made and characterised: ‘sandwich’, ‘interdigitated’ and ‘segmented’ varistors. The varistor active layer thickness, the electrode surface value and shape were varied. The Ul characteristics of these varistors were compared mutually, and with the Ul characteristics of the smallest chip varistors. In accordance with the results obtained, it has been shown that thick film printed varistors composed of ZnO and with additives could be applied as discrete components or integrated into a hybrid circuit.
Microelectronics International 12/1993; 10(1):5-9. · 0.60 Impact Factor
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ABSTRACT: Two shapes of interdigitated planar varistors were made using
thick-film technology on alumina substrates. These varistor were based
on ZnO paste. The distance between varistor electrodes were changed from
0.2 to 1.91 mm, and the total length of the electrodes from 49 to 230
mm. The varistor threshold voltages were obtained in the region of
1100-3100 VAC. The threshold voltages were proportional to the distance
between electrodes. The influence of electrode geometry on U -
I characteristics was analyzed
Electrotechnical Conference, 1991. Proceedings., 6th Mediterranean; 06/1991
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ABSTRACT: Presents the dielectric properties of polycrystalline SrF<sub>12 </sub>O<sub>19</sub> in the microwave range and far infrared range. Samples were made from powder pressed in a magnetic field and sintered in air at 1200°C. The experimental results and numerically calculated dielectric permittivity in the far infrared range show that the dielectric permittivity holds a microwave value and in mm-wave range. The transmission characteristics of a thick film Sr- hexaferrite isolator in fin line technique were observed in the range 32.7-39.2 GHz. The bandwidth over which the isolation loss is greater than 20 dB is about 2 GHz (at around 36 GHz). Ferrite devices in this geometry have the advantage of being compact and of low cost compared to the ferrite devices in conventional structures
Dielectric Materials, Measurements and Applications, 1988., Fifth International Conference on; 07/1988
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ABSTRACT: Ni-ferrite inductors were realized in thick film multilayer technology on Al2O3 substrate using Pd/Ag conductive paste, Al2O3 dielectric paste and Ni-ferrite paste. Three different constructions of square spiral inductors were printed, fired and measured : "simple" spiral, "reverse" spiral and "outer" spiral. While "simple" spiral contains one conductive layer, the other two types have two conductive layers. Additional magnetic thick layers were placed on the bottom and the top of inductor constructions. Inductors were measured on the network analyzer in the HF range (up to x 100MHz). An original CAD, based on well known method of current images, was developed to predict and explain the experimental results. Obtained results indicate the possibility of using thick film spiral inductors in the HF range for the same application as the chip inductors, but except the fact that this type of inductors could be used as a discrete hybrid component, it could be directly incorporated in the hybrid circuits (such as filters etc.).
http://dx.doi.org/10.1051/jp4:1997148.
