scholarly journals In the frequency range between 1 kHz and 1 MHz

2009 ◽  
Vol 63 (3) ◽  
pp. 209-216 ◽  
Author(s):  
Vasa Radonic ◽  
Goran Radosavljevic ◽  
Nelu Blaz ◽  
Ljiljana Zivanov ◽  
Walter Smetana
Keyword(s):  
Equivalent Circuit ◽  
Loss Tangent ◽  
Complex Permittivity ◽  
Low Frequency ◽  
Small Variation ◽  
Frequency Range ◽  
Characteristic Parameters ◽  
Capacitive Method ◽  
User Friendly

In this paper, a capacitive method for characterization of LTCC tapes in the frequency range between 1kHz and 1MHz using HP 4277A LCZ meter is presented. The principle of operation using a parallel plate capacitor and equivalent circuit as a parallel connection of capacitance and a resistor is explained and characterization of test samples is measured. The fabrication process in LTCC technology and the causes that can produce the changing of characteristic parameters of substrates in fabrication are explained in detail. We indicated the importance of knowing permittivity in the function of frequency during projecting and simulating electronic components and circuits in LTCC technology. Measurements of complex permittivity, loss tangent, Q-factor based on the proposed formulas are made for LTCC tapes samples. Small variation of measured capacitance and loss tangent is obtained, approximately about 2% in whole frequency range. The value of loss tangent is approximately the same as the value specified by manufacturers. The calculated parameters for complex permittivity have bigger values then those recommended by manufacturers before firing. In the process of sintering, sheet density and microstructure of commercial tapes are changed for all used materials, causing changes of electric characteristics, especially permittivity. In the low frequency range, below 50 kHz, there is a higher variation of characteristic parameters. In this range, the parallel resistance of the equivalent circuit is on the top level of the instruments limit and these results are not reliable. A specific user-friendly program is developed which enables automatic control of measurement, recalculation of important values and processing of results.

scholarly journals Electromagnetic Characterization of a Composite (RE-CB-MT) by Time Domain Spectroscopy

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Amina Bounar ◽  
Nacerdine Bouzit ◽  
Nacerdine Bourouba
Keyword(s):  
Time Domain ◽  
Ternary Mixture ◽  
Strong Dependence ◽  
Low Frequency ◽  
Theoretical Models ◽  
Dielectric Behavior ◽  
Frequency Range ◽  
Time Domain Spectroscopy ◽  
Percolation Phenomenon

The aim of this article is to study the dielectric behavior (ε, σ) in microwaves domain of composites made with Epoxy Resin (RE), Carbon Black (CB), and Magnesium Titanate (MT) on a large band of frequency. This kind of composites is very solicited for applications and miniaturization of the components circuits (cavities, antennas, substrates, etc.) in hyperfrequency electronics. In this study we have also highlighted the effect of the fillers nature and their concentrations on the behavior of these composites. The results obtained by time domain spectroscopy (TDS) have revealed the strong dependence of complex permittivity of the composite materials on both the nature and the concentration of conductive environment. Low frequency analysis (500 MHz) has been investigated to determine the conductivity of composites which is related to the percolation phenomenon. Moreover, the comparison between experimental results and theoretical models shows that the modeling Lichtenecker law is applicable to the ternary mixture in this frequency range and is in accordance with the approach postulated by Bottreau.

Dielectric Studies of Binary Mixtures of 1-Propanol and Fluorobenzene

2013 ◽  
Vol 209 ◽  
pp. 203-206 ◽  
Author(s):  
Ashvin N. Prajapati ◽  
Vipinchandra A. Rana ◽  
A.D. Vyas ◽  
S.P. Bhatanagar ◽  
D.H. Gadani
Keyword(s):  
Dielectric Constant ◽  
Binary Mixtures ◽  
Complex Permittivity ◽  
High Frequency ◽  
Low Frequency ◽  
Microwave Frequency ◽  
Static Dielectric Constant ◽  
Frequency Range ◽  
Optical Dielectric Constant ◽  
Optical Dielectric

Complex permittivity spectra of 1-Propanol (1-PrOH), Fluorobenzene (FB) and their binary mixtures are obtained in radio and microwave frequency range using Vector network analyzer (VNA) operating in the frequency range 0.3 MHz to 3.0 GHz and standard microwave benches operated at 9.1 GHz and 19.61 GHz. Static dielectric constant (ε0) and high frequency limiting dielectric constant (ε∞1) for binary mixtures of 1-PrOH and FB are obtained by extrapolating the complex permittivity data towards low frequency side and high frequency side on complex plane plots. Optical dielectric constant (ε∞ = n2) for binary mixtures are measured using Abbe's refractometer. Excess static dielectric constant (ε0)E, Kirkwood correlation parameters (g, geff and gf) and Bruggeman factor (fB) are determined from the values of static dielectric constant (ε0) and optical dielectric constant (ε∞). These parameters have been discussed to explore the molecular interaction between the molecular species.

Microwave Absorbing Property of Thin Coating in the Broadband Low-Frequency Range

2018 ◽  
Vol 916 ◽  
pp. 33-37
Author(s):  
Le Chen ◽  
Zhao Zhan Gu ◽  
Ming Xue Zhang
Keyword(s):  
Reflection Loss ◽  
Complex Permittivity ◽  
Carbonyl Iron ◽  
Low Frequency ◽  
Complex Permeability ◽  
Frequency Range ◽  
Microwave Absorbing ◽  
Absorbing Property ◽  
Lower Frequency Region ◽  
Minimum Reflection Loss

Coatings with flake carbonyl-iron powder as absorber and polyurethane resin as matrix were prepared. The complex permittivity, complex permeability and microwave-absorbing properties were investigated in the frequency range of 2–18 GHz. Both the complex permittivity and permeability of the flaky carbonyl-iron were increased compared to the spherical powders. The minimum reflection loss decreased and the matching frequency shifted to the lower frequency region with increase in the coating thickness. The band width can reach nearly 16GHz as the RL was below than-4 dB with thickness only 1.4 mm. The minimum reflection loss value of-14.5 dB was obtained at 3.56 GHz for the 1.6mm coatings with 89 wt% carbonyl-iron powders. These results showed that the coatings were favorable for the broadband low-frequency microwave absorption with a small thickness.

Characterization of Heavy Metal Contaminated Wastewater Using a Coaxial Sensor and Electromagnetic Wave Reflection Technique

2014 ◽  
Vol 548-549 ◽  
pp. 678-682 ◽  
Author(s):  
N. Puangngernmak ◽  
S. Chalermwisutkul
Keyword(s):  
Heavy Metal ◽  
Reflection Coefficient ◽  
Complex Permittivity ◽  
Industrial Wastewater ◽  
Frequency Range ◽  
Liquid Samples ◽  
Measurement Results ◽  
Interesting Approach ◽  
Copper Zinc

Industrial wastewater control is an important issue for protection of the environment. Liquid characterization using radio frequency signal is an interesting approach for selective detection of heavy metal contaminants in industrial wastewater. A simple sensor based on open-ended coaxial structure filled with the liquid under test is proposed. Liquid samples for the experiments are copper, zinc and nickel solutions with various concentrations of 1, 10, 100 and 1000 mg/liter each. From the measurement results using a vector network analyzer (VNA) in combination with the proposed sensor, the concentration of a specific contaminant can be determined by the magnitude of the measured reflection coefficient in a frequency range lower than 2 GHz. Applying a capacitive model of the sensor, complex permittivity of the liquid under test can be calculated from the measured reflection coefficient. Obvious relationship between the imaginary part of complex permittivity and the concentration of contaminant in a frequency range lower than 2 GHz was observed. The type of contaminants in the liquid samples can be identified by the position of the resonant peaks when the magnitude of reflection coefficient is plotted in the spectrum. The frequency range for contaminant’s identification lies between 2 and 3 GHz.

scholarly journals AC Equivalent Circuit Model of an Electrochemical Accelerometer for 3D Numerical Simulation in the Low-Frequency Range

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4686
Author(s):  
Qiuzhan Zhou ◽  
Yuzhu Chen ◽  
Jikang Hu ◽  
Boshi Lyu
Keyword(s):  
Numerical Simulation ◽  
Equivalent Circuit ◽  
Characteristic Curve ◽  
Equivalent Circuit Model ◽  
Low Frequency ◽  
Circuit Model ◽  
Frequency Range ◽  
Element Analysis ◽  
Amplitude Frequency Characteristic ◽  
Vibration Sensors

The electrochemical principles presented in this paper can be applied to the manufacture of vibration sensors for oil and gas exploration, as well as long-period vibration sensors for the observation of natural earthquakes. To facilitate the manufacture of high-volume electrochemical accelerometer (EAM), this paper presents an AC equivalent circuit model of an EAM in a low-frequency range. A 3D time-dependent numerical simulation based on finite element analysis was designed to combine a complex chemical reaction with electric circuit theory. A sensitive chip channel model was constructed by using partial differential equations and the problem caused by a designed mathematical model was solved by using multi-physics finite element analysis. When the electrochemical properties of an electrochemical vibration sensor and its design parameters as well as the parameters of the AC equivalent circuit model are considered, the abstract processing of the sensor on the equivalent circuit is better accomplished. The effectiveness of the proposed simulation model and the equivalent circuit model were verified by comparing the amplitude-frequency characteristic curve of the equivalent circuit with the amplitude-frequency characteristic curve of the single-channel simulation model of the sensitive chip. These model not only have great significance for the design guidance of an external conditioning circuit but also provide an effective method to decouple the output signal and noise of the sensor reaction cavity.

Synthesis and Characterization of Magnetoelectric Nanocomposites

2009 ◽  
Vol 155 ◽  
pp. 173-188
Author(s):  
Kanhaiya Lal Yadav
Keyword(s):  
Annealing Temperature ◽  
Strong Dependence ◽  
Low Frequency ◽  
Magnetic Characteristics ◽  
Frequency Range ◽  
Field Frequency ◽  
Maximum Value ◽  
Citrate Gel Process ◽  
Small Crystallite

A simple citrate gel process was used to prepare nanocomposites of xCuFe2O4–(1−x)BiFeO3 (henceforth, CFBF) and xNi0.75Co0.25Fe2O4-(1-x)BiFeO3 (henceforth, NCFBF) with x=0.1, 0.2, 0.3 and 0.4. The phase was found to be formed at 500 °C and 700 °C for CFBF and NCFBF respectively. TEM observation showed that the average particles size is around 40 nm. The variation of the dielectric constant and the dielectric loss with frequency showed dispersion in the low frequency range. All the samples exhibit strong magnetic characteristics. The coercivity and squareness increased with the increase in annealing temperature and were maximum for samples annealed at 500°C and 700°C for CFBF and NCFBF nanocomposites, respectively, and further decrease in coercivity is attributed to decrease in aspect ratio and pinning effects in the nanocrysatllites. The ME coefficient αE showed strong dependence on HBias and maximum value of ME coefficients were 303 and 309 mV/cm Oe at magnetic field frequency of 50 kHz for CFBF and NCFBF nanocomposites respectively. The large values of ME coefficients are attributed to low coercivity, large magnetization and small crystallite size of constituent phases.

scholarly journals Electromagnetic characterization of Ni0.5Zn0.3Co0.2Fe2O4 bulk ceramics in the 1MHz-12GHz frequency range

2021 ◽  
Vol 15 (2) ◽  
pp. 136-145
Author(s):  
Vera Lucia de Brito ◽  
Julia Maria de Morais Santos ◽  
João Paulo Machado ◽  
Cristina Bormio-Nunes ◽  
Francisco Carvalho
Keyword(s):  
Complex Permittivity ◽  
Sintered Sample ◽  
Magnetic Behaviour ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Ferrite Sample ◽  
Complex Magnetic Permeability ◽  
Permittivity Measurements

In this paper, NiZnCo ferrite was produced by solid state synthesis, calcination at 1000?C and sintering at 1250?C in air atmosphere. The microstructure and phases of the sintered sample were analysed by scanning electron microscopy and X-ray diffraction, respectively. The magnetic properties of the ferrite were evaluated by magnetization and magnetostriction measurements. The complex magnetic permeability and complex permittivity were also measured between 1MHz-12GHz and the reflection loss (RL) was calculated in the 100MHz-12GHz frequency range. The results show that the ferrite sample presents magnetostrictive behaviour and a saturation magnetization of 71 Am2/kg. Complex permittivity measurements indicate that the material has dielectric behaviour in the whole frequency range studied, with "? varying between 7-40, and magnetic behaviour in frequencies between 1MHz-5GHz. The minimum RL was found at frequencies between 2.4-3.3GHz and the calculated RL value for a thickness of 3mm was lower than ?10 dB in frequencies between 2.3-7.3GHz. These results indicate potential application as microwave absorber in the S band.

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