scholarly journals Comparison of Dielectric Constant & Loss Factor for Preliminary, Oven Dried and Saturated Grains Using Ku Band Microwave Frequency

2017 ◽  
Vol 6 (9) ◽  
pp. 1076-1084
Keyword(s):  
Dielectric Constant ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Ku Band

scholarly journals The Effects of SLS on Structural and Complex Permittivity of SLS-HDPE Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Abubakar Dantani Meli ◽  
Zulkifly Abbas ◽  
Mohd Hafiz Mohd Zaid ◽  
Nor Azowa Ibrahim
Keyword(s):  
Dielectric Constant ◽  
Complex Permittivity ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Soda Lime ◽  
Physical Structure ◽  
Host Matrix ◽  
Lower Dielectric Constant ◽  
Absorbing Material ◽  
Diffraction Patterns

RS-4050 is a rigid epoxy based magnetic castable microwave absorbing material; it has been used in many areas of waveguide application as a microwave waveguide terminations and dummy loads. In recent years, there is a demand for composites material with lower dielectric constant higher loss factor for microwave application. This research, the effect of soda lime silica (SLS) on structural and complex permittivity of soda lime silica-high density polyethylene (SLS-HDPE) composites was conducted in order to explore the possibility of substituting RS-4050 with SLS-HDPE composites as a microwave waveguide terminations and dummy loads. Elemental weight composition of the SLS glass powder and HDPE was identified through scaling of different percentage of SLS and HDPE. X-ray diffraction (XRD) was used to investigate the crystallinity behavior of SLS-HDPE composites. The proposed SLS-HDPE composites material was studied at frequencies 8 to 12 GHz. The study was conducted using waveguide Agilent N5230A PNA technique. The effect of microwave frequency on complex permittivity properties for SLS-HDPE composites of different percentages of SLS and HDPE (10% SLS-90% HDPE, 20% SLS-80% HDPE, 30% SLS-70% HDPE, 40% SLS-60% HDPE, and 50% SLS-50% HDPE) were investigated. Results showed the diffraction patterns reveal good amorphous quality with a genuinely properties structure. The microwave frequency and composites percentages significantly influenced the complex permittivity (real and imaginary) properties of the composites. Moreover, the complex permittivity increased as the percentage of SLS filler increased in the host matrix HDPE as a result of increased in composite density due to less volume being occupied by the filler as the percentage increased. The complex permittivity of the smallest and largest percentages of SLS (10% and 50%) was (2.67-j0.05) and (3.45-j0.35), respectively. The study revealed that the best sample for waveguide application as microwave terminator is 50% SLS as it has the highest dielectric constant, highest loss factor, and highest loss tangent as compared to 10% SLS to 40% SLS. Also 50% SLS has the highest absorption properties as compare to 10% SLS, 20% SLS, 30% SLS, or 40% SLS. The XRD physical structure of the SLS-HDPE composites revealed the absorption characteristics of different percentages of the materials. The SLS-HDPE composites can be applied in the area of waveguide as a microwave waveguide terminations and dummy loads.

Electromagnetic Properties of Concrete and Their Significance in Nondestructive Testing

1997 ◽  
Vol 1574 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Oral Buyukozturk
Keyword(s):  
Dielectric Constant ◽  
Nondestructive Testing ◽  
Loss Factor ◽  
Electromagnetic Waves ◽  
Imaging Techniques ◽  
Electromagnetic Property ◽  
Microwave Frequency ◽  
Electromagnetic Properties ◽  
Frequency Variation ◽  
Hardened Concrete

Electromagnetic properties of hardened concrete specimens are measured over a microwave frequency range from 0.1 to 20 GHz. The experimentally obtained values provide information about the behavior of concrete and its interaction with electromagnetic waves. In addition to the frequency variation, the effect of different moisture contents on the electromagnetic properties is studied. Properties of mortar specimens and constituents of concrete, that is, coarse aggregates, sand, and cement, are also measured. An open-ended coaxial probe method is used for the measurement of real and imaginary parts of complex permittivity of concrete. The physical significance of the measured data in nondestructive testing, including penetration depth and detectability, is discussed. The results of electromagnetic property measurements indicate that the dielectric constant of dry concrete appears to be frequency independent over the range from 0.1 to 20 GHz, whereas the loss factor increases over that range. The moisture content of concrete significantly affects the dielectric constant and loss factor. The quantitative results obtained from this research will serve as a basis in applying wideband microwave imaging techniques for nondestructive testing of concrete using radar. The results can also be used for selecting the optimum combinations of radar measurement parameters for better detection.

scholarly journals The Analysis of Dielectric Constant, Loss Factor and Q-Factor of Selected Fruits at Microwave Frequency Range

2020 ◽  
pp. 57-66
Author(s):  
J. T. Ikyumbur ◽  
A. A. McAsule ◽  
N. S. Akiiga ◽  
Z. E. Andrawus ◽  
S. T. Kungur
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Dielectric Loss Factor ◽  
Q Factor ◽  
Frequency Range ◽  
Temperature Changes ◽  
Problem Solving Environment ◽  
Lower Frequencies

The dielectric constant, dielectric loss factor and Q-Factor of orange, red and green apples were studied at Microwave frequency range. An algorithm was written using the Debye equations and the interactive problem-solving environment of Maple-18 was used to generate results for the dielectric constant, loss factor and quality factor. The variation in the dielectric constant, loss factor and Q-factor as both frequency and temperature changes respectively within   and  range were shown graphically. The dielectric constant of all the fruits were higher at lower frequencies, it then decreases continuously as frequency increases. On the other hand, the loss factor of this fruits were small at lower frequencies but increased to its peak before decreasing continuously for all temperatures. Interestingly, the fruits’ Q-Factor were higher at lower frequencies and temperatures but decreases rapidly as the frequency increases. The contribution of the space charge, orientation, ionic and electronic polarizations to the dielectric constant, dielectric loss factor and Q-Factor of these fruits at lower frequency and higher frequency were discussed. The effect of the excess sugar and water content on the dielectric constant, loss factor and Q-Factor attributed to the appearance of vibrational peaks was also discussed. This work hereby provides a guidance in developing new microwave processes.

Study on the Dielectric Properties of Biomass Material of Tobacco Stems

2013 ◽  
Vol 634-638 ◽  
pp. 2570-2578 ◽  
Author(s):  
Wen Hua Zi ◽  
Xiao Long Zhang ◽  
Lan Wang ◽  
Jin Hui Peng ◽  
Lin Chen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Dielectric Loss Factor ◽  
Dipolar Relaxation ◽  
Genetic Characteristics ◽  
Position Location

An Agilent E4980A precision the LCR meter was used to estimate the effect of frequency, moisture content, position, location and variety on dielectric properties for biomass material of tobacco stems at microwave frequency of 2MHz. The dielectric properties of tobacco stems were significantly affected by frequency and moisture content. Both dielectric constant and dielectric loss factor rapidly declined first and then slowed with increasing frequency at lower moisture content. Increasing the moisture content, dielectric constant increased with the increasing frequency by orders of magnitude, while dielectric loss factor increased first and then decreased with dielectric relaxation emerging, where the dipolar relaxation frequency and the max of the dielectric loss factor also increased. Dielectric properties of the biomass material of tobacco stem were also affected by position, location and variety to some degree. The dielectric properties variation of K326 and Yun 87 was similar to each other which reflected their same genetic characteristics. At the frequency of 2MHz, dielectric constant and dielectric loss factor were mainly at 50-100 and 0.005-0.020, respectively.

scholarly journals Measurement and Analysis of Dielectric Properties of Agricultural By-product Powders in Microwave Frequency Range

2019 ◽  
Vol 78 ◽  
pp. 02012
Author(s):  
Runeng Zhong ◽  
Tai Xiang ◽  
Qinhong Zheng ◽  
Bo Xu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Powder Materials ◽  
Microwave Assisted ◽  
Measurement And Analysis ◽  
By Products

Dielectric properties play an important role in the microwave-assisted application of nonmagnetic agriculture-related media. In this paper, the practical requirements for the lack of quantitative data on the dielectric properties of agricultural media in microwave-assisted applications are obtained. The dielectric properties data of four kinds of agricultural by-products powder (Potato powder, Pseudo -ginseng Powder, Gastrodia elata powder, Dendrobium chrysotoxum Lindl powder) under microwave frequency were measured, and related factors were analyzed. The results show that the uncalibrated coaxial transmission reflection method can be used to measure and analyse the dielectric properties of high frequency bands of powder materials. Dielectric constant (ε ′) and Dielectric loss factor (ε '') of agricultural by-products at room temperature have a relationship between microwave frequency and moisture content. It is a dependent and the mathematical relation is satisfied. The influence of microwave frequency and moisture content on the dielectric properties is as follows: lows: ε′>ε′′>tanδ. Under the conditions of civil microwave frequency (2.45GHz) and moisture content (2% ~ 25%), the dielectric constant and the dielectric loss factor of different kinds of agricultural by-products powder are in the range of 3.5 ~ 9 and 0.1 ~ 3.2 respectively. The results provide data basis for microwave processing and quality monitoring of agricultural by-products powder. The technical method is suitable for the measurement and analysis of the dielectric properties of powder materials.

Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Bulk Density ◽  
Water Activity ◽  
Free Space ◽  
Loss Factor ◽  
Dielectric Loss Factor ◽  
List Type

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.

Phase Development and Dielectric Properties of 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3 Ceramic

2011 ◽  
Vol 700 ◽  
pp. 58-62
Author(s):  
Rachanusorn Roongtao ◽  
Supagorn Rugmai ◽  
Wanwilai C. Vittayakorn
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Factor ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Phase Development ◽  
Scanning Electron

The 0.98BaTiO3-0.02Ba (Mg1/3Nb2/3) O3ceramics has been synthesized through a conventional mixed-oxide by using BT nanopowder and BMN micropowder. The phase purity of the powders and the ceramics was examined using X-ray diffraction (XRD). The 0.98BT-0.02BMN powders were sintered to 92% of the theoretical density at a temperature of 1300 °C for 2 h. The microstructure of the sintered surface was investigated using scanning electron microscopy (SEM). The dielectric constant (εr) and loss factor (tanδ) of the sintered pellets at Curie temperture were 3000 and 0.015, respectively.

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