Numerical Simulation and Experimental Validation of RF Drying

1996 ◽  
Vol 430 ◽  
Author(s):  
S. Bringhurst ◽  
M. J White ◽  
M. F. Iskander
Keyword(s):  
Microwave Sintering ◽  
Fdtd Method ◽  
Fdtd Simulation ◽  
Ceramic Ware ◽  
Rf Heating ◽  
Simulation Results ◽  
Effective Use ◽  
Difference Time ◽  
Experimental Effort ◽  
Fiber Optic Temperature

AbstractThe Finite-Difference Time-Domain (FDTD) method has been used by our group to simulate a wide variety of Radio Frequency (RF) and induction-drying processes and realistic, microwave-sintering experiments. Many results were presented and some guidelines towards the effective use of the microwave and RF heating technologies of ceramic ware were developed.In this paper we describe an experimental effort which was used to validate the FDTD simulation results. Specifically an experimental RF dryer, Thermax Model No. T3GB operating at 25 MHz, was used to dry ceramic ware of various materials, sizes, and shapes and the temperature distribution pattern was monitored using six fiber-optic temperature probes. The measured heating patterns were then compared with the FDTD simulation results. Many of the guidelines developed using the numerical simulations were confirmed experimentally.Results from various comparisons between simulation and experimental data will be presented. Additional results from the simulation efforts illustrating possible procedures for improving the efficiency and the uniformity of RF drying will also be described

Effect of Metal Intercalating on Transmission Characteristics of One-Dimensional Photonic Crystal

2011 ◽  
Vol 418-420 ◽  
pp. 679-683
Author(s):  
Bei Jia He ◽  
Xin Yi Chen ◽  
Jian Bo Wang ◽  
Jun Lu ◽  
Jian Chang ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Plasma Frequency ◽  
Fdtd Method ◽  
Transmission Characteristics ◽  
Material Characteristic ◽  
One Dimensional ◽  
Dimensional Photonic Crystal ◽  
Simulation Results ◽  
The One ◽  
Difference Time

To expand the bandgap's width of the one-dimensional photonic crystal, a crystal named SiO2/Metal/MgF2 is formed by joining some metals into the crystal SiO2/MgF2. Furthermore the Finite Difference Time Domain (FDTD) method is used to explore the metals' influence on the crystal's transmission characteristics. The simulation results show that the metals joined could expand the width of the one-dimensional photonic crystal's bandgap effectively and the bandgap's width increases when the metals' thickness increases. Meanwhile the bandgap's characteristic is affected by the metals' material-characteristic. The higher the plasma frequency is, the wider the bandgap's width will be and the more the number of the bandgaps will be. On the other hand, the metals' damping frequency has no significant effect on the bandgap, but would make the bandgap-edge's transmittance decrease slightly.

Finite-Difference Time-Domain (FDTD) Simulation of Microwave Sintering in Multimode Cavities

1992 ◽  
Vol 269 ◽  
Author(s):  
Ray L. Smith ◽  
Magdy F. Iskander ◽  
Octavio Andrade ◽  
Hal Kimrey
Keyword(s):  
Microwave Sintering ◽  
Fdtd Simulation ◽  
Critical Parameters ◽  
Sintering Process ◽  
Microwave Cavities ◽  
Microwave Effect ◽  
Picket Fence ◽  
Realistic Representation ◽  
Difference Time

ABSTRACTMicrowave sintering of ceramics in multimode cavities, particularly the use of picket-fence arrangements, has recently received considerable attention. Various types of ceramics have been successfully sintered and, in some cases, a desirable and unique “microwave effect” has been observed.At present, various aspects of the sintering process such as sample sizes and shapes, types of insulations, and the desirability of including a process stimulus such as SiC rods are considered forms of art and highly dependent on human expertise. The simulation of realistic sintering experiments in a multimode cavity may provide a better understanding of critical parameters involved and allow for the development of guidelines towards the optimization of the sintering process.In this paper, we utilize the FDTD technique to model various geometrical arrangements and material compatibility aspects in multimode microwave cavities and to simulate realistic sintering experiments. The FDTD procedure starts with the simulation of a field distribution in multimode microwave cavities that resembles a set of measured data using liquid crystal sheets. Also included in the simulation is the waveguide feed as well as a dielectric loading plate placed at the base of the cavity. The FDTD simulation thus provides realistic representation of a typical sintering experiment. Aspects that have been successfully simulated include types of insulation, role of SiC rods on the uniformity of the resulting fields, problems that may result from presence of thermocouples, and the possible shielding effects that may result from excessive use of SiC. These results as well as others showing the electromagnetic fields and power-deposition patterns in multiple ceramic samples are presented.

FDTD Simulation of Induction Heating of Conducting Ceramic Ware

1996 ◽  
Vol 430 ◽  
Author(s):  
Mikel J White ◽  
Magdy F. Iskander ◽  
Shane Bringhurst
Keyword(s):  
Electric Field ◽  
Induction Heating ◽  
Energy Savings ◽  
Fdtd Simulation ◽  
Ceramic Ware ◽  
Heating Process ◽  
Axial Electric Field ◽  
Multiple Sample ◽  
Radiation Processes ◽  
Difference Time

AbstractInduction heating for the treatment of metals has been in commercial use since the mid 1960's. Traditional advantages of induction heating over the convection or radiation processes include speed of heating, possible energy savings, and the ability to customize the coil design to optimize the heating process. In this paper we used the Finite-Difference Time-Domain (FDTD) technique to simulate and analyze the induction heating process for highly conducting ceramics. In order to analyze frequency effects, simulations were performed at 300 kHz, 2 MHz, and 25 MHz. It is found that at higher frequencies coils with a pitch of 2″ or greater became capacitive and generate a large, axial, electric-field component. This new axial electric field, in addition to the normally encountered azimuthal field, causes an improvement in the uniformity of the power deposition in the ceramic sample. If the sample occupies a large portion of the coil, uniformity may also be improved by using a variable-pitch coil, or by extending the length of the coil a few turns beyond the length of the sample. In a production-line arrangement, where multiple sample are place inside the coil, it is shown that maximum uniformity is achieved when the samples are placed coaxially.

Simulation and Experimental Research on Crosstalk of Multiconductor Cable’s Core Lines

2011 ◽  
Vol 135-136 ◽  
pp. 901-906
Author(s):  
Chuan Chuan Wang ◽  
Chang Qing Zhu ◽  
Zhi Feng Gu
Keyword(s):  
High Voltage ◽  
Fdtd Method ◽  
Distributed Parameters ◽  
Metal Shield ◽  
Grounding Line ◽  
Voltage Signal ◽  
Core Line ◽  
Simulation Results ◽  
Difference Time ◽  
Very High

In order to research the crosstalk of multiconductor cable’s different core lines, based on finite-difference time-domain (FDTD) method, the Crosstalk of the four core lines cable without metal shield layer is researched by simulation. Results show that because of the cable’s distributed parameters, the far end voltage of disturbing core line is smaller than near end voltage, the voltage of disturbed core lines is smaller than that of disturbing core line evidently. But when cable is working in thunder and rain, the grounding line of the cable may induce very high voltage, and the high voltage may disturb the core lines of cable that used to transfer useful signals, so the crosstalk can’t be neglected. Experiment is done with four core lines cable without metal shield layer that lay on the earth. Experimental and simulation results are nearly same, which are compared. Because of the influence of experimental loss waste, wire connection and so on, voltage got by experiment is smaller than that got by simulation. Results show that FDTD method is effective in analyzing the influence of the lightning voltage signal.

scholarly journals Reverse Design of On-Chip Terahertz Demultiplexers

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1093
Author(s):  
Guofeng Zhu ◽  
Feng Huang ◽  
Zhenrong Dai ◽  
Xuewei Ju ◽  
Shuncong Zhong ◽  
...  
Keyword(s):  
Finite Difference Time Domain ◽  
Design Method ◽  
Research Field ◽  
Fdtd Simulation ◽  
Terahertz Waves ◽  
Bandwidth Optimization ◽  
Simulation Results ◽  
On Chip ◽  
Adjacent Channels ◽  
Difference Time

The reverse design method (RDM) is a frontier direction in the optical research field. In this work, RDM is applied to the design of terahertz demultiplexers, including two-port and three-port terahertz demultiplexers, with areas of 3 mm × 3 mm and 5 mm × 5 mm, respectively. The Finite-Difference Time-Domain (FDTD) simulation results show that the terahertz waves at frequencies of 0.5 THz and 0.417 THz can be well separated by the two-port demultiplexer, and the transmittances of the two outputs reach as high as 0.75 after bandwidth optimization. Meanwhile, the three-port terahertz demultiplexer can have terahertz waves separated from three Ports, and the crosstalk between adjacent channels is less than −18 dB.

FDTD Modelling of Triangular Gold Nanoparticle Pairs

2014 ◽  
Vol 703 ◽  
pp. 220-223
Author(s):  
Yang Fan
Keyword(s):  
Electric Field ◽  
Gold Nanoparticle ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Fdtd Method ◽  
Field Enhancement ◽  
Electric Field Enhancement ◽  
Plasmon Resonances ◽  
Simulation Results ◽  
Difference Time

The optical properties of triangular gold nanoparticle pairs are investigated by numerical simulations using Finite-difference time-domain (FDTD) method. The simulation results show the significant red shifts of plasmon resonances as the size of nanoparticle is increased. The large electric field enhancement is also verified by calculating the local electric field distributions.

scholarly journals Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

2018 ◽  
Vol 9 ◽  
pp. 2599-2608 ◽  
Author(s):  
Anna Gapska ◽  
Marcin Łapiński ◽  
Paweł Syty ◽  
Wojciech Sadowski ◽  
Józef Eugeniusz Sienkiewicz ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Fdtd Method ◽  
Space Distribution ◽  
Fdtd Simulation ◽  
Initial Thickness ◽  
Structural Investigations ◽  
Au Film ◽  
Annealing Conditions ◽  
Difference Time ◽  
Good Agreement

Plasmonic platforms based on Au nanostructures have been successfully synthesized by directional solidification of a eutectic from Au and the substrate. In order to determine homogeneous shape and space distribution, the influence of annealing conditions and the initial thickness of the Au film on the nanostructures was analyzed. For the surface morphology studies, SEM and AFM measurements were performed. The structure of platforms was investigated using XRD and XPS methods. Structural investigations confirmed, that nanostructures consist of metallic Au, growing along the [111] direction. The most homogeneous seems to be the platform obtained by solidification of a 2.8 nm Au film, annealed at 550 °C for 15 min. This sample was subsequently chosen for theoretical calculations. Simulations of electromagnetic field propagation through the produced samples were performed using the finite-difference time domain (FDTD) method. The calculated absorbance, as a result of the FDTD simulation shows a quite good agreement with experimental data obtained in the UV–vis range.

scholarly journals Metal-semiconductor-metal (MSM) photodetectors with plasmonic nanogratings*

2011 ◽  
Vol 83 (11) ◽  
pp. 2107-2113 ◽  
Author(s):  
Narottam Das ◽  
Ayman Karar ◽  
Chee Leong Tan ◽  
Mikhail Vasiliev ◽  
Kamal Alameh ◽  
...  
Keyword(s):  
Light Absorption ◽  
Enhancement Factor ◽  
Signal Propagation ◽  
Optical Signal ◽  
Fdtd Simulation ◽  
Absorption Enhancement ◽  
Metal Semiconductor Metal ◽  
Simulation Results ◽  
Msm Photodetectors ◽  
Difference Time

We discuss the light absorption enhancement factor dependence on the design of nanogratings inscribed into metal-semiconductor-metal photodetector (MSM-PD) structures. These devices are optimized geometrically, leading to light absorption improvement through plasmon-assisted effects. Finite-difference time-domain (FDTD) simulation results show ~50 times light absorption enhancement for 850 nm light due to improved optical signal propagation through the nanogratings. Also, we show that the light absorption enhancement is strongly dependent on the nanograting shapes in MSM-PDs.

Non-quasi-static Effects Simulation of Microwave Circuits based on Physical Model of Semiconductor Devices

2020 ◽  
Vol 35 (9) ◽  
pp. 992-998
Author(s):  
Ke Xu ◽  
Xing Chen ◽  
Qiang Chen
Keyword(s):  
Physical Model ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Circuit Simulation ◽  
Semiconductor Devices ◽  
Simulation Method ◽  
Fdtd Simulation ◽  
Lumped Element ◽  
Simulation Results ◽  
Difference Time

This work explores analyzing the non-quasistatic effects of a microwave circuit by employing a physical model-based field-circuit co-simulation method. Specifically, it uses the semiconductor physical model to characterize the semiconductor devices, and simulates the lumped circuit by cooperating semiconductor physical equations into Kirchhoff’s circuit equations. Then the lumped circuit simulation is hybridized with the finite-difference time-domain (FDTD) simulation by interfacing EM (electromagnetic) field quantities with lumped-element quantities at each timestep. Taken a microwave limiter circuit as an example, the simulation results agree well with the measured results, which prove that this method can characterize non-quasi-static effects well. As a comparison, the equivalent circuit modelbased co-simulation cannot characterize the non-quasistatic effects accurately.

Effect of Rectangular Microstrip Antenna with Cross Metal Patches Based on Near-Zero-Index

2014 ◽  
Vol 602-605 ◽  
pp. 2811-2815
Author(s):  
Yan Rong Zhang ◽  
Ji Jun Wang ◽  
Zhi Pan Zhu ◽  
Lei Lei Gong
Keyword(s):  
Finite Difference Time Domain ◽  
Microstrip Antenna ◽  
Fdtd Method ◽  
Index Of Refraction ◽  
Antenna Effect ◽  
Left Handed ◽  
Simulation Results ◽  
Rectangular Microstrip Antenna ◽  
Difference Time ◽  
Zero Index

In this paper, cross metal patches are inserted inside the conventional rectangular microstrip antenna, and thus it can work at two frequencies. The finite difference time domain (FDTD) method is selected to study effect of this left-handed metamaterial with near-zero-index of refraction. Compared with conventional rectangular microstrip antenna, effect of near-zero-index from positive and negative on conventional rectangular microstrip antenna are studied. Simulation results show this antenna works at two frequencies. Compared with conventional microstrip antenna, near-zero-index can improve antenna’s gain obviously.

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