A. Leggieri, F. Di Paolo, D. Passi
Univeristy of Rome "Tor Vergata" - Department of Electronic Engineering, Rome, Italy
This paper describes the design and characterization of an 8 slots resonant cavity Magnetron, which undergoes thermal-structural effects due to cathode heating. The proposed study involves Thermal Stress, Eigen-frequency and Particle Tracing analysis based on COMSOL Multiphysics®. Magnetrons are well known and often utilized High Power Radiofrequency Vacuum Tube oscillators. In order to ...
COMSOL Multiphysics® Investigation of Radiative and Nonradiative Channels of Quantum Emitter Fluorescence near Hyperbolic Metamaterial
A. Pavlov, V. Klimov, I. Zabkov, D. Guzatov
Lebedev Physical Institute, Moscow, Russia
Moscow Institute of Physics and Technology, Dolgoprudnj, Russia
State University of Grodno, Grodno, Belarus
Effective control over single atom emission might lead to major breakthrough in the field of nanotechnology. It is believed that use of hyperbolic metamaterials (HMM) can be helpful. COMSOL Multiphysics® was used to model interaction of electric dipole with effective HMM and calculate emission rate of dipole in comparison to that value in the absence of metamaterial. Dielectric nanoantennas of ...
J. Zhang, Z. Wang, J. Chen
College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, Hunan, China
COMSOL Multiphysics® software was used to simulate and analyze the transmission attenuation spectra of the negative curvature hollow-core fiber (NCHCF) over the wavelength from 2.7 μm to 4.2 μm. The effect of thickness of capillaries and the effect of the distance between the capillaries on confinement loss spectra were studied, which agreed well with the high-loss and low-loss bands predicted ...
A. Haidary, P. Grütter, Y. Miyahara
Physics Department, McGill University, Montreal, QC, Canada
A wide variety of near-field optical phenomena such as apertureless near-field scanning microscopy (ANSM) at optical and terahertz (THz) regimes and surface enhanced Raman scattering relies on the electric field enhancement at the end of a sharp tip. Achieving and controlling this electric field enhancement is a key challenge for a wide range of applications such as surface modification, data ...
A. Leggieri, D. Passi, F. di Paolo
Dipartimento di Ingegneria Elettronica, Università degli Studi di Roma Tor Vergata, Rome, Italy
This paper describes the Virtual Prototype of a Dielectric Window or High Power Microwave Vacuum Tubes and Linear Accelerators. Design formulas are provided and Computer Aided Design techniques based on COMSOL Multiphysics® software are proposed. The virtual prototype considers the Thermo-mechanical effects due to the joule effect induced by the power which crosses the DW and the Thermal contact ...
T. Santos, L.C. Costa[1,2], M. Valente[1,2], J. Monteiro[1,2], and J. Sousa
University of Aveiro, Portugal
I3N, Aveiro, Portugal
TEKA Portugal S.A., Ílhavo, Portugal
In microwave heating applications, the energy is introduced directly into the volume of the material and as consequence the quality of the process is highly dependent on the uniformity of the electromagnetic field distribution along it. That is, the non uniformity of the heating is a potential problem with serious consequences. Thermal runaway is the most critical, in materials with temperature ...
S. C. Hegde
VIT University, Vellore, Tamil Nadu, India
The coaxial cable is one of the most commonly used bandwidth limited signal transmission line.Dispersion is a signal distortion phenomenon which arises due to frequency dependence of phase velocity of signal components. This phenomenon was explained through time domain approach by studying time taken by signals of various frequencies to propagate through the cable, which eventually may cause ...
R. W. Pryor ,
 Pryor Knowledge Systems, Inc., Bloomfield Hills, MI, USA
Dielectric heating is an important, widely employed electromagnetic heating technology utilized by consumers, small businesses and industry. This model is used to explore the physical differences manifested when different frequencies are utilized to execute the heat generation process on similar materials in similar geometries. This model is of interest to people with applications in RF or ...
M. Trujillo, E. Berjano
Universidad Politécnica de Valencia, Valencia, Spain
Radiofrequency ablation is a minimally invasive techinique which is used to treat some kinds of cancer. The realism of theoretical models is very important. An influential factor in this realism is mathematical functions that model the temperature-dependence of tissue thermal and electrical conductivities. The aim of this work is to review the mathematical functions employed to model the ...
M. Siler, O. Brzobohaty, V. Karasek, P. Zemanek
Inst. Scientific Instruments of the ASCR, Brno, Czech Republic
Metallic nanoparticles (NPs) are nowadays used in various areas of biology, chemistry or physics. Focused laser beams, optical tweezers, may be used to manipulate such NPs. However, experimental studies showed that there is a discrepancy between their predicted and observed behavior. Models assuming the spherical shape of a nanoparticle predict spatial confinement only for particles smaller than ...