Electromagnetic power absorption due to bumps and trenches on flat surfaces

Abstract

This paper presents a study of the absorption of electromagnetic power that results from the interaction of electromagnetic waves and cylindrical bumps or trenches on flat conducting surfaces. Configurations are characterized by means of adequately selected dimensionless variables and parameters so that applicability to mathematically equivalent (but physically diverse) systems can be achieved easily. Electromagnetic fields and absorption increments caused by such surface defects are evaluated by means of a high-order integral equation method which resolves fine details of the field near the surface, and which was validated by fully analytical approaches in a range of computationally challenging cases. The computational method is also applied to problems concerning bumps and trenches on imperfect conducting planes for which analytical solutions are not available. Typically, we find that absorption is enhanced by the presence of the defects considered, although, interestingly, absorption can also be significantly reduced in some cases-such as, e.g., in the case of a trench on a conducting plane where the incident electric field is perpendicular to the plane. Additionally, it is observed that, for some small-skin-depths large-wavelengths, the absorption increment is proportional to the increase in surface area. Significant physical insight is obtained on the heating that results from various types of electromagnetic incident fields. V C 2014 AIP Publishing LLC. [http://dx

High-Performance Computational Electromagnetics in Frequency-Domain and Time-Domain

“…The contribution [17] is in fact much more general: in our method configurations are characterized by means of adequately selected structural elements so that physically diverse systems can be treated with minimal variations of a basic mathematical structure. Our studies of a variety of configurations [18] gave rise to interesting conclusions concerning the character of asperity-enhanced absorption. We found that typically absorption is enhanced by the presence of asperities, although, interestingly, absorption can also be significantly reduced in some cases-such as, e.g., in the case of a trench on a conducting plane where the incident electric field is perpendicular to the plane.…”

“…The contributions [17,18] concern electromagnetic scattering by asperities (bumps or cavities) on otherwise undisturbed planar regions. Relying on use of Sommerfeld integrals we thus developed integral solvers which enable accurate evaluation of energy absorption for asperities of arbitrary shape.…”

“…Meaningful progress concerning well conditioned integral algorithms took place as a result of work sponsored by this contract, including rigorous mathematical theory and powerful numerical algorithms with applicability in a number of fields of science and engineering [12][13][14][15][16][17][18][19][20][21]. A variety of problems and configurations were thus considered, including problems of scattering by open surfaces [12][13][14]; improved integral methods for closed surfaces [15]; problems concerning propagation and scattering by penetrable scatterers [16]; studies of absorption properties of conducting materials containing asperities [17,18]; as well as new methods for evaluation of Laplace eigenfunctions on general domains and under challenging boundary conditions [19,20].…”

“…A variety of problems and configurations were thus considered, including problems of scattering by open surfaces [12][13][14]; improved integral methods for closed surfaces [15]; problems concerning propagation and scattering by penetrable scatterers [16]; studies of absorption properties of conducting materials containing asperities [17,18]; as well as new methods for evaluation of Laplace eigenfunctions on general domains and under challenging boundary conditions [19,20]. A rigorous convergence proof for the original methods [22] was provided in [21].…”

Effects of temperature dependence of electrical and thermal conductivities on the Joule heating of a one dimensional conductor

“…Joule heating limits the operation of most current carrying components and devices, ranging from large high power systems to nanoscale wires and devices. The coupled thermal-electrical conduction problem is important for wirearray Z-pinches, 1 power transmission lines, 2 high power microwave devices, 3,4 and electrical contacts. [5][6][7][8][9] In a Zpinch, in particular, coupled thermal-electrical conduction is responsible for an electrothermal instability.…”