EM programmer's notebook: Foreword by the Editors

[No abstract available]Editoria

EM programmer's notebook: Foreword by the Editors

[No abstract available]Editoria

IEEE Antennas and Propagation Magazine: Foreword by the editors

[No abstract available]Editoria

Foreword by the editors

[No abstract available]Editoria

Forewod by the editors

[No abstract available]Editoria

On the Properties of Materials for Designing Filters at Optical Frequencies

Frequency Selective Surfaces/Volumes (FSS/Vs), periodic structures with frequency selective properties, have widely been used for millimeter and microwave applications. Some applications include filters (band pass, band stop), reflectors, radoms etc. FSS/Vs typically consist of a single or multiple material layers. Multiple layers (with each layer having a different frequency selectivity) are used for broadband applications. In recent years there has been an interest in using these structures at optical wavelengths. One of the applications is in thermophotovoltaic filters used to convert thermal energy into electricity. The filter is designed to transmit those wavelengths that can be efficiently converted into electricity, and to reflect other spectra, which leads to energy conservation and an increase in overall system efficiency. These filters can be used in space missions to help decrease energy consumption and reduce spacecraft mass, cost, and fuel loading. Numerical simulations of such filters are very limited in the literature. Existing modeling approaches are based on the assumption of purely metallic (perfectly conducting) structures on substrates. however, in practice, metals have finite conductivity that can lead to power absorption in the metal. At optical frequencies the usual material properties and perfect electric conductor (PEC) assumption is not applicable. Moreover, the conventional methods, such as using resistive sheets or lossy dielectrics to simulate metallic losses, are not accurate. The goal is to provide a new approach for modeling metallic losses more accurately at the optical frequencies

Hybrid finite element-fast spectral domain multilayer boundary integral modeling of doubly periodic structures

Hybrid finite element (FE)-boundary integral (BI) analysis of infinite periodic arrays is extended to include planar multilayered Green's functions. In this manner, a portion of the volumetric dielectric region is modeled via the FE method whereas uniform multilayered regions are characterized using a multilayered Green's function. As such, thick uniform substrates can be modeled without loss of efficiency and accuracy. The multilayered Green's function is analytically computed in the spectral domain and the resulting BI matrix-vector products are evaluated via the fast spectral domain algorithm (FSDA) without explicit generation of the BI-matrix. Furthermore, the number of Floquet modes in the BI expansion is kept very few by appropriately placing the BI surfaces within the computational unit cell. As a result, the computational cost of the method is very little and the model can easily be adapted to various requirements. Examples of frequency selective surface (FSS) arrays are analyzed with this method to demonstrate the accuracy and capability of the approach