We study the effect of coherency saturation in spatially or temporally periodical structures with randomization, applicable to a very broad class of systems. We derive a simple analytical formula in the case of uncorrelated deviations of periods with Gaussian probability distribution. Using Monte Carlo simulations, we also demonstrate that many other distributions show statistical properties th...

A uthor...................... ................................................................ Department of Electric$ Engineering and Computer Science January 25, 2006 Certified by....... .............................. Jin A. Kong Professor of Electrical Engineering Thesis Supervisor C ertified by.. ............................................ Bae-Ian Wu Research Scientist Thesis Supervisor Ac...

The objective of this paper is to design impedance surfaces for the solution of the problem of electromagnetic compatibility of antennas. In a recent paper, corresponding surfaces were used to reduce coupling between antennas located on a plane. These surfaces were made artificially, e.g., by loading a conducting surface with corrugations. The design of the impedance structure is done for a giv...

In this thesis a previously developed framework for modelling diversity of approximately periodic time series is considered. In this framework the diversity is modelled deterministically, exploiting the irregularity of chaos. This is an alternative to other well established frameworks which use probability distributions and other stochastic tools to describe diversity. The diversity which is to...

We predict the existence of evanescent modes with unlocked phases in two-dimensional (2D) dielectric periodic structures. Contrary to what is known for one-dimensional structures, where evanescent fields lock to the host modulation, we show that in 2D systems a new class of evanescent modes exists with an unlocked real part of the wave vector. Hence, beams constructed from such unlocked evanesc...

The behavior of longitudinal wakefields of very short bunches, excited in in multicell accelerating structures has been studied. Computations were performed in structures proposed for future linear colliders (like TESLA, SBLC and NLC) for bunch lengths down to 50 micrometers. The loss factor, which gives the global energy loss of the bunch, and the profile of the wake function, which is of majo...

We examine the influence of roofs’ shapes on the boundary layer of a simplified urban canopy by computing non-stationary Navier-Stokes flow over a periodic pattern. The solution is obtained by means of finite element method (FEM). We use non-conforming Crouzeix-Raviart elements for velocity and piecewise constant elements for pressure. The resulting linear system is solved by the multigrid meth...

Periodic patterns are observed when supported lipid monolayers doped with low concentrations of fluorescent lipid probes are observed with epi-fluorescence microscopy. Monolayers of dipalmitoyl phosphatidylcholine were examined on air-water interfaces and also on alkylated glass coverslips. The patterns are formed by periodic arrays of solid-phase lipid domains in equilibrium with fluid-phase l...

Spatial transforms are a popular technique for designing periodic structures that are macroscopically inhomogeneous. The structures are often required to be anisotropic, provide a magnetic response, and to have extreme values for the constitutive parameters in Maxwell's equations. Metamaterials and photonic crystals are capable of providing these, although sometimes only approximately. The prob...

Theory of thermal emission from periodic structures. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We provide a momentum space formulation for thermal emission f...