Physical optics

About: Physical optics is a research topic. Over the lifetime, 5342 publications have been published within this topic receiving 101388 citations. The topic is also known as: wave optics.

Scattering of electromagnetic spherical wave by a perfectly conducting disk

Abstract: The scattering of electromagnetic spherical wave by a perfectly conducting circular disk is studied by using the method of Kobayashi Potential (abbreviated as KP method). The formulation of the problem yields the dual integral equations (DIE). The spherical wave is produced by an arbitrarily oriented dipole. The unknowns are the induced surface current (or magnetic fleld) and the tangential components of the electric fleld on the disk. The solution for the surface current is expanded in terms of a set of functions which satisfy one of a pair (equations for the magnetic fleld) of Maxwell equations and the required edge condition on the surface of the disk. At this stage we have used the vector Hankel transform. Applying the projection solves the rest of the pair of equations. Thus the problem reduces to the matrix equations for the expansion coe-cients. The matrix elements are given in terms of the inflnite integrals with a single variable and these may be transformed into inflnite series that are convenient for numerical computation. The far fleld patterns of the scattered wave are computed and compared with those computed based on the physical optics approximation. The agreement between them is fairly good.

Physical and geometrical optics for 2-D rough surfaces with power-law height spectra

Abstract: Random rough surfaces with slowly decaying power spectral density can have infinite slope variance. Such surfaces do not satisfy the classical curvature criterion for validity of the physical optics (PO) approximation, and the infinite frequency geometrical optics limit or specular point scattering model breaks down. We show for two-dimensional surfaces with infinite slope variance that the Gaussian form of the classical geometrical limit generalizes to a stable distribution function. We also show that the PO integral is insensitive to surface components with spatial frequency above a cutoff wavenumber, which explains past observations that PO can be accurate for surfaces with power law spectra. This result leads to a general validity condition for the PO approximation in the backscattering direction for power-law surfaces, which in the case of a k/sup -4/ spectrum requires that the significant slope of the surface be less than 0.03.

Modelling and Measuring Reflection Due to Flat Dielectric Surfaces at 5.8 GHz

Abstract: Indoor radio channel planning tools implement different models to simulate propagation mechanisms such as transmission or reflection. The specular reflection formulation is commonly used instead of more complete scattering models. This happens because its coding is less complicated and the software runs faster than when considering reflection in all directions, not yet specular. In this paper, results from measurements are presented, consisting of the effect of constructive walls on an oblique incident wave. These experimental outcomes are modelled by means reflection pattern computations. Physical optics scattering model is used in its classical formulation, and it is then modified to take into account antenna pattern effects in the measurements. The comparison between measurements and simulations is also presented, showing good agreement. Measurements show that low reflective walls produce reflections in several directions across the incidence region. In these situations, the use of algorithms that compute reflection pattern, instead of just specular reflection coefficients, will lead to better agreement with actual results

Differential geometrical methods in the study of optical transmission (scalar theory). I. Static transmission case

Abstract: Static optical transmission is restudied by postulation of the optical path as the proper element in a three-dimensional Riemannian manifold (no torsion); this postulation can be applied to describe the light–medium interactive system. On the basis of the postulation, the behaviors of light transmitting through the medium with refractive index n are investigated, the investigation covering the realms of both geometrical optics and wave optics. The wave equation of light in static transmission is studied modally, the postulation being employed to derive the exact form of the optical field equation in a medium (in which the light is viewed as a single-component field). Correspondingly, the relationships concerning the conservation of optical fluid and the dynamic properties are given, and some simple applications of the theories mentioned are presented.