Multiple Electromagnetic Scattering by Randomly Distributed and
Oriented Obstacles
Abstract
Scattering of electromagnetic waves by discrete, randomly distributed objects is addressed. In
general, the non-intersecting scattering objects can be of arbitrary form, material and shape. The
main aim of the talk is to calculate the coherent reflection and transmission characteristics of a
finite or semi-infinite slab containing discrete, randomly distributed scatterers. Typical
applications of the results are found at a wide range of frequencies (radar up to optics), such as
attenuation of electromagnetic propagation in rain, fog, and clouds etc. The integral
representation of the solution of the deterministic problem constitutes the underlying framework of
the stochastic problem. Conditional averaging and the employment of the Quasi Crystalline
Approximation lead to a system of integral equations in the unknown expansion coefficients. Of
special interest is the slab geometry, which implies a system of integral equations in the depth
variable. Explicit solutions for tenuous media and low frequency approximations can be obtained for
spherical obstacles. Some numerical simulations that relate to the homogenization problem are also
presented.
Brief biography for Prof. Gerhard Kristensson
Gerhard Kristensson received his B.S. degree in mathematics and physics in 1973, and the Ph.D.
degree in theoretical physics in 1979, both from the University of Göteborg, Sweden. In 1983, he
was appointed Docent in theoretical physics at the University of Göteborg.
During 1977-1984 he held a research position sponsored by the National Swedish Board for Technical
Development (STU) and he was Lecturer at the Institute of Theoretical Physics, Göteborg from 1980-
1984. In 1984-1986, he was a Visiting Scientist at the Applied Mathematical Sciences group, Ames
Laboratory, Iowa State University. He held a Docent position at the Department of Electromagnetic Theory, Royal Institute of Technology, Stockholm during 1986-1989, and in 1989, he was appointed
the Chair of Electromagnetic Theory at Lund Institute of Technology, Sweden. He retired from his
chair December 31, 2014, and he is now Professor Emeritus at Lund University.
In 1992, 1997 and 2007 he was a Visiting Erskine Fellow at the Department of Mathematics,
University of Canterbury, Christchurch, New Zealand. In fall 2015, he was a visiting scientist at
the Department of Mathematics, Colorado State University, CO, USA.
Gerhard Kristensson has served as a member of the Board of Editors of Wave Motion, the Editorial
Board and the International Advisory Panel of Inverse Problems, and the Review Board of Journal of
Electromagnetic Waves and Applications and Progress in Electromagnetic Research.
He is a Fellow of the Institute of Physics, and during 1991-2014, he served as a board member of
the Swedish National committee of Radio Science (SNRV). From 1994-2005, he was the chairman of
Commission B of SNRV and Official Member of URSI, Commission B for Sweden. He was the chairman of
SNRV during 2006-2014, and at the same time, he was the official representative for Sweden in the
International Union of Radio Science (URSI).
Kristensson has a general interest in electromagnetic scattering problems (incl. inverse scattering
problems) and wave propagation in inhomogeneous media. The propagation of transient electromagnetic
waves in complex media, such as dispersive anisotropic and bi-isotropic media, are stressed. High
frequency scattering methods, asymptotic expansions, optical fibers, antenna problems, and mixture
formulas are also of interest, as well as radome design problems and homogenization of complex
materials.
He has written five books and he is the author of over hundred journal and conference publications.