Direct and Inverse Computational Methods for Electromagnetic Scattering in Biological Diagnostics

Scattering theory has had a major roll in twentieth century mathematical physics. Mathematical modeling and algorithms of direct,- and inverse electromagnetic scattering formulation due to biological tissues are investigated. The algorithms are used for a model based illustration technique within the microwave range. A number of methods is given to solve the inverse electromagnetic scattering problem in which the nonlinear and ill-posed nature of the problem are acknowledged.Comment: 61 pages, 5 figure

Propagation environment modeling using scattered field chamber

This thesis covers the development of the Reverberation Chamber as a measurement tool for cell phone tests in electronic production. It also covers the development of the Scattered Field Chamber as a measurement tool for simulations of real propagation environments. The first part is a more ”general knowledge about Reverberation Chambers”-part that covers some important phenomena like unstirred power and position dependence that might occour in a small Reverberation Chamber used for cell phone tests. Knowing how to deal with these phenomenas, give the possibility to use the chamber as a measurement tool for production tests even though it is too complex for a simple test of the antenna function. The second part shows how to alter some important propagation parameters inside the chamber to fit some real world propagation environments. The 3D plane wave distribution, the polarization and the amplitude statistics of the plane waves are all altered with simple techniques that are implementable all together. A small, shielded anechoic box with apertures is used to control 3D plane wave distribution and polarization. Antennas that introduce unstirred power in the chamber are used to control the statistics

Microwave mammography for breast cancer detection

International audienc

Robot controlled data acquisition system for microwave imaging

International audienc

A study of different fabrics to increase radar cross section of humans.

This purpose of the study was to increase the visibility on radar for unprotected pedestrians with the aid of conducting fabric. The experiment comprised measurements of four types of fabric to determine the radio frequency properties, such as radar cross section (RCS) for the vehicle radar frequency 77 GHz and transmission (shielding) in the frequency range 3-18 GHz. Two different thicknesses of polypyrrole (PPy) nonvowen fabric were tested and one thickness for 30 % and 40 % stainless steel fabrics respectively. A jacket with the thinner nonvowen material and one with 40 % steel were tested and compared to an unmodified jacket in the RCS measurement. The measurement showed an increase in RCS of 4 dB for the jacket with the 40 % steel lining compared to the unmodified jacket. The transmission measurement was aimed at determining the fabric with the highest transmission of an incoming radio wave. The 30 % steel fabric and the two thicknesses of the nonvowen fabrics were tested. One practical application is for example the use of radar reflective material in search and rescue (SAR) clothes. The study showed that the 30 % steel fabric was the best candidate for further RCS measurements