Studies on Some Electromagnetic Field Problems in Static and Low Radio Frequency Range

In this thesis the following problems are studied and solutions developed.;1.2) Dependence of fields on surface current, antenna souce, electromagnetic parameters of lossy media are also attempted. For these purposes the related problems mentioned below are also studied and solutions are developed. The surface current concepts that are used in physical optics and for calculation RCS (Radar cross section) in HF (high frequency) and VHF (very high frequency) ranges are also examined and conclusions drawn.;i) Suitablity of existing methods for determination of surface current based on surface impedance, Leontovitch boundary condition and other classical boundary conditions are studied by correclating the energy conservation parameters. Here the energy conservation parameter means energy losses due to surface conduction, hysteresis loss, eddy current loss and energy loss due to dipole and multipole radiations.;ii) Dependance of antenna fields due to a loop type of antenna on the physical dimensions and the electromagnetic parameters in lossy media are investigated and examined. The lossy media due it's high conductivity values seriously affect the fields and the attenuation of fields is examined. For this purpose scalar Green's function methods are used and results are compared with other types of solution for special cases.;1.1) State of the art technology review on low frequency electromagnetic scattering phenomena is done and problems involved with existing modeling concepts for low frequency near field calculations are discussed. An algorithmic method is developed for the above purpose and the distance as well as frequency variation of fields are examined. Comparisons are drawn using scalar and dyadic Green's function methods and numerical computation techniques using a desk top PC.;iii) A method for theoretical determination of magnetic permeability of ferromagnetic alloys and construction steel is developed to study the dependance of surface current on it.;iv) An experimental method for determination of dielectric constant of a metallic substance is developed to study the dependance of surface current on it.;Finally the possibility of development of mathematical solution using the techniques of boundary value problems and data generated by the methods developed are also discussed for low frequency near field calculations. Main computational softwares with the relevant problems.