Accession Number : AD0702139

Title :   THE DIFFRACTION OF ELECTROMAGNETIC WAVES BY DIELECTRIC STEPS IN WAVEGUIDES,

Corporate Author : ILLINOIS UNIV URBANA ANTENNA LAB

Personal Author(s) : Royer,Erlind G. ; Mittra,Raj

Report Date : JAN 1970

Pagination or Media Count : 85

Abstract : The problem of determining the scattered electromagnetic fields when a dielectric step discontinuity is placed in a waveguide is considered here. The case of a dielectric step which is semi-infinite in extent is presented first. Althouth an exact method of solution is not known at this time, it is shown that the recently introduced modified residue calculus technique can be successfully extended to obtain a very accurate approximate solution of the semi-infinite dielectric step. A unique advantage of this method of solution is that the degree of accuracy obtained is independent of the relative permittivity of the dielectric material and of the frequency. Thus, very high permittivities of frequencies can be considered without an attendant increase in computational complexity. Numerical data are presented which confirm the accuracy of the solutions obtained. The accurate determination of the total field is easily accomplished using the method of this study and is demonstrated. A further extension of the modified residue calculus method yields the approximate solution for the case of a finite dielectric step. This extension also enjoys the advantages mentioned above. The phase shifting abilities of the finite step are demonstrated by calculations which show the effects of varying the step height and the step length. (Author)

Descriptors :   (*WAVEGUIDES, DIELECTRICS), DIFFRACTION, ELECTROMAGNETIC RADIATION, NUMERICAL ANALYSIS, PERTURBATION THEORY

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE