Document Type
Thesis
Date of Award
5-31-1988
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
Edip Niver
Second Advisor
Gerald Martin Whitman
Abstract
Propagation of high frequency fields as a superposition of Gaussian beams instead of geometrical ray fields has potential advantages in complicated environments because the beams do not fail in ray optic transition regions. While the Gaussian beam method can be made rigorous through self consistent stacking of displaced and tilted beams on a Gabor phase space lattice, with retention of full beam spectra, computation is facilitated when the propagation domain is covered with paraxially approximated nontilted beams. The spectral deficiencies introduced by this simplified propagation model depend on the propagation environment. They are examined here for a plane wave coupling into a slit-perforated cylinder where multiple internal reflections, with focusing, generate a profusion of ray caustics that wouldd be difficult to keep track of, and to correct for, by uniformized geometrical ray tracing. Beam tracing, on the other hand, requires no knowledge of the caustic locations and produces continuous field data throughout. A systematic choice of the beam stack comprises nontilted narrow-waist beams which are spaced according to the Gabor prescripticn along the incident wavefront portion penetrating the cavity. These beams have been traced paraxially through multiple reflections, being either trapped inside or escaping through the aperture. The interior field has been synthesized along radial cuts which pass through prominent caustics, and has been compared to with a refernce solution generated by the method of moments [E.Arvas, to appear in AEU]. The beam solution reprocuces the general shape of the continuous field profile but does not adequately restore the amplitude. It is expected that a better field synthesis is attainable with by propagating the initial Gabor stack with full spectra.
Recommended Citation
Mourad, Christine Issa, "High frequency gaussian beams solution of a plane wave coupling into cylindrical cavity" (1988). Theses. 3152.
https://digitalcommons.njit.edu/theses/3152
