Analysis of three-dimensional field distributions for focussed unapodized/apodized annular beams

The study of focal shift in focused beams using unapodized apertures has been well documented. However, not much work has been done on apodized apertures. In this thesis we use a Fourier-Optic approach to analyze the field distribution of a focused beam around the region of geometrical focus. The analytical formulation developed is general in nature as it is valid for any arbitrary aperture functions. This is then applied to some specific cases. Two cases of interest that are considered are the unapodized and the Gaussian apodized annular apertures. In order to study the intensity distributions around the geometrical focus, simulation results are presented using closed form analytical expressions and approximate integral forms. Specific emphasis is placed on the focal shift in the two apertures and on the effect of changing various parameters. A prognosis for future work using a-Modulation on Gaussian apodized annular apertures is also presented.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Electrical Engineering

Department dc:contributor.department

Electrical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1990

Author dc:creator

• Bhabu, Shaleen J.

Chair dc:contributor.committeechair

• Poon, Ting-Chung

Committee members dc:contributor.committeemember

• Besieris, Ioannis M.
• Claus, Richard O.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-02132009-171334

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/41042