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Off Bragg blazing for TM polarization with rectangular gratings Chen, Wei

Abstract

Perfect blazing to the m=-l spectral order was once assumed to be possible for only Bragg angle incidence, i.e. for an angled = sin- 1 (^) from the normal to the grating surface, where d/A is the grating period in wavelengths. The diffracted beam is then back in the direction of incidence, an inconvenience in most applications such as multiplexers, de-multiplexers and frequency scanned antennas. Off Bragg blazing is preferable and now can be done with high efficiency. Here off Bragg blazing for T M polarized incidence on rectangular groove gratings is investigated numerically and design curves are presented. It is a consequence of reciprocity that off Bragg blaze angles must occur in pairs #1 and 62 and these are related by a generalization of the Bragg equation sin 9\ + sin 92 — 2 • F°r groove width to period ratios a/d=0.5 perfect off Bragg blazing occurs most frequently for periods 0.9<d/A<1.0 and groove depth 0.1<h/A<0.24. It is for periods d/A in this range that the larger deviations 6\ — 82 are possible. Off Bragg blazing is found to occur for 0.4<a/d<0.9999, but the larger deviations and hence the more potentially useful designs appear to occur foxa/d K, 0.5. The numerical results correlate well with earlier numerical and experimental data. E.V.

Item Metadata

Title
Off Bragg blazing for TM polarization with rectangular gratings
Creator
Chen, Wei
Publisher
University of British Columbia
Date Issued
1994
Description
Perfect blazing to the m=-l spectral order was once assumed to be possible for only Bragg angle incidence, i.e. for an angled = sin- 1 (^) from the normal to the grating surface, where d/A is the grating period in wavelengths. The diffracted beam is then back in the direction of incidence, an inconvenience in most applications such as multiplexers, de-multiplexers and frequency scanned antennas. Off Bragg blazing is preferable and now can be done with high efficiency. Here off Bragg blazing for T M polarized incidence on rectangular groove gratings is investigated numerically and design curves are presented. It is a consequence of reciprocity that off Bragg blaze angles must occur in pairs #1 and 62 and these are related by a generalization of the Bragg equation sin 9\ + sin 92 — 2 • F°r groove width to period ratios a/d=0.5 perfect off Bragg blazing occurs most frequently for periods 0.9<d/A<1.0 and groove depth 0.1<h/A<0.24. It is for periods d/A in this range that the larger deviations 6\ — 82 are possible. Off Bragg blazing is found to occur for 0.4<a/d<0.9999, but the larger deviations and hence the more potentially useful designs appear to occur foxa/d K, 0.5. The numerical results correlate well with earlier numerical and experimental data. E.V.
Extent
2550285 bytes
Genre
Thesis/Dissertation
Type
Text
File Format
application/pdf
Language
eng
Date Available
2009-01-09
Provider
Vancouver : University of British Columbia Library
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
DOI
10.14288/1.0065137
URI
http://hdl.handle.net/2429/3414
Degree
Master of Applied Science - MASc
Program
Electrical and Computer Engineering
Affiliation
Applied Science, Faculty of; Electrical and Computer Engineering, Department of
Degree Grantor
University of British Columbia
Graduation Date
1995-05
Campus
UBCV
Scholarly Level
Graduate
Aggregated Source Repository
DSpace

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Rights

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.