{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/20049"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/20049","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Efficient high-frequency techniques for scattering by realistic targets","abstract":"A significant problem in electromagnetics is the computation of the scattered far fields for large, complex targets, such as tanks or aircraft. Since it is often necessary to determine the scattering at multiple angles and frequencies, speed of calculation can be critical as well. This work has direct applications in areas such as RCS reduction and target identification, with the latter being the main thrust of this thesis. In order to do these computations, high-frequency approximate techniques must be used.","abstract_html":"A significant problem in electromagnetics is the computation of the scattered far fields for large, complex targets, such as tanks or aircraft. Since it is often necessary to determine the scattering at multiple angles and frequencies, speed of calculation can be critical as well. This work has direct applications in areas such as RCS reduction and target identification, with the latter being the main thrust of this thesis. In order to do these computations, high-frequency approximate techniques must be used.","abstract_has_math":false,"creators":["Christensen, Michael Corey"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical and Computer Engineering","degree_department":null,"school":null,"contributors":["Lee, Shung-Wu"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:27:11Z","date_published":"2011-05-07T12:27:11Z","updated_at":"2026-07-22T22:25:15Z","subjects":["Engineering, Electronics and Electrical"],"languages":["eng"],"rights":["Copyright 1995 Christensen, Michael Corey"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624316","(UMI)AAI9624316"],"render_values":[{"text":"AAI9624316","href":null,"code":true},{"text":"(UMI)AAI9624316","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/20049","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Lee, Shung-Wu"]},{"key":"dc:creator","label":"Author","values":["Christensen, Michael Corey"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:27:11Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical and Computer Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Electronics and Electrical"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1995 Christensen, Michael Corey"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624316","(UMI)AAI9624316","http://hdl.handle.net/2142/20049"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A significant problem in electromagnetics is the computation of the scattered far fields for large, complex targets, such as tanks or aircraft. Since it is often necessary to determine the scattering at multiple angles and frequencies, speed of calculation can be critical as well. This work has direct applications in areas such as RCS reduction and target identification, with the latter being the main thrust of this thesis. In order to do these computations, high-frequency approximate techniques must be used.","It has been found that computer graphics rendering techniques can be used to significantly improve the time necessary to achieve very good high-frequency first-bounce scattering results for an arbitrarily complex target. This is done using an area of memory known at the z-buffer.","\"An improvement over our previous implementations of shooting and bouncing rays is also presented. For the case of a ray at grazing incidence on the surface of a target, unrealistic results were predicted. By adding a \"\"shape function\"\", which accounts for the phase variation over the projected raytube surface, better results can be determined.\"","In an attempt to handle a more general problem, a shooting and bouncing rays solution to the bulk material case is presented, for both lossless and lossy materials. This includes problems containing bulk materials alone, and problems integrating various other materials, such as conductors. Previously, only surfaces with thin layers of material have been implemented, using a simple reflection coefficient. A number of different cases are presented and are compared to results obtained using a two-dimensional method of moments code. It is found that good accuracy can be obtained for many cases.","Made available in DSpace on 2011-05-07T12:27:11Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624316.pdf: 4608884 bytes, checksum: 827142628bf2a111392c2be87d6a219f (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:41:13Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:17:48-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["Efficient high-frequency techniques for scattering by realistic targets"]}]}],"canonical_facts":{"dc:contributor":["Lee, Shung-Wu"],"dc:creator":["Christensen, Michael Corey"],"dc:date":["2011-05-07T12:27:11Z","10000-01-01","1995"],"dc:description":["A significant problem in electromagnetics is the computation of the scattered far fields for large, complex targets, such as tanks or aircraft. Since it is often necessary to determine the scattering at multiple angles and frequencies, speed of calculation can be critical as well. This work has direct applications in areas such as RCS reduction and target identification, with the latter being the main thrust of this thesis. In order to do these computations, high-frequency approximate techniques must be used.","It has been found that computer graphics rendering techniques can be used to significantly improve the time necessary to achieve very good high-frequency first-bounce scattering results for an arbitrarily complex target. This is done using an area of memory known at the z-buffer.","\"An improvement over our previous implementations of shooting and bouncing rays is also presented. For the case of a ray at grazing incidence on the surface of a target, unrealistic results were predicted. By adding a \"\"shape function\"\", which accounts for the phase variation over the projected raytube surface, better results can be determined.\"","In an attempt to handle a more general problem, a shooting and bouncing rays solution to the bulk material case is presented, for both lossless and lossy materials. This includes problems containing bulk materials alone, and problems integrating various other materials, such as conductors. Previously, only surfaces with thin layers of material have been implemented, using a simple reflection coefficient. A number of different cases are presented and are compared to results obtained using a two-dimensional method of moments code. It is found that good accuracy can be obtained for many cases.","Made available in DSpace on 2011-05-07T12:27:11Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624316.pdf: 4608884 bytes, checksum: 827142628bf2a111392c2be87d6a219f (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:41:13Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:17:48-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9624316","(UMI)AAI9624316","http://hdl.handle.net/2142/20049"],"dc:language":["eng"],"dc:rights":["Copyright 1995 Christensen, Michael Corey"],"dc:subject":["Engineering, Electronics and Electrical"],"dc:title":["Efficient high-frequency techniques for scattering by realistic targets"],"dc:type":["text"],"thesis:degree_discipline":["Electrical and Computer Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:15Z"}