{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/120975"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/120975","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Rim-Mounted Reconfigurable Surfaces for Interference Nulling in Focus-Fed Axisymmetric Reflector Antenna Systems","abstract":"This thesis addresses the use of an electronic reconfigurable surface (ERS) attached to an axisymmetric paraboloidal reflector antenna to mitigate interference through nulling for radio astronomy applications. The ERS is a reflectarray that consists of multiple elements, which can be electronically controlled to modify the reflected field. Previous research focused on a \"conformal\" system with elements placed on a parabololoidal surface extending beyond the unmodified reflector. These studies concluded that nulling could be achieved without compromising the gain and shape of the main lobe. This thesis builds on previous research by addressing two topics. The first topic is minimization of the ERS rim width. A closed form expression for the minimum width required for effective nulling in the close-in sidelobes is derived in this thesis. The second topic addressed in this thesis is ERS configurations comprised of flat panels as an alternative to the conformal ERS implementation. Flat panels may be easier to manufacture compared to their conformal counterpart. Flat panel ERS implementations are evaluated, and it is concluded that they are a suitable alternative to conformal ERS implementation.","abstract_html":"This thesis addresses the use of an electronic reconfigurable surface (ERS) attached to an axisymmetric paraboloidal reflector antenna to mitigate interference through nulling for radio astronomy applications. The ERS is a reflectarray that consists of multiple elements, which can be electronically controlled to modify the reflected field. Previous research focused on a "conformal" system with elements placed on a parabololoidal surface extending beyond the unmodified reflector. These studies concluded that nulling could be achieved without compromising the gain and shape of the main lobe. This thesis builds on previous research by addressing two topics. The first topic is minimization of the ERS rim width. A closed form expression for the minimum width required for effective nulling in the close-in sidelobes is derived in this thesis. The second topic addressed in this thesis is ERS configurations comprised of flat panels as an alternative to the conformal ERS implementation. Flat panels may be easier to manufacture compared to their conformal counterpart. Flat panel ERS implementations are evaluated, and it is concluded that they are a suitable alternative to conformal ERS implementation.","abstract_has_math":false,"creators":["Yip, Alec Johnathan"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Electrical Engineering","degree_department":"Electrical Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Ellingson, Steven W."],"committee_members":["Buehrer, Richard M.","Davis, Bradley A."],"year":2024,"date_issued":"2024-08-20","date_published":"2024-08-20","updated_at":"2026-07-22T22:18:39Z","subjects":["Adaptive antennas"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:41360"],"render_values":[{"text":"vt_gsexam:41360","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/120975","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Ellingson, Steven W."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Buehrer, Richard M.","Davis, Bradley A."]},{"key":"dc:contributor.department","label":"Department","values":["Electrical Engineering"]},{"key":"dc:creator","label":"Author","values":["Yip, Alec Johnathan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2024-08-21T08:01:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2024-08-21T08:01:02Z"]},{"key":"dc:date.issued","label":"Date","values":["2024-08-20"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Adaptive antennas"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:41360"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/120975"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis addresses the use of an electronic reconfigurable surface (ERS) attached to an axisymmetric paraboloidal reflector antenna to mitigate interference through nulling for radio astronomy applications. The ERS is a reflectarray that consists of multiple elements, which can be electronically controlled to modify the reflected field. Previous research focused on a \"conformal\" system with elements placed on a parabololoidal surface extending beyond the unmodified reflector. These studies concluded that nulling could be achieved without compromising the gain and shape of the main lobe. This thesis builds on previous research by addressing two topics. The first topic is minimization of the ERS rim width. A closed form expression for the minimum width required for effective nulling in the close-in sidelobes is derived in this thesis. The second topic addressed in this thesis is ERS configurations comprised of flat panels as an alternative to the conformal ERS implementation. Flat panels may be easier to manufacture compared to their conformal counterpart. Flat panel ERS implementations are evaluated, and it is concluded that they are a suitable alternative to conformal ERS implementation."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["This thesis utilizes the state-of-the art electronic reconfigurable surface (ERS) attached to a reflector antenna to mitigate interference for radio astronomy applications. The ERS is an array that can be controlled electronically to modify the radiation from the reflector. Previous research focused on configuring the ERS attached conformally to the reflector to null interference in a direction. This thesis appends previous research by addressing two topics. The first topic is the minimization of the ERS width for the conformal implementation. A closed form expression for the minimum ERS width is derived in this thesis. The second topic is to explore an ERS topology that consists of flat panels attached to the reflector. This topology is explored since flat ERS panels may be easier to manufacture. It is concluded that the flat panel ERS implementation is a suitable alternative to the conformal ERS implementation for interference mitigation."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Rim-Mounted Reconfigurable Surfaces for Interference Nulling in Focus-Fed Axisymmetric Reflector Antenna Systems"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Ellingson, Steven W."],"dc:contributor.committeemember":["Buehrer, Richard M.","Davis, Bradley A."],"dc:contributor.department":["Electrical Engineering"],"dc:creator":["Yip, Alec Johnathan"],"dc:date.accessioned":["2024-08-21T08:01:02Z"],"dc:date.available":["2024-08-21T08:01:02Z"],"dc:date.issued":["2024-08-20"],"dc:description.abstract":["This thesis addresses the use of an electronic reconfigurable surface (ERS) attached to an axisymmetric paraboloidal reflector antenna to mitigate interference through nulling for radio astronomy applications. 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Flat panel ERS implementations are evaluated, and it is concluded that they are a suitable alternative to conformal ERS implementation."],"dc:description.abstractgeneral":["This thesis utilizes the state-of-the art electronic reconfigurable surface (ERS) attached to a reflector antenna to mitigate interference for radio astronomy applications. The ERS is an array that can be controlled electronically to modify the radiation from the reflector. Previous research focused on configuring the ERS attached conformally to the reflector to null interference in a direction. This thesis appends previous research by addressing two topics. The first topic is the minimization of the ERS width for the conformal implementation. A closed form expression for the minimum ERS width is derived in this thesis. The second topic is to explore an ERS topology that consists of flat panels attached to the reflector. This topology is explored since flat ERS panels may be easier to manufacture. It is concluded that the flat panel ERS implementation is a suitable alternative to the conformal ERS implementation for interference mitigation."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:41360"],"dc:identifier.uri":["https://hdl.handle.net/10919/120975"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Adaptive antennas"],"dc:title":["Rim-Mounted Reconfigurable Surfaces for Interference Nulling in Focus-Fed Axisymmetric Reflector Antenna Systems"],"dc:type":["Thesis"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:39Z"}