{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/98335"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/98335","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Modeling and design of near-field antennas with periodic structures","abstract":"In this dissertation, the one- and two-dimensional periodic structures are modelled and adopted in the design of near-field antennas. First, the discontinuous Galerkin time-domain (DGTD) method is applied to model the scattering from periodic structures. The modelling of dispersive media is incorporated into a three-dimensional DGTD scheme, which is capable of studying plasmonic periodic structures at optical frequencies. Various numerical examples are presented to demonstrate the applications of the proposed algorithm. Second, a new methodology for modelling and characterization of one-dimensional periodic structures with nonstraight geometries is developed. The one-dimensional zero-phase-shift line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, the full dispersion characteristics, including phase and attenuation constants, of the ZPSL are analyzed in a loop configuration. Based on the dispersion characteristics, a periodic ZPSL loop antenna with uniformly distributed unit cells is studied, and a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is designed for an improved near-field performance. Fourth, a low-profile directional ZPSL loop antenna is proposed by placing an artificial magnetic conductor (AMC) reflector behind a ZPSL grid-loop antenna. The grid-loop configuration is designed such that an enhanced magnetic field distribution can be realized on the electrically large ZPSL loop antenna with a simple feeding network. The AMC reflector with four-arm spiral unit cells is included to achieve a directional field distribution as well as to further increase the magnetic field intensity. Fifth, two low-profile ZPSL loop antennas are proposed to achieve a directional magnetic near-field distribution. The current distributions on the antennas are studied to realize the desired near-field pattern. Besides the directional distribution, both the antennas exhibit enhanced magnetic field intensities in the forward direction. All of the antennas are exemplified as a reader antenna for ultra-high frequency (UHF) near-field radio frequency identification (RFID) systems.","abstract_html":"In this dissertation, the one- and two-dimensional periodic structures are modelled and adopted in the design of near-field antennas. First, the discontinuous Galerkin time-domain (DGTD) method is applied to model the scattering from periodic structures. The modelling of dispersive media is incorporated into a three-dimensional DGTD scheme, which is capable of studying plasmonic periodic structures at optical frequencies. Various numerical examples are presented to demonstrate the applications of the proposed algorithm. Second, a new methodology for modelling and characterization of one-dimensional periodic structures with nonstraight geometries is developed. The one-dimensional zero-phase-shift line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, the full dispersion characteristics, including phase and attenuation constants, of the ZPSL are analyzed in a loop configuration. Based on the dispersion characteristics, a periodic ZPSL loop antenna with uniformly distributed unit cells is studied, and a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is designed for an improved near-field performance. Fourth, a low-profile directional ZPSL loop antenna is proposed by placing an artificial magnetic conductor (AMC) reflector behind a ZPSL grid-loop antenna. The grid-loop configuration is designed such that an enhanced magnetic field distribution can be realized on the electrically large ZPSL loop antenna with a simple feeding network. The AMC reflector with four-arm spiral unit cells is included to achieve a directional field distribution as well as to further increase the magnetic field intensity. Fifth, two low-profile ZPSL loop antennas are proposed to achieve a directional magnetic near-field distribution. The current distributions on the antennas are studied to realize the desired near-field pattern. Besides the directional distribution, both the antennas exhibit enhanced magnetic field intensities in the forward direction. All of the antennas are exemplified as a reader antenna for ultra-high frequency (UHF) near-field radio frequency identification (RFID) systems.","abstract_has_math":false,"creators":["Zeng, Yunjia"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Jin, Jianming","Bernhard, Jennifer","Schutt-Ainé, José","Gong, Songbin"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-09-29T17:56:26Z","date_published":"2017-09-29T17:56:26Z","updated_at":"2026-07-22T22:24:35Z","subjects":["Numerical method","Periodic structures","Near field","Magnetic field","Dispersion analysis","Equivalent circuit","Loop antenna","Artificial magnetic conductor","Radio frequency identification","Ultrahigh frequency","Directional antenna","Antenna array","Parasitic array"],"languages":["en"],"rights":["Copyright 2017 Yunjia Zeng"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/98335","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Jin, Jianming","Bernhard, Jennifer","Schutt-Ainé, José","Gong, Songbin"]},{"key":"dc:creator","label":"Author","values":["Zeng, Yunjia"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017-09-29T17:56:26Z","2017-07-09","2017-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"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":["Numerical method","Periodic structures","Near field","Magnetic field","Dispersion analysis","Equivalent circuit","Loop antenna","Artificial magnetic conductor","Radio frequency identification","Ultrahigh frequency","Directional antenna","Antenna array","Parasitic array"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2017 Yunjia Zeng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/98335"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["In this dissertation, the one- and two-dimensional periodic structures are modelled and adopted in the design of near-field antennas. First, the discontinuous Galerkin time-domain (DGTD) method is applied to model the scattering from periodic structures. The modelling of dispersive media is incorporated into a three-dimensional DGTD scheme, which is capable of studying plasmonic periodic structures at optical frequencies. Various numerical examples are presented to demonstrate the applications of the proposed algorithm. Second, a new methodology for modelling and characterization of one-dimensional periodic structures with nonstraight geometries is developed. The one-dimensional zero-phase-shift line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, the full dispersion characteristics, including phase and attenuation constants, of the ZPSL are analyzed in a loop configuration. Based on the dispersion characteristics, a periodic ZPSL loop antenna with uniformly distributed unit cells is studied, and a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is designed for an improved near-field performance. Fourth, a low-profile directional ZPSL loop antenna is proposed by placing an artificial magnetic conductor (AMC) reflector behind a ZPSL grid-loop antenna. The grid-loop configuration is designed such that an enhanced magnetic field distribution can be realized on the electrically large ZPSL loop antenna with a simple feeding network. The AMC reflector with four-arm spiral unit cells is included to achieve a directional field distribution as well as to further increase the magnetic field intensity. Fifth, two low-profile ZPSL loop antennas are proposed to achieve a directional magnetic near-field distribution. The current distributions on the antennas are studied to realize the desired near-field pattern. Besides the directional distribution, both the antennas exhibit enhanced magnetic field intensities in the forward direction. All of the antennas are exemplified as a reader antenna for ultra-high frequency (UHF) near-field radio frequency identification (RFID) systems.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Yunjia Zeng, accepted the attached license on 2017-07-05 at 20:56.","The student, Yunjia Zeng, submitted this Dissertation for approval on 2017-07-05 at 21:14.","This Dissertation was approved for publication on 2017-07-09 at 14:02.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11319 on 2017-09-29 at 11:28:00","Made available in DSpace on 2017-09-29T17:56:26Z (GMT). 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The modelling of dispersive media is incorporated into a three-dimensional DGTD scheme, which is capable of studying plasmonic periodic structures at optical frequencies. Various numerical examples are presented to demonstrate the applications of the proposed algorithm. Second, a new methodology for modelling and characterization of one-dimensional periodic structures with nonstraight geometries is developed. The one-dimensional zero-phase-shift line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, the full dispersion characteristics, including phase and attenuation constants, of the ZPSL are analyzed in a loop configuration. Based on the dispersion characteristics, a periodic ZPSL loop antenna with uniformly distributed unit cells is studied, and a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is designed for an improved near-field performance. Fourth, a low-profile directional ZPSL loop antenna is proposed by placing an artificial magnetic conductor (AMC) reflector behind a ZPSL grid-loop antenna. The grid-loop configuration is designed such that an enhanced magnetic field distribution can be realized on the electrically large ZPSL loop antenna with a simple feeding network. The AMC reflector with four-arm spiral unit cells is included to achieve a directional field distribution as well as to further increase the magnetic field intensity. Fifth, two low-profile ZPSL loop antennas are proposed to achieve a directional magnetic near-field distribution. The current distributions on the antennas are studied to realize the desired near-field pattern. Besides the directional distribution, both the antennas exhibit enhanced magnetic field intensities in the forward direction. All of the antennas are exemplified as a reader antenna for ultra-high frequency (UHF) near-field radio frequency identification (RFID) systems.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Yunjia Zeng, accepted the attached license on 2017-07-05 at 20:56.","The student, Yunjia Zeng, submitted this Dissertation for approval on 2017-07-05 at 21:14.","This Dissertation was approved for publication on 2017-07-09 at 14:02.","DSpace SAF Submission Ingestion Package generated from Vireo submission #11319 on 2017-09-29 at 11:28:00","Made available in DSpace on 2017-09-29T17:56:26Z (GMT). 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