{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/73021"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/73021","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"On the accuracy of estimating input impedance of probe-fed air-substrate microstrip patch antennas using the theory of characteristic modes","abstract":"Two different techniques based on the theory of characteristic modes are developed to estimate the input impedance of air-substrate, coaxial probe-fed, microstrip patch antennas with arbitrarily shaped patches. Such an antenna with an L-shaped patch is fabricated and experimentally measured, and a case study performed comparing the accuracy of the two methods. The results of both methods require a downward frequency scaling on the order of 8% to better agree with experiment, attributable to losses in the real-world materials. The simpler method (the virtual probe model) is shown to provide good input resistance predictions, but the input reactance is shown to require compensation in the form of series inductance and capacitance. The more involved method (the wire probe model) is demonstrated to provide both good input resistance and reactance estimates with only a frequency scaling. The results and conclusions of this case study are then used to draw implications for future work involving application of the theory of characteristic modes to antenna feeds.","abstract_html":"Two different techniques based on the theory of characteristic modes are developed to estimate the input impedance of air-substrate, coaxial probe-fed, microstrip patch antennas with arbitrarily shaped patches. Such an antenna with an L-shaped patch is fabricated and experimentally measured, and a case study performed comparing the accuracy of the two methods. The results of both methods require a downward frequency scaling on the order of 8% to better agree with experiment, attributable to losses in the real-world materials. The simpler method (the virtual probe model) is shown to provide good input resistance predictions, but the input reactance is shown to require compensation in the form of series inductance and capacitance. The more involved method (the wire probe model) is demonstrated to provide both good input resistance and reactance estimates with only a frequency scaling. The results and conclusions of this case study are then used to draw implications for future work involving application of the theory of characteristic modes to antenna feeds.","abstract_has_math":false,"creators":["Gibbons, Brian"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Bernhard, Jennifer T."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-01-21T19:56:10Z","date_published":"2015-01-21T19:56:10Z","updated_at":"2026-07-22T22:26:07Z","subjects":["Theory of Characteristic Modes (TCM)","Antenna Input Impedance","Input Resistance","Input Reactance","Microstrip Patch Antenna (MSA)","Air Substrate","Coaxial Probe Feed Model","Antenna Feed","Virtual Probe Model","Wire Probe Model"],"languages":["en"],"rights":["Copyright 2014 Brian B. 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The simpler method (the virtual probe model) is shown to provide good input resistance predictions, but the input reactance is shown to require compensation in the form of series inductance and capacitance. The more involved method (the wire probe model) is demonstrated to provide both good input resistance and reactance estimates with only a frequency scaling. The results and conclusions of this case study are then used to draw implications for future work involving application of the theory of characteristic modes to antenna feeds.","Item withdrawn by Laura Spradlin (lspradl2@illinois.edu) on 2014-12-09T21:51:37Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Gibbons_Brian.pdf: 8176375 bytes, checksum: 7c6f30b7332a8cec9b4af1e57c5a8f9a (MD5) Gibbons_Brian.pdf: 8176375 bytes, checksum: 7c6f30b7332a8cec9b4af1e57c5a8f9a (MD5)","Made available in DSpace on 2015-01-21T19:56:10Z (GMT). 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