University of Illinois Urbana-Champaign

On the accuracy of estimating input impedance of probe-fed air-substrate microstrip patch antennas using the theory of characteristic modes

Gibbons, Brian

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Brian_Gibbons.pdf

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https://hdl.handle.net/2142/73021

Description

Title
On the accuracy of estimating input impedance of probe-fed air-substrate microstrip patch antennas using the theory of characteristic modes
Author(s)
Gibbons, Brian
Issue Date
2015-01-21
Director of Research (if dissertation) or Advisor (if thesis)
Bernhard, Jennifer T.
Department of Study
Electrical & Computer Eng
Discipline
Electrical & Computer Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2015-01-21T19:56:10Z
Keyword(s)
  • 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
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.
Graduation Semester
2014-12
Permalink
http://hdl.handle.net/2142/73021
Copyright and License Information
Copyright 2014 Brian B. Gibbons

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