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

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Gibbons, Brian

Contributors dc:contributor

• Bernhard, Jennifer T.

• 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

Statement dc:rights

• Copyright 2014 Brian B. Gibbons

Language dc:language

en

Handle dc:identifier

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

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/73021