Estimating air-substrate microstrip patch antenna input impedance with characteristic mode theory

Brian B. Gibbons, Jennifer Truman Bernhard

Research output: Contribution to journalArticlepeer-review


The theory of characteristic modes (TCM) for PEC bodies is showing great promise and application in the analysis, design, and placement of antennas. Its use for input impedance estimation, however, is still largely dependent on the idealized delta-gap model. Because TCM depends on all conductors, even feed structures, care must be taken for certain classes of antennas if estimating input impedance; probe-fed microstrip patch antennas (MSAs) are one example. In this paper, two different coaxial probe feed models are developed to estimate the input impedance of thin, arbitrarily shaped, air-dielectric MSAs using TCM. Their accuracy is compared with experimental results for a case study of an L-shaped MSA. Results show the importance of including all metal structures, including feeds, in TCM analyses.

Original languageEnglish (US)
Pages (from-to)2190-2196
Number of pages7
JournalMicrowave and Optical Technology Letters
Issue number9
StatePublished - Sep 2017


  • antenna input impedance
  • coaxial probe feed model
  • microstrip patch antenna
  • theory of characteristic modes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Estimating air-substrate microstrip patch antenna input impedance with characteristic mode theory'. Together they form a unique fingerprint.

Cite this