Sub-Structure Characteristic Mode Analysis of Microstrip Antennas Using a Global Multitrace Formulation

Ran Zhao, Yuyu Lu, Guang Shang Cheng*, Wei Zhu, Jun Hu, Hakan Bagci

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


A characteristic mode (CM) method that relies on a global multitrace formulation (MTF) of surface integral equations (SIEs) is proposed to compute the modes and the resonance frequencies of microstrip patch antennas with finite dielectric substrates and ground planes. Compared to the coupled formulation of electric field and Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) integral equations, global MTF allows for more direct implementation of a sub-structure CM method. This is achieved by representing the coupling of the electromagnetic fields on the substrate and ground plane in the form of a numerical Green function matrix, which yields a more compact generalized eigenvalue equation. The resulting sub-structure CM method avoids the cumbersome computation of the multilayered medium Green function [unlike the CM methods that rely on mixed-potential integral equations (MPIEs)] and the volumetric discretization of the substrate (unlike the CM methods that rely on volume-surface integral equations), and numerical results show that it is a reliable and accurate approach to predicting the modal behavior of electromagnetic fields on practical microstrip antennas.

Original languageEnglish (US)
Pages (from-to)10026-10031
Number of pages6
JournalIEEE Transactions on Antennas and Propagation
Issue number12
StatePublished - Dec 1 2023


  • Characteristic mode (CM) analysis
  • microstrip patch antenna
  • multitrace formulation (MTF)
  • surface integral equations (SIEs)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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