This paper examines two different approaches that can be used to model patch antennas and cavities fed by a coaxial cable. The probe model represents the feed as a current filament along the center conductor of the coaxial cable. The coaxial-cable model enforces the analytical field distribution at the cable opening. These two models have been implemented in a hybrid FEM/MoM code. A power bus structure and a cavity geometry with coaxial-cable feeds are investigated. Numerical results obtained for these two examples are compared with measurements. It is shown that the probe model should only be applied to electrically short feeding structures, while the coaxial cable model can be applied to both electrically short and electrically long feeding structures.

Meeting Name

IEEE International Symposium on Electromagnetic Compatibility (2000: Aug. 21-25, Washington, DC)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

EMI Modeling; Antenna Feeds; Cable Opening; Cavity Geometry; Cavity Sources; Center Conductor; Coaxial Cable Fed Cavities; Coaxial Cable Feeds; Coaxial Cable Model; Coaxial Cables; Current Filament; Electrically Long Feeding Structures; Electrically Short Feeding Structures; Electromagnetic Interference; Electromagnetic Shielding; Field Distribution; Finite Element Analysis; Finite Element Modeling; Hybrid FEM/MoM Code; Measurements; Method of Moments; Microstrip Antennas; Patch Antenna; Power Bus Structure; Probe Model; Shielding Enclosures; Transmission Line Theory

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2000 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Aug 2000