Numerical and experimental results of a microwave noncontact, nondestructive detection and evaluation of disbonds and thickness variations in stratified composite media are presented. The aperture admittance characteristics of a flange mounted rectangular waveguide radiating into a layered, generally lossy dielectric media backed or unbacked by a conducting sheet is modeled. The theoretical implementation is based on a Fourier transform boundary matching technique to construct the field components in each medium, coupled with a stationary form of the terminating aperture admittance of the waveguide. The model can serve as a reliable test bed for real-time examination of layered composite media. Experimental results for several cases are presented which show good agreement with the theoretical findings. This is a versatile technique for near-field in situ interrogation of stratified composite media which provides for high resolution measurements.


Electrical and Computer Engineering

Keywords and Phrases

Composite Materials; Dielectric Materials; Directional Patterns (Antenna); Electric Impedance; Electric Network Analysis; Fourier Transforms; In Situ Processing; Microwave Measurement; Microwaves; Nondestructive Examination; Thickness Measurement; Variational Techniques; Aperture Admittance; Disbond; Fourier Transform Boundary Matching Technique; Microwave Noncontact Examination; Stratified Composite Media; Thickness Variations; Rectangular Waveguides

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 1994 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Mar 1994