A microwave nondestructive technique for detection and evaluation of disbonding and delamination in layered-dielectric-slabs backed by a conducting plate is discussed. The theoretical development begins by considering an incident wave illuminating such a medium and then formulating the characteristics of the wave reflected by the metal plate. An effective reflection coefficient is determined in this way whose phase characteristics are used in the detection and evaluation of delaminations in the media. The characteristics of this phase as a function of several parameters such as delamination dielectric constant and thickness, slab dielectric constant, and thickness and the frequency of operation are investigated. The description of an experimental apparatus is given and it is used to perform several experiments to test and verify the theory. Very good agreement was obtained between the theoretical and experimental results.


Electrical and Computer Engineering

Keywords and Phrases

Composite Materials; Dielectric Materials; Microwave Measurements; Microwaves - Reflection; Delamination Detection; Layered Dielectric Slabs; Microwave Nondestructive Technique; Laminated Products; Adhesion; Dielectric measurements; Nondestructive testing; Thickness measurement

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 1990 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Dec 1990