Open-ended sensors for microwave nondestructive evaluation of layered composite media. Ph.D. Thesis
The need to monitor the composition, integrity, and maintenance of materials, structures and equipments gave rise to the development of the field of NonDestructive Testing and Examination (NDT & E). With the prevalent use of metals due to their strength, early NDT techniques were established to deal mostly with metallic media. The advent of new lightweight and exceptionally strong dielectric composite materials, replacing metals in many applications, has diversified the field of NDT & E tremendously. The low conductivity associated with these dielectric materials such as plastics, ceramics and carbon fiber composites has rendered many traditional and conventional NDT techniques ineffective. The ability of microwaves to penetrate inside dielectric media and their sensitivity to minute structural and dimensional variations within the medium, coupled with availability of large bandwidths are of great significance. Microwave techniques have reemerged recently not only to fill many gaps left vacant by traditional NDT & E techniques, but also to further expose new alleys in this expanding and demanding field. Near-field interaction of electromagnetic waves with different material media is a complex process. Without a thorough understanding of the nature of reflection, attenuation and scattering mechanisms involved, even the most careful measurements may render themselves useless. The objective of this work is to take a forward step toward filling some of the existing gaps for concise theoretical formulations and practical implementation in application to microwave NDT & E of layered dielectric composite media. Models pertaining to analysis of electromagnetic radiation into layered, generally lossy dielectric composite media from two prevalent sensors, namely, an open-ended rectangular waveguide and an open-ended coaxial line are introduced.
- Research Organization:
- Colorado State Univ., Fort Collins, CO (United States)
- OSTI ID:
- 147179
- Resource Relation:
- Other Information: TH: Ph.D. Thesis; PBD: 1992
- Country of Publication:
- United States
- Language:
- English
Similar Records
Wake-field studies on photonic band gap accelerator cavities
Modeling of Photonic Band Gap Crystals and Applications