Microwave and millimeter-wave non-destructive testing and evaluation
(NDT&E) is generally understood to mean using high-frequency
electromagnetic energy to inspect and characterize materials and
structures. In spite of possessing some distinct advantages in certain
applications to other NDT&E techniques, microwave NDT&E has only found
compared limited practical application during the past 45 years. These
advantages include lack of a need for contact between the sensor and the
object being inspected, the ability to penetrate dielectric materials,
and superior sensitivity to certain material constituents and flaws. One
factor contributing to this minimal acceptance by the NDT &E community
has been a generally poor understanding in this community of the theory
and practice that underlie the technology. This situation exists partly
because of a paucity of microwave NDT&E textbook and reference material.
Some chapters, reviews, and books aimed at filling this need have been
published in the past but, for the most part, this material is based on
the use of older microwave technology. However, during the past ten
years great strides have been made in ternlS of the cost, size, and ease
of use of microwave components. In addition, recent advances in modeling
and measurement techniques have expanded the range of applications for
microwave NDT&E. Such applications include inspecting modern materials
such as composites, detecting and characterizing surface flaws, and
evaluating the compressive strength of cement structures. These advances
have created an urgent need for up-to-date textbook material on this
subject.
