Near-Field Microwave and Embedded Modulated Scattering Technique (MST) for Dielectric Characterization of Materials

Abstract

Several approaches to using combined near-field microwave NDT techniques, utilizing openended rectangular waveguides, and embedded modulated scatterer technique (MST) for the determination of the dielectric properties of a material have been investigated in the past. A technique currently under investigation involves using the ratio of dynamic forward-and reverse-biased reflection coefficients, measured at the aperture of the waveguide. One important aspect of this method is that the ratio of reflection coefficients is not a function of the relative location or polarization of MST probe to the waveguide, Formulation of the ratio of dynamic reflection coefficients is presented, as well as preliminary measurements showing the coherent ratio of reflection coefficients to be relatively constant as a function of location in freespace.

Distributed Machine Learning in Materials that Couple Sensing, Actuation, Computation and Communication

“…During the same time, microelectromechanical systems (MEMS) were developed, which resulted in a suite of sensors and actuators, including accelerometers, gyroscopes, pressure sensors, LEDs, ultrasonic transducers and microphones, which are on the millimeter scale. Small, inexpensive components such as these has allowed for active sensing to be embedded into engineering materials, to assist with monitoring the local properties of a structure [57][58][59][60]. Microcontrollers and microprocessors have also become available on a similar scale.…”