Microwave and millimeter-wave signals span the frequency range of ~300 MHz to 300 GHz, corresponding to a wavelength range of 1000 mm to 1 mm. Signals at these frequencies can easily penetrate inside dielectric materials and composites, and interact with their inner structures. The relatively small wavelengths and wide bandwidths associated with these signals enable the production of high spatial-resolution images of materials and structures.

When used for NDT&E, these innovative techniques effectively address a myriad of important inspection concerns, including the following:

• Materials characterization
• Stratified composite inspection
• Fatigue crack detection and sizing
• Cure state evaluation for a wide range of materials
• Pitting and corrosion detection under coatings
• Wide range of cementitious materials characterization
• Structural health monitoring (SHM)
• Microwave thermography
• Embedded sensors, hybrid methods using modulated scatterer techniques (MST), and frequency selective surface (FSS) based sensors
• Near-field, lens-focused and 3D real-time synthetic aperture radar (SAR) imaging
• Microwave and millimeter wave noninvasive diagnosis of human skin for cancer and burns