The portable microwave interferometry system has been successfully applied to measurement of material properties and detection of defects in a wide range of dielectric materials including: advanced aerospace composite matrix ceramics, composite ceramic armor, fiber reinforced resin components, reinforced rubber components and High Density Poly Ethylene (HDPE) pipe. Performance for field and manufacturing applications has been validated on test specimens, which included: manufacturing and service induced defects in actual samples and engineered features in specially fabricated surrogates. The portable, non-contact NDE system requires access to only one surface, and no coupling medium. Recent developments include: multi-channel instrumentation with frequency modulation and sampling, for 44 layer stack imaging; and phase plane analysis for depth and density measurement. System configuration advances include: hardware evolution to small portable units, development of precision measurement with fixed work stations, and integration in 6 axis fully automated robotic work stations. Related development includes position–self-aware functionality for the hand held probe; permitting direct, handheld examination of components. Metrology and detection capability has been validated using in-process measurement on actual parts; manufacturing and service induced defects in actual parts; specially fabricated surrogates and ballistic impact and non-ballistically damaged specimens. Other NDE methods, including through-transmission X-ray, X-ray computed tomography, destructive examination, and nondestructive measurement are used to verify defects and other detected anomalies. The microwave interference scanning system has been shown to reliably detect cracks, laminar features and material property variations. The development of this portable system will provide a useful tool for nondestructive testing of dielectric materials in the field and in manufacturing environments. This work is supported by, and test samples provided by, US Army Tank- Automotive Research, Development and Engineering Center (TARDEC), US Army Research Laboratory, US Air Force Research Laboratory under Small Business Innovative Research (SBIR) projects.