30 GHz Linear High-Resolution and Rapid Millimeter Wave Imaging System for NDE

High-resolution millimeter-wave imaging for nondestructive testing applications offers certain unique and practical advantages. Traditionally, imaging for this purpose is performed by raster scanning a single probe/antenna across a two-dimensional (2D) grid. Raster scanning requires bulky, slow and expensive scanning platforms, in addition to being a slow process. Utilizing an array of probes significantly reduces these limitations. This paper presents the design of a linear one-dimensional millimeter wave imaging array operating at 30 GHz and capable of rapid image production. The imaging array is 150 mm long, operates in quasi-mono-static reflection mode, and provides coherent vector reflection coefficient data for generating high spatial resolution synthetic aperture radar images. This imaging array performs fast electronic scan along one dimension and may be readily moved along the other direction to produce 2D images, greatly reducing the required scan time compared to raster scanning. The design and utility of this imaging array along with several imaging examples are presented in this paper.