Development of Vibration-Imaging Radar (VirA)

The development and application of vibration-imaging radar (VirA) is described in this paper. Microwave VirA is a 17-GHz FMCW imaging radar with 64-ch receiving units for digital beam-forming (DBF) processing. It is used to observe infrastructure such as bridges or buildings in two dimensions at up to 1000 s
^-1
, after which any displacement or vibration in the image caused by the phase variation in the image signal is extracted. Since VirA can image and measure surface-distributed vibrations in two dimensions, it is useful not only for infrastructure monitoring but also for civil engineering projects. Furthermore, millimeter-wave VirA has been developed with the aim of attaining a higher level of accuracy. High-purity chirp signal generation, a key technology, as well as the millimeter-wave VirA prototype, are described.