Improvements in distance measurement and SAR-imaging applications by using ultra-high resolution mm-wave FMCW radar systems

Due to advances in technology, resulting in coverage of even higher, and rarely used, frequency regions with low-cost semiconductors, ultra wideband radar systems are getting more feasible for several kinds of applications. In this contribution, the effects of using radar systems with an ultra high spatial resolution, in combination with high precision distance measurements, especially for solid bulk material, and short range synthetic aperture radar (SAR) imaging are discussed. Furthermore, measurements with a wideband (24.5GHz bandwidth) radar sensor in these applications have been done to demonstrate the advantages, of the high resolution. Especially distance measurement applications with many targets or disturbing scatterers benefit from the wide bandwidth. Here, for the measured scenario an accuracy enhancement of a factor 4 to 8 has been obtained by increasing the bandwidth from 4GHz to 24.5 GHz. Furthermore, short range SAR images with a nearly isotropic resolution of 1.3 cm in range, and 1.5 cm in azimuth direction (−6 dB width, Hanning window) are presented. The use of 24.5 GHz bandwidth, and the accordingly better range resolution, which is now in the same dimension as the azimuth resolution, drastically increases the image quality compared to images taken with 4 GHz bandwidth.