mimo fmcw技术研究

The USE of radar systems for civil applications has in- creased significantly over the last years. The development of complete integrated radar circuits operating in the millimeter- wave range has led to a low-cost and compact realization of mul- tichannel systems [1], [2]. Such systems can not only be used for the classical target range and velocity measurement, but add the capability to mea- sure the angular position of targets relative to the radar. Con- trary to the range and velocity measurement problem, where resolution of different targets is coupled to the used bandwidth and measurement time, the angular resolution is determined by the aperture of the used antenna array. This leads to one of the major challenges in array processing: to improve the angular resolution, it is necessary that the antenna array’s aperture is increased, but in order to avoid the violation of the sampling theorem in the spatial domain, it is inevitable to keep the dis- tances between the array elements smaller than , where denotes the free-space wavelength at the highest used frequency, which, in turn, leads to a large number of necessary array ele- ments and therefore channels. This is often not feasible because of the resulting high hardware complexity and the large amount of data that is generated from the increased number of channels.