Design of a Multifrequency FMCW Radar

This paper pertains to the design aspects of a multifrequency FMCW radar with emphasis on the engineerig problems involved in its implementation. This radar generates 8 separate FMCW signals which are then additively mixed and radiated. The target return also comprises returns at these frequencies. The signals are then split into their constituents and processed collectively to obtain an extremely high resolution synthetic image of the target. The ultimate objectives of the radar are multiple: 1. to study waveforms of variable and flexible transmitted power spectra. 2. to study ultra-wide band processing techniques, without the need to have an ultra-wide instantaneous bandwidth. 3. to study coherent, non-coherent and mixed processing concepts. The radar itself will belong to the class of LPI radars. The high resolutions obtained by this technique are comparable to those that can be achieved by ultra-wide band radar. The additional advantage here is that this radar can be built using essentially "bought - out" items i.e. it does not require any radically new technology. The paper discusses the problems involved in the implementation of this radar with special emphasis on the critical items viz. the design of the power combiner and the power resolver. It finally analyses the results achieved in the implementation of these critical units.