Fractional-N PLL based FMCW sweep generator for an 80 GHz radar system with 24.5 GHz bandwidth

[摘要] A phase-locked loop (PLL) based frequency synthesizer capable of generatinghighly linear broadband frequency sweeps as signal source of a highresolution 80 GHz FMCW radar system is presented. The system achieves a wideoutput range of 24.5 GHz starting from 68 GHz up to 92.5 GHz. Highfrequencies allow the use of small antennas for small antenna beam angles.The wide bandwidth results in a radar system with a very high rangeresolution of below 1.5 cm. Furthermore, the presented synthesizer providesa very low phase noise performance of −80 dBc/Hz at 80 GHz carrier frequency and 10 kHzoffset, which enables high precision distance measurements with lowrange errors. This is achieved by using two nested phase-looked loops withhigh order loop filters. The use of a fractional PLL divider anda high phase frequency discriminator (PFD) frequency assures an excellentramp linearity.

[学科分类] 电子、光学、磁材料