Realization of a Sliding-Correlator-Based Continuous-Wave Pseudorandom Binary Phase-Coded Radar Operating in W-Band

In this paper, we present a continuous-wave (CW) mm-wave radar, which is based on binary phase-coded pseudorandom signals. The receiving section is operated as a sliding correlator, which allows to greatly reduce the bandwidth required in the baseband blocks of the system. A certain class of pseudorandom sequences, with so-called almost perfect autocorrelation properties, is used as probing signal. This leads to a good dynamic range, even for short sequence lengths. The presented hardware is based on a SiGe front-end chip, which includes a frequency multiplier to generate a 79-GHz carrier from a fixed-frequency source operating at 4.39 GHz. A field-programmable gate array generates the binary sequences with a bit rate of 1 Gb/s. This sequence is modulated onto the W-band carrier by binary phase-shift keying modulators realized within the SiGe chip. In this way, a flexible prototype was realized that was used to perform different radar experiments ranging from static single-target scenarios to range-Doppler measurements with multiple targets. It could be shown that the realized pseudorandom radar achieves a range resolution of 15 cm and ranging standard deviations in the millimeter range. This is comparable to frequency-modulated CW measurements with a bandwidth of 2 GHz, which were carried out using the same hardware for comparison purposes.