Calibrated and Frequency Traceable D-Band FMCW Radar for VNA-like S-Parameter Measurements
Timo Jaeschke, Simon Kueppers, Nils Pohl, Jan Barowski
Abstract
In this paper a D-band frequency modulated continuous wave (FMCW) radar system and a signal processing chain for vector network analyzer(VNA)-like S-parameter measurements are presented. The radar sensor covers an ultra-wide 56GHz (126GHz–182GHz, 36.4%) sweep bandwidth and can be equipped with a standard WM-1651 [1] (WR-6.5) waveguide flange. To achieve measurement-grade phase stability a cascaded multi-phase-locked-loop (PLL) frequency traceable reference clock concept is introduced and system stability measurements are presented. Finally, a FMCW radar calibration concept is provided to allow complex (magnitude and phase) S-parameter measurements with cost-effective wide-band FMCW radar sensors. To demonstrate the achieved system performance and the potential of this approach, material characterization measurements are presented and compared to conventional VNA measurement equipment with waveguide extenders.