Rabe, Hanno; Denicke, Eckhard; Zietz, Christian; Armbrecht, Gunnar; Rolfes, Ilona (Institut für Hochfrequenztechnik und Funksysteme, Hannover, Germany)
Radar systems at microwave frequencies are the state-of-the-art solution for precise and robust level measurements in industrial tank environments as they allow the application in harsh environments. Horn antennas or dielectric antennas enable highly directive measurements. However, the physical aperture size of the antenna is restricted by the standardized nozzle and flange diameters of the tank. This limits the beam sharpness of the antenna which is necessary to prevent unwanted backscattering from objects surrounding the medium surface such as stirrers, pipes or the tank wall. These parasitic reflectors add disturbances to the radar output signal and jeopardize the unambiguity of the measurement task. To overcome these drawbacks, this contribution evaluates a multistatic antenna approach offering the capability of beamforming in conjunction with an imaging algorithm to exploit the information of the scatterer positions in order to isolate the level reflection among all occurring reflections. This leads to an increase of the robustness of the measurement.