A measurement device (11) comprising a transmitter (10) for providing a transmitted signal； a signal splitter (12) for splitting the transmitted signal into transmitted signal components； a set of planar dielectric layers (14) spaced apart and parallel to each other to provide a channel (16) for agricultural material to flow above or below the set of planar dielectric layers (14), each dielectric planar member having an upper side (18) and a lower side (20)； an outer set of conductive patches on one of the outer sides (22) of the set of planar dielectric layers, where transmit patches (30) of the outer set of conductive patches are coupled to the transmitter (10) via the signal splitter (12) and where receive patches (32) of the outer set of conductive patches are coupled to one or more receivers (34) to receive a radio frequency fringing field associated with the transmitted signal of one or more adjacent corresponding transmit patches； a detector (40) associated with one or more respective receivers (34) for determining or estimating an attenuation； and an electronic data processing unit (42) configured to evaluate the estimated attenuation to estimate an amount, volume, mass, flow or yield of the agricultural material.
