Ove Schimmer

Non-contacting determination of moisture content in bulk materials using sub-nanosecond UWB-pulses

This paper presents a new approach of noncontacting moisture determination in bulk materials utilizing time-domain transmissometry. The described method is independent of the mass per area of the material under test and does not suffer from measurement ambiguities, which are well known from frequency-domain methods. Ultra-wideband quasi-Gaussian monocycle pulses are applied with a cycle width of approximately 400 ps. The measurement signal is transmitted through the material over free space using double-ridged horn antennas. The received signal is acquired in the time domain and analyzed with different methods of data processing. The results obtained with multiple linear regression, principal component analysis, and artificial neural networks are compared with each other. Furthermore, a possible hardware implementation for a dedicated time-domain transmissometer is proposed based on a earlier developed time-domain reflectometer for the determination of food quality.This paper presents a new approach of noncontacting moisture determination in hulk materials, which is independent of the mass per area of the material. It also dues not suffer from measurement ambiguities, which are well known from frequency domain methods. UWB quasi ganssian monocycle pulses are applied with a cycle width of approximately 400ps. The measurement signal is transmitted through the material over free space. The received signal is acquired in the time-domain and analysed, using multivariate calibration techniques. Principal component analysis and principal component regression yield the best results. Two different types of antennas and their influence on the accuracy of the measurements are investigated.

UWB-Sensors for Industrial Applications

Apart of the new perspectives ultra wideband technology opens in communications, it also permits the development of a new class of electromagnetic industrial sensors, which is based on multi-parameter measurements. This paper presents three versions of experimental UWB-sensors of the new kind and demonstrates their capabilities. A non-contacting free space sensor for determining the moisture content of granular materials, a contacting sensor for estimating the storage time and quality of foodstuffs, and a sensing system for detecting and locating foreign bodies in material streams are described. The fundamental system design for all sensors is quite similar and based on pulses with picosecond rise times. An engineered version of the sensor system is presented for the quality sensor.

UWB-sensors in food quality management — the way from the concept to market

A long and well known subfield of the ultra-wideband technology is the time-domain-reflectometry (TDR), which found its ways in a wide field of applications. This paper describes different aspects regarding the way from the first concept of a TDR prototype instrument towards a fully engineered device, suitable for food quality management in an industrial scale. The concept of the described TDR widely depends on the frequency range of the task to be solved, thus is one of the most important aspects in the chain of development. Furthermore industrial requirements with respect to handling of the device and the integration in existing systems have to be kept in mind.