Frank Daschner - Academia.edu (original) (raw)
Papers by Frank Daschner
Electromagnetic Aquametry
ABSTRACT The frequency dependence of dielectric material properties of porous mineral materials s... more ABSTRACT The frequency dependence of dielectric material properties of porous mineral materials such as soil are not only disturbing in applications with high frequency electromagnetic (HF-EM) techniques but also contain valuable information of the material due to strong contributions by interactions between an aqueous pore solution and mineral phases. This circumstance opens the possibility to estimate physico-chemical parameters such as water content, texture, mineralogy and matric potential with broadband HF-EMmeasurement techniques. In this context, a multivariate approach was applied to analyse coupled hydraulic and dielectric material properties of a silty clay soil.
Tissue Engineering Part C: Methods, 2012
This paper presents a free-space method for the determination of the permittivity of non-dispersi... more This paper presents a free-space method for the determination of the permittivity of non-dispersive low-loss rectangular shaped dielectric objects. The dielectric object under investigation is illuminated by a sub-nanosecond pulse radiated from a linear polarized transmitting antenna. A scattered pulse is received by a dual polarized line array. The object can be moved orthogonally to the line array forming a virtual two dimensional antenna array. Several objects of different shape, size, orientation and permittivity are measured. It is supposed that the time domain data contains information about the shape and the permittivity. The data is then subjected to multivariate analysis to separate those effects due to the geometry of the object from those due to its dielectric properties. Results for the determination of the permittivity independent of shape, size and orientation using principal component regression and artificial neural networks are presented. It is shown that the determ...
This paper presents a dual polarized antenna for UWB sensor applications. The antenna consists of... more This paper presents a dual polarized antenna for UWB sensor applications. The antenna consists of four circular radiating elements forming two dipoles excited in even mode in both polarizations. The geometry avoids directly crossed baluns but requires two power dividers and four tapered baluns because of four feeding points. It provides an input return loss better than 7dB over a frequency band from 2GHz to 5.7GHz. The isolation between both ports is better than 30dB. At 5GHz a gain of 5.2dB is achieved. The dimensions of the antenna including the feeding network and absorbers are 50mm×50mm×143.5mm. A line array of four antennas was built as part of a free-space measurement system for the non-contacting permittivity determination of irregular shaped dielectric objects.
The frequency dependence of dielectric material properties of porous mineral materials such as so... more The frequency dependence of dielectric material properties of porous mineral materials such as soil are not only disturbing in applications with high frequency electromagnetic (HF-EM) techniques but also contain valuable information of the material due to strong contributions by interactions between an aqueous pore solution and mineral phases. This circumstance opens the possibility to estimate physico-chemical parameters such as water content, texture, mineralogy and matric potential with broadband HF-EMmeasurement techniques. In this context, a multivariate approach was applied to analyse coupled hydraulic and dielectric material properties of a silty clay soil.
2007 IEEE International Conference on Ultra-Wideband, 2007
ABSTRACT
2012 IEEE International Conference on Ultra-Wideband, 2012
ABSTRACT This paper presents a method for the non-contacting moisture prediction of small objects... more ABSTRACT This paper presents a method for the non-contacting moisture prediction of small objects using m-sequences. The objects under test are placed in a free-space transmission path. Their UWB impulse responses are captured using an m-sequence method which provides high signal quality by means of ultra low jitter and noise. The size of the objects is in the range of the coherence length and smaller than the footprints of the antennas. The impulse responses depend on the moisture content (dielectric properties) and the geometry. Multivariate calibration is applied in order separate these influences and to develop a statistical model for the moisture content. For the prediction of moisture content an accuracy of 0.55% was achieved while it was varied in a range between 4.3% and 23.4%.
2008 IEEE International Conference on Ultra-Wideband, 2008
ABSTRACT
Proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference [Cat. No. 00CH37066], 2000
In this paper a method for determining the composition of foodstuffs from the measured microwave ... more In this paper a method for determining the composition of foodstuffs from the measured microwave dielectric spectra using an open ended coaxial probe is presented. The dielectric spectra of several kinds of meat were collected in the range of 200 MHz to 12 GHz. The data are used to predict the composition of the materials applying principal component analysis and regression. Effects of the reduction of the used bandwidth on the performance are investigated. Optimal frequency ranges with respect to measurement accuracy and hardware effort for an instrument are defined
ICMMT 2000. 2000 2nd International Conference on Microwave and Millimeter Wave Technology Proceedings (Cat. No.00EX364), 2000
In this paper, a novel microwave measurement approach is presented, which is capable of determini... more In this paper, a novel microwave measurement approach is presented, which is capable of determining selected food properties from the dielectric spectrum. Such properties could be the water content, a possible amount of additionally added water, the content of conducting ions or the percentage of other constituents, having a noticeable influence on the effective complex permittivity versus frequency. The approach
2011 IEEE International Conference on Ultra-Wideband (ICUWB), 2011
ABSTRACT This paper presents a new approach for the accurate free-space characterization of irreg... more ABSTRACT This paper presents a new approach for the accurate free-space characterization of irregularly shaped and arbitrarily oriented dielectric objects. The objects under test are illuminated by UWB-pulses and the scattered pulses are collected by an array of receiving antennas. The scattered pulses contain information about the geometrical properties as well as the dielectric properties; a multivariate calibration method is supposed to be able to separate these properties. A classification algorithm is applied prior to the multivariate calibration. It provides a classification into two classes, low or high permittivity. The statistical calibration method is then applied separately in each class. This leads to a significant improvement of the accuracy of the determination of the dielectric properties compared to processing without classification.
Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications, 2013
2012 19th International Conference on Microwaves, Radar & Wireless Communications, 2012
This paper presents considerations regarding the signal quality for free-space UWB measurements. ... more This paper presents considerations regarding the signal quality for free-space UWB measurements. Scattered pulses from various small and irregularly shaped objects are subjected to multivariate calibration in order to develop a statistical model for the moisture content. The accuracy of this model strongly depends on both short term and long term variations of the received signals. Amplitude noise and jitter are referred to as short term variations. Low noise and low jitter are crucial for the accuracy of the multivariate calibration methods. The dependence of the signal quality on the accuracy is investigated. Furthermore, the influence of long term variations, e.g. temperature differences, is considered.
2013 IEEE International Conference on Ultra-Wideband (ICUWB), 2013
ABSTRACT
Photonic Metamaterials: From Random to Periodic, 2006
ABSTRACT
Advances in Radio Science, 2006
In order to verify simulations of a concave lens based upon a photonic crystal, it was scaled and... more In order to verify simulations of a concave lens based upon a photonic crystal, it was scaled and built for the application in the microwave range. Its field distribution was measured between 5.5 and 12 GHz. Due to the effective refractive index smaller than 1, focusing points were found in spite of the concave shape. The survey of the field
Electromagnetic Aquametry
ABSTRACT The frequency dependence of dielectric material properties of porous mineral materials s... more ABSTRACT The frequency dependence of dielectric material properties of porous mineral materials such as soil are not only disturbing in applications with high frequency electromagnetic (HF-EM) techniques but also contain valuable information of the material due to strong contributions by interactions between an aqueous pore solution and mineral phases. This circumstance opens the possibility to estimate physico-chemical parameters such as water content, texture, mineralogy and matric potential with broadband HF-EMmeasurement techniques. In this context, a multivariate approach was applied to analyse coupled hydraulic and dielectric material properties of a silty clay soil.
Tissue Engineering Part C: Methods, 2012
This paper presents a free-space method for the determination of the permittivity of non-dispersi... more This paper presents a free-space method for the determination of the permittivity of non-dispersive low-loss rectangular shaped dielectric objects. The dielectric object under investigation is illuminated by a sub-nanosecond pulse radiated from a linear polarized transmitting antenna. A scattered pulse is received by a dual polarized line array. The object can be moved orthogonally to the line array forming a virtual two dimensional antenna array. Several objects of different shape, size, orientation and permittivity are measured. It is supposed that the time domain data contains information about the shape and the permittivity. The data is then subjected to multivariate analysis to separate those effects due to the geometry of the object from those due to its dielectric properties. Results for the determination of the permittivity independent of shape, size and orientation using principal component regression and artificial neural networks are presented. It is shown that the determ...
This paper presents a dual polarized antenna for UWB sensor applications. The antenna consists of... more This paper presents a dual polarized antenna for UWB sensor applications. The antenna consists of four circular radiating elements forming two dipoles excited in even mode in both polarizations. The geometry avoids directly crossed baluns but requires two power dividers and four tapered baluns because of four feeding points. It provides an input return loss better than 7dB over a frequency band from 2GHz to 5.7GHz. The isolation between both ports is better than 30dB. At 5GHz a gain of 5.2dB is achieved. The dimensions of the antenna including the feeding network and absorbers are 50mm×50mm×143.5mm. A line array of four antennas was built as part of a free-space measurement system for the non-contacting permittivity determination of irregular shaped dielectric objects.
The frequency dependence of dielectric material properties of porous mineral materials such as so... more The frequency dependence of dielectric material properties of porous mineral materials such as soil are not only disturbing in applications with high frequency electromagnetic (HF-EM) techniques but also contain valuable information of the material due to strong contributions by interactions between an aqueous pore solution and mineral phases. This circumstance opens the possibility to estimate physico-chemical parameters such as water content, texture, mineralogy and matric potential with broadband HF-EMmeasurement techniques. In this context, a multivariate approach was applied to analyse coupled hydraulic and dielectric material properties of a silty clay soil.
2007 IEEE International Conference on Ultra-Wideband, 2007
ABSTRACT
2012 IEEE International Conference on Ultra-Wideband, 2012
ABSTRACT This paper presents a method for the non-contacting moisture prediction of small objects... more ABSTRACT This paper presents a method for the non-contacting moisture prediction of small objects using m-sequences. The objects under test are placed in a free-space transmission path. Their UWB impulse responses are captured using an m-sequence method which provides high signal quality by means of ultra low jitter and noise. The size of the objects is in the range of the coherence length and smaller than the footprints of the antennas. The impulse responses depend on the moisture content (dielectric properties) and the geometry. Multivariate calibration is applied in order separate these influences and to develop a statistical model for the moisture content. For the prediction of moisture content an accuracy of 0.55% was achieved while it was varied in a range between 4.3% and 23.4%.
2008 IEEE International Conference on Ultra-Wideband, 2008
ABSTRACT
Proceedings of the 17th IEEE Instrumentation and Measurement Technology Conference [Cat. No. 00CH37066], 2000
In this paper a method for determining the composition of foodstuffs from the measured microwave ... more In this paper a method for determining the composition of foodstuffs from the measured microwave dielectric spectra using an open ended coaxial probe is presented. The dielectric spectra of several kinds of meat were collected in the range of 200 MHz to 12 GHz. The data are used to predict the composition of the materials applying principal component analysis and regression. Effects of the reduction of the used bandwidth on the performance are investigated. Optimal frequency ranges with respect to measurement accuracy and hardware effort for an instrument are defined
ICMMT 2000. 2000 2nd International Conference on Microwave and Millimeter Wave Technology Proceedings (Cat. No.00EX364), 2000
In this paper, a novel microwave measurement approach is presented, which is capable of determini... more In this paper, a novel microwave measurement approach is presented, which is capable of determining selected food properties from the dielectric spectrum. Such properties could be the water content, a possible amount of additionally added water, the content of conducting ions or the percentage of other constituents, having a noticeable influence on the effective complex permittivity versus frequency. The approach
2011 IEEE International Conference on Ultra-Wideband (ICUWB), 2011
ABSTRACT This paper presents a new approach for the accurate free-space characterization of irreg... more ABSTRACT This paper presents a new approach for the accurate free-space characterization of irregularly shaped and arbitrarily oriented dielectric objects. The objects under test are illuminated by UWB-pulses and the scattered pulses are collected by an array of receiving antennas. The scattered pulses contain information about the geometrical properties as well as the dielectric properties; a multivariate calibration method is supposed to be able to separate these properties. A classification algorithm is applied prior to the multivariate calibration. It provides a classification into two classes, low or high permittivity. The statistical calibration method is then applied separately in each class. This leads to a significant improvement of the accuracy of the determination of the dielectric properties compared to processing without classification.
Ultra-Wideband Radio Technologies for Communications, Localization and Sensor Applications, 2013
2012 19th International Conference on Microwaves, Radar & Wireless Communications, 2012
This paper presents considerations regarding the signal quality for free-space UWB measurements. ... more This paper presents considerations regarding the signal quality for free-space UWB measurements. Scattered pulses from various small and irregularly shaped objects are subjected to multivariate calibration in order to develop a statistical model for the moisture content. The accuracy of this model strongly depends on both short term and long term variations of the received signals. Amplitude noise and jitter are referred to as short term variations. Low noise and low jitter are crucial for the accuracy of the multivariate calibration methods. The dependence of the signal quality on the accuracy is investigated. Furthermore, the influence of long term variations, e.g. temperature differences, is considered.
2013 IEEE International Conference on Ultra-Wideband (ICUWB), 2013
ABSTRACT
Photonic Metamaterials: From Random to Periodic, 2006
ABSTRACT
Advances in Radio Science, 2006
In order to verify simulations of a concave lens based upon a photonic crystal, it was scaled and... more In order to verify simulations of a concave lens based upon a photonic crystal, it was scaled and built for the application in the microwave range. Its field distribution was measured between 5.5 and 12 GHz. Due to the effective refractive index smaller than 1, focusing points were found in spite of the concave shape. The survey of the field