Braunschweig, Germany
Braunschweig, Germany

Time filter

Source Type

Scherger B.,University of Marburg | Born N.,University of Marburg | Jansen C.,University of Marburg | Schumann S.,University of Marburg | And 3 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2012

We present a terahertz transmission blaze-grating, which can be fabricated, easily, cost efficiently and in large numbers using compression molding of micro-powder. The diffraction properties of the grating are derived by simulation of electro-magnetic field scattering and are compared with angle-dependent measurements obtained in a terahertz time-domain setup. An excellent match between simulation and measurement is found, demonstrating the ability of the terahertz transmission blaze-grating for spatial dispersion of terahertz waves. Thus, this and similar terahertz transmission blaze-gratings can be used as dispersive elements for applications such as spectrometers or novel THz imaging systems. © 2011-2012 IEEE.


Ahmadi-Boroujeni M.,University of Tehran | Altmann K.,University of Marburg | Scherger B.,University of Marburg | Jansen C.,University of Marburg | And 3 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2013

In this paper, we introduce a parallel-plate ladder waveguide (PPLWG) for THz waves. The characteristics of the guided modes of this structure which belong to the category of spoof surface plasmons are studied using the generalized multipole technique and its potential applications are discussed. Moreover, the proposed structure is experimentally investigated in a THz time-domain spectroscopy system and a comparison between the calculated and measured amplitude and phase characteristics is given. It is shown that the dominant mode of the PPLWG can be excited by an incident focused beam and a high degree of field confinement in the THz regime can be achieved. © 2011-2012 IEEE.


Gente R.,University of Marburg | Jansen C.,University of Marburg | Geise R.,Institute for Electromagnetic Compatibility | Peters O.,University of Marburg | And 5 more authors.
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz | Year: 2012

Scaled radar cross section measurements are a commonly employed tool in civil and military aviation. We propose a flexible setup which makes use of a fiber-coupled THz time domain spectrometer and a two circle goniometer. Measurements are performed on reference objects and on scale model aircraft. © 2012 IEEE.


Stecher M.,University of Marburg | Jansen C.,University of Marburg | Ahmadi-Boroujeni M.,University of Tehran | Lwin R.,University of Sydney | And 4 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2012

In this paper, we report on a new form of polymeric 2D photonic crystal filters for THz frequencies fabricated using a standard fiber drawing technique. The band stop filters were modeled and designed using the generalized multipole technique. The frequency and angle-dependent transmission characteristics of the photonic crystal structures were characterized in a THz time-domain spectrometer. © 2011 IEEE.


Gente R.,University of Marburg | Jansen C.,University of Marburg | Jansen C.,Terahertz Communications Laboratory | Geise R.,Institute for Electromagnetic Compatibility | And 7 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2012

The knowledge of the radar cross section (RCS) of aircraft and other objects is of great interest both for civil and military applications. Scaled setups are often used in order to facilitate RCS measurements in a well-defined laboratory environment. As radar frequencies steadily increase, for high scaling factors these measurements have to be carried out in the THz regime. In this paper, we propose an experimental setup consisting of a fiber- coupled THz time-domain spectrometer integrated with a two circle goniometer, which enables bistatic scaled RCS measurements. To assess the accuracy of the setup, measurements on reference objects as well as on scale model aircraft are performed. The measured data of the reference objects is compared to the theoretical predictions. As for the aircraft, the comparison between a Panavia 200 Tornado and a Lockheed F117 Nighthawk is made and the influence of individual components like bombs on the overall RCS is evaluated. © 2012 IEEE.


Jansen C.,University of Marburg | Jansen C.,Terahertz Communications Laboratory | Priebe S.,TU Braunschweig | Priebe S.,Terahertz Communications Laboratory | And 8 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2011

Recent years have seen a tremendous increase in the demand for wireless bandwidth. To support this demand by innovative and resourceful use of technology, future communication systems will have to shift towards higher carrier frequencies. Due to the tight regulatory situation, frequencies in the atmospheric attenuation window around 300 GHz appear very attractive to facilitate an indoor, short range, ultra high speed THz communication system. In this paper, we investigate the influence of diffuse scattering at such high frequencies on the characteristics of the communication channel and its implications on the non-line-of-sight propagation path. The Kirchhoff approach is verified by an experimental study of diffuse scattering from randomly rough surfaces commonly encountered in indoor environments using a fiber-coupled terahertz time-domain spectroscopy system to perform angle- and frequency-dependent measurements. Furthermore, we integrate the Kirchhoff approach into a self-developed ray tracing algorithm to model the signal coverage of a typical office scenario. © 2011 IEEE.


Jacob M.,TU Braunschweig | Jacob M.,Terahertz Communications Laboratory | Priebe S.,TU Braunschweig | Priebe S.,Terahertz Communications Laboratory | And 8 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2012

Current indoor wireless communication systems are shifting from classical microwave bands towards mm wave frequencies, whereas here the 60 GHz band is of special interest. Future systems are expected to work at even higher carrier frequencies in the sub-mm band beyond 300 GHz. In indoor wave propagation channels of such systems, diffraction occurs at a multitude of objects and hence must be considered for propagation simulations. Although the relevance of diffraction has been thouroughly studied at lower frequencies, it has not yet been analyzed methodically in the mm and sub-mm wave frequency range. This paper presents an extensive measurement campaign of the diffraction at objects like edges, wedges and cylinders for frequencies of 60 and 300 GHz. Different materials, realistic antennas as well as transmission through the objects are taken into account. Theoretical approaches are validated against the measurement results. Furthermore, shadowing of rays by persons is investigated and modeled with the help of diffraction. Finally, ray tracing is applied in an office scenario in order to evaluate the impact of diffraction on mm and sub-mm wave indoor channel characteristics. © 2006 IEEE.


Priebe S.,TU Braunschweig | Priebe S.,Terahertz Communications Laboratory | Britz D.M.,ATandT Inc. | Jacob M.,TU Braunschweig | And 7 more authors.
IEEE Transactions on Terahertz Science and Technology | Year: 2012

At Terahertz (THz) frequencies, passive space-borne Earth exploration services may be interfered by upcoming active communication applications. Aiming for coexistent use of the THz band by both active and passive applications, this paper identifies critical scenarios where interference can possibly occur. Atmospheric attenuation simulations are used along with appropriate propagation models to account for correct scenario-specific wave propagation conditions. Furthermore, distance-dependent measurements of the path loss are taken at 300 GHz. The atmospheric attenuation and propagation models are then employed in order to simulate possible interference powers for the individual reference scenarios under worst case-conditions. Based on existing data for the maximum allowed interference, guidelines for appropriate system specifications of active THz hardware (e.g., transmit power constraints) are developed and achievable system performances are evaluated. Countermeasures against potential interference are discussed. Thus, any interference can be anticipated and compensated for already in the early design phase of THz communication systems. © 2011-2012 IEEE.


Priebe S.,TU Braunschweig | Priebe S.,Terahertz Communications Laboratory | Jastrow C.,Terahertz Communications Laboratory | Jastrow C.,Physikalisch - Technische Bundesanstalt | And 8 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2011

Ultrabroadband Terahertz communication systems are expected to help satisfy the ever-growing need for unoccupied bandwidth. Here, we present ultra broadband channel measurements at 300 GHz for two distinct indoor scenarios, a point-to-point link of devices on a desktop and the connection of a laptop to an access point in the middle of an office room. In the first setup, measurements are taken with regard to distance, different antenna types and device displacements. Additionally, an interference constellation according to the two-ray model is examined. In the second setup, the focus is on the detection and characterization of the LOS- and the NLOS-paths in an indoor environment, including a maximum of two reflections. Temporal channel characteristics are examined with regard to maximum achievable symbol rates. Furthermore, ray obstruction due to objects in the transmission path is investigated. © 2011 IEEE.


Priebe S.,TU Braunschweig | Priebe S.,Terahertz Communications Laboratory | Kannicht M.,TU Braunschweig | Jacob M.,TU Braunschweig | And 3 more authors.
Journal of Communications and Networks | Year: 2013

Ultra broadband communication systems operated at THz frequencies will require the thorough knowledge of the propagation channel. Therefore, an extensive measurement campaign of 50 GHz wide indoor radio channels is presented for the frequencies between 275 and 325 GHz. Individual ray paths are resolved spatially according to angle of arrival and departure. A MIMO channel is recorded in a 2×2 configuration. An advanced frequency domain ray tracing approach is used to deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of the ray tracing algorithm. Resulting ray tracing accuracies are discussed. © 2013 KICS.

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