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Antenna calibration requires the exact knowledge of the phase center position. In addition, the accuracy of calibration is often affected by multi-path propagation. We present an approach to reliably estimate the phase center position and to correct for multi-path propagation effects and demonstrate the performance of this approach with horn antennas in the W-band between 75 GHz and 110 GHz.
The emission of a full body scanner Rohde & Schwarz QPS 100TM has been measured traceable to the SI units in the operation frequency range of the device between 70 GHz and 80 GHz. The measurements which have been performed with a calibrated spectrum analyzer and calibrated horn antennas are discussed with regard to the safety limits for non-ionizing electromagnetic radiation.
Reliable in-vitro millimeter and sub-millimeter wave exposure investigations need well characterized radiation sources, accurate phantom models and calibrated SAR/temperature-rising probes. A practical setup is presented for studies regarding the human skin exposure at frequencies above 30 GHz. A standard-gain horn antenna is used to provide a Gaussian beam and known field-intensity on the sample,...
Along with the steady increase of data rates in communication applications, the utilized bandwidths are growing accordingly, thus requiring higher carrier frequencies in face of the almost entirely occupied spectrum in the mm wave range and below. Therefore, channel measurements up to the lower THz frequency range are necessary for the development of modern and future communication systems. In this...
For the modeling and design of communication systems in the lower THz frequency range the propagation conditions need to be known. We show a comparison of ultra broadband channel measurements from 50 GHz to 325 GHz in different scenarios related to typical office and industry environments.
We have designed 4x4-phased-array patch antennas at 77 and 94 GHz using simulations based on the finite integration technique in the time-domain. The antennas are designed for communications and for the development of antenna measuring techniques. They have been fabricated and characterized with regard to input impedance and antenna diagrams.
Due to the growing demand for bandwidth the tendency to employ higher frequencies up to the THz range has increased in the last few years. Yet, for implementing future THz communication systems, adequate test and characterization measurements are essential. In this paper we present channel propagation measurements in a typical office environment covering the wide frequency range from 50 GHz up to...
In a project funded by the German Federal Office for Radiation Protection (BfS) two different human skin cell types (HaCaT and HDF) have been exposed under defined environmental conditions to continuous-wave THz radiation at three distinct frequencies of 106 GHz, 380 GHz and 2.52 THz with free-space power densities between 0.03 mW/cm2 and 1.96 mW/cm2 adjusted traceable to the SI units. In three independent...
Indoor wireless communication channels will be operated in the 60 GHz band soon and will work at 300 GHz and beyond in the foreseeable future. Although diffraction occurs at a multitude of objects in indoor environments and needs to be considered for reliable propagation simulations, very few work exists on this topic in the mm and sub-mm wave bands. Here, we present measurements of the diffraction...
The constantly growing need for unoccupied and unregulated bandwidth will lead to the extension of operation frequencies of ultrabroadband communication systems into the lower Terahertz frequency range. Here we present first channel measurements at 300 GHz for two simple indoor scenarios, a point-to-point link on a desktop and a connection from a desktop to an access point within an office room. For...
In vitro field exposition experiments with biological samples performed to explore possible detrimental effects of non-ionizing radiation on biological systems require appropriate experimental setups, careful control and monitoring of environmental and exposition conditions and a reliable dosimetry to quantify the amount of stress imposed upon the sample. In the Terahertz frequency range, the experimental...
Using THz radiation as reliable measurement tool requires the accurate knowledge of beam properties. We present approaches to scan beam profiles and measure the radiation power traceable to SI units between 0.1 and 2.5 THz.
This paper presents ultra broadband channel measurements in a typical office room. The measured channel impulse response and transfer function is compared to a ray tracing simulation performed with a 3D model of the scenario. Additionally, we show reflection losses of the building materials in the room which are required as input data for the ray tracing algorithm.
Due to the pervasive use of broadcasting devices for mobile applications, ambient levels of radio frequency (RF) power, particularly in cities and work places, tend to increase in the EU. The project described here will enable directive EC 2004/40/EC “Physical Agents Directive” to be implemented across Europe by ensuring that the necessary artefact standards and measurement techniques exist to allow...
Due to the wide-spread use of broadcasting devices for mobile applications, surrounding levels of radio frequency (RF) radiation, particularly in cities and work places, tend to increase in the EU. A project funded by the EU aims to address the health and exposure requirements for the electromagnetic fields that are in wide-spread public use. This includes the development of traceable electromagnetic...
Recently, analogue video signal transmission at 300 GHz has been demonstrated using a versatile Schottky mixer based measurement system designed for terahertz communication channel modelling and propagation studies. In this reported work, digital signal transmission at 300 GHz using this system is demonstrated and analysed. The performance of the digital transmission setup is characterised with respect...
This paper gives an overview of current issues in the field of mm-wave and THz communications. A concept for radio channel modeling is presented together with the latest channel investigation results in this frequency range. In addition we discuss the status quo of standardization activities and the worldwide ongoing spectrum allocation plans.
Initiated by the German Federal Office for Radiation Protection (BfS) field exposition experiments have been designed to examine genotoxic effects of THz radiation in vitro. Under defined environmental conditions, two different human skin cell types are exposed to continuous-wave radiation at six distinct frequencies between 100 GHz and 2.52 THz originating from different sources of THz radiation...
Complex measurement systems being assembled on site have been found to suffer from electromagnetic interference although components of the systems passed the required electromagnetic compatibility (EMC) tests. We present an on-site test system that allows for the EMC evaluation of on-site assembled large measuring system installations in the frequency range from 27 MHz up to 5.8 GHz and propose a...
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