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Martin Jacob - IEEE Xplore Author Profile

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In this work, the estimation of suitable antenna configurations for mm-wave communications supported by ray tracing simulations is presented. The influence of human blockage on the propagation channel in the conference room is investigated. Simulations were done for different numbers of persons. By the obtained results we can estimate the best antenna configuration for the specific environment.Show More
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 confi...Show More
This paper presents an extension and a holistic validation of the IEEE 802.11ad 60 GHz human blockage model. In order to validate the modeling methodology, it is compared with real-time broadband radio channel measurements. In addition, the model is extended by the functionality of taking into account multiple persons. Based on the extended model, the impact of multiple persons on the 60 GHz radio...Show More
In this paper, fundamental investigations of human shadowing at 60 GHz are presented. Different electromagnetic models are analyzed regarding their accuracy and computional effort. Therefore, different geometrical representations of the human body, namely circular cylinders with different dielectric properties, the dielectric elliptic cylinder, and the so-called multiple knife edge (MKE) model are...Show More
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 diffractio...Show More
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 acc...Show More
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. F...Show More
Antenna misalignment can lead to a severe performance deterioration of wireless THz communication links. In this paper, we propose to model the misalignment as a random process. Based on the misalignment model, Monte Carlo simulations are conducted in order to assess the impact of misalignment on THz communication channels in an office scenario. Ray tracing accounts for correct propagation conditi...Show More
This paper presents results of a systematic 2×2 MIMO channel measurement campaign, which has been carried out in order to analyze the impact of human body shadowing (HBS) on the 60 GHz wideband channel. A piecewise linear and two analytical models, namely the double knife-edge (DKE) model and a cylinder approach incorporating the uniform theory of diffraction (UTD), are used to approximate and to ...Show More
This article investigates the influence of antenna directivities on the characteristics of THz communication channels. Gain diagrams of various actual antenna types like a horn antenna, an additional lense or a waveguide are measured at 300 GHz and compared to a simplified beam model. Ray tracing simulations are performed in an office room, accounting for realistic propagation conditions. The simu...Show More
Using a similar approach to that applied in acoustics and in microwave reverberation chambers, a theory of wideband propagation in a closed environment is discussed. Here, a room environment is viewed as a lossy cavity, characterized by diffuse scattering from walls and internal obstacles. For experimental results, measurements from 3 to 8 GHz were performed in a 24 passenger section of an aircraf...Show More
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 consid...Show More
New ultra high data rate systems in the 60 GHz band, especially those targeting high definition video indoor transmission, have a strong requirement for Quality of Service to prevent link outage, and this has to be performed at the MAC level. This paper describes a new simulation platform for these ultra high data rate wireless systems. This new tool models the complete wireless system, including ...Show More
In this paper, the evaluation of different 60 GHz WLAN antenna designs is presented. Based on ray tracing and human blockage the radio propagation in a living room scenario is modeled. Then simulated 3D antenna patterns of conventional and smart antennas are linked to the radio channel data. The performance of the antennas is compared in terms of the coverage probability within the living room.Show More
Satellite positioning accuracy is degraded by multipath propagation between satellite and the receiver. In this paper we give an overview of a new approach to model and correct this impairment, and present some preliminary results. High accuracy 3D laser scanning is utilized to model the environment. This gives an accurate basis for the characterization of the satellite to earth radio channel by u...Show More
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 ran...Show More
This paper presents the human blockage model based on the authors' work in the framework of the IEEE 802.11ad 60 GHz channel model development. The human blockage model combines ray tracing simulations, an electromagnetic diffraction model and a random walk model for human movement. In addition to the stochastic model the impact of human blockage on wireless communications is analyzed.Show More
In this paper, we present an approach for the modeling of non-specular scattering at rough surfaces in the THz frequency range by means of the Kirchhoff scattering theory. The practical implementation of the Kirchhoff model in a ray tracing algorithm is discussed. Ray tracing simulation results are compared with measurements for the purpose of validation. The size of the relevant active scattering...Show More
This paper presents the modeling of both coherent and incoherent scattering processes from rough surfaces at THz frequencies with the focus on polarization aspects. In a ray tracing algorithm, coherent scattering is implemented based on the Kirchhoff theory whereas a perturbation approach is used for the incoherent contribution. Geometrical depolarization is accounted for by means of the Jones cal...Show More
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...Show More
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.Show More
This paper presents a dynamic 60 GHz radio channel model for system level simulations with MAC Protocols. It is based on radio propagation measurements investigating the influence of moving humans on the 60 GHz channel, which has been performed in the framework of IEEE 802.11ad 60 GHz WLAN standardization.Show More
In this paper, wideband reflection and transmission properties of different materials are presented for a frequency range between 110 and 135 GHz. In particular, bistatic reflection profiles and transmission losses are measured for concrete, medium density fiberboard (MDF), gypsum plasterboard and double pane window glass samples. These measurements are compared with simulation results derived usi...Show More
A comparison of ultra-wideband (UWB) and 60 GHz channels inside a car is carried out in this paper. Measurements with a vector network analyzer (VNA) in the frequency bands of 5–8.5 GHz and 67–70.5 GHz have been carried out and the large-scale and small-scale parameters have been investigated. The results are shown for different antenna configurations and polarizations as well as for an empty car ...Show More
The Saleh-Valenzuela multipath channel model (SVmodel) is often used for the modeling of communication channels in confined environments . The model assumes multipath components (MPC) arriving at the receiver in clusters. Instead of identifying clusters from the power delay profile (PDP) via visual inspection as proposed in , this paper proposes a systematic algorithm for cluster identification in...Show More