This paper proposes a measurement based modeling of D-band indoor channels. Different indoor environments were considered including Line-of-Sight (LOS) and Non Line-of-Sight (NLOS) conditions. Double steering at the transmitter and receiver sides was performed allowing angular characterization of the channel. Path loss, delay spread, angular spread, intra-and inter-cluster characteristics were also modeled. These characteristics were then compared to the ones obtained in other millimeter wave bands for the same environment.

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International audienceAbstractThis paper presents the characterization by three different techniques of a new lossy material made of carbon fibers loaded epoxy foam that can be used as an absorber in anechoic-chambers. The composite was characterized using free space, waveguide and coaxial probe techniques. Dielectric characteristics obtained from the three techniques are different and this is explained by the required dimensions of measured samples, not always representative of the porous form of the composites loaded with long fibers. Our study points out that the free space technique is the most appropriate to measure such composite samples with porosities and load having millimeter dimensions. Dielectric probe and waveguide are not suitable due to a small volume of measure which is not representative of the entire composite. The achieved prototype confirmed this result with a measured reflection coefficient very close to the simulation achieved with the dielectric characteristics obtained by the free space technique

This paper presents a characterization method for extracting the reflection coefficient of materials and the real part of their permittivity. The characterization is performed in a real environment, as opposed to the classical measurement methods that require an anechoic chamber. In order to reduce the effects of the multipath propagation, a free space bistatic measurement was performed at different distances Material-Antennas in far field. By using a Teflon sample and a commercial absorbing material sample, measurements have been performed in order to validate the characterization technique.

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International audience—This paper presents a topology for improving the performance of straight wedge absorbing materials at oblique angles of incidence. The optimization process is based on a genetic algorithm and allows one to obtain a low reflection coefficient within a wide band of frequencies. We investigate the performance by comparison between the straight wedge absorber and the optimized wedge absorber. These wedge absorbers were simulated in the CST Microwaves Studio software, using a polymer foam material