Frequency-dependence characterization of electromagnetic reverberation in indoor scenarios based on 1-40 GHz channel measurements

A novel model for the reverberation time is proposed in this letter, based on room electromagnetics theory. While the commonly used models consider absorption based on a constant rate of wall interactions within a given time, the proposed model takes the variance of interactions into account. Moreover, the frequency dependence of electromagnetic reverberation characteristics in indoor environments is experimentally investigated from 1 to 40 GHz. The reverberation time is found to be a decreasing function of frequency. A model is then developed to predict the room & x0027;s quality factor, reverberation time, and average absorption coefficient. Good agreement is obtained with the limited results reported in the literature for similar scenarios. This approach aims to be an accurate alternative to the reverberation time measurements and computations in indoor environments by linking it to the theory of electromagnetic fields in cavities

Assessment of LTCC-Based Dielectric Flat Lens Antennas and Switched-Beam Arrays for Future 5G Millimeter-Wave Communication Systems

[EN] This paper presents the design, low-temperature co-fired ceramics (LTCC) fabrication, and full experimental verification of novel dielectric flat lens antennas for future high data rate 5G wireless communication systems in the 60 GHz band. We introduce and practically completely evaluate and compare the performance of three different inhomogeneous gradient-index dielectric lenses with the effective parameters circularly and cylindrically distributed. These lenses, despite their planar profile antenna configuration, allow full 2-D beam scanning of high-gain radiation beams. A time-domain spectroscopy system is used to practically evaluate the permittivity profile achieved with the LTCC manufacturing process, obtaining very good results to confirm the viability of fabricating inhomogeneous flat lenses in a mass production technology. Then, the lenses performance is evaluated in terms of radiation pattern parameters, maximum gain, beam scanning, bandwidth performance, efficiencies, and impedance matching in the whole frequency band of interest. Finally, the performance of the three lenses is also experimentally evaluated and compared to a single omni-directional antenna and to a ten-element uniform linear array of omni-directional antennas in real 60 GHz wireless personal area network indoor line-of-sight (LOS) and obstructed-LOS environments, obtaining interesting and promising remarkable results in terms of measured received power and root-mean-square delay spread. At the end of this paper, an innovative switched-beam antenna array concept based on the presented cylindrically distributed effective parameters lens is also introduced and completely evaluated, confirming the potential applicability of the proposed antenna solution for future 5G wireless millimeter-wave communication system.This work was supported in part by the Spanish Inter-Ministerial Commission on Science and Technology (CICYT) under Projects TEC2013-47360-C3-1-P, TEC2013-47360-C3-2-P, and TEC2016-78028-C3-1-P, by FEDER and the Unidad de Excelencia Maria de Maeztu MDM-2016-0600, which is financed by the Agenda Estatal de Investigacion, Spain, and by the "Ministerio de Economia" through the FPI fellowship program.Imbert, M.; Romeu, J.; Baquero Escudero, M.; Martinez-Ingles, M.; Molina-García-Pardo, JM.; Jofre, L. (2017). Assessment of LTCC-Based Dielectric Flat Lens Antennas and Switched-Beam Arrays for Future 5G Millimeter-Wave Communication Systems. IEEE Transactions on Antennas and Propagation. 65(12):6453-6473. https://doi.org/10.1109/TAP.2017.2767821S64536473651

Channel sounding and indoor radio channel characteristics in the W-band

This work presents directional radio channel measurements in the W-band using a commercial versatile channel sounder based on a vector network analyzer (VNA), capable of measuring scattering parameters from 75 to 500 GHz with frequency converters. The commercial setup has been modified by increasing the distance for one of the converters using precision coaxial cables and avoiding the use of amplifiers. Firstly, initial distance-dependent single-input single-output (SISO) measurements of indoor radio channels are presented to assess the validity of the setup in the 75 110 GHz frequency band with highly directive horn antennas. Then, single-input multiple-output (SIMO) radio channels were measured at 94 GHz using one directional and one omnidirectional antenna mounted on two positioners. Initial channel characterization is presented comprising root mean square (rms) delay spread, rms angular spread, K-factor, and path loss in an indoor environment at 94 GHz.This work was supported by MINECO, Spain (TEC2013-47360-C3-2-P TEC2013-47360-C3-3-P) and by European FEDER funds.Martínez Inglés, M.; Gaillot, D.; Pascual-García, J.; Molina-García-Pardo, JM.; Rodriguez Rodriguez, JV.; Rubio Arjona, L.; Juan Llacer, L. (2016). Channel sounding and indoor radio channel characteristics in the W-band. EURASIP Journal on Wireless Communications and Networking. 30:1-8. doi:10.1186/s13638-016-0530-7S1830D Zico, Ultra-wideband and 60 GHz communications for biomedical applications. Springer. http://link.springer.com/book/10.1007%2F978-1-4614-8896-5 .L Jofre, J Romeu, S Capdevila, J Abril, E Nova, M Alonso, The “challenging” world of Terahertz radiation and imaging. Proceedings of the 5th European Conference on Antennas and Propagation (EUCAP), 2011, pp. 3470–3475M Kawase, “Non-destructive evaluation method of pharmaceutical tablet by terahertz-time-domain spectroscopy: application to sound-alike medicines”, J. Infrared Millimeter Terahertz Waves, 34(9), 566–571KD Anderson, 94 GHz propagation in the evaporation duct. IEEE Trans. Antennas Propag. 38(5), 746–753 (1990)K Aydin, Y-M Lure, Millimeter wave scattering and propagation in rain: a computational study at 94 and 140 GHz for oblate spheroidal and spherical raindrops. IEEE Trans. Geosci. Remote Sens. 29(1), 593–601 (1991)C Gloaguen, An experiment for propagation studies at 94 GHz. Eighth Int. Conf. Antennas Propagation 1, 406–409 (1993)A Kajiwara, “Indoor propagation measurements at 94 GHz,” personal, indoor and mobile radio communications, 1995. Sixth IEEE Int. Symp PIMRC’95. Wireless Merging Inf. Superhighway 3, 1026 (1995)J Helminger, J Detlefsen, H Groll, Propagation properties of an indoor-channel at 94 GHz. Int. Conf. Microw Millimeter Wave Technol.Proc 98, 9–14 (1998)R Piesiewicz, R Geise, M Jacob, J Jemai, T Kurner, “Indoor channel measurements of point-to-point ultra broadband short range links between 75 GHz and 110 GHz”, in International Symposium Antennas and Propagation Society, 2008, pp. 1–4A Brizzi, A Pellegrini, Y Hao, “Experimental characterization of the propagation on the human torso at W band”, in Radio Science Meeting (Joint with AP-S Symposium), USNC-URSI, 2013, p. 39K Haneda, J Järveläinen, A Karttunen, M Kyro, J Putkonen, Indoor short-range radio propagation measurements At 60 and 70 GHz, in EuCAP 2014, The Hague, The Netherlands, 2014, pp. 1–4S Promwong, J Takada, Free space link budget estimation scheme for ultra wideband impulse radio with imperfect antennas. IEICE Electronics Express 1(7), 188–192 (2004)NL Johnson, S Kotz, N Balakrishnan, Continuous univariate distributions, vol. 1 (Wiley-Interscience, Hoboken, 1993)A Richter, Estimation of radio channel parameters: models and algorithms (Dr.-Ing. dissertation, TU Ilmenau, Ilmenau, Germany, 2005

Massive MIMO Indoor Transmissions at 38 and 65 GHz Applying Novel HBF Techniques for 5G

The 5G Infrastructure Public Private Partnership (5GPPP) has recently published a white paper about 5G service indoors, since up to now, it had mainly focused on the outdoors. In an indoor environment, the requirements are different since the propagation mechanism differs from other scenarios. Furthermore, previous works have shown that space frequency block code (SFBC) techniques applied to multiple antennas improve performance compared to single-input single-output (SISO) systems. This paper presents an experimental study in an indoor environment regarding the performance of a massive multiple-input multiple-output (mMIMO) millimeter-wave (mmWave) system based on the 5G New Radio (NR) standard in two frequency bands. In a first step, the 38 and 65 GHz bands are compared by applying a low-complexity hybrid beamforming (HBF) algorithm. In a second step, the throughput and the maximum achievable distance are studied using a new algorithm that combines the SFBC technique and HBF. Results show, at 38 GHz with HBF and aggregated bandwidths (4 × 100 MHz), a maximum throughput of 4.30 Gbit/s up to 4.1 m. At 65 GHz, the SFBC + HBF algorithm improves the communication distance by 1.34, 1.61, or 1.75 m for bandwidths of 100, 200, or 400 MHz, respectively

Experimental parameterization of a diffuse scattering model at 60 GHz

In this work a measurement campaign is carried out to find the best diffuse scattering model parameters for three typical indoor materials: glass, plasterboard and chipboard. Diffuse scattering is modeled in this work using the effective roughness approach. A time gating technique is applied to both measured and simulated time responses to single out the received power of the diffuse scattered component. The comparison between measured and simulated relative received powers allows the inference of the best-fit parameters values, as shown in the results

Experimental investigation of the characteristics of the electromagnetic reverberation in the UWB bands

International audienc

Experimental investigation of electromagnetic reverberation characteristics as a function of UWB frequencies

International audienc

Polarimetric analysis of reverberation times for 94 GHz indoor communication

This paper presents a measurement-based analysis of both the specular- and dense multipath components (SMC and DMC) at 94 GHz in an indoor environment. A total of 15 positions were measured with a virtual antenna array system, from which we have calculated Power Delay Profiles (PDP). A method was developed that allowed for the full-polarimetric estimation of the specular propagation paths, after which the remainder was regarded as the diffuse spectrum. The behavior of the reverberation time, known from the theory of room electromagnetics, was analyzed based on this diffuse spectrum