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ABSTRACT: A five-element inverted-F antenna array on mobile terminal for both multiple input multiple output (MIMO) communications and radio direction finding (RDF) applications is presented. The multi-element antenna (MEA) system has been designed to be used in the frequency band of the future Long Term Evolution (LTE) system at 3400-3600 MHz and integrated along the edges of the upper ground plane of a clamshell type mobile terminal. Without using any specific multi-antenna isolation techniques, the antennas have been optimized to have acceptable mutual coupling and small envelope correlation in order to provide enhanced capacity with multiple input multiple output (MIMO) techniques. The ambiguities of the proposed design in RDF applications have also been investigated. A prototype has been fabricated and tested. Good agreement between numerical simulations and experimental results has validated the antenna concept.
Antennas & Propagation Conference, 2009. LAPC 2009. Loughborough; 12/2009
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ABSTRACT: In this paper, the feasibilities of emerging high throughput radio channels are investigated. Specifically, the performance and capacities of ultrawide band (UWB), 5 GHz multiple-in and multiple-out (MIMO) and 60 GHz MIMO radio channels are studied based on regulations and standardization in IEEE 802.15.3a, 802.11n and 802.15.3c, respectively. The analysis shows that in the UWB channel for single-in and single-out (SISO) transmission, it is difficult to achieve high data rates of between 110 and 480 Mbps over short ranges of less than 10 meters. Since very high or unpractical antennas are required in radio link budget of system. MIMO is the key to high rate wireless communications. In the 5 GHz and 60 GHz MIMO channels, tests were performed for determining data rate, range and configurations. In the 5 GHz MIMO channel both the minimum and maximum configurations are determined for supporting 54-600 Mbps rate and up to 200 m range. In the 60 GHz MIMO channel, configurations are determined for achieving gigabit and multigigabit capacities with less than 10 m ranges. Results are also compared with experimental measurement data in order to provide reliable parameters and useful information for system development and standardization groups.
Communications and Networking in China, 2009. ChinaCOM 2009. Fourth International Conference on; 09/2009
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ABSTRACT: The 60 GHz radio is being foreseen as a very promising candidate for future gigabit wireless communications due to the intrinsic large amount available bandwidth. This band has been proposed for wireless personal area networks (WPANs) aiming at multi-gigabit and short-trange (<10 m) multimedia applications. The 60 GHz band regulation and standardization efforts are currently underway worldwide.
Antennas and Propagation Society International Symposium, 2009. APSURSI '09. IEEE; 07/2009
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ABSTRACT: In this paper, the performance of 60 GHz MIMO system is analyzed based on experimental data. The mutual information (MI) of the measured channel is compared to the MI of an iid MIMO Rayleigh channel. It is seen that the mean MI of the channels are quite close to each other. Then, the MI of the MIMO system is compared to the one of a MIMO system with antenna selection. It is found that, when considering switching networks with realistic losses, the performance decreases drastically and, in most cases, MIMO antenna selection leads to lower MI than traditional MIMO with the same number of RF chains. Finally, the achievable data-rate of a realistic 4 times 4 MIMO system is calculated, based on the experimental data. It is shown that with 500 MHz bandwidth such a system can provide multigigabit communications at distance up to 10 m.
Wireless Communication, Vehicular Technology, Information Theory and Aerospace & Electronic Systems Technology, 2009. Wireless VITAE 2009. 1st International Conference on; 06/2009
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ABSTRACT: This paper presents the performance evaluation of a system using beam steering technique at RX, based on 60 GHz MIMO measurement data. The mutual information of this system is compared to the one of a traditional MIMO system, considering ideal and realistic phase shifters. It is found that with lossless phase shifters and power combiner, the mean mutual information obtained by selecting the best beam out of 5 is higher than the one of 2times2, 3times3 and 4times4 MIMO at low SNR. When considering realistic components, the mean mutual information obtained by selecting the best beam out of 5 is only higher than the one of 2times2 MIMO at low SNR. In both cases (with lossless and realistic phase shifters) MIMO outperforms beam steering at high SNR.
Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on; 04/2009
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ABSTRACT: This paper discusses the issues in antenna design for future mobile communications terminals caused by the addition of more and more antennas into the devices. There can be more than 10 different radios in the terminal and some of them will utilise adaptive antenna systems with more than 5 antennas. Thus it is possible that a future terminal device will have more than 20 antennas. This can be either a threat or an opportunity depending on the viewpoint of e.g. a terminal manufacturer or an antenna manufacturer, respectively. The challenges connected to the large number of antennas are the volume required by the antennas in a small terminal, coupling between the antennas and finding locations for the antennas where user interaction is low. The possible solutions include minimisation of the size of antenna elements, re-use of the same antennas in many systems, and methods to isolate the antenna elements from each others.
Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on; 04/2009
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ABSTRACT: The boom of the wireless communications industry during the last 10 to 20 years created an increased need for developing particularly small-antenna measurement techniques. Since then, the research on small communications antenna measurements has followed the evolution of numerous new radio systems and the increase in the operating frequencies. The purpose of this paper is to give an overview of the most recent research on novel measurement methods for small antennas from the UHF band to the 60-GHz band. The subjects include multi-probe antenna measurement systems, spherical scanning techniques, probe correction techniques, probes, and 60-GHz on-wafer antenna measurements.
Antenna Technology, 2009. iWAT 2009. IEEE International Workshop on; 04/2009
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ABSTRACT: This paper presents a wide band 60 GHz MIMO channel measurement system using a VNA and 3-D arrays at both ends. It uses virtual antenna arrays which can be reconfigured easily. The bandwidth of the system is 3.5 GHz, which leads to a time resolution of 0.29 ns. This fine resolution is suitable for characterizing dense multipaths in indoor environments. Line of sight (LOS) and obstructed line of sight (OLOS) measurements were performed with 64-element arrays at both TX and RX. Preliminary results (power delay profiles) are presented.
Radio and Wireless Symposium, 2009. RWS '09. IEEE; 02/2009
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ABSTRACT: The mutual information (MI) of several multiple-input-multiple-output (MIMO) antenna selection configurations has been studied based on 60-GHz MIMO channel measurement data. Several array shapes with different numbers of available antennas have been considered. The effect of the switching network (either lossless or with realistic losses) as well as the influence of the selection criterion [either maximum signal-to-noise ratio (SNR) or optimum capacity criterion (OCC)] has been analyzed. It is found that in the best case (optimum capacity criterion and lossless switching network) antenna selection can increase the MI by up to 127% as compared to traditional MIMO systems. Nevertheless, with more reasonable conditions (maximum SNR criterion, realistic switching network) the MI decreases drastically, with a maximum improvement of only 11% as compared to traditional MIMO systems.
IEEE Antennas and Wireless Propagation Letters 02/2009; · 1.37 Impact Factor
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ABSTRACT: This letter presents a planar omnidirectional antenna structure with wide beam for applications in the 60-GHz band. The antenna was designed using only one metal layer on top of a quartz substrate, which is very cost efficient. The optimal structure, of size 4.5 times 4.3 mm<sup>2</sup>, exhibits a gain of 1.4 dBi plusmn 0.5 dBi in the omnidirectional plane and a half power beam width of about 75 deg in the perpendicular plane. The bandwidth with return loss at least 10 dB covers the 57-64-GHz license-free band, which is commonly considered for very high data rate communications. The consistency of the simulated results was successfully checked with measurements.
IEEE Antennas and Wireless Propagation Letters 02/2008; · 1.37 Impact Factor
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ABSTRACT: Realistic channel measurements are central for reliable channel characterization and terminal antenna evaluation. This is due to the complex signal propagation behavior inherent in mobile communications. The need for evaluating new systems utilizing multielement antenna terminals in a more efficient and faster way has been a driving force for an extensive and multidimensional research area in our institute. In this paper we present a MEasurement based antenna test-bed (ME BAT) for the evaluation of multielement mobile terminal antenna systems. The method combines measured directional channel library and the radiation patterns of antennas under test (AUT).
Electromagnetics in Advanced Applications, 2007. ICEAA 2007. International Conference on; 10/2007
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ABSTRACT: In this paper a method which increases both mutual coupling and efficiency is presented. It is based on hardware modification and applied to patch antenna arrays. It is seen that by increasing the mutual coupling, the channel capacity is increased significantly. In addition, this method removes, over a certain frequency band, the main drawback of mutual coupling: the losses at the ports level. The benefits of this method on the channel capacity are analyzed for 3 antenna structures. The channel capacity is calculated using a measurement based tool called MEBAT. The effects of this method are shown both by simulations and measurements.
Antennas and Propagation Society International Symposium, 2007 IEEE; 07/2007
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ABSTRACT: Nowadays, the need for high-data-rate-communication channels is increasing and will ineluctably continue to increase in the future. From a theoretical point of view, the multiple input multiple output (MIMO) approach seems to be one of the best solutions to provide such a high capacity. This paper presents a millimeter-wave MIMO channel measurement system developed in the Radio Laboratory of Helsinki University of Technology. The system is based on a sounder and virtual antenna arrays: The antenna arrays are obtained by two 2-D scanners which shift a single transmit antenna and a single receive antenna. Measurements in line of sight (LOS) and non-LOS are reported from what the MIMO channel capacity is calculated for various antenna array sizes. Furthermore, from the same measurements, the direction of departure and direction of arrival are estimated
IEEE Transactions on Instrumentation and Measurement 07/2007; · 1.21 Impact Factor
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ABSTRACT: This paper presents the design of a fully integrated antenna with directional diversity in the 60 GHz band using MEMS process on high resistivity silicon wafer. This active antenna designed for MIMO systems integrates switches and phase shifters.
Electronics, Circuits and Systems, 2006. ICECS '06. 13th IEEE International Conference on; 01/2007
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ABSTRACT: This paper presents the results of ultra-wide band (UWB) indoor channel measurements performed in a hall, a meeting room, and a corridor with both LOS and NLOS scenarios. The channel multipath propagation characteristics are investigated by examining the power delay profiles, path loss, power distribution, and rms delay spread. It is found that in UWB channels, the appearance of multipath components are in the forms of diffuse, single dominant and clustered paths, their appearance is highly dependent on the measurement environments. UWB radio is robust to multipath fading due to the small fading margin and the high multipath diversity gain it has. Moreover, the UWB measurement results are compared with the results obtained in traditional wideband 60 GHz indoor channels.
Ultra-Wideband, 2005. ICU 2005. 2005 IEEE International Conference on; 10/2005
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ABSTRACT: Nowadays the need for high-data-rate-communication channels is increasing and will ineluctably continue to increase in the future. From a theoretical point of view, MIMO (multiple input multiple output) approach seems to be one of the best solutions to provide such a high capacity. This paper presents a mm-wave MIMO channel measurement system developed in the Radio Laboratory of Helsinki University of Technology. The system is based on virtual antenna arrays: the antenna arrays are obtained by two 2D scanners which shift a single transmit antenna and a single receive antenna. Measurements in LOS (line of sight) and NLOS (non line of sight) are reported, from what the MIMO channel capacity is calculated and the DOD (direction of departure) and DOA (direction of arrival) are estimated
Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE; 06/2005
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ABSTRACT: Computer-generated holograms (diffractive elements) can be used for shaping millimeter-wave beams, e.g., for producing a plane wave in a compact space. An amplitude hologram has earlier been demonstrated to be able to form arbitrary beams at 310 GHz and has proven to be a feasible alternative as a focusing element in a compact antenna test range (CATR) at mm-wavelengths. It was used successfully for Odin satellite antenna tests at 119 GHz. In a recent study we have designed and constructed a compact antenna test range for 322 GHz and measured the ADMIRALS representative test object, which is a 1.5-meter offset paraboloid antenna.
Aerospace Conference, 2004. Proceedings. 2004 IEEE; 04/2004
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Journées Nationales Microondes (JNM2009).
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COST 2100, Pervasive Mobile & Ambient Wireless Communications.
