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Sample-Selection Method for Arbitrary Fading Emulation Using Mode-Stirred Chambers
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microwave and Terahertz Technology.
2010 (English)In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 9, 409-412 p.Article in journal (Refereed) Published
Abstract [en]

Mode-stirred chambers (MSCs) consist of one or more resonant cavities coupled in some way in order to allow the measurement of different antenna parameters such as antenna efficiency, correlation, diversity gain, or multiple-input-multiple-output (MIMO) capacity, among others. In a single-cavity MSC, also known as a reverberation chamber (RC), the environment is isotropic and the amplitude of the signal is Rayleigh distributed. Real environments, however, rarely follow an isotropic Rayleigh-fading scenario. Previous results have shown that a Rician-fading emulation can be obtained via hardware modification using an RC. The different methods lack from an accurate emulation performance and are strongly dependent upon chamber size and antenna configurations. With the innate complexity of more-than-one-cavity MSC, the coupling structure generates sample sets that are complex enough so as to contain different clusters with diverse fading characteristics. This letter presents a novel method to accurately emulate a more realistic Rician-fading distribution from a Rayleigh-fading distribution by selecting parts of the sample set that forms different statistical ensembles using a complex two-cavity multi-iris-coupled MSC. Sample selection is performed using a genetic algorithm. Results demonstrate the potential of MSCs for versatile MIMO fading emulation and over-the-air (OTA) testing. The method is patent protected by EMITE Ing., Murcia, Spain.

Place, publisher, year, edition, pages
2010. Vol. 9, 409-412 p.
Keyword [en]
Diversity gain, mode-stirred chamber (MSC), multiple-output (MIMO) capacity
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-136546DOI: 10.1109/LAWP.2010.2049729ISI: 000277885900003OAI: oai:DiVA.org:uu-136546DiVA: diva2:377278
Available from: 2010-12-14 Created: 2010-12-13 Last updated: 2016-04-18Bibliographically approved
In thesis
1. Wireless Sensor Network Systems in Harsh Environments and Antenna Measurement Techniques
Open this publication in new window or tab >>Wireless Sensor Network Systems in Harsh Environments and Antenna Measurement Techniques
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wireless sensor network (WSN) has become a hot topic lately. By using WSN things that previously were difficult or impossible to measure has now become available. One of the main reasons using WSN for monitoring is to save money by cost optimization and/or increase safety by letting the user knowing the physical status of the monitored structure. This thesis considers four main topics, empirical testing of WSN in harsh environments, antenna designs, antenna measurements and radio environment emulation.

The WSN has been tested in train environment for monitoring of ball bearings and inside jet engines to monitor strain of blades and temperatures. In total, two investigations have been performed aboard the train wagon and one in the jet engine. The trials have been successful and provide knowledge of the difficulties with practical WSN applications. The key issues for WSN are robust communication, energy management (including scavenging) and physical robustness.

For the applications of WSN in harsh environments antennas has to be designed. In the thesis, two antennas has been designed, one for train environment and one for the receiver in the jet engine. In the train environment, a more isotropic radiation pattern is preferable; hence a small dual layered patch antenna is designed. The antenna is at the limit of being electrically small; hence slightly lower radiation efficiency is measured. For the WSN in the jet engine, a directive patch array is designed on an ultra-thin and flexible substrate. The thin substrate of the antenna causes rather lower radiation efficiency. But the antenna fulfils the requirements of being conformal and directive.

In reverberation chambers are used to measure antennas, but there are difficulties to provide a realistic radio environment, for example outdoor or on-body. In this thesis, a large reverberation chamber is designed and verified. It enables measurement between 400 MHz and 3 GHz. Also, a sample selection method is designed to provide a post processing possibilities to emulate the radio environment inside the chamber. The method is to select samples from a data set that corresponds to a desired probability density function. The method presented in this thesis is extremely fast but the implementation of the method is left for future research.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 75 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1126
Wireless Sensor Network, Antenna, Jet engine, Train, Reverberation chamber, WISENET, Wisejet
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Telecommunications Communication Systems Embedded Systems
Research subject
Engineering Science with specialization in Microwave Technology
urn:nbn:se:uu:diva-218891 (URN)978-91-554-8884-0 (ISBN)
Public defence
2014-04-04, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Available from: 2014-03-13 Created: 2014-02-19 Last updated: 2014-04-29

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