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Wireless Sensor Network Systems in Harsh Environments and Antenna Measurement Techniques
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
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.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1126
Keyword [en]
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
Identifiers
URN: urn:nbn:se:uu:diva-218891ISBN: 978-91-554-8884-0 (print)OAI: oai:DiVA.org:uu-218891DiVA: diva2:697748
Public defence
2014-04-04, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Projects
WISENETWiseJet
Available from: 2014-03-13 Created: 2014-02-19 Last updated: 2014-04-29
List of papers
1. Field Operational Testing for Safety Improvement of Freight Trains using Wireless Monitoring by Sensor Network
Open this publication in new window or tab >>Field Operational Testing for Safety Improvement of Freight Trains using Wireless Monitoring by Sensor Network
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2013 (English)In: IET Wireless Sensor Systems, ISSN 2043-6386, E-ISSN 2043-6394Article in journal (Refereed) Published
Abstract [en]

Today, the majority of wagon failures on railroad systems are because of the poor maintenance of ball bearings, which causes emergent stops and delays. The existing stationary detectors, lack in predicting failures which cause troubles in scheduling maintenance. During the fall of 2011, a trial was performed by applying a wireless sensor network (WSN) aboard a train wagon with the objective to demonstrate a proof of concept for monitoring the temperature of ball bearings aboard the train wagon. This trial investigates several key aspects when applying sensor networks such as radio wave propagation, energy scavenging and performance of the WSN aboard the wagon. Two wireless links were used in the WSN. The aboard network communicates at 2.45 GHz, and the external communication is an 868 MHz radio frequency identification radio link. Since the energy in the WSN node is limited, appropriate energy scavenging devices are also presented and evaluated in a lab environment. Effort has been made to overcome these problems. The energy consumption in the network is still a problem; the most promising energy scavenging technique is piezoelectric harvesting by vibrations, which in the experiments scavenged 2.32 mW.

Keyword
Wireless sensor network, train
National Category
Communication Systems Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-218887 (URN)10.1049/iet-wss.2013.0048 (DOI)
Projects
Wisenet
Available from: 2014-02-19 Created: 2014-02-19 Last updated: 2017-12-06Bibliographically approved
2. Reliability Experiments for Wireless Sensor Networks in Train Environment
Open this publication in new window or tab >>Reliability Experiments for Wireless Sensor Networks in Train Environment
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2009 (English)In: European Microwave Week (EuMWeek), Second European Wireless Technology Conference, EuWIT, 2009, 37-40 p.Conference paper, Published paper (Refereed)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering with specialization in Signal Processing; Engineering Science with specialization in Microwave Technology
Identifiers
urn:nbn:se:uu:diva-120593 (URN)
Conference
European Microwave Week (EuMWeek), Second European Wireless Technology Conference, EuWIT
Projects
WISENET
Available from: 2010-03-15 Created: 2010-03-15 Last updated: 2016-04-14Bibliographically approved
3. Design of a miniaturized patch antenna for easy deployment on metal surfaces
Open this publication in new window or tab >>Design of a miniaturized patch antenna for easy deployment on metal surfaces
2013 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 55, no 4, 723-727 p.Article in journal (Refereed) Published
Abstract [en]

A small dual-layer patch antenna designed for placement on a large conducting surface is presented. It uses the surrounding metal as a ground plane in order to reduce its size. The result is a small patch antenna with good radiation qualities in metallic surroundings. It can also be used in applications where shielding sensitive equipment from radiated fields is necessary, by using the shielding as the metal surface. It is constructed for use with the IEEE 802.15.4 standard at the 2.45 GHz ISM band. The lower layer is made in Fr-4 with standard height and width. This makes eventual serial production cheaper. The antenna has a measured total efficiency between 1.5 dB and 3.6 dB in the frequency range it is designed for. The longest side is 18.35 mm, equaling 14.9% of the wavelength.

Keyword
patch antennas, metallic environment, antenna measurements, compact antennas, microstrip antennas
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-197965 (URN)10.1002/mop.27437 (DOI)000315524800008 ()
Available from: 2013-04-08 Created: 2013-04-08 Last updated: 2017-12-06Bibliographically approved
4. Empirical Tests of Wireless Sensor Network in Jet Engine Including Characterization of Radio Wave Propagation and Fading
Open this publication in new window or tab >>Empirical Tests of Wireless Sensor Network in Jet Engine Including Characterization of Radio Wave Propagation and Fading
2014 (English)In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 13, 762-765 p.Article in journal (Refereed) Published
Keyword
Wireless Sensor Network, Jet engine, Propagation
National Category
Communication Systems Other Electrical Engineering, Electronic Engineering, Information Engineering Embedded Systems
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-218889 (URN)10.1109/LAWP.2014.2316311 (DOI)000335565400002 ()
Available from: 2014-02-19 Created: 2014-02-19 Last updated: 2017-12-06Bibliographically approved
5. Design and Evaluation of a Conformal Patch Antenna Array for use with Wireless Sensor Network inside Jet Engines
Open this publication in new window or tab >>Design and Evaluation of a Conformal Patch Antenna Array for use with Wireless Sensor Network inside Jet Engines
2013 (English)Conference paper, Published paper (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Communication Systems
Identifiers
urn:nbn:se:uu:diva-218890 (URN)
Conference
European Conference on Antennas and Propagation (EuCAP), Gothenburg.
Available from: 2014-02-19 Created: 2014-02-19 Last updated: 2014-04-29
6. Large Ad Hoc Shielded Room with Removable Mode Stirrer for Mobile Phone Antenna Tests
Open this publication in new window or tab >>Large Ad Hoc Shielded Room with Removable Mode Stirrer for Mobile Phone Antenna Tests
2013 (English)In: IEEE transactions on electromagnetic compatibility (Print), ISSN 0018-9375, E-ISSN 1558-187X, Vol. 55, no 1, 21-27 p.Article in journal (Refereed) Published
Abstract [en]

Reverberation chambers (RC) are widely used for measuring antenna performance and parameters for MIMO systems. RCs for mobile phone antenna tests are often specially designed for this purpose. The lowest frequency of operation of an RC is decided by its size. With a trend of lower frequency bands being allocated for mobile phones, the minimum size of RCs for mobile phone antenna tests increases, and is approaching the size of a normal room. At the same time, many large shielded rooms are already in use for various electrical measurements. In this paper, a standard shielded room designed for EMC testing is used as an RC for mobile phone antenna tests. To complete the RC, a large mode stirrer is built. The fact that the room is also used for other tests requires a detachable, foldable, and lightweight stirrer design. Therefore, metal meshes are evaluated for the design of the mode stirrer. The performance of the used room is verified by standard tests for RCs, and it is verified that it is possible to measure antennas from about 400 MHz up to 4 GHz with good accuracy. The size of the room also enables measurements including humans carrying mobile phones or body area networks.

Keyword
Antenna measurements, electromagnetic propagation, electromagnetic shielding, microwave communication, microwave radio propagation
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-197409 (URN)10.1109/TEMC.2012.2204758 (DOI)000315118100003 ()
Available from: 2013-03-28 Created: 2013-03-25 Last updated: 2017-12-06Bibliographically approved
7. Sample-Selection Method for Arbitrary Fading Emulation Using Mode-Stirred Chambers
Open this publication in new window or tab >>Sample-Selection Method for Arbitrary Fading Emulation Using Mode-Stirred Chambers
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.

Keyword
Diversity gain, mode-stirred chamber (MSC), multiple-output (MIMO) capacity
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-136546 (URN)10.1109/LAWP.2010.2049729 (DOI)000277885900003 ()
Available from: 2010-12-14 Created: 2010-12-13 Last updated: 2017-12-11Bibliographically approved
8. Sample Selection Algorithms for Enhanced MIMO Antenna Measurements Using Mode-Stirred Reverberation Chambers
Open this publication in new window or tab >>Sample Selection Algorithms for Enhanced MIMO Antenna Measurements Using Mode-Stirred Reverberation Chambers
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2012 (English)In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 60, no 8, 3892-3900 p.Article in journal (Refereed) Published
Abstract [en]

Mode-stirred reverberation chambers (MSRCs) are a useful tool for measuring several wireless-related MIMO antenna parameters. In a conventional single-cavity MSRC, the emulated fading environment is isotropic and the amplitude of the signal is Rayleigh distributed. Previous contributions have enhanced the emulation capabilities of MSRCs so as to include the ability to emulate Rician- and non-isotropic fading environments. In this contribution, arbitrary amplitude probability density functions (PDF) emulation using a MSRC is presented by selecting parts of the sample set that forms different statistical ensembles. Several algorithms are presented and compared in terms of computation time and power accuracy using simulated as well as measured data from different MSRCs to obtain Rician, on-body and amplitude PDFs of standardized models. The technique is patent-protected by EMITE.

Keyword
Algorithms, antenna measurements, fading channels, genetic algorithms
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-182546 (URN)10.1109/TAP.2012.2201103 (DOI)000308435800037 ()
Available from: 2012-10-11 Created: 2012-10-11 Last updated: 2017-12-07Bibliographically approved

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Citation style
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  • modern-language-association-8th-edition
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  • en-US
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  • nn-NO
  • nn-NB
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  • Other locale
More languages
Output format
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  • asciidoc
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