Design of an Antenna for a Wireless Sensor Network for Trains

UPTEC F11 066

Examensarbete 30 hp December 2011

Design of an Antenna for a Wireless Sensor Network for Trains
Malkolm Hinnemo

Abstract
Design of an Antenna for a Wireless Sensor Network for Trains
Malkolm Hinnemo

Teknisk- naturvetenskaplig fakultet UTH-enheten Besöksadress: Ångströmlaboratoriet Lägerhyddsvägen 1 Hus 4, Plan 0 Postadress: Box 536 751 21 Uppsala Telefon: 018 – 471 30 03 Telefax: 018 – 471 30 00 Hemsida: http://www.teknat.uu.se/student

An antenna for a wireless sensor network for trains is designed and built. The network will monitor temperature and vibrations of the wheel bearings on the train wagons. Doing this will allow for an earlier detection of damaged wheels, which will ease planning of maintenance and reduce wear on the rails considerably. The requirement of the system is that it is to be installed without any cables attached to the sensor nodes. This calls for wireless communication, and that for that antennas are needed. A train is a difficult environment to transmit electromagnetic (EM) waves in. It is full of metal and EM-waves cannot pass through a conducting material. Having much metal in its vicinity also affects the function of the antenna. This needs to be taken into consideration when making the design. The constructed antenna is a small dual-layer patch antenna. Dual layer means that it is constructed out of two sheets known as substrates of isolating material with different characteristics. The lower one of these substrates is made in such a way that integration with a circuit board is possible. Such integration would reduce the production cost considerably. The antenna is designed for direct placement on a conducting surface. This surface could be part of the train. 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. The longest side is 18.35 mm, equaling 14.9 % of the wavelength that the antenna

References: [1] M.Grudén, A.Westman, J.Platbardis, P.Hallbjörner, A.Rydberg, “Reliability Experiments for Wireless Sensor Networks in Train Environment”, Wireless Technology Conference 2009. EuWIT 2009, European, Rome. [2] P.J.Soh, G.A.E.Vandenbosch, V.Volski. H.M.R.Nurul, “Characterization of a Simple Broadband Textile Planar Inverted-F Antenna (PIFA) for on Body Communications”, ICECom, 2010 Conference preceedings, 20-23sept 2010 [3] T.Alvez, R.Augustine, M.Grzeskowiak, B.Poussot, D.Delcroix, S.Protat, J.-M.Laheurte, P.Queffelec, “BAN antenna design using ferrite polymer composite”, Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on, 23-27 March 2009 [4] R. Wagnsness, “Electromagnetic Fields”, 2nd ed., John Wiley & Sons, Inc. 1986 [5] C.A.Balanis, “Antenna Theory”, 3rd ed. New Jersey USA, John Wiley & Sons 2005. [6] http://www.antenna-theory.com/antennas/patches/antenna.php [7] K.Sakaguchi, N.Hasabe, “A small microstrip antenna consisting of a slot cut radiator and short pins”, Antennas and Propagation, 1991. ICAP, Seventh international conference on (IEEE), 15-18 apr. 1991 [8] D.M. Pozar, “Microwave Engineering”, 3rd ed. John Wiley & Sons, Inc. 2005 [9] S.Vajha, S.N.Prasad, “Design and modeling of proximity coupled patch antenna”, Antennas and Propagation for Wireless Communications, 200 IEEE-APS Conference on, 6-8 nov 2000 [10] P.Hallbjörner, C.Shi, A.Rydberg, “Reverberation Chamber for Accurate Antenna Measurements Within 2-30 GHz”,Microwave conference 2007, European, 9-12 oct 2007 [11] Uwe Zimmerman, Researcher in Solar Cell Technology at Uppsala University, 2011-09-07, “Oral source” [12] Stefan Hellsten, Mechanic at Infranord, 2011-11-16, “Oral source” 49