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PPS Uetliberg-AntennaWireless Lan Antenna competition
Summer 2010
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Antennas Simulation Competition Timetable Informations
Outline
• Antenna Fundamentals• Simulation• Competition• Timetable• General information
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Antennas Simulation Competition Timetable Informations
Antenna FundamentalsAntennas
transmission line antenna free space
E-field amplitudeat the E-plane:
Source
E-plane
Antenna:A component which takes electromagnetic energy from free space and directs it into a transmission line (or vice versa = Reciprocity)
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Antennas Simulation Competition Timetable Informations
Antenna FundamentalsAntennas
Far Field Approximation
Gain (Gewinn)
Directivity (Richtfaktor)
Input impedance, reflection factor
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Antennas Simulation Competition Timetable Informations
1) Wire antennas
Electrically small: Resonant:
Dipole Loop Antennas Helix
<<λ <<λ ≈ λ/2
-Low directivity-Low efficiency-Small input impedance-High input reactance
-Real input impedance-Small bandwidth
Wide band:
- Bandd width >2:1- example:
Log periodic dipole Array
Antennas
Different antenna types
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Antennas Simulation Competition Timetable Informations
2) Aperture antennas
Antennas
Different antenna typesPyramidal
horn
Conicalhorn
Rectangularwaveguide
RectangularPatch
CircularPatch
-Micro- and millimeter wave -High directivity-Medium bandwidth-Size: some wavelength
2) Aperture antennas-Micro- and millimeter wave-Low directivity-Low effeciency-Resonant structure-Small bandwidth-Very cheap to maufacture (PCB technique)-Flat design, easy to integrate
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Antennas Simulation Competition Timetable Informations
Fields from the elements in the array interfere constructively for certain directions ( maxima) and destructively for other directions ( nulls)
maximumΣ
ΣΣ
minimum(~zero)
Array antenna
× =
-allows to increase the gain for most antennas-very space consuming
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Antennas Simulation Competition Timetable Informations
mobile communication Antennas
GSM
880 - 960 MHz
1710 - 1880 MHz
max. power: 2 W
UMTS
1920 – 1980 MHz uplink
2110 – 2165 MHz downlink
max. power: 0.25 W
Wlan
2412 – 2484 MHz
max. power: 0.1 W
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Antennas Simulation Competition Timetable Informations
Simulation software• Finite Elemente (FEM)
– Solver for discrete frequencies– Tetrahedal volume discretisation– computes fields within the
computational
• Post processing computes field patterns and network entities
• CAD Oberfläche zur Eingabe der Geometrie
• HFSS, CST, COMSOL
Simulation
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Antennas Simulation Competition Timetable Informations
Yagi – Antenne
Surface currents
Simulation
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Antennas Simulation Competition Timetable Informations
Yagi – Antenne
Electric field strength distribution
Simulation
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Antennas Simulation Competition Timetable Informations
Fernfeldberechnung – AnpassungSimulation
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Antennas Simulation Competition Timetable Informations
Richtdiagramm Darstellung
3D plot Cartesian plot
Simulation
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Antennas Simulation Competition Timetable Informations
Simulation software FEKO• FEKO (electromagnetic field
computation for arbitrary surfaces)
• Method of Moments (MoM)• Support CAD input (CadFeko)• Automatic discretisation of
surfaces by means of segments and triangles
• Solver computes the current at the surface of the discretised objects and derives the electromagnetic fields for the whole computational space
• Suitable for large domains
Simulation
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Antennas Simulation Competition Timetable Informations
Wireless LAN antenna competitionCompetition
• Objectiv: build a high gain Wireless LAN antenna
• teams of 2 or 3 persons
• personal guidance for each group
• use literature, simulation software, internet and build it
• test your ideas @ home with a simple WLAN adapter
• final measurement in our antenna room on May 11th
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Antennas Simulation Competition Timetable Informations
Wireless LAN antenna competitionCompetition
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Antennas Simulation Competition Timetable Informations
PPS testat conditions• build an high gain antenna – your design
• Simulation of the antenna pattern
• Measurement of the antenna pattern (2D)
• 10 page report– english or german– Includes antenna theory, simulation and measurements
• 10 minute presentation (english)
Competition
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Antennas Simulation Competition Timetable Informations
PPS Timetable
gather Antenna Fundamenals
Simulation Measurements
Optimisation
Presentation and Report
Theory
Praxis
Documentation
Timetable
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Antennas Simulation Competition Timetable Informations
Timetable
• March 2nd 2010 Introduction
• March 9th 2010 EMF 1 – Fachpraktikum
• March xxth 2010 Introduction to FEKO
• March 22nd 2010 Demonstration for measurements @ home
• April 2010 biweekly meeting of each group
• May 4th 2010 visit of the Uetliberg Tower
• May 11th 2010 Wire LAN antenna competition
• June 1st 2010 Presentation of your results (report and talk)
Timetable
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Antennas Simulation Competition Timetable Informations
General Information
• Homepagehttp://www.ifh.ee.ethz.ch/~fieldcom/pps-antenna/
• simulation sofware Feko:http://www.feko.info
• literature:„Antenna Theory, Analysis and Design”, Constantin A. Balanis, 1997„Antennenbuch”, Karl Rothammel, 1984Versuchsanleitung Fachpraktikum Antennen (AW, EMF1)Skript „Felder und Komponenten II“
• contact:Dimitra Psychogiou, [email protected], x27826, ETZ-K60.1 Thomas Kaufmann, [email protected], x25007, ETZ-K60.1Christian Beyer, [email protected], x27625, ETZ-K87
Infos