pps uetliberg-antenna wireless lan antenna...
TRANSCRIPT
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PPS Uetliberg-Antenna
Wireless Lan Antenna competition Summer 2011
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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 Fundamentals
Antennas
transmission line antenna free space
E-field amplitude
at the E-plane:
Source
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 Fundamentals
Antennas
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
<<l <<l ≈ l/2
-Low directivity
-Low efficiency
-Small input impedance
-High input reactance
-Real input impedance
-Small bandwidth
Wide band:
- Bandwidth >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 types
Pyramidal
horn
Conical
horn
Rectangular
waveguide
Rectangular
Patch
Circular
Patch
-Micro- and millimeter wave
-High directivity
-Medium bandwidth
-Size: some wavelength
3) Microstrip 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) maximum S
SS
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 domain
• Post processing computes
field patterns and network
entities
• CAD user interface to define
the geometry
• HFSS, CST, COMSOL
Simulation
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Antennas Simulation Competition Timetable Informations
Yagi – Antenna
Surface currents
Simulation
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Antennas Simulation Competition Timetable Informations
Yagi – Antenna
Electric field strength distribution
Simulation
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Antennas Simulation Competition Timetable Informations
Far field calculations - Matching
Simulation
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Antennas Simulation Competition Timetable Informations
Directivity plots
3D plot Cartesian plot
Simulation
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Antennas Simulation Competition Timetable Informations
Simulation Software HFSS
• High-Frequency Structure Simulator (HFSS) using FEM
• Available on tardis!
• Support CAD input
• Automatic discretisation of volumes by means of tetrahedra
• Solver computes the fields inside the whole domain
• Absorbing boundaries imitate the extension to infinity
• Antenna parameters are extratcted based on the field values
• Suitable for complex geometries and materials
Simulation
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Antennas Simulation Competition Timetable Informations
Wireless LAN antenna competition
Competition
• Objectiv: build a high gain Wireless LAN antenna
• teams of 2 or 4 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 competition
Competition
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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
Optimization
Presentation and Report
Theory
Praxis
Documentation
Timetable
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Antennas Simulation Competition Timetable Informations
Timetable
• March 2nd 2011 Introduction
• Individually EMF 1 – Fachpraktikum
• March 9th 2011 Introduction to HFSS
• March 16nd 2011 Demonstration for measurements @ home
• April 2011 biweekly meeting of each group
• May 12th 2011 (?) visit of the Uetliberg Tower
• May 19th 2011 Wire LAN antenna competition
• June 1st 2011 Presentation of your results (report and talk)
Timetable
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Antennas Simulation Competition Timetable Informations
General Information
• Homepage
http://www.ifh.ee.ethz.ch/~fieldcom/pps-antenna/
• simulation sofware HFSS:
http://www.ansoft.com/products/hfss
• literature:
„Antenna Theory, Analysis and Design”, Constantin A. Balanis, 1997
„Antennenbuch”, Karl Rothammel, 1984
Versuchsanleitung Fachpraktikum Antennen (AW, EMF1)
Skript „Felder und Komponenten II“
• contact:
Dimitra Psychogiou, [email protected], x27826, ETZ-K60.1
Christian Beyer, [email protected], x27625, ETZ-K87
(Thomas Kaufmann, [email protected], x25007, ETZ-K60.1)
Infos