pps uetliberg-antenna wireless lan antenna...

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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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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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Antenna FundamentalsAntennas

Far Field Approximation

Gain (Gewinn)

Directivity (Richtfaktor)

Input impedance, reflection factor

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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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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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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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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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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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Yagi – Antenne

Surface currents

Simulation

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Yagi – Antenne

Electric field strength distribution

Simulation

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Fernfeldberechnung – AnpassungSimulation

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Richtdiagramm Darstellung

3D plot Cartesian plot

Simulation

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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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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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Wireless LAN antenna competitionCompetition

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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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PPS Timetable

gather Antenna Fundamenals

Simulation Measurements

Optimisation

Presentation and Report

Theory

Praxis

Documentation

Timetable

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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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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

pps uetliberg-antenna wireless lan antenna...

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