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  • WLAN Antenna

    PPS Antenna Tower Uetliberg

    Mathias Aebersold

    Matthias Bucher

  • Overview

    Introduction to WLAN

    Building our own antenna

    Demonstration (next time)

    Conclusion (next time)

  • Introduction to WLAN

    Wireless LAN connection over 30-100m

    Since 1997

    Various standards (a,b,g,n) with different specifications

    WiMax

  • Technology behind WLAN

    Modulation: Orthogonal frequency-division multiplexing, Quadrature amplitude modulation

    Frequencies: 2.4 and/or 5 GHz

    Channels

    No encryption per default

  • WLAN Standards

    Source: http://en.wikipedia.org/wiki/IEEE_802.11

  • Building our antenna

    Types

    Our choice

    Building our antenna

  • Building our antenna - Types

    types

    omnidirectional antenna

    sector beam antenna

    radiated beam antenna

  • Wlan-antenna-types

    examples:

    sources:

    http://ecx.images-amazon.com/images/I/11NB6H3HJAL._AA240_.jpg

    http://www.germes-online.com/direct/dbimage/50036375/Yagi_Antenna.jpg

    ~ 25/25~ 30360 /30angle

    ~10dBi~ 15dBi~ 5dBigain

    BiQuadYagiStandard

  • Our choice

    criteria:

    easy to build

    cheap(er)

    high power gain

    BiQuad-antenna based on a cd-spindle

  • Legal aspects

    Construction is legal, running it maybe not

    frequencies must be between: 2,4 - 2,48

    Ghz

    limitation: 100mW = 20dBm of transmitting power

  • BiQuad-Antenna

    radiated beam

    source: http://www.lecad.uni-lj.si/~leon/other/wlan/biquad/radiation-wire.html

  • BiQuad-Antenna

    Distance radiator reflector

    best at H=0.1315 ~120*0.1315=16mm

    source: http://www.lecad.uni-lj.si/~leon/other/wlan/biquad/radiation-wire.html

  • BiQuad-Antenna

    Dimension of the radiator

    Best at H=0.23 29~mm

    source: http://www.lecad.uni-lj.si/~leon/other/wlan/biquad/radiation-wire.html

  • Building our antenna

    What do you need?

    Construction/Specifications

    Hints

  • Building our antenna - Material

    cd spindle

    1 cd

    copper wire (~50cm, cross-section: 2.5mm2)

    a short antenna/coaxial-cable

    some tools

  • Building our antenna - Construction

    reflector

    preparing the spindle

    stick: 18mm (antenna 16mm over ground)

    rasp a cross

  • Building our antenna - Construction

    antenna

    bend radiator

    31mm, 29mm

  • Building our antenna - Construction

    the cable

    damping

    short distance

    Length theoretical:multipleof/2

    practical: additional adapter,

    unknown cable, etc.

    try and error

  • Building our antenna - Construction

    puttingalltogether

  • Building our antenna - Hints

    copper oxidises use hairspray or similar

    attach antenna cable on the back of the spindle aswell

  • Demonstration

    Try it out!

  • Evaluation

    It works!

    How well?

    For which purposes?

    Price

  • Standard vs BiQuad Antenna

    Short distance indoor:

    Standard

    -25dBm -20dBm -54dBm

    -24dBm -29dBm

    -25dBm -30dBm

    -51dBm -48dBm -59dBm

    -51dBm -54dBm

    -50dBm -69dBm

    Antenna BiQuad No Antenna

    1m direct

    1m sidewards

    1m backwards

    3m direct

    3m sidewards

    3m backwards

  • Standard vs BiQuad Antenna

    Long distance outdoor:

    1 3 6 10 14 28 32 39 44 50 60

    0

    10

    20

    30

    40

    50

    60

    70

    80

    90

    Signal/Noise Ratio vs. Distance

    Qualitt BiQuad

    Qualitt Standard

    Distance in meters

    Sig

    na

    l/No

    ise

    Ra

    tio in

    dB

    m

  • Standard vs BiQuad Antenna

    Standard:

    Indoor usage

    Short distances

    Multiple clients

    Cheap

    BiQuad:

    Outdoor usage

    Long and short distances

    Point-to-point connection

    Also cheap, but takes some effort to build it

  • Questions?

    more information about our antenna:

    vallstedt-networks.de/?Fotogalerien/Quad

    Google

    Questions?

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