Electromagnetic Wave, Waveguide,

1

• Electromagnetic Wave, Waveguide,
• and Antenna

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Propagation

• Reflection and Scattering
• Refraction
• Interference
• Multipath
• Path loss
• http//www.cisco.com/univercd/cc/td/doc/product/wi
  reless/bbfw/ptop/p2pspg02/spg02ch2.htm

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Propagation in Air

• Ionosphere
• Ionized particles
• 80-300 km
• Ground Plane
• Modes
• Direct line of sight
• Earth curvature
• Ground wave
• Sky wave
• Space wave

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Sky Waves

• Long Wavelength
• Ground and ionosphere
• http//www.vlf.it/thierry/waveguide_propagation.ht
  ml
• Short Wavelength

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Waveguide

• Metallic Waveguide
• Dielectric Waveguide
• Dielectric Media
• Cable
• Polyethylene
• Teflon
• PCB
• Rigid Alumina, PTFE
• Flexible Polyimide
• Dielectric constant
• Loss tangent

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Applications of Waveguides

• Long Haul
• Performance
• Loss, dispersion
• Networking
• Quick connect
• Termination
• Printed Circuit Board
• RF and microwave packaging

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Waveguide Analysis

• Wave Equation
• Periodic in time
• Helmholtz Equation
• Periodic in z
• Transverse Modal Equation
• Boundary Conditions
• Waveguide Theory
• http//www.fnrf.science.cmu.ac.th/theory/waveguide
  /

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Modes

• Guided Modes
• Discrete possibly multiple
• Radiation Modes
• Continuous
• Evanescent Field
• Exponentially decaying

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Waveguide Properties

• Polarization
• TEM
• TE, TM
• Hybrid modes
• Propagation Constant
• Loss
• Dispersion

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Dispersion

• Frequency Dependent Refractive Index
• Material dispersion
• Waveguide modal dispersion (single mode)
• Inter-modal dispersion (multimode)
• Pulse broadening
• www.lunatechnologies.com/files/24introchromaticdis
  persionweb.pdf

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Waveguide Devices

• Directional Coupler
• Multi hole
• Lumped element,
• stripline
• Frequency dependent
• Mini Circuits
• www.minicircuits.com/pages/appnote/do-it-yourselfc
  ouplers.pdf

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New Developments

• Negative Index Materials
• http//www.ee.duke.edu/drsmith/neg_ref_home.htm
• Photonic Bandgap Materials
• http//www.pbglink.com/

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Antenna

• Electrical Element
• Impedance
• Power
• Radiation
• Coupling of energy from waveguide to free space
  or vice versa
• Polarization
• Efficiency
• Directionality
• Radiation pattern (far field)
• Antenna gain
• Advantage over isotropic (point source) radiation

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Oscillating Dipole

• Reference
• http//dept.physics.upenn.edu/courses/gladney/phys
  151/lectures/lecture_apr_07_2003.shtml

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Dipole Antenna

• Dipole Length
• Half wavelength
• Bandwidth
• Polarization
• Parallel to antenna axis
• Efficiency
• Radiation resistance 67 ?
• Loss resistance 5 ?
• 0.93
• Antenna Gain, G
• 2.14 dBi
• Effective Area
• Radiation Pattern
• Reference http//www.signalengineering.com/ultimat
  e/antenna_basics.html

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Dipole Antenna Project
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Antennae

• Marconi (?/4)
• Dipole (?/2)
• Yagi
• Loop

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Antennae

• Long Wire
• Rhombic
• Parabolic

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Antenna Loading

• Coil in Series
• Resonance and bandwidth
• Effective length
• Calculator
• http//eweb.chemeng.ed.ac.uk/jack/radio/software/l
  oading.html
• Capacitor at Top

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Radiation Pattern

• 10-element Yagi
• Reference
• http//www.astronwireless.com/radiation_patterns.h
  tml

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Antenna Feed

• Center Feed
• Dipole
• Horn Feed
• Parabolic

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Antenna Simulation

• Lawrence Livermore NEC4
• Demo
• http//www.eznec.com/demoinfo.htm

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Array

• Multi-Element Interference
• Linear Array
• Phased Array
• Agility
• Multi-beam
• http//www.knovel.com/knovel2/Toc.jsp?SpaceID1008
  4BookID701
• Smart or Adaptive Antenna for Mobile
• http//www.comsoc.org/livepubs/surveys/public/4q99
  issue/lehne.html
• Aerospace
• http//www.cfa.harvard.edu/lincoln/ska/
• ska.workshop/weinreb.pdf

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Practical Applications

• Radio
• Whip antenna
• Loopstick
• Twin T antenna
• TV
• VHF Rabbit ear antenna
• UHF Loop antenna
• How to Adjust?
• http//www.kyes.com/antenna/antennadex.html

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Practical Applications

• Wi-Fi
• Vertical Omnis
• Ceiling Dome
• Rubber Duck
• Desk Top
• Cellular Phone
• Radar Detector
• Projects
• http//www.wlan.org.uk/antenna-page.html

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Chapter Review

• EM Wave in Free Space
• Line of sight, ground wave, space wave
• Guided Wave
• Equation and boundary condition
• Modal properties field pattern, effective index
• Dispersion
• Single mode
• Technology Review Topics
• Negative index and photonic bandgap
• Antenna
• Dipole
• Pattern, Gain
• Array
• Practical Applications