Transmission Line and Termination

1

• Transmission Line and Termination

2
Transmission Line Analysis

• Wavelength Versus Distance
• Lumped
• Distributed
• Pulse Transition Versus Propagation Delay
• Single Mode
• Frequency response
• Propagation (timing and phase) delay
• Loss and dispersion
• Pulse distortion
• Multimode
• Modal analysis
• Multi Lines
• Crosstalk
• Interference

3
Transmission Lines

• Metallic
• Parallel Wire Pair
• FM and TV antenna
• Twisted Wire Pair
• Phone line
• 10BaseT Ethernet
• http//www.swhowto.com/CAT5_Ch1.htm
• Coaxial Cable
• RG58
• Metallic Conduit
• Planar Striplines
• Printed circuit board
• Hybrid IC carrier
• Dielectric
• Fiber
• Glass
• Polymer

4
Characteristic Impedance

• Impedance
• ZV/I for an infinite cable
• Coaxial Cable
• CATV, lab, microwave instrumentation
• Loss
• Frequency dependent
• Skin depth
• http//www.ipm.virginia.edu/process/PVD/Pubs/thesi
  s4/chapter2.pdf
• TEM mode
• Unbalanced

5
Coaxial Cables
Coax Attenuation in db per 100 feet (On 27MHz) Velocity Factor Description
RG-8 1.15 dB .66 50 Ohm coax
RG-59 2.0 dB .66 75 Ohm coax
RG-8/U Foam 0.85 dB .80 50 Ohm coax, Foam Dielectric
RG-59/U Foam 1.5 dB .79 75 Ohm coax, Foam Dielectric
Belden 9913 0.7 dB .84 Premium 50 Ohm coax
1/2" Hardline 0.35 dB .81 Special coax, expensive!
RG-8X (Mini-8) 1.2 dB .78 Small 50 Ohm coax. Preferred over RG-58. Recommended for mobile installations.
RG-58 2.35 dB .66 50 Ohm coax
RG-213 1.35 dB .66 50 Ohm coax.
RG-11/U Foam 0.85 dB .80 75 Ohm coax.
RG-11/U 1.35 dB .66 75 Ohm coax

• http//www.rfcafe.com/references/electrical/coax_c
  hart.htm

6
Coax Connectors

• BNC
• Type N
• SMA
• APC7
• K

7
Coax Connectors
8
Twin Lead Cable

• Balanced
• 300 ?
• Balun
• Balanced to unbalance transformer

9
Twisted Wire Pair

• Network Cables
• Cat 3, 4, 5, 5E, 6, ..
• DSL wiring at home
• http//www.smellyeyeball.com/dsl/

10
(No Transcript)
11
Striplines

• Micro Stripline
• Embedded Stripline
• Coplanar Stripline
• Loss
• Metallic
• Skin depth
• Localized current flow
• Dielectric
• Loss tangent
• Surface roughness

12
Transmission Line Termination

• Impedance Matching
• Termination
• Mismatch
• Reflection
• Time Domain Picture
• http//www.williamson-labs.com/xmission.htm
• Frequency Domain Analysis

13
Reflection and Transmission

• Reflection
• Standing Wave Ratio
• Wave Visualization
• http//www.educatorscorner.com/index.cgi?CONTENT_I
  D2483

14
Impedance Matching

• Effective Impedance
• Load impedance
• Cable in front of load
• Frequency dependent
• Bandwidth
• Smith chart
• http//www.educatorscorner.com/index.cgi?CONTENT_I
  D2482
• Impedance Matching
• Transformer
• www.minicircuits.com/pages/pdfs/tran14-2.pdf
• Stub
• http//www.ee.surrey.ac.uk/Personal/D.Jefferies/st
  ubs.html
• Application
• http//www.sss-mag.com/pdf/arrl_circles.pdf

15
Time Domain Reflectometry

• Principle
• Launch a pulse or a step waveform into the cable
• Monitor reflected signal
• Delay location of mismatch
• Magnitude amount of mismatch
• Equipment
• http//www.tek.com/Measurement/App_Notes/55_14601/
  eng/55W_14601_1.pdf
• Pulse generator

16
Time Domain Reflectometry

• Measurements
• http//bwrc.eecs.berkeley.edu/Classes/EE290C_S04/l
  ectures/Lect03_measurement.pdf
• http//literature.agilent.com/litweb/pdf/5988-6505
  EN.pdf
• Build Your Own TDR
• http//www.web-ee.com/Schematics/TDR/tdr.htm

17
Analysis for Digital Pulse

• Pulse Analysis
• http//www.mwrf.com/Articles/Print.cfm?ArticleID5
  433
• Pulse Distortion
• EESoft Modeling http//eesof.tm.agilent.com/pdf/as
  ia_forum_2004_07.pdf

18
Reading and Exercise

• Reading
• http//cktse.eie.polyu.edu.hk/eie403/Transmissionl
  ine.pdf
• Exercise
• http//courses.ece.uiuc.edu/ece450/Homework/HW3_F2
  004.pdf
• Reference
• http//www.connectorwizard.com/reference/articles/
  pdfs/GoldenStandard_Part2.pdf

19
Chapter Review

• Transmission Lines
• balanced and unbalance
• Balum
• Characteristic Impedance
• Reflection Coefficient
• Voltage Standing Wave Ratio
• Smith Chart
• Impedance Matching
• Time Domain Reflectometry