elct564 spring 2012 5/20/20151elct564 chapter 3: waveguides and transmission lines
TRANSCRIPT
![Page 1: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/1.jpg)
ELCT564 Spring 2012
04/18/23 1ELCT564
Chapter 3: Waveguides and Transmission Lines
![Page 2: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/2.jpg)
Waveguides
04/18/23 2ELCT564
Metal Waveguides
Dielectric Waveguides
![Page 3: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/3.jpg)
Comparison of Waveguides and Tlines
04/18/23 3ELCT564
Transmission Line Waveguide
Two or more conductors separated by some insulating medium (two-wire, coaxial, microstrip, etc.
Metal waveguides are typically one enclosed conductor filled with an insulating medium while a dielectric waveguide consists of multiple dielectrics
Normal operating mode is the TEM or quasi-TEM mode (can support TE and TM modes but these modes are typically undesirable.
Operating modes are TE or TM modes (can not support a TEM mode)
No cutoff frequency for the TEM mode. Tline can transmit signals from DC up to high frequency
Must operate the waveguide at a frequency above the respective TE or TM mode cutoff frequency for that mode to propogate
Significant signal attenuation at high frequencies Lower signal attenuation at high frequencies
Small cross section line can transmit only low power levels
Can transmit high power levels
Large cross section tlines can transmit high power leves.
Large cross section waveguides are impractical due to large size and high cost.
![Page 4: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/4.jpg)
General Solutions for TEM, TE and TM Waves
04/18/23 4ELCT564
![Page 5: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/5.jpg)
General Solutions for TEM, TE and TM Waves
04/18/23 5ELCT564
TEM Waves
TE Waves
TM Waves
Attenuation due to Dielectric Loss
![Page 6: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/6.jpg)
Parallel Plate Waveguide
04/18/23 6ELCT564
TEM Waves
![Page 7: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/7.jpg)
Parallel Plate Waveguide
04/18/23 7ELCT564
TM Waves
![Page 8: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/8.jpg)
Parallel Plate Waveguide
04/18/23 8ELCT564
TE Waves
![Page 9: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/9.jpg)
Summary of Results for Parallel Plate Waveguide
04/18/23 9ELCT564
![Page 10: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/10.jpg)
Rectangular Waveguide
04/18/23 10ELCT564
TE Waves
![Page 11: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/11.jpg)
Rectangular Waveguide
04/18/23 11ELCT564
TM Waves
![Page 12: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/12.jpg)
Summary of Results for Rectangular Waveguide
04/18/23 12ELCT564
![Page 13: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/13.jpg)
Example I
04/18/23 13ELCT564
Consider a length of Teflon-filled (εr=2.08, tanδ=0.0004) copper K-band rectangular waveguide, having dimensions a=1.07 cm and b=0.43 cm. Find the cutoff frequencies of the first five propagating modes. If the operating frequency is 15 GHz, find the attenuation due to dielectric and conductor losses.
![Page 14: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/14.jpg)
Example II
04/18/23 14ELCT564
![Page 15: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/15.jpg)
Circular Waveguide
04/18/23 15ELCT564
TE Waves
![Page 16: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/16.jpg)
Circular Waveguide
04/18/23 16ELCT564
TM Waves
![Page 17: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/17.jpg)
Summary of Results for Cirular Waveguide
04/18/23 17ELCT564
![Page 18: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/18.jpg)
Example I
04/18/23 18ELCT564
Find the cutoff frequencies of the first two propagating modes of a Teflon-filled (εr=2.08, tanδ=0.0004) circular waveguide with a=0.5cm. If the interior of the guide is gold plated, calculated the overall loss in dB for a 30cm length operating at 14GHz.
![Page 19: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/19.jpg)
Example II
04/18/23 19ELCT564
![Page 20: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/20.jpg)
Attenuation of Waveguides
04/18/23 20ELCT564
![Page 21: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/21.jpg)
Coaxial Line
04/18/23 21ELCT564
Higher Order Modes
![Page 22: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/22.jpg)
Coaxial Line: Example
04/18/23 22ELCT564
Consider a piece of RG-401U coaxial cable, with inner and outer conductor diameter of 0.0645’’ and 0.215’’, and a Teflon dielectric(εr=2.2). What is the highest usable frequency before the TE11 waveguide mode starts to porpagate?
=563.4 m-1
=18.15GHz
Field lines for TEM mode of a coaxial line
Field lines for TE11 mode of a coaxial line
![Page 23: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/23.jpg)
Coaxial Connectors
04/18/23 23ELCT564
Connector Type Other names
Female Male Maximum Frequency
Phone plugs and jacks
TS, TRS 100 kHz
RCA Phono plugs and jacks
10MHz
UHF PL-259 300MHz
F Video 250MHz to 1 GHz
BNC 2GHz
C 12 GHz
Type N 12GHz or more
SMA 12 GHz or more
2.4mm 50GHz
![Page 24: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/24.jpg)
Strip Line
04/18/23 24ELCT564
![Page 25: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/25.jpg)
Strip Line: Example
04/18/23 25ELCT564
Find the width for a 50Ω copper stripline conductor, with b=0.32 cm and εr=2.2. If the dielectric loss tangent is 0.001 and the operating frequency is 10 GHz, calculate the attenuation in dB/λ. Assume a conductor thickness of t=0.1mm.
![Page 26: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/26.jpg)
Microstrip Line
04/18/23 26ELCT564
![Page 27: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/27.jpg)
MicroStrip Line: Example
04/18/23 27ELCT564
Calculate the width and length of a 50Ω copper microstrip line, with a 90o phase shift at 2.5GHz. The substrate thickness is d=0.127 cm, with εr=2.2.
![Page 28: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/28.jpg)
Wave Velocities and Dispersion
04/18/23 28ELCT564
Dispersion: If the phase velocity is different for different frequencies, then the individual frequency components will not maintain their original phase relationships as they propagate down the transmission line or waveguide, and signal distortion will occur.
Group Velocity
Calculate the group velocity for a waveguide mode propagating in an air-filled guide. Compare this velocity to the phase velocity and speed of light.
![Page 29: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/29.jpg)
Summary of Transmission Lines and Waveguides
04/18/23 29ELCT564
Characteristic Coax Waveguide Stripline Microstrip
Modes: Preferred Other
TEMTE, TM
TE10TM, TE
TEMTM,TE
Quasi-TEMHybrid TM, TE
Dispersion None Medium None Low
Bandwidth High Low High High
Loss Medium Low High High
Power Capacity Medium High Low Low
Physical Size Large Large Medium Small
Ease of Fabrication Medium Medium Easy Easy
Integration with Others Hard Hard Fair Easy
![Page 30: ELCT564 Spring 2012 5/20/20151ELCT564 Chapter 3: Waveguides and Transmission Lines](https://reader035.vdocument.in/reader035/viewer/2022081501/56649d0c5503460f949dfef7/html5/thumbnails/30.jpg)
Other Lines and Guides
04/18/23 30ELCT564