Download presentation
Presentation is loading. Please wait.
Published bySaul Gibbs Modified over 9 years ago
1
EMLAB 1 Transmission line
2
EMLAB 2 An apparatus to convey energy or signal from one place to another place. Transmitter to an antenna connections between computers in a network hydroelectric generating plant and a substation several miles away interconnect between components of a stereo system CATV service provider and your TV set Connections between devices on a circuit board Transmission line
3
EMLAB 3 Example – Cable TV
4
EMLAB 4 Example – Computer network
5
EMLAB 5 Example – Electric power transmission line
6
EMLAB 6 Example – Printed circuit board
7
EMLAB 7 Example – Printed circuit board
8
EMLAB 8 Types of transmission lines Microstrip line Coaxial cable Two-wire transmission line
9
EMLAB 9 Distribution of electric field strengths of typical TEM lines E/H distributions vary as the structures of transmission lines change. For electromagnetic compatibility, E/H should be confined to small area. Microstrip Two-wire Parallel plate
10
EMLAB 10 Field representation in waveguides
11
EMLAB 11 Wave Solution TEM mode (Transverse electromagnetic mode)
12
EMLAB 12 Parallel plate waveguide With a wide enough line trace, variation along y-axis can be ignored.
13
EMLAB 13 i (z, t) v (z, t) + - zz L z C z i (z+ z, t) v (z+ z,t) + - i (z, t) zz v (z, t) + - Transmission line 등가 회로
14
EMLAB 14 Transmission line eq. solution
15
EMLAB 15 Transmission line 의 특징 H E Direction of propagation H 1.For a magnetic field and an electric field propagating in the same direction, the ratio of E and H (E + /H + ) is kept constant. 2.For a voltage and a current current propagating in the same direction, V + /I + ratio is equal to Z 0. 3.When the ratio is disturbed, reflected waves are generated.
16
EMLAB 16 +V-+V- Reflection coefficient
17
EMLAB 17 +V-+V- +V-+V- +V-+V- +V-+V- +V-+V- Z s = 20 Z 0 = 50 Z L = 1k 0.5m Influence of line length on load voltage Impedance mismatched VinVout R R2 R=1k Ohm MLIN R R1 R=20 Ohm VtPulse SRC1 t Z 0 = 50
18
EMLAB 18
19
EMLAB 19 Ringing : Time domain
20
EMLAB 20 Signal source Load ~ Mismatched load Ringing
21
EMLAB 21 Impedance matching – Digital logic ~ ~ Source matching Load matching
22
EMLAB 22 Impedance matching topologies
23
EMLAB 23 Frequency domain solution β : propagation constant, v p : speed of light
24
EMLAB 24 Phasor representation +V-+V-
25
EMLAB 25 Transmission line terminated with short, open Zs = Zo V refl V inc For reflection, a transmission line terminated in a short or open reflects all power back to source In phase (0 ) for open o Out of phase (180 ) for short V refl o
26
EMLAB 26 Transmission Line Terminated with 25 Ω Zs = Zo Z L = 25 W V refl V inc Standing wave pattern does not go to zero as with short or open
27
EMLAB 27 Equivalent input impedance
28
EMLAB 28 Input impedance of short
29
EMLAB 29 Input impedance of open
30
EMLAB 30 Some transmission line examples case 1) matched load
31
EMLAB 31 case 2) unmatched load
32
EMLAB 32 Ringing : Time/frequency domain
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.