Transmission Lines & Impedance Matching

Click For Summary
SUMMARY

This discussion focuses on solving a problem related to transmission lines and impedance matching at an 800 MHz frequency. The user seeks to determine the amplitude of the voltage (Vmatched) when the load impedance is matched, utilizing the voltage equation of a transmission line. The approach involves setting the voltage at the load (V_L) and manipulating the equation to account for matched conditions by setting the reflection coefficient (γ) to zero. A suggestion is made to consider the amplitudes of the incoming and reflected waves to simplify the problem-solving process.

PREREQUISITES
  • Understanding of transmission line theory
  • Familiarity with characteristic impedance (Z0)
  • Knowledge of voltage equations for transmission lines
  • Concept of reflection coefficient (γ)
NEXT STEPS
  • Study the concept of impedance matching in transmission lines
  • Learn about the calculation of standing wave ratios (SWR)
  • Explore the impact of load impedance on voltage and current in transmission lines
  • Investigate the use of Smith charts for impedance matching
USEFUL FOR

Electrical engineering students, RF engineers, and anyone involved in the design and analysis of transmission lines and impedance matching techniques.

AngelofMusic
Messages
58
Reaction score
0
Hi all, I'm currently studying up on transmission lines for my next midterm, and I stumble onto this problem.
Given information: A 800 MHz transmission line that is lossless
- Vmax, Vmin, V_L for a given load impedance R_L.
- Characteristic impedance of a line
- length of a line & [tex]\lambda[/tex]
Is it possible to find the amplitude of the voltage (Vmatched) assuming that instead of the original load impedance, the line is now matched?
So far, I've tried to use the voltage equation of a transmission line
[tex]V(z) = \frac{Z_0 V_g}{Z_0 + Z_g} e^{-j\beta z} [1+\gamma e^{-j2\beta (l-z)}][/tex]
I set V(z=l) = V_L, which is given. And I solve for the value of the big fraction in front. Then I use that equation again, except set [tex]\gamma = 0[/tex] for the matched case.
Is this the right approach to solving this problem?
I do get an answer out of this one, but it's not one that seems obvious or intuitive. Is there a better approach to this? Or an incredibly simple answer to this problem?
Any help would be appreciated!
 
Physics news on Phys.org
Standing Wave

Perhaps I am wrong, but I think there is a simple way.
Are Vmax and Vmin given? They result from adding or subtracting a wave going towards the load and a reflected wave from the load. Can you solve for the amplitudes of those two waves?
If the load were macthed, what is the amplitude of the incoming wave? The reflected wave?
Hope this helps.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
5K
  • · Replies 7 ·
Replies
7
Views
4K
Replies
24
Views
3K
  • · Replies 18 ·
Replies
18
Views
3K
Replies
8
Views
3K
Replies
33
Views
4K
  • · Replies 2 ·
Replies
2
Views
6K
Replies
3
Views
2K
Replies
1
Views
2K