How can I understand reflection coefficient for a certain circuit?

In summary, the reflection coefficient, denoted by Gamma, is a measure of the ratio of the electric field strength of the reflected wave to that of the incident wave. It can be calculated using the formula Gamma = (ZL - Zs)/(ZL + Zs), where ZL and Zs represent the load impedance and source impedance, respectively. Understanding the concept of reflection coefficient is important in RF circuits and can be learned through studying transmission line concepts.
  • #1
genxium
141
2
How can I understand "reflection coefficient" for a certain circuit?

Homework Statement



I'm a beginner in RF circuit, though I've learned something about low frequency oscillator design, some new concepts still confuse me a lot, like the "reflection coefficient".

I google it and found the definition of "reflection coefficient" on wiki,
http://en.wikipedia.org/wiki/Reflection_coefficient"
but the definition of it for a certain circuit (like the figure with Vs,Zs,ZL in wiki) is still quite confusing for me >_<

Any one can explain how Gamma=(ZL-Zs)/(ZL+Zs) represents the "ratio of the electric field strength of reflected wave to that of incident wave"?

Homework Equations



Gamma=E-/E+ , Gamma=(ZL-Zs)/(ZL+Zs)


The Attempt at a Solution



none by far, I'm a beginner just for a simple concept explanation...
 
Last edited by a moderator:
Physics news on Phys.org
  • #2


I won't give you the full explanation here, but I will try to point you in the right direction.

When I was in college, I first learned about reflection coefficient from 'Engineering Electromagnetics' by Inan and Inan. This text will give you a good description of reflection coeff. and related concepts, with respect to transmission lines.

I would say, learning about RC with respect to t-lines is a good idea. It is a good compromise between time spent, and understanding what it is. It gives you the idea that, when dealing with RF stuff, you need to be a bit more conscious of physical aspects of a circuit, than you do with low-freq. circuits. However, the t-line approach spares you the rigorous work required to understand the reflection coeff. from a pure-EM approach.

Remember, fundamentally, RC is pretty simple, although the math may get difficult. You have a EM wave incident on a boundary. What comes back? That's mostly it. Circuits, t-lines, etc, are just special cases of this very general def'n.
 

Related to How can I understand reflection coefficient for a certain circuit?

1. What is the reflection coefficient and why is it important in circuit analysis?

The reflection coefficient is a measure of the amount of signal that is reflected back from a circuit compared to the amount that is transmitted. It is important in circuit analysis because it helps determine the impedance and signal loss in a circuit, which can affect the performance of the circuit.

2. How is the reflection coefficient calculated?

The reflection coefficient is calculated by dividing the difference between the incident and reflected voltage by the sum of the incident and reflected voltage. This can also be expressed in terms of current.

3. What is the significance of a positive or negative reflection coefficient?

A positive reflection coefficient indicates that the reflected signal is in phase with the incident signal, while a negative reflection coefficient indicates that the reflected signal is out of phase. This can affect the impedance and signal loss in the circuit, and can be used to analyze the behavior of components like resistors, capacitors, and inductors.

4. How does the reflection coefficient change in different types of circuits?

The reflection coefficient can vary depending on the type of circuit and the components used. In a series circuit, the reflection coefficient is affected by the impedance of the components, while in a parallel circuit, it is affected by the admittance of the components. In addition, the length and frequency of the signal can also impact the reflection coefficient.

5. Can the reflection coefficient be used to analyze the performance of a circuit?

Yes, the reflection coefficient can provide valuable information about the impedance, signal loss, and other characteristics of a circuit that can affect its performance. By analyzing the reflection coefficient, engineers and scientists can make improvements to the design and functionality of circuits to optimize their performance.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
18
Views
2K
  • Electrical Engineering
Replies
7
Views
1K
  • Advanced Physics Homework Help
Replies
1
Views
644
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Electrical Engineering
Replies
5
Views
2K
  • Electromagnetism
Replies
8
Views
1K
Replies
4
Views
712
  • Introductory Physics Homework Help
Replies
3
Views
257
  • Quantum Physics
Replies
20
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
3K
Back
Top