Question on: Smith charts, power and transmission lines

In summary, the conversation discusses the possibility of computing the fraction of time average incident power dissipated in a load on a lossless transmission line with a given characteristic impedance. It is possible to calculate this without knowing the voltage or current, by considering the impedance mismatch between the characteristic impedance and the load impedance. The term "Transmission Coefficient" can be investigated to determine the amplitude of the transmitted signal.
  • #1
vysero
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I would simply like to know: Given a lossless transmission line with a certain characteristic impedance Z terminated in a load L. How can I go about computing the fraction of the time average incident power arriving that is dissipated in the load? Is this possible without knowing the voltage or current; is this possible only knowing L and Z?
 
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  • #2
I assume L is the impedance of the load.
Yes it is possible. You need to consider the impedance mismatch between Z and L, part of the energy will be transmitted, part reflected.
You need to investigate the term "Transmission Coefficient" to know the amplitude of the transmitted signal. You know L ...
 

What is a Smith chart and how is it used?

A Smith chart is a graphical tool used in radio frequency (RF) engineering to analyze and optimize transmission line circuits. It is a plot of normalized impedance or admittance, and helps visualize how a signal behaves as it travels along a transmission line. It is commonly used in the design of antennas, filters, amplifiers, and other RF components.

What is the significance of power in transmission lines?

Power is an important factor in transmission lines as it determines the maximum amount of energy that can be transmitted through the line without experiencing excessive losses. In RF engineering, the goal is to maximize power transfer from the source to the load, while minimizing reflections and losses along the transmission line.

What is the difference between forward and reflected power in transmission lines?

Forward power, also known as incident power, is the power that is transmitted from the source to the load. Reflected power is the power that is reflected back towards the source due to impedance mismatches along the transmission line. Ideally, the goal is to have all of the power be forward power, with no reflections.

How are Smith charts used to analyze power in transmission lines?

Smith charts allow engineers to visualize the behavior of power along a transmission line. By plotting the normalized impedance or admittance, engineers can identify areas of high and low power transfer, as well as locations of impedance mismatches and reflections. This information can then be used to optimize the design of the transmission line for maximum power transfer.

What are some common applications of Smith charts in RF engineering?

Smith charts are commonly used in the design and analysis of various RF components such as antennas, filters, amplifiers, and matching networks. They can also be used to troubleshoot and diagnose issues with transmission line circuits, such as identifying the cause of signal loss or reflections. Additionally, they are useful for impedance matching, which is essential for efficient power transfer in RF systems.

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