- #1
Open circuited quarter wave transmission line
- Engineering
- Thread starter reddvoid
- Start date
In summary, the conversation discusses the calculation of voltage and impedance in a mismatched 1/4 wave transmission line. The suggested method is to first calculate the impedance at the open end, then find the ratio of that impedance to the generator's 50 ohms. This ratio can then be used to calculate the voltage. The use of ABCD parameters is also mentioned as a method for handling various types of mismatches.
- #2
skeptic2
- 1,775
- 59
You're going about it wrong. First calculate the impedance at the open end of the transmission line. Hint, it's not infinite. A mismatched 1/4 wave transmission line acts like a transformer. After you calculate the impedance at the open end, then calculate the ratio of that impedance to the 50 ohms of the generator. Lastly, how does the ratio of voltages compare to the ratio of impedances of a transformer? If you first find the ratio of impedances then from that you can find the ratio of voltages. Once you've done that you would just multiply the input voltage by the voltage ratio.
- #3
- 8,032
- 869
I would use ABCD parameters, concatenating the ABCD parameters for the 50 ohm source resistor with the abcd parameters for the xmsn line. This method can handle any kind of oddball mismatches, such as in this case the 300 ohm xmsn line to the 50 ohm source, and any desired length of line (here λ/4) and far-end termination impedance (here ∞).
I'm sure that's overkill here & that there's an esier way, as skeptic2 is suggesting. Just pointing out that abcd parameters can handle the most general cases.
I'm sure that's overkill here & that there's an esier way, as skeptic2 is suggesting. Just pointing out that abcd parameters can handle the most general cases.
- #4
- #5
MrWarlock616
- 160
- 3
Your handwriting is cool. 
FAQ: Open circuited quarter wave transmission line
1. What is an open circuited quarter wave transmission line?
An open circuited quarter wave transmission line is a type of transmission line used in radio frequency systems. It consists of a length of transmission line that is one quarter of the wavelength of the signal being transmitted. One end of the line is left open, while the other end is connected to the source or load.
2. What is the purpose of an open circuited quarter wave transmission line?
The purpose of an open circuited quarter wave transmission line is to match the impedance of the source to the impedance of the load. This allows for maximum power transfer and minimizes signal reflections.
3. How does an open circuited quarter wave transmission line work?
An open circuited quarter wave transmission line works by creating a standing wave pattern along the line. This standing wave pattern has a node at the open end and an antinode at the connected end. This allows for the impedance to be matched between the source and the load.
4. What are the advantages of using an open circuited quarter wave transmission line?
One of the main advantages of using an open circuited quarter wave transmission line is its ability to match impedances and minimize signal reflections. This results in better signal quality and less loss of power. Additionally, this type of transmission line is relatively simple and inexpensive to construct.
5. Are there any limitations to using an open circuited quarter wave transmission line?
One limitation of an open circuited quarter wave transmission line is that it can only be used for a specific frequency, which is determined by the length of the line. This means that it is not suitable for transmitting a wide range of frequencies. Additionally, this type of transmission line is more sensitive to environmental factors, such as temperature and humidity, which can affect its performance.
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