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ai.xuexi
Antenna Theory Regular
Joined: 01 Jan 2012
Posts: 14
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 Posted: Sun Mar 31, 2013 2:10 am Post subject: why EM wave can not be radiated from the open end of transmi |
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why EM wave can not be radiated from the open end of transmission line?
The open end has vary electro field.
I think vary electro field can generate vary megnetic field. and continue!
why we need antenna?
Thank you! |
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bigSteve
Antenna Wizard
Joined: 14 Mar 2009
Posts: 265
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| Posted: Sun Mar 31, 2013 4:02 am Post subject: Transmission Line Antenna |
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Yes - an open circuit of a transmission line will radiate a bit. This is similar to a very thin patch antenna. However, it will not radiate very efficiently and the bandwidth will be very low.
The antennas job is to convert the voltage and current on a transmission line to radiated fields at the frequencies of interest in an efficient manner.
A short transmission line will have low radiation efficiency and not much bandwidth. It will be difficult to tune a transmission line for radiation at the desired frequency. |
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ai.xuexi
Antenna Theory Regular
Joined: 01 Jan 2012
Posts: 14
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| Posted: Fri Apr 05, 2013 10:19 pm Post subject: |
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I konw the results.
But how to explain this using Maxwell equations? |
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