why EM wave can not be radiated from the open end of transmission line?

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xuexucheng

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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!

Thank you!
 

hi, its matter of impedance miss match , for open end return loss is equal to 1 and therefore nothing radiate is'nt?
 
An open transmission line of non-zero diameter will surely radiate EM waves, as long as an electromagnetic field extents into open space. The efficiency depends on the cable diameter to lambda ratio.
 
how much will be radiated?
why it can totally radiated?
 

Radiation from the open waveguide is possible, and it is a complex function of waveguide type, the field distribution in it, and the wave length. It also depends on external medium properties, so the open-end structures are often used as sensors.
Check Wikipedia and good textbooks on electromagnetics on details.
 

But how to explain this using Maxwell equations intuitively?

Thank you a lot!
 

1. Consider a TL with open end
2. Sketch the E field lines
3. Imagine the coupling with H-field
 
I never solved the Maxwell equations "intuitively". The problem of an open line end is the boundary-definition problem, not the equations, BTW.
 
jiripolivka said:
I never solved the Maxwell equations "intuitively". The problem of an open line end is the boundary-definition problem, not the equations, BTW.
Click to expand...

Thank you very much for your reply.
Could you explain the detail of your boundary-definition problem?
I can not understand intuitively. I think the Maxwell equations are the basic principle of the EM.
 

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