Explanation of Electric Waves

CraigH

I am currently studying antenna's and the concept of reflected waves and reflected power inside conductors really confuses me.

When I imagine an AC current flow inside a conductor I imagine all the electrons to have an equilibrium position before the AC voltage is applied, and then once it is applied all the electrons oscillate back and forwards in phase with the AC voltage sin wave that was applied.
If you measure the current at any point in this conductor you will see that the current is positive (meaning the charge inside the conductor has a net flow in one direction) then it will be zero, and then it will be negative (meaning the charge inside the conductor has a net flow in the other direction). If you measure the current at two different points along this conductor the waves you get will be exactly the same, meaning all the electrons are moving in one direction, then stopping, and then moving in the other direction at the same time.

If this is the case then I do not understand how current can be reflected and you can get reflected power, and standing waves. However these these things are constantly mentioned in my RF Engineering and Electromagnetism lectures, particularly when talking about antenna's.

Will some one please help? It will be much appreciated!

Thank You!!

nsaspook

Put aside the electrons and current flow for a while and concentrate on how the fields move in the space around the antenna.

This might help to visualize it. http://www.physicsforums.com/showpos...4&postcount=17

CraigH

Thank you, This video has helped explain waves and impedance matching better than any lecturer or even modern video or animation ever has.