Hello everyone,
I have a little question regarding the current distribution over a slot antenna.
if I want to reverse the current direction over a certain location on a slot antenna, how can we do that?
Under fixed operating mode, without perturbation, it is not possible. Therefore, use perturbation.
If you change the operating mode, the current distribution (or fields) will be changed depending on operating mode.
Perturbation means by cutting slots (to separate closely spaced parts where you want opposite currents) or adding capacitors or inductors (to get rapid phase change, which is required for change of current direction). Usually you require a half of a wavelength distance for current to go from a peak one way to a peak the other. Cutting a slot means that this distance can be around the end of the slot. Current may not do what you want, even then! That what simulation tool are for.
Getting rapidly changing current direction usually results in a reduction in bandwidth and a reduction in antenna efficiency. It is required for superdirectivity.
Thank you for your great reply, Mr. White.
If i increased the metal strip by half wavelength then the size would become large, the slot is very good option bu what the shape do you think that realize current reversing?
I'm thinking about introducing a short-circuited TL at the desired location to reflect current by 180degree, but the problem is how to introduce such short circuit on a CPW configuration!!!!
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