Voltage and current profiles on patch antenna

[yefj]

Hello on the antenna bellow we have L=half wave length.
I understand that we have open circuit on the edges so currect is zero on edges
but why its maximal in the middle ,and why voltage acts by going from +vmax on one edge to -Vmax on other edge.
is there some physical explanation for it?
Thanks.

 

[BradtheRad]

It might be easier to understand by going back to earlier days...
When the antenna had twin-lead cable attached across a gap at midpoint. The antenna was 1/2 wavelength, yet separated into two halves. I guess it's to provide a node to tap for current (a power source, as it were) in order to drive components in a receiver (impedance matching, preamplifier, detector).

Anyway that describes the VHF tv antenna, in the form of 'rabbit ears' or the driver element of a yagi.

Thinking about the UHF antenna for contrast and comparison...
This often was a circular loop or bowtie, connected to two screw terminals. It's hard to figure out (conceptually speaking) whether the leads are connected at the midpoint or at the ends.