why is the voltage distribution a quarter wavelength out of phase with current in a half wavelength dipole antenna?
as show in this photo:
https://www.electronics-notes.com/images/antenna-dipole-half-wave-current-voltage-01.svg

It makes sense that in a graph over time, the voltage at the ends of the antenna is a quarter wavelength behind the current measured at the feed. But voltage distribution is over x; isn't the voltage in phase with current over distance?

I was under the impression that at the feed point, current is in phase with voltage. What makes it go 90 degrees out of phase in an antenna?