How does the feed point impedance of a horizontal 1/2 wave dipole antenna change as the antenna height is reduced to 1/10 wavelength above ground?

توضیح

The earth acts as a mirror that inverts the phase of a horizontally polarized antenna, and as the dipole is brought close to that image the cancellation reduces its radiation resistance, so the feed point impedance falls steadily as the height drops toward 1/10 wavelength.