Richard Harrison wrote:
Cecil, W5DXP wrote:
"Does this cause and effect chain of events result in aphase lag between
electric and magnetic fields?"

Never saw a phase lag suggested. As radiation impedance is a resistance
even in free space, I expect rise and fall in electric and magnetic
fields is simultaneous even as they speed away at the velocity of light.
Which came first, the electric or the magnetic?

The ratio of E to H fields of a wave is known as the wave impedance. It
has both a magnitude and a phase angle (or real and imaginary
components). The impedance of a plane wave propagating through a medium
is the intrinsic impedance of the medium. For example, the ratio of E to
H of a plane wave propagating through space equals the intrinsic
impedance of space. The intrinsic impedance of space is purely real
(~377 + j0 ohms), which tells you that the ratio of E to H of a plane
wave propagating through it is purely real. This means there is no phase
difference between the two - E and H are in phase.

But the intrinsic impedance of many materials (e.g., dirt) isn't purely
real, so there is a non-zero phase angle between E and H fields of plane
waves propagating through them.

The ratio of E to H is also often complex in the near field around an
antenna, and usually with a magnitude other than 377 ohms. So in that
region, there's also a phase difference between E and H.

Roy Lewallen, W7EL