Electric field pull on EM wave due to copper trace wave guidance

Question

My background is electrical engineering, but I have a physics related question. An AC signal is guided by electric copper pairs, one a trace, the other a reference plane.

I read that the EM wave consists of a circular polarized wave, correct? Circular waves contain an angular momentum, correct?

It is the case that the electrostatic pull on the wave keeps the wave guided between the two copper rails?

Does it explain the following: If you would have a sharp corner of 90 degrees, the EM waves have a lesser electrostatic coupling with both the trace and the reference plane resulting in an impedance discontinuity, thus producing partial reflection?

Would like to know your thoughts.

Answer 1

What you call "electrostatic pull" is what I think you mean by line capacitance per unit length. I would not use the expression that the wave is being "pulled", instead I would say that the wave is generated/induced, etc., by the time varying currents and by the accumulating (oscillating) charges on the metal, and that those currents and charges are affected by the capacitance between and along the lines.

In this view any new discontinuity or obstacle along the line will impede your current flow (inductance) or collect charges (capacitance), hence their effect on the transmission and reflection of the propagating waves along the line.

Never think of an EM wave as one where the magnetic field is generated by the electric and the electric field is generated buy the magnetic field, etc. Always think of them as being generated directly by the current and charge sources, and then it will make sense...