Owen Duffy wrote:
"If that is the meaning, then the situation you describe of 90-degree
phase difference between E and I is rather specific, it can only occur
with a distortionless line AND a load that is (s/c OR o/c OR purely
reactive).

No. Walter is exactly right, and don`t drag any distortionless line into
the discussion. That is a device for audio circuits. For RF, you only
need a low-loss (Zo = R) transmission line.

Best regards, Richard Harrison, KB5WZI