[Radio Wrangler]

Ordinary diodes, whether plain silicon junctions or Schottky cannot carry reverse current, so the effective current in the reverse direction is caused by reducing the DC bias current, so the effective reverse-going signal current cannot be less than the bias current... thereafter you get rectification and massive distortion.

PIN diodes will do plenty of reverse current at RF. Orders of magnitude more than the bias current. Just so long as the frequency is above the carrier decay time limit. It's their superpower!

David