Optical and microwave are sort of an arbitrary distinction, so you're also right :) There's even the "millimeter wave" designation, or E(xtremely)HF. Different

Optical and microwave are sort of an arbitrary distinction, so you're also right :) There's even the "millimeter wave" designation, or E(xtremely)HF. Different frequencies scatter differently. This isn't bad: https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet70/oet70a.pdf https://transition.fcc.gov/Bureaus/Engineering_Technology/Do...