I think it a question of diffusion. I thought of an experiment you can use to test it. In a room that can be made completely dark, place a target on one wall and stand by the opposite wall. Take the headlight off your bike. Turn out the room lights spin around a few times. Now with just one flash of your light, try to hit the target. Most likely you missed. Don’t move the bike light. Now place the diffused glass in front of the light. I predict some light will hit the target. Your not so smooth chin diffuses the radio waves as the glass diffuses light. This might be why greenhouses use diffused glass.
If you don’t have a bike light and some diffused glass, you can just use a a rifle and a shotgun. Be careful that you don’t point either gun at your chin.
Just as the shotgun has less range than a rifle, it will, because of its diffusion, hit the target many more times. I think that is called the shotgun effect. Some guys use this approach when looking for romance.
On the other hand, I struggled with physics in eighth grade, so maybe I have just wasted your time if you have read this far. Sorry.