I don’t think that roughness or smoothness would make much difference.
My car has rather smooth glasses, yet snow and ice stick to them quite well, but there are some defrost/heating provisions.
I believe the solution for these devices should be the same, adding a heater of some kind.
I seem to remember having read somewhere that in very cold climates dummy programs were run to keep CPU’s at 100% thus generating more heat, buy no idea if it can be enough on a cube and in your situation.
but seriously, some types of wet snow will stick to anything and the case has nothing to do with it. Even the round and slippery ATL suffers from wet snow, but of course 60GHz is more sensitive to it
Hi! This has worked very well for me in similar situations:
Before you start wasting energy and creating some complicated setups for doing that.
Apply Teflon (PTFE) spray on the affected surfaces. Snow or anything else won´t stick and it remains there for years.
Before applying PTFE, you should clean the surface thoroughly, preferably with some isopropyl alcohol, so to get rid of any dust and fat first.
That´s cheaper and probably even environmentally friendly, as you just need minuscule amounts.
Also Teflon is the thing used often in coax cables and other HF cables as isolation as it has great HF properties. So it probably wont affect the 60GHz in that thin coating form.
You may also want to look at anti-graffiti coatings, some of them have highly hydrophobic components, and they surely can stand a year of sunshine.
Now that woland gave us the idea , look at this: http://www.hirecpaint.com/
HIREC® / Super Hydrophobic Water Repellent Coating Series
Super Hydrophobic Coatings for Antenna, Radome and Dish Applications
though, unlike PTFE based spray or car-wax like products, I don’t think you can find those easily.