Does you need to tovel the glass plate from a microwave in a mikvah, and do you need a Bracha?
The Star-K says tovel WITHOUT a beracha.
As always, for a matter of practical halacha, CYLOR. But AFAIK something that doesn't touch food does not require t'vila.
Since it is made out of glass and many times the actual food will directly touch the plate as yydl indicated, You should tovel with a b’racha. (S.A. Y.D. 120:1)
The Kof-K says the tray doesn't need to be toveled if it doesn't touch the food.
Microwave Oven Tray- A glass microwave oven tray does not require tevilah if no food actually touches the glass. If food is placed directly on the glass piece then the tray should be toveled with a beracha.
This part is speculation: The Star-K psak to tovel without a bracha might be a more general psak to cover both people that use the tray touching the food and people that do not. People that use tray touching the food would need to tovel with a bracha, but those that don't use the tray touching the food would not have to tovel at all. The Star-K might be recommending to tovel without a bracha in order to cover both cases. CYLOR