My youngest noticed that when the microwave is going, her bluetooth connection from her iPad to her hearing aids gets glitchy. Then my husband mentioned that when ever I start the microwave, the TV connection goes out. Our microwave is in a strange location, tucked into a hole on the end of the kitchen island. Our router and internet connection are on the counter opposite. Options on moving either device so they don’t face each other are low, and all the possibilities involve drilling new holes. So I tried taking my largest cookie sheet and propping it up against the microwave to block the interference. It seems to work. It is an ugly hack, so I might design a decorative door with patterned perforated metal in the future. Conductive metal blocks microwave radiation. As long as the holes are smaller than the electromagnetic waves coming out, it should work and still provide ventilation. Here is an interesting article on microwaves and wireless devices from Wired, which supports my thinking.