What's the function of the mica in the microwave oven?
If mica blocks are not used, small objects such as cockroaches will enter the waveguide, but the magnetron will be damaged.
The 5 floor is right, isolated from the role, because the window is the strongest magnetic ATC microwave emission, if not installed fume and hot mica plate is easy to damage to the magnetron, even with mica plate isolation may enable the magnetron antenna cap burn.
Mica sheet is dustproof (mainly soot), high temperature resistant and barrier free microwave. Without mica, soot can easily enter the emitter of the magnetron and cause damage to the magnetron.
