What Does a Waveguide Cover Do?

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Updated August 17, 2022

If you have been experimenting with the various features of a microwave, you may wonder what does a waveguide cover do. The best microwaves tend to include a waveguide cover as part of the general operation process, after all, so it can be helpful to learn what they do. Keep reading to find out.


  • A microwave oven features a component called the waveguide, which helps direct the heated electromagnetic waves to properly cook food.
  • A waveguide cover is a simple plastic or mica lid that is affixed over the waveguide so as to protect it from errant crumbs, grease, and food particles.
  • If your waveguide cover becomes burned, chipped, or cracked, acquire a replacement unit and conduct the replacement yourself.

What is a Waveguide in a Microwave Oven?

The waveguide is a crucial part of any microwave oven, as it directs the radio waves, aka microwaves, from the magnetron to the interior of the microwave. The waveguide ensures that the electromagnetic waves are directed where they belong – inside of and surrounding your preferred food items. All microwaves include a waveguide, so if you are questioning what a combination microwave is, you can be sure that this type of oven also includes a waveguide.

For more tips on microwave management, check out our guides covering what to do when the microwave blows a fuse, how to cook correctly in a microwave, remove a fishy smell in a microwave, and finally, what happens when you put foil in a microwave.

What is a Waveguide Cover?

Waveguides lead directly to the rest of a microwave’s internal components. Left exposed, crumbs, food particles, and grease can muck up the overall operation of a microwave. A cover works to protect the waveguide itself and the rest of the microwave, so you won’t have to go searching where to donate a microwave if it breaks down. These covers tend to be made from microwave-safe plastic, mica, or similar material and they are usually affixed on the side of the cavity directly in front of the waveguide itself.

Insider Tip

For the mechanically inclined, you can make your own cover by cutting a sheet of mica to fit.

What Does a Waveguide Cover Do?

A waveguide cover, as previously mentioned, exists to protect the waveguide and the internal mechanisms of the microwave oven from grease, dirt, and whatever else is floating around the internal cavity. If the cover becomes chipped, burned, or cracked, cease operation of the microwave immediately, as you could damage the unit. You will not, however, be at risk from any microwave radiation sourced from microwave energy.

Can You Replace a Waveguide Cover?

Yes. You can purchase a replacement cover and conduct the replacement yourself. Contact the manufacturer of your microwave for information on purchasing the correct cover for your unit. The replacement process will vary depending on the design of your microwave, but you can usually complete the task in just a few minutes or so. You may need some common household tools. Also, be sure the microwave oven has been powered down for a period of time and is unplugged before you attempt any maintenance or service repair tasks.


Can I operate my microwave oven without the waveguide cover?

You will not be at risk for any radiation from an errand electromagnetic wave or two, but you will eventually damage the microwave oven itself. In other words, we do not recommend it.

How to stop a microwave from sparking?

To stop your microwave oven from sparking, immediately power it down and unplug it. Also, be sure to keep the door closed in case a fire breaks out or if you see a microwave spark.

Can I tape a waveguide cover?

Tape may not be microwave-safe and could contribute to damaging a microwave’s electrical components. Use an actual microwave waveguide cover instead. A cardboard cover could work.

STAT: The first structure for guiding waves was proposed by J. J. Thomson in 1893, and was first experimentally tested by Oliver Lodge in 1894. (source)

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