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I need to build special equipment for a microwave oven ( 2.45 (GHz)). But even glass and plastics do heat up in microwave ovens. Where can I find a list of the materials that are the most transparent to this frequency ?

Thanks

Manu de Hanoi
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    Have you tried borosilicate glass (not normal glass)? How do you account for secondary heating effects? – joojaa Jun 22 '19 at 10:23
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    Could you give us more information about how you are using the material in your design so we can narrow down the possibilities for you ? There are many materials which have a suitable dielectric loss factor that you can use. – William Hird Jun 22 '19 at 21:35
  • I am building a vacuum microwave dehydrator. When the food is nearly dry, the glass bowl containing the food (and plastic fittings) heat up a lot defeating the purpose of dehydrating under vacuum/low temp. – Manu de Hanoi Jun 23 '19 at 11:19
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    You can use Teflon, although not cheap , it has a dielectric loss rating of .0002 @ 3GHZ, will not absorb moisture , and has little or no chemical reaction with any food. – William Hird Jun 24 '19 at 17:44
  • @WilliamHird yes, Ive had good results with my teflon fittings so far. Do you have a table of materials vs dielectric constant @ 3 ghz ? – Manu de Hanoi Jun 25 '19 at 01:50
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    @ManudeHanoi: You can Google the electrical characteristics of just about any material. – William Hird Jun 25 '19 at 17:33
  • "*I am building a vacuum microwave dehydrator.*" That information should be in the question, not buried in the comments. Hit the [edit] link ... – Transistor Jul 06 '20 at 22:47

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Selecting a material with a low dielectric constant (Relative permittivity) will be the most transparent. Specifically, you need to select one that is low for the use temperature and for the use frequency of 2.5GHz. This level of information is not easy to come by, but there are some online tables that will give ballpark dielectric constants. Looks like polypropylene is a common consumer material for use in microwave ovens.

ericnutsch
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