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Microwave ovens use oscillating electric field of microwaves to heat up the food. Consider following design of an oven, which runs on electric field, one may call it field oven. The oven is a rectangular box similar to microwave oven. However, the opening is not in the front but on the top in the form of a hole or cavity, not a door. Think of a 15 -20 cm dia of hole on top of box. the cookware sits in this hole, such that the brim of the cookware extends few cm above the top surface of the hole. material of cookware is chosen to suit the application. Front and back sides are parallel plates of a capacitor. A high frequency say few ghz or 100s of mhz of AC is applied to the capacitor plates. The required electronics is attached outside the box. Hence, in the oven (the box) high frequency AC electric field is generated. 1) Will this work for cooking the food?

Note the difference is that it uses AC electric field instead of em waves for cooking. Some em waves will be produced as by product because of AC source, it can be contained or directed.

2) Microwave ovens suffer from skin depth issues, hence the cooking happens only few cm from surface. Will this new design also suffer from skin effect?

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    $\begingroup$ Not sure I understand what you are proposing. Where is the food? Inside to cookware on top of the box? In the box underneath the cookware? Maybe you could draw a picture $\endgroup$ – Daniel K Sep 8 '18 at 14:49
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    $\begingroup$ The capacitance of a parallel-plate cap made from two sides of an average sized oven will be tiny - of the order of 1pF. Unless less you use insanely high voltages (MV, not kV), the amount of energy in the electric field in the oven will also be tiny - too small to cook anything in a reasonable length of time. (Whether the energy in the field would actually get transferred to the food is a separate question, of course) $\endgroup$ – alephzero Sep 8 '18 at 15:33
  • $\begingroup$ @alephzero thanks for the very useful input, i will work on that. but my question is if the oscillating electric field energy will be transferred to food or not? if you know, please share. $\endgroup$ – qazxsw Sep 9 '18 at 4:34
  • $\begingroup$ @DanielKiracofe of course the food is in cookware. why else use the cookware? Think of a 15 -20 cm dia of hole on top of box. the cookware sits in this hole, such that the brim of the cookware extends few cm above the top surface of the hole. material of cookware is chosen to suit the application. $\endgroup$ – qazxsw Sep 9 '18 at 4:38
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    $\begingroup$ If only you had staed the question as clearly as you have just done in your comment. You also have the question about skin effect.... $\endgroup$ – Solar Mike Sep 9 '18 at 5:25
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Microwaves are oscillating electromagnetic fields. They are absorbed by (frustrated) rotational modes of molecules. These articles explain the basics.

Electromagnetic basis of microwave heating

Basic principles of microwave and recent developments

A capacitor generates an electric field between its plates. Oscillating fields induce (frustrated) rotations, ionic vibrations, and electronic oscillations in the material between the plates depending on the frequency of the field. These articles explain the modes of polarization.

Mechanisms of polarization

Dielectric polarization

Dielectric polarization

The principles of dielectric absorption of an oscillating electric field at microwave frequencies are the same as those for the absorption of microwaves. Therefore, oscillating electric fields will (and do) heat the material when they are absorbed.

The practical limitations of replacing a basic microwave oven with a capacitor AC-field oven are likely to be that one will not be able to generate or sustain input powers that are comparable to a basic microwave oven (1 kW) across a parallel plate capacitor.

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  • $\begingroup$ Thanks for the answer. Will the electric field oven suffer from skin depth effect like microwave oven? $\endgroup$ – qazxsw Sep 10 '18 at 5:52
  • $\begingroup$ The information in the articles should address your question. $\endgroup$ – Jeffrey J Weimer Sep 10 '18 at 13:00

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