Here at the Strategist, we like to think of ourselves as crazy (in the good way) about the stuff we buy, but as much as we’d like to, we can’t try everything. Which is why we have People’s Choice, in which we find the best-reviewed products and single out the most convincing ones. (You can learn more about our rating system and how we pick each item here.)
The best size microwave for you will depend on how much space you have available and how much food you'll need to heat up at a time. If your space is limited or you're only heating food for one person, a 0.5 cubic-foot model may be a good choice. If you're furnishing a gourmet kitchen, you may want a 2.5 cubic-foot combination microwave-convection oven.
Another misconception is that microwave ovens cook food "from the inside out", meaning from the center of the entire mass of food outwards. This idea arises from heating behavior seen if an absorbent layer of water lies beneath a less absorbent drier layer at the surface of a food; in this case, the deposition of heat energy inside a food can exceed that on its surface. This can also occur if the inner layer has a lower heat capacity than the outer layer causing it to reach a higher temperature, or even if the inner layer is more thermally conductive than the outer layer making it feel hotter despite having a lower temperature. In most cases, however, with uniformly structured or reasonably homogenous food item, microwaves are absorbed in the outer layers of the item at a similar level to that of the inner layers. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling/grilling (infrared) or convection heating—methods which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating further.[citation needed]
The radiation produced by a microwave oven is non-ionizing. It therefore does not have the cancer risks associated with ionizing radiation such as X-rays and high-energy particles. Long-term rodent studies to assess cancer risk have so far failed to identify any carcinogenicity from 2.45 GHz microwave radiation even with chronic exposure levels (i.e. large fraction of life span) far larger than humans are likely to encounter from any leaking ovens.[64][65] However, with the oven door open, the radiation may cause damage by heating. Every microwave oven sold has a protective interlock so that it cannot be run when the door is open or improperly latched.

For convenience in the kitchen, nothing beats the microwave, which allows you to cook and reheat food from the inside out. After more than 100 hours of research and testing, we think that the Toshiba EM925A5A-BS is the best microwave for most kitchen counters. It’s easy to operate, has a number of express cooking options that heat food quickly and evenly, and even has a mute button so you can cook in silence.

Many reviewers of this Panasonic microwave oven rave about its power, efficiency, and spacious interior. “We have been totally delighted with this microwave,” writes one. “We have had to scale back cooking times because of the incredible cooking power. The spacious interior and ease of use are just the best.” Another says, “Constant microwave power emission cooks to total satisfaction with no cold spots. Baked potatoes are the best I’ve ever had in my life, and I’m old, smooth, creamy, uniform texture throughout. No overdone skins. Sensor cooking works too. At this price, it’s a steal.” Part of what sets this microwave apart is the stylish stainless-steel front, with several reviewers noting that it “blends in well with a kitchen with stainless-steel appliances and black, as well.”
It is possible for metal objects to be microwave-oven compatible, although experimentation by users is not encouraged. Microwaving an individual smooth metal object without pointed ends, for example, a spoon or shallow metal pan, usually does not produce sparking. Thick metal wire racks can be part of the interior design in microwave ovens (see illustration). In a similar way, the interior wall plates with perforating holes which allow light and air into the oven, and allow interior-viewing through the oven door, are all made of conductive metal formed in a safe shape.
Countertop microwaves are some of the most popular models, and there are many options to choose from. They are quick and easy to install—just plug them in—and you can move them around as needed, making them a top choice for renters. The main downside of countertop microwaves is that they take up valuable counter space, which can be frustrating if you have a small kitchen. 
A microwave oven heats food by passing microwave radiation through it. Microwaves are a form of non-ionizing electromagnetic radiation with a frequency in the so-called Microwave Region (300 MHz to 300 GHz). Microwave ovens use frequencies in one of the ISM (industrial, scientific, medical) bands, which are otherwise used for communication amongst devices that don't need a license to operate, so they do not interfere with other vital radio services.

Thanks to its compact form, retro appearance, and efficient functionality, the Daewoo Retro Microwave is our top pick for heating up food in a dorm room. Available in three colors—turquoise, red, and white—the microwave features a digital control pad that lets you choose your function and set power levels, while a retro-inspired turn knob is used to set cook time. Its 10-inch turntable is large enough for most single servings, and its 700-watt power should be sufficient for heating up leftover pizza and ramen. It also powers down in between uses, saving you money on your energy bill. There's no timer or clock display, however. A few customers noted issues with button functionality over time, but most people find this microwave more than suitable for everyday needs.

Frozen dinners, pies, and microwave popcorn bags often contain a susceptor made from thin aluminium film in the packaging or included on a small paper tray. The metal film absorbs microwave energy efficiently and consequently becomes extremely hot and radiates in the infrared, concentrating the heating of oil for popcorn or even browning surfaces of frozen foods. Heating packages or trays containing susceptors are designed for a single use and are then discarded as waste.
The GE JES1656SRSS used to be our main pick, but has been discontinued. Its replacement, the new GE JES1657SMSS, did well in our tests overall. However, we found that at 1.6 cubic foot, it’s too big for most things you’re ever likely to cook or reheat in a microwave. That said, this model would be a good option for anyone wanting a unit large enough to fit a 9-by-13-inch casserole dish. Like most microwaves we tested, it didn’t defrost meat well, and it lacks a control to silence the beeping.
The best size microwave for you will depend on how much space you have available and how much food you'll need to heat up at a time. If your space is limited or you're only heating food for one person, a 0.5 cubic-foot model may be a good choice. If you're furnishing a gourmet kitchen, you may want a 2.5 cubic-foot combination microwave-convection oven.

Performance aside, simply using this microwave is a lot of fun. The buttons and dials have a satisfyingly crisp click to them, similar to punching letters on a typewriter. The Breville also features some extra convenience with a designated noise level button for one-push incognito mode, and a button labeled “A Bit More” that adds 20 seconds to the cook time.
Modern microwave ovens use either an analog dial-type timer or a digital control panel for operation. Control panels feature an LED, liquid crystal or vacuum fluorescent display, in the 90s brands such as Panasonic and GE began offering models with a scrolling-text display showing cooking instructions, numeric buttons for entering the cook time, a power level selection feature and other possible functions such as a defrost setting and pre-programmed settings for different food types, such as meat, fish, poultry, vegetables, frozen vegetables, frozen dinners, and popcorn.
The exploitation of high-frequency radio waves for heating substances was made possible by the development of vacuum tube radio transmitters around 1920. By 1930 the application of short waves to heat human tissue had developed into the medical therapy of diathermy. At the 1933 Chicago World's Fair, Westinghouse demonstrated the cooking of foods between two metal plates attached to a 10 kW, 60 MHz shortwave transmitter.[3] The Westinghouse team, led by I. F. Mouromtseff, found that foods like steaks and potatoes could be cooked in minutes.