The flatbed microwave oven is an upgraded version of the turntable microwave oven, The working principle of them is similar but not totally the same.
1. The turntable microwave oven serves to rotate the food on the glass tray by the turntable shaft while it's being heated. The microwave is emitted from a fixed place that is located on the side of the cavity. So the rotation helps to ensure even cooking by exposing all sides of the food to the microwave energy directly. Therefore, compared to the flatbed microwave oven, the turntable microwave oven heats food faster;
2. The flatbed microwaves don't have a turntable shaft to distribute the heat throughout the food being cooked (or heated). The rotating turntable is gone, and the heat is distributed evenly through the foods via the ceramic base of the microwave which has a rotating antenna underneath it. flatbed microwave ovens circulate the microwaves throughout the oven cavity to cook the food evenly;
3. The turntable microwave oven has the advantage of fast heating speed, while the disadvantage is that the turntable shaft and the tray are not easy to clean and the cooking space is also limited;
4. The flatbed microwave oven has the advantage that the whole base of the inside of the microwave can be utilized for heating food in multiple dishes as there is no turntable or tray that your food has to fit onto. Besides, with no turntable to work around or remove when it's time to clean up, the flatbed microwave is far easier to clean. No awkward spots, just a clear open space that is easy to wipe over and remove any spills or stains. However, its heating or cooking may need much more time than the turntable microwave oven.