1. Field of the Invention
The present invention relates to a microwave oven, and more particularly, to a microwave oven having a circular polarized wave stirrer. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for uniformly heating food.
2. Discussion of the Related Art
Unlike the related art cooking device using an external heating method through heat conduction and heat radiation, the microwave oven heats and cooks food by using approximately 2450 megahertz (MHz) of microwave generated from a magnetron. Generally, food is a nonconductive substance (i.e., a neutral substance), however, the molecules forming the food consist of a molecular dipole having a positive charge and a negative charge. When an electric field is applied to the food, the positive charge of all of the molecules forming the food is aligned to face the negative charge, and the negative charge is aligned to face the positive charge. Additionally, when the electric field is changed, the aligned molecules rotate in accordance with the direction of the changed electric field. As the molecules repeat the alignment process, friction occurs among each molecule, thereby generating heat within the food. The microwave oven discharges a microwave changing the electric field direction for about 2,450 million times per second. Accordingly, the molecules within the food rotate for about 2,450 million times in one second, thereby generating a corresponding amount of friction heat.
Recently, a wide range of methods for uniformly and thoroughly heating food in the microwave oven has been proposed. For example, a turntable microwave oven heats food by rotating the food on a built-in turntable, and a stirrer fan microwave oven or a rotating antenna microwave oven changes the radiative condition of the microwave in order to enhance the heating of the food. In the stirrer fan microwave oven and the rotating fan microwave oven, a stirrer fan or a rotating fan disperses the microwave radiated from a waveguide into a cavity. Such heating methods can uniformly heat the food by rotating the food along the circumferential direction, however, the food cannot be heated uniformly and equally along the diametral direction.