A microwave heating device includes a heating chamber that accommodates an object to be heated, a microwave generator configured to generate microwaves, a wave guide tube configured to guide the microwaves to the heating chamber, and an electromagnetic field distribution adjustment device provided in a predetermined two-dimensional region within the heating chamber. The electromagnetic field distribution adjustment device has a plurality of metal pieces and a plurality of switches. The plurality of metal pieces are arranged to fill the predetermined two-dimensional region. The plurality of switches connect the plurality of metal pieces with one another. A serially connected row of metal pieces is configured by connecting one metal piece among the plurality of metal pieces to at most two metal pieces adjacent to the one metal piece through at least two of the plurality of switches. The present exemplary embodiment can achieve a low-cost electromagnetic field distribution adjustment device that heats an object to be heated more uniformly, while preventing a drop in heating efficiency.

A stirrer shaft for a microwave oven includes a shaft body configured to connect between a stirrer motor on a first end of the shaft body, and a set of stirrer blades spaced apart from the stirrer motor. The stirrer body includes a flow passage therethrough for equalizing pressure in a sealed stirrer cavity of the microwave oven.

Ferrite powder of the present invention is ferrite powder detectable with a metal detector, comprising: soft ferrite particles containing Mn of 3.5 mass % or more and 20.0 mass % or less and Fe of 50.0 mass % or more and 70.0 mass % or less. It is preferable that a volume average particle diameter of the particles constituting the ferrite powder is 0.1 μm or more and 100 μm or less. It is preferable that magnetization by a VSM measurement when magnetic field of 5 K.Math.1000/4πA/m is applied is 85 A.Math.m.sup.2/kg or more and 98 A.Math.m.sup.2/kg or less.

Ferrite powder of the present invention is ferrite powder detectable with a metal detector, comprising: soft ferrite particles containing Mn of 3.5 mass % or more and 20.0 mass % or less and Fe of 50.0 mass % or more and 70.0 mass % or less. It is preferable that a volume average particle diameter of the particles constituting the ferrite powder is 0.1 μm or more and 100 μm or less. It is preferable that magnetization by a VSM measurement when magnetic field of 5 K.Math.1000/4πA/m is applied is 85 A.Math.m.sup.2/kg or more and 98 A.Math.m.sup.2/kg or less.

An electromagnetic cooking device is disclosed. The device comprises an enclosed cavity configured to receive a food load and a plurality of amplifiers configured to amplify a first RF signal and a second RF signal thereby supplying the RF signals to the enclosed cavity. A controller is in communication with the plurality of amplifiers. The controller is configured to control the first RF signal and the second RF signal along a stirring path between a first approximate resonant mode and a second approximate resonant mode of the enclosed cavity. Each of the resonance modes comprises a frequency and phase shift between the first RF signal and the second RF signal.

An electromagnetic cooking device is disclosed. The device comprises an enclosed cavity configured to receive a food load and a plurality of amplifiers configured to amplify a first RF signal and a second RF signal thereby supplying the RF signals to the enclosed cavity. A controller is in communication with the plurality of amplifiers. The controller is configured to control the first RF signal and the second RF signal along a stirring path between a first approximate resonant mode and a second approximate resonant mode of the enclosed cavity. Each of the resonance modes comprises a frequency and phase shift between the first RF signal and the second RF signal.

The present invention is a heater or heating device that uses microwave energy to generate heat quickly. The heater generates heat quickly by forcing air over microwave-heated oil or non-freeze liquid. As a non-limiting embodiment, the heater preferably includes most or all of the following components: an outer casing or housing, at least one air intake vent, a magnetron, a microwave emitter, a wave scatterer, at least one fluid holder, fluid, a capacitor, a transformer, a microwave containment casing, and a perforated microwave guard. As another non-limiting embodiment, the heater preferably includes most or all of following components: an outer casing or housing, a cooling fan, a magnetron, a microwave emitter, a wave scatterer, at least one non-freeze liquid holder, non-freeze liquid, a capacitor, a transformer, a microwave containment casing, a glass tube, a metal tube, a fan coil, a pump, a reservoir and expansion tank, and a fill plug.

A microwave mode stirrer apparatus having a stirring member with microwave-transmissive regions is disclosed, along with methods of performing microwave stirring using the microwave mode-stirring apparatus. The microwave-transmissive regions can be in the form of holes or can include microwave-transmissive material. The stirring member can have a variety of configurations, and the microwave-transmissive regions can have a variety of sizes and shapes. A microwave oven that uses the mode stirrer apparatus for drying green ceramic-forming bodies is also disclosed.

Disclosed herein is a microwave oven having an improved structure with which foods can be effectively heated. The microwave oven includes: a housing including a cooking chamber having a bottom surface; at least one first reflective portion formed on the bottom surface of the cooking chamber; a magnetron provided to generate microwave radiation; and a tray disposed apart from the bottom surface of the cooking chamber and supporting food to be heated. The at least one first reflective portion extends a given height (h) above a reference level (RL).

This disclosure includes methods and systems that utilize energy absorption monitoring for intelligent electronic ovens with energy steering. One disclosed method for heating an item in an electronic oven includes introducing an application of energy into a heating chamber using an energy source coupled to an injection port, changing a distribution of the application of energy in the heating chamber by setting a configuration of the oven to a first configuration, and measuring an energy return from the heating chamber while the oven is in the first configuration. The measuring is conducted using a radio frequency directional power sensor. The method also includes determining that the energy return from the heating chamber exceeds a level, adjusting, in response to determining that the energy return exceeds the level, the configuration of the oven from the first configuration to an altered first configuration, and saving the altered first configuration in a memory.