A method for controlling a power of an electromagnetic cooking device is shown. The method includes controlling a power supply to deliver a power level to the amplifier and monitoring at least one RF feed delivered to an enclosed cavity. The method further includes identifying an output power based on the RF feed and comparing the output power to a maximum power. A power difference of the output power compared to a target power is determined, and the power difference is compared to a plurality of difference thresholds. Based on the comparison, the power level is adjusted by a plurality of power adjustment magnitudes.

An embodiment of a heating system includes a cavity configured to contain a load, a thermal heating system (e.g., a convection, radiant, and/or gas heating system) in fluid communication with the cavity and configured to heat air, and an RF heating system. The RF heating system includes an RF signal source configured to generate an RF signal, first and second electrodes positioned across the cavity and capacitively coupled, a transmission path electrically coupled between the RF signal source and one or more of the first and second electrodes, and a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes. At least one of the first and second electrodes receives the RF signal and converts the RF signal into electromagnetic energy that is radiated into the cavity.

An embodiment of a heating system includes a cavity configured to contain a load, a thermal heating system (e.g., a convection, radiant, and/or gas heating system) in fluid communication with the cavity and configured to heat air, and an RF heating system. The RF heating system includes an RF signal source configured to generate an RF signal, first and second electrodes positioned across the cavity and capacitively coupled, a transmission path electrically coupled between the RF signal source and one or more of the first and second electrodes, and a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes. At least one of the first and second electrodes receives the RF signal and converts the RF signal into electromagnetic energy that is radiated into the cavity.

A thermal increase system may include first and second cavities disposed on opposite sides of a first electrode. The first cavity may have a first height that is approximately equal to a second height of the second cavity. The first electrode may be disposed within a containment structure that is capacitively coupled to the first electrode. An upper wall of the containment structure may include a second electrode that is capacitively coupled to the first electrode. A bottom wall of the containment structure may include a third electrode that is capacitively coupled to the first electrode. The first electrode may receive the RF signal from an RF signal source, which may cause electric field magnitudes within the first and second cavities to increase, which may increase the temperature of loads disposed within the first and/or second cavities.

A thermal increase system may include first and second cavities disposed on opposite sides of a first electrode. The first cavity may have a first height that is approximately equal to a second height of the second cavity. The first electrode may be disposed within a containment structure that is capacitively coupled to the first electrode. An upper wall of the containment structure may include a second electrode that is capacitively coupled to the first electrode. A bottom wall of the containment structure may include a third electrode that is capacitively coupled to the first electrode. The first electrode may receive the RF signal from an RF signal source, which may cause electric field magnitudes within the first and second cavities to increase, which may increase the temperature of loads disposed within the first and/or second cavities.

In a solid-state heating system, once a load with specific load characteristics has been placed in a heating cavity, a processing unit produces control signals that indicate an excitation signal frequency and one or more phase shifts, which constitute a combination of parameter values. Multiple microwave generation modules produce RF excitation signals characterized by the frequency and the phase shift(s). Multiple microwave energy radiators radiate, into the heating cavity, electromagnetic energy corresponding to RF excitation signals received from the microwave generation modules. Power detection circuitry takes reflected RF power measurements, and the processing unit determines a reflected power indication based on the measurements. The process is repeated for different combinations of the parameter values, and an acceptable combination of parameter values is determined and stored in a memory of the heating system. Acceptable combinations of parameter values similarly may be determined and stored for other loads with different load characteristics.

In a solid-state heating system, once a load with specific load characteristics has been placed in a heating cavity, a processing unit produces control signals that indicate an excitation signal frequency and one or more phase shifts, which constitute a combination of parameter values. Multiple microwave generation modules produce RF excitation signals characterized by the frequency and the phase shift(s). Multiple microwave energy radiators radiate, into the heating cavity, electromagnetic energy corresponding to RF excitation signals received from the microwave generation modules. Power detection circuitry takes reflected RF power measurements, and the processing unit determines a reflected power indication based on the measurements. The process is repeated for different combinations of the parameter values, and an acceptable combination of parameter values is determined and stored in a memory of the heating system. Acceptable combinations of parameter values similarly may be determined and stored for other loads with different load characteristics.

A microwave treatment device includes a plurality of radiation parts, a transmission line, and a plurality of feeding parts. The plurality of radiation parts includes first, second, and third radiation parts, and radiates a microwave. The transmission line has a loop line structure provided with a plurality of branch parts including first, second, and third branch parts, and transmits the microwave to the first, second, and third radiation parts respectively connected to the first, second, and third branch parts. The plurality of feeding parts includes the first feeding part and the second feeding part arranged in the transmission line at an interval of ¼ or less of the wavelength of the microwave, and transmits the microwave to the transmission line. According to this aspect, a radiation part that radiates the microwave can be selectively switched. This enables the intended heating distribution to be achieved.

A microwave treatment device includes a plurality of radiation parts, a transmission line, and a plurality of feeding parts. The plurality of radiation parts includes first, second, and third radiation parts, and radiates a microwave. The transmission line has a loop line structure provided with a plurality of branch parts including first, second, and third branch parts, and transmits the microwave to the first, second, and third radiation parts respectively connected to the first, second, and third branch parts. The plurality of feeding parts includes the first feeding part and the second feeding part arranged in the transmission line at an interval of ¼ or less of the wavelength of the microwave, and transmits the microwave to the transmission line. According to this aspect, a radiation part that radiates the microwave can be selectively switched. This enables the intended heating distribution to be achieved.

An oven includes a housing that defines a cooking space and that includes an upper frame defining an upper wall facing the cooking space, a heating unit disposed at the upper frame and configured to transfer heat to the cooking space, an antenna disposed at the upper frame and configured to emit, toward the cooking space, radio waves transmitted from a radio wave generator that is electrically connected to an external power source, and a forming part that protrudes upward from the upper frame and accommodates the antenna therein. The forming part covers the antenna from the cooking space.