Abstract: A defrosting system includes an RF signal source, one or more electrodes proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrode(s), and an impedance matching network electrically coupled along the transmission path between the output of the RF signal source and the electrode(s). The system also includes measurement circuitry coupled to the transmission path and configured to measure one or more parameters that include voltage, current, forward signal power, reflected signal power, and S11 along the transmission path. A system controller is configured to monitor the measurements, and to modify operation of the system when a rate of change of any of the monitored parameter(s) exceeds a predetermined threshold. The impedance matching network may be a single-ended network or a double-ended network.

Abstract: A system includes a radio frequency (RF) signal source configured to supply an RF signal. An electrode is coupled to the RF signal source and a transmission path is between the RF signal source and the electrode. The transmission path is configured to convey the RF signal from the RF signal source to the electrode to cause the electrode to radiate RF electromagnetic energy into a cavity. Power detection circuitry is coupled to the transmission path and configured to repeatedly measure RF power values including at least one of forward RF power values and reflected RF power values along the transmission path. A controller is configured to determine that a load in the cavity is a low-loss load based on a rate of change of the RF power values, and cause the RF signal source to supply the RF signal with the one or more desired signal parameters.

Abstract: A defrosting system includes an RF signal source, an electrode proximate to a cavity within which a load to be defrosted is positioned, and a transmission path between the RF signal source and the electrode. The system also includes power detection circuitry coupled to the transmission path and configured repeatedly to take forward and reflected RF power measurements along the transmission path. A system controller repeatedly determines, based on the forward and reflected RF power measurements, a calculated rate of change, and repeatedly compares the calculated rate of change to a threshold rate of change. When the calculated rate of change compares favorably with the threshold rate of change, the RF signal source continues to provide the RF signal to the electrode until a determination is made that the defrosting operation is completed, at which time the RF signal source ceases to provide the RF signal to the electrode.

Abstract: A device includes an antenna configured to be disposed within a cavity of an appliance. The appliance includes an electrode and the antenna includes a sheet of conductive material having a surface area that is equal to or greater than a surface area of the electrode. The device includes a voltage sensor coupled to the antenna, an output device, and a controller coupled to the voltage sensor and the output device. The controller is configured to generate an output at the output device. The output is determined by a voltage of the antenna.

Abstract: A device includes a semiconductor die including a transistor. The transistor includes a plurality of parallel transistor elements. Each transistor element includes a drain region, a source region, and a gate region. The semiconductor die includes a first temperature sensor between a first transistor element in the plurality of transistor elements and a second transistor element in the plurality of transistor elements. The first temperature sensor is configured to generate a first output signal having a magnitude that is proportional to a temperature of the first temperature sensor.

Abstract: A defrosting system includes an RF signal source, two electrodes proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrodes, and an impedance matching network electrically coupled along the transmission path between the output of the RF signal source and the electrodes. The system also includes power detection circuitry coupled to the transmission path and configured to detect reflected signal power along the transmission path. A system controller is configured to modify, based on the reflected signal power, values of variable capacitors of the impedance matching network to reduce the reflected signal power. The impedance matching network may be a single-ended network or a double-ended network.

Abstract: A system and method for defrosting a load are presented. Radio frequency (RF) signals are supplied to a transmission path that is electrically coupled to one or more electrodes that are positioned proximate to a cavity to cause the one or more electrodes to radiate RF electromagnetic energy. An RF power value of the RF signal along the transmission path is periodically measured resulting in RF power values and a rate of change of the RF power values is determined. A low-loss indicator value is determined using the RF power values, wherein the low-loss indicator value is at least partially determined by a dielectric loss of a load in the cavity. A controller determines, using the rate of change of the RF power values and the low-loss indicator value, that the load is in a defrosted state and stops supplying the RF signals.

Abstract: A defrosting system includes an RF signal source, two electrodes proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrodes, and an impedance matching network electrically coupled along the transmission path between the output of the RF signal source and the electrodes. The system also includes power detection circuitry coupled to the transmission path and configured to detect reflected signal power along the transmission path. A system controller is configured to modify, based on the reflected signal power, a value of a variable passive component of the impedance matching network to reduce the reflected signal power. The impedance matching network may be a single-ended network or a double-ended network.

Abstract: Example systems have a defrost system that can receive a first RF signal at a first frequency to defrost a load. An air treatment device can receive a second RF signal at a second frequency and perform an air treatment process. An RF signal source has a power output, and a switching arrangement selectively electrically connects the defrost system and the first air treatment device to the power output of the RF signal source. A controller can electrically connect one of the defrost system and the first air treatment device to the power output of the RF signal source. When the defrost system is electrically connected, the RF signal source outputs the first RF signal at the first frequency, and when the first air treatment device is electrically connected, the RF signal source outputs the second RF signal at the second frequency.

Abstract: A thermal increase system includes one or more multi-level electrodes configured to radiate electromagnetic energy into a cavity in response to receiving a radio frequency (RF) signal from an RF signal source. Each multi-level electrode is positioned adjacent to a wall of the cavity, and each multi-level electrode includes a base portion coupled to an elevated portion. A radiating surface of the elevated portion is at a height of at least 0.5 centimeters (cm) from a radiating surface of the base portion.

Abstract: An embodiment of a heating system includes a cavity configured to contain a load, a thermal heating system, and an RF heating system. The RF heating system includes a system controller, an RF signal source, one or more electrodes that receive an RF signal from the RF signal source and radiate resultant electromagnetic energy into the cavity, and a variable impedance matching network coupled between the RF signal source and the one or more electrodes. The system controller may monitor an impedance state of the variable impedance matching network to identify the occurrence of a change point. The system controller may estimate the mass of the load and a time and/or energy requirement for cooking the load based on the change point. The system controller may take action by turning off the RF heating system and/or thermal heating system when the time or energy requirement has been met.

Abstract: A purification apparatus includes a radio frequency (RF) signal source that generates an RF signal, first and second electrodes, and a conduit. The first electrode receives the RF signal and converts it into electromagnetic energy that is radiated by the first electrode. The conduit includes input and output ports and a chamber. The input and output ports are in fluid communication with the chamber, and the chamber is configured to receive an electrodeless bulb. The chamber is defined by first and second boundaries that are separated by a distance that is less than the wavelength of the RF signal so that the chamber is sub-resonant. The first electrode is physically positioned at the first boundary, and the second electrode is physically positioned at the second boundary. The first and second electrodes and the chamber form a structure that capacitively couples the electromagnetic energy into an electrodeless bulb within the chamber.

Abstract: A thermal increase system includes a cavity, a first electrode disposed in the cavity, a second electrode disposed in the cavity, and a self-oscillator circuit that produces a radio frequency signal that is converted into electromagnetic energy that is radiated into the cavity by the first and second electrodes. The self-oscillating circuit includes the first electrode and the second electrode. In an embodiment, the first electrode is a first plate in a capacitor structure and the second electrode is a second plate in the capacitor structure. The cavity and a load contained within the cavity operates as a capacitor dielectric of the capacitor structure. A resonant frequency of the self-oscillator circuit is at least partially determined by a capacitance value of the capacitor structure.

Abstract: A device includes a semiconductor die including a transistor. The transistor includes a plurality of parallel transistor elements. Each transistor element includes a drain region, a source region, and a gate region. The semiconductor die includes a first temperature sensor between a first transistor element in the plurality of transistor elements and a second transistor element in the plurality of transistor elements. The first temperature sensor is configured to generate a first output signal having a magnitude that is proportional to a temperature of the first temperature sensor.

Abstract: 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.

Abstract: A system is configured to perform an operation that results in increasing a thermal energy of a load. The system includes a radio frequency signal source configured to supply a radio frequency signal, an electrode coupled to the radio frequency signal source, and a variable impedance network that includes at least one variable passive component. The variable impedance network is coupled between the radio frequency signal source and the electrode. The system includes a controller configured to determine an operation duration based upon a configuration of the variable impedance network, and to cause the radio frequency signal source to supply the radio frequency signal for the operation duration.

Abstract: A defrosting system includes a radio frequency (RF) signal source, at least one electrode proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrode, at least one bus bar in the transmission path that includes multiple ports to which the electrode may be coupled, a repositionable shelf that is attached to the electrode, and multiple support structures disposed at side-walls of the cavity that support the repositionable shelf. Standoff isolators may attach the electrode to the repositionable shelf and may electrically isolate the electrode from the repositionable shelf. The vertical position of the electrode may be changed by moving the repositionable shelf to be supported by different support structures of the multiple support structures while coupling the electrode to a different port of the multiple ports of the bus bar.

Abstract: A defrosting system includes an RF signal source, an electrode proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrode, and an impedance matching network electrically coupled along the transmission path between the output of the RF signal source and the electrode. The system also includes power detection circuitry coupled to the transmission path and configured to detect reflected signal power along the transmission path. A system controller is configured to modify, based on the reflected signal power, an inductance value of the impedance matching network to reduce a ratio of the reflected signal power to the forward signal power. The impedance matching network includes a plurality of fixed-value, lumped inductors positioned within a fixed inductor area.

Abstract: An RF system includes an RF signal source and a single-ended or double-ended impedance matching network. Non-linear devices, such as gas discharge tubes, are coupled in parallel with components of the impedance matching network. The non-linear devices are insulating below a breakdown voltage and conductive above the breakdown voltage. The system also includes measurement circuitry configured to measure one or more parameters that reflect changes in the impedance of the impedance matching network. A system controller modifies operation of the system when a rate of change of any of the monitored parameter(s) exceeds a predetermined threshold.

Abstract: A defrosting system includes an RF signal source, one or more electrodes proximate to a cavity within which a load to be defrosted is positioned, a transmission path between the RF signal source and the electrode(s), and an impedance matching network electrically coupled along the transmission path between the RF signal source output and the electrode(s). A system controller is configured to modify, based on the reflected signal power, values of variable passive components of the impedance matching network to reduce the reflected signal power. The system controller may be configured to estimate the mass of the load by comparing component value(s) of one or more variable passive components of the impedance matching network with a component value table stored in memory, where stored mass values correspond to the stored component values. Desired signal parameters for the RF signal may be determined based on the estimated mass of the load.