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.

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 defrosting system includes an RF signal source, one or more electrodes, a transmission path between the RF signal source and the electrode(s), and an impedance matching network coupled along the transmission path. A system controller may modify the impedance matching network to reduce the reflected signal power. The system controller may determine an initial estimate of the mass of the load. Desired signal parameters for the RF signal may be determined based on the initial estimated mass of the load. The system controller may determine a refined estimate of the load mass based on a rate of change of an S11, VSWR, or reflected power parameter measured at the transmission path, or based on elapsed time between matches. Refined signal parameters for the RF signal may be determined based on the refined estimated mass.

An apparatus for relaying microwave field intensity in a microwave cavity. In some embodiments, the apparatus comprises a microwave transparent substrate with at least one Radio Frequency (RF) detector that is capable of detecting a microwave field and generating a signal associated with a field intensity of the detected microwave field and a transmitter that receives the signal associated with the detected microwave field from the RF detector and transmits or stores information about the detected microwave field intensity. In some embodiments, the apparatus relays the microwave intensity via a wired, wireless, or optical transmitter located in proximity of the RF detector.

A microwave heating apparatus comprises: a housing, arranged to define a cavity; a semiconductor RF generator, configured to provide at least one RF signal; and a plurality of RF antennas, arranged in a distributed way within the cavity and configured to radiate the at least one RF signal from the semiconductor RF generator, such that items received in the cavity are dielectrically heated by the radiation.

The present disclosure provides a radio frequency detecting device, a detecting method, and a microwave oven, and the radio frequency detecting device comprises: a signal transmitting device configured to generate and transmit multiple forward frequency detecting signals of different frequencies; a signal receiver configured to receive multiple reverse frequency detecting signals reflected by the load; a first detection device configured to detect each first parameter corresponding to each of the forward frequency detecting signals; a second detection device configured to detect each second parameter of each of the reverse frequency detecting signals; and a microcontroller configured to determine a state parameter of the load based on the multiple frequencies and the first parameter and the second parameter corresponding to each of the frequencies.

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.

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.

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.

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.