A method for identifying a cooking level of a food load in an electromagnetic cooking device is disclosed. The method includes controlling a frequency and a phase of a first RF signal and a second RF signal and amplifying the first RF signal and the second RF signal thereby generating a first RF feed and a second RF feed. The method further includes emitting the first RF feed and the second RF feed into an enclosed cavity to heat a food load and measuring at least one reflection signal. The method further includes calculating a Q-factor for the enclosed cavity based on the reflection signal, monitoring the Q-factor, and identifying a change in the Q-factor exceeding a predetermined change threshold. In response to identifying the change exceeding the predetermined change threshold, a cooking level for the food load is identified.

A method for analyzing a frequency response of a cooking device is disclosed. The method comprises controlling a plurality of RF signals within an operating range of the cooking device at plurality of phase shifts between a first RF signal and a second RF signal. A plurality of efficiencies of at least one reflection signal in the resonant cavity are measured in response to a plurality of RF feeds generated from the RF signals for the plurality of phase shifts. The frequency response of the resonant cavity is modeled with a numeric model and a plurality of interpolation parameters for the numeric model are calculated based on the plurality of measured efficiencies of the RF feeds. The frequency response of the cavity is estimated for the operating range of the cooking device based on the numeric model with the plurality of interpolation parameters.

The present invention discloses a method of controlling transmitting frequencies of microwave source, which includes the following steps of: a) collecting reflection frequencies of a load according to a pre-set sampling rate; b) calculating a change rate of the reflection frequencies collected in the step a; c) setting a reflection frequency threshold and a change rate threshold; d) comparing the reflection frequencies and the change rate with the reflection frequency threshold and the change rate threshold respectively; wherein if the reflection frequencies or the change rate is less than the threshold goes to step e or returns to the step a; e) sending control signals to the microwave source and tuning the transmitting frequencies; and f) returning to step a. The present invention also discloses a microwave transmission system thereof. The present invention can be applied in controlling microwave source consists of single magnetron tube or multiple magnetron tubes.

A microwave generating system includes a modular architecture which is configurable to provide power output from under 1-kilowatt to over 100-kilowatts. The various power levels are achieved by combining the RF outputs of multiple RF power amplifiers in a corporate structure. The system can be used on any ISM band. Each system component incorporates a dedicated embedded microcontroller for high performance real-time control response. The components are connected to a high speed digital data bus, and are commanded and supervised by a control program running on a host computer.

Method of irradiating a load placed in a cavity by radiating UHF or microwave radiation into the cavity. The method includes setting transmission durations, by setting for each of a plurality of frequencies, a respective transmission duration, repeatedly causing energy to be transmitted into the cavity at the plurality of frequencies according to a duty cycle, wherein the duty cycle defines an allotted transmission time for each of the plurality of frequencies, and switching ON or OFF transmission of the energy at certain frequencies, so that over a plurality of repetitions of the duty cycle the energy is transmitted at each of the plurality of frequencies for the respective transmission duration.

Provided is a microwave treatment apparatus that can properly treat a treatment target using microwaves. The apparatus includes: a vessel 10 in which a treatment target 2 is arranged; a microwave irradiating unit 20 that irradiates an internal portion of the vessel 10 with microwaves; and heat generating member 30 that is provided inside the vessel 10 along the treatment target 2, generates heat by absorbing part of microwaves used for irradiation by the microwave irradiating unit 20, and transmits part of the microwaves. The microwave irradiating unit 20 irradiates a portion in which the heat generating member 30 is provided with microwaves, thereby heating the treatment target 2 from the outside through heat generation at the heat generating member 30, and directly heating the treatment target 2 with microwaves transmitted through the heat generating member 30.

Microwave dryer of a print system with modulation of the microwave source using FSK. In one embodiment, a microwave dryer includes a microwave source coupled with a waveguide. The waveguide transports electromagnetic energy to dry wet colorant applied by a printer to print media. The microwave source provides the electromagnetic energy at an operating frequency. The microwave dryer also includes a processor coupled with an FSK modulator that modulates the operating frequency of the microwave source. The processor determines a modulating signal with a modulating frequency based on a period of time for the print media to traverse the waveguide, and applies binary values that represent the number of frequencies to an input of the FSK modulator to cause the FSK modulator to output the series of discrete frequencies over the period of time to vary intensity positions of the electromagnetic energy across the width of the print media.

An electromagnetic cooking device and method of controlling the same is provided herein. The cooking device includes a cavity in which a liquid is placed and a plurality of RF feeds configured to introduce electromagnetic radiation into the cavity for heating the liquid. A controller is provided and is configured to analyze forward and backward power at the plurality of RF feeds to calculate efficiency; determine and monitor a coefficient of variation of the efficiency; detect a heating state in the liquid based on changes in the coefficient of variation; and adjust a power level of the electromagnetic radiation in response to detection of the heating state.

Methods of curing polyimide to tune the coefficient of thermal expansion are provided herein. In some embodiments, a method of curing a polymer layer on a substrate, includes: (a) applying a variable frequency microwave energy to the substrate to heat the polymer layer and the substrate to a first temperature; and (b) adjusting the variable frequency microwave energy to increase a temperature of the polymer layer and the substrate to a second temperature to cure the polymer layer.

A microwave treatment device according to one aspect of the present disclosure includes a heating chamber, a microwave generator, an amplifier, a feeder, a detector, a controller, and a storage. The microwave generator generates a microwave having an arbitrary frequency in a predetermined frequency band. The amplifier amplifies the microwave and outputs the amplified microwave as incident microwave power. The feeder supplies the incident microwave power to the heating chamber. The detector detects the incident microwave power and reflected microwave power that returns from the heating chamber to the feeder. The storage stores the incident microwave power and the reflected microwave power in association with the frequency of the microwave and time elapsed since the start of heating. The controller causes the microwave generator to execute a frequency sweep over the predetermined frequency band. The controller controls the microwave generator and the amplifier on the basis of the incident microwave power and the reflected microwave power detected during the frequency sweep.

According to the present aspect, the heating evenness can be improved.