Electromagnetic wave heating device

An electromagnetic-wave heating device comprising:

• an oscillator for outputting and transmitting a frequency band of electromagnetic waves;
• a radiating antenna connected to the oscillator and having a resonance structure in which resonance by the electromagnetic waves in a frequency band transmitted from the oscillator occurs, the resonance structure forming a radio-frequency strong-electric-field region in which the electromagnetic-wave heating device carries out heating of an object to be heated;
• a signal extraction unit provided in a transmission line extending from the oscillator to the radiating antenna, for extracting reflected-wave information representing a waveform of a reflected wave returning from the radiating antenna;
• a phase-difference information generating unit for generating, by arithmetic processing utilizing the reflected-wave information and incident-wave information representing a waveform of an incident wave transmitted from the oscillator to the radiating antenna, phase-difference information representing a phase difference between the incident wave and the reflected wave;
• and
• a control unit for repeatedly performing a control process of:
• detecting, based on the phase-difference information and on reference information about a state in which the incident-wave phase and the reflected-wave phase are equal, a direction of oscillation-frequency adjustment whereby a difference between a resonant frequency in the radiating antenna and the oscillation frequency of the oscillator is reduced, and
• controlling the oscillation frequency based on the detected adjustment direction.