High frequency heating device having an energy feed system including a cylindrical wave guide

A high frequency heating device comprising:

• a high frequency oscillator having an output portion which includes an output antenna;
• a heating chamber for accommodating an object to be heated, said heating chamber having a wall;
• and
• a cylindrical wave guide having an end which is coupled to said output portion of said high frequency oscillator and having an opposite end which is coupled to said wall of said heating chamber, said output antenna of said high frequency oscillator being disposed on the center axis of said cylindrical wave guide, and said wall of said heating chamber having at least one arcuate slit formed therein, with the center of curvature of said at least one arcuate slit being positioned on the center axis of said cylindrical wave guide, said at least one arcuate slit being positioned on said wall so that a fundamental frequency electromagnetic wave generated by said high frequency oscillator is transmitted to said heating chamber with a small loss and harmonic components of the fundamental frequency electromagnetic wave are propagated to said heating chamber with greater attenuation.

A high frequency heating device comprising:

• a microwave energy source which includes a magnetron having an antenna stub, the antenna stub having a longitudinal axis;
• a hollow wave guide having first and second ends and having a longitudinal axis which extends through the first and second ends, the wave guide additionally having an inner surface which is rotationally symmetrical with respect to the longitudinal axis of the wave guide, the microwave energy source being mounted at the first end of the wave guide, with the longitudinal axis of the antenna stub coinciding with the longitudinal axis of the wave guide;
• and
• a heating chamber for accommodating an object to be heated, the heating chamber having a flat wall with an arcuate slit therein, the second end of the wave guide being connected to the wall so that the wall is perpendicular to the longitudinal axis of the wave guide and so that the slit communicates with the wave guide, the slit having a center of curvature which is positioned on the longitudinal axis of the wave guide.