PURPOSE: To generate a uniform electric field without causing cavity resonance, by dividing a central conductor in the direction of propagation of energy and by providing an Mn-Zn ferrite tile on the inner wall and ceiling of an outer conductor.
CONSTITUTION: An outer conductor 7 giving an electric field shield function is formed, for instance, of a tin-plated steel plate single shield. On the wall and ceiling of the outer conductor 7, an Mn-Zn ferrite tile 8 whose loss increases at a frequency of about 10MHz or below is stuck so as to suppress the occurrence of cavity resonance in the case where a higher mode is generated. A central conductor 9 is constituted by split conductors 9a, 9b and 9c of a strip line, which are divided along the direction 10 of propagation of energy. The division of the central conductor 9 in the direction 10 of propagation of energy enables the suppression of a current perpendicular to the direction of propagation, which is caused by the higher mode. The central conductor 9 is supplied with a power from a single power amplifier through an impedance transformer 14 and a tapered part 16.
MIURA TARO
KATSUMATA MASASHI
