Abstract: A coaxial probe includes an inner conductor, an outer conductor, and a dielectric interposed between the inner and outer conductors, the top-end portion of the coaxial probe having a substantially circular cone shape between the top-end of the inner conductor and the end of the outer conductor so that a portion of the inner conductor and a portion of the dielectric are exposed, and the height of the substantially circular cone portion being set at a value at which a reflection coefficient exhibits substantially a minimum value. The dielectric constant of the dielectric is preferably within the range of about 0.132 times to about 0.6 times as large as the dielectric constant of a surrounding substance (living tissue, i.e., an object to which an electromagnetic wave is irradiated).

Abstract: A coaxial probe includes an inner conductor, an outer conductor, and a dielectric interposed between the inner and outer conductors, the top-end portion of the coaxial probe having a substantially circular cone shape between the top-end of the inner conductor and the end of the outer conductor so that a portion of the inner conductor and a portion of the dielectric are exposed, and the height of the substantially circular cone portion being set at a value at which a reflection coefficient exhibits substantially a minimum value. The dielectric constant of the dielectric is preferably within the range of about 0.132 times to about 0.6 times as large as the dielectric constant of a surrounding substance (living tissue, i.e., an object to which an electromagnetic wave is irradiated).