Patent ID: 10036361

Abstract:
An ignition device is provided, the ignition device comprises a coaxial structural body comprising an inner conductor 2, an outer conductor 3, and an insulator 4 that insulates both the conductors 2 and 3, which are coaxially provided with one another along an axial direction. A connection terminal 5 is arranged at one axial end side of the coaxial structural body and connecting the inner conductor 2 and the outer conductor 3 to the electromagnetic wave oscillator MW. The inner conductor 2 has a linearly extended part protruding at another axial end side of the coaxial structural body extending outwards from the outer conductor 3 in the axial direction and a spirally extended part continuously extending from the linearly extended part in a reversed direction and in a spiral manner that winds around the linearly extended part of the inner conductor 2 in a predetermined number of turns around the linearly extended part such that the inner conductor 2 forms a resonance structure and the spirally extended part 20 with the resonance structure is obtained. A diameter and a length of the inner conductor 2 that is extended outwards from the outer conductor 3, and the number of turns of the spirally extended part of the inner conductor 2 are determined such that a capacitive reactance XC and an inductive reactance XL of the spirally extended part are substantially equal to each other.