Inside a multilayer dielectric substrate, there are a spiral-shaped first slot set in a part of a first ground conductor layer and a spiral-shaped second slot in a part of a second ground conductor layer put on the front surface of the multilayer dielectric substrate, the first slot and the second slot are opposite in a spiral winding direction and the first slot and the second slot overlap with each other as viewed from the top face, so that a resonance phenomenon can be produced at a frequency lower than a resonance frequency of a resonator with a conventional structure.
1. A resonator for producing a resonance phenomenon at a resonance frequency, comprising:
a dielectric substrate;
a ground conductor layer having a slot formed into a spiral shape with a turning number of one time or more, which is disposed on a back surface of the dielectric substrate;
a spiral conductor interconnection disposed on a front surface of the dielectric substrate and formed into a spiral shape with a turning number of one time or more; and
a connection through conductor disposed so as to go through the dielectric substrate for connecting an inner termination portion of the spiral conductor interconnection or a vicinity thereof and a ground conductor region inside the slot in the ground conductor layer, wherein
the slot and the spiral conductor interconnection overlap with each other as viewed from a top face.
2. The resonator as defined in claim 1 , wherein the connection through conductor is connected to the ground conductor region in a vicinity of a spiral center of the slot in the ground conductor layer.
3. The resonator as defined in claim 1 , wherein a winding direction of the slot and a winding direction of the spiral conductor interconnection are opposite to each other.
4. The resonator as defined in claim 1 , wherein the slot and the spiral conductor interconnection are disposed so that, as viewed from the top face, respective spiral centers are aligned with each other and respective outer edges are almost aligned with each other.
5. The resonator as defined in claim 4 , wherein an outer termination portion of the slot and an outer termination portion of the spiral conductor interconnection are disposed at positions symmetric with respect to a spiral center of the slot as viewed from the top face.