To increase a printing accuracy for a spiral radiation conductor formed on the surface of a base and also to reduce an effective dielectric constant of the base.
An antenna device 10 includes a base 11 made of a dielectric material having a nearly rectangular parallelepiped shape, a spiral radiation conductor 12 formed so as to surround side surfaces 11C to 11F of the base 11, a power supply electrode 14 and a grounding electrode 15 formed on a bottom surface 11B of the base 11. In the respective side surfaces 11C to 11F of the base 11, spiral regions for the radiation conductor 12 to be formed are relatively projected, and the other region is formed with a recess having a predetermined depth. Since the base 11 has such recess or projection on its sides, mere printing a conductor paste on projected side surfaces 13b of the base 11 enables formation of a radiation conductor having a predetermined shape at a predetermined location.
HARIHARA YASUMASA
Ogata Japanese
Yasuyuki Kurose