Patent ID: 6222489
Filing Date: 2001-04-24
Classification: H01Q

Abstract:
An antenna device, comprising:an antenna unit including: a basic body comprising at least one of dielectric ceramic and magnetic ceramic, at least one conductor disposed at least one of inside and on a surface of the basic body, and a feeding electrode for applying a voltage to the conductor, disposed on the surface of the basic body;a mounting board on which said antenna unit is mounted;a ground part in association with said mounting board and adapted to resonate with said antenna unit; anda length in the polarization direction of a radio wave of said ground part being about .lambda./4 or more, where .lambda. is a wavelength of the radio wave,said basic body comprising;a first generally planar sheet having a plurality of spaced, first conductors formed on one major surface thereof,a second generally planar sheet having a plurality of spaced second conductors formed on one major surface thereof;said first and second generally planar sheets being laminated together to form an elongated structure wherein respective pairs of said first and second conductors are coupled to one another to form respective spiral loops of a spiral antenna so that a central axis of said spiral antenna extends generally parallel to a longitudinal direction of said elongated structure;each of said sheets being formed of a material having a relative permeability of 1<.mu.<7 or a dielectric constant .epsilon. of 1<.epsilon.<130; anda feeding terminal coupled to one end of said spiral antenna so that said antenna unit forms a mono-pole antenna, said antenna unit and ground part together functioning as a dipole antenna.