Patent ID: 8421678

Claim:
An antenna apparatus, comprising: a dielectric substrate including a ground conductor formed on a back surface of the dielectric substrate; a radiation conductor formed on a front surface of the dielectric substrate, the antenna apparatus configured to directly transmit and receive a wireless digital signal by baseband transmission via a feed point of the radiation conductor; and at least one notched portion formed substantially at a center position on one side of the radiation conductor, which intersects an electric field plane of the radiation conductor, wherein the radiation conductor reduces waveform distortion of a transmitted wireless digital signal by forming the at least one notched portion on the one side of the radiation conductor, which intersects the electric field plane defined by an electric field when the antenna apparatus is excited, so that at least a third-order harmonic signal level becomes larger than a fundamental wave signal level, the dielectric substrate further comprises at least one groove, which is formed in at least one position that intersects the electric field plane in the vicinity of the at least one notched portion, the dielectric substrate includes at least two grooves, and the two grooves are formed symmetrically with respect to the magnetic field plane.