Patent ID: 7623073

Claim:
A radar apparatus comprising: a transmitting unit which radiates a radar pulse to a space via a transmitting antenna; a receiving unit which receives the radar pulse reflected from an object existing in the space via a receiving antenna; an analysis processing unit which explores the object existing in the space based on a receiving output from the receiving unit; and a control unit which controls at least one of the transmitting unit and the receiving unit based on an output from the analysis processing unit, wherein the transmitting antenna and the receiving antenna respectively comprise first and second linearly polarized antenna elements, and the first and second linearly polarized antenna elements respectively include: a dielectric substrate; a ground conductor which is overlapped on a first surface of the dielectric substrate; a linearly polarized antenna element formed on a second surface of the dielectric substrate which is opposite to the first surface of the dielectric substrate; a plurality of metal posts in which a first end side of each of the plurality of metal posts is connected to the ground conductor, and pierces through the dielectric substrate along a thickness direction thereof, wherein a second end side of each of the plurality of metal posts is extended to the second surface of the dielectric substrate, and the plurality of metal posts are provided at predetermined intervals to form a cavity so as to surround the antenna element; and a conducting rim which short-circuits the second end side of each of the plurality of metal posts along a line direction of the plurality of metal posts on the second surface of the dielectric substrate, wherein the conducting rim extends by a predetermined distance in a direction of the antenna element, wherein the plurality of metal posts are provided at the predetermined intervals to form separated cavities such that the plurality of metal posts surround the first linearly polarized antenna element and the second linearly polarized antenna element while separating the first linearly polarized antenna element and the second linearly polarized antenna element, and wherein a first conducting rim and a second conducting rim are provided on the second surface of the dielectric substrate, the first conducting rim and the second conducting rim short-circuiting the second end side of each of the plurality of metal posts along the line direction of the plurality of metal posts, and the first conducting rim and the second conducting rim being extended by the predetermined distance toward the directions of the first linearly polarized antenna element and the second linearly polarized antenna element.