Patent ID: 8077107

Claim:
An antenna apparatus comprising: a finite ground plane; a plate-like conductive element configured to include a first conductive plate disposed so as to oppose the finite ground plane and a second conductive plate that shorts a first edge of the first conductive plate to the finite ground plane; an antenna configured to include an antenna element, and a feeding point feeding power to the antenna element, which is positioned in the vicinity of a second edge in a side opposite to the first edge of the first conductive plate; and a coaxial line configured to feed the feeding point, wherein the plate-like conductive element propagates an electromagnetic wave which is radiated from the antenna and incorporated into a space between the first conductive plate and the finite ground plane from the second edge side of the first conductive plate, by means of reflection between the first conductive plate and the finite ground plane toward an inside surface of the second conductive plate to reflect the electromagnetic wave on the inside surface, and propagates a reflected electromagnetic wave by means of reflection between the first conductive plate and the finite ground plane toward the second edge side of the first conductive plate to output the electromagnetic wave outside the space so that a desired phase delay induced in the electromagnetic wave, the antenna is a dipole antenna having two antenna elements and the feeding point, an outer conductor of the coaxial line is connected to one of the two antenna elements and is shorted by the finite ground plane, and an inner conductor of the coaxial line is connected to the other one of the two antenna elements.