Abstract: In a microstrip antenna, a dielectric member is disposed on a grounded conductive plate. A patch antenna element is disposed on the dielectric member. Each of a plurality of conductive rods has an electrical length corresponding to one quarter of a wavelength at a resonance frequency of the microstrip antenna. The rods are arranged on an edge portion of a face of the conductive plate facing the patch antenna element, with an interval which is an electric length corresponding to a half or less of the wavelength at the resonance frequency, such that each of the rods extends perpendicularly to the conductive plate while one end thereof is electrically connected to the conductive plate.

Abstract: An antenna apparatus is mounted on a vehicle body provided with a spoiler made of an insulating resin. A feeder element is disposed in the spoiler such that the vehicle body serves as ground without providing a ground element in the spoiler.