PURPOSE: To make the on-vehicle antenna small while keeping the characteristic of the antenna.
CONSTITUTION: A radiation element 21 consists of a table 22 arranged in parallel with a ground conductor plate 14, a vertical feeding flat plate 23 bonded vertically to the table 22, a capacitance addition plate 25 bonded to a lower end of the vertical feeding flat plate 23 vertically and a post 24 bonded vertically to the table 22 at a prescribed distance from the center of the vertical feeding flat plate 23. A core wire of a coaxial feeder 15 is connected by solder or the like to the middle of the lower end of the vertical feeding flat plate 23 penetrated through from the lower side of the ground conductor plate 14. A distance T0 is set between the capacitance addition plate 25 and the ground conductor plate 14 and the lower end of a post 24 is bonded to the ground conductor plate 14. Current paths of various length are considered through the adoption of the vertical feeding flat plate 23 and a broad resonance frequency band is obtained. The Q of the antenna is reduced and the impedance of the feeding point is decreased.
NISHIKAWA KUNITOSHI
SATO KAZUO
TOYOTA MOTOR CORP