To provide an in-vehicle radio device which reduces a manufacturing cost and performs stable radio communication, and an in-vehicle printed circuit board for the radio communication using a radio device.
The in-vehicle radio device is formed of a case 10 mounting various circuits inside, and an antenna unit which is mounted on the side of the case, and integrally formed of an antenna conductor and a ground conductor. A conductor whose area is larger than the ground conductor of the antenna unit forms one side of the case, and at least, it is formed in a position corresponding to the mounting position of the antenna unit, or mounted between the one side and the antenna unit. The front side wall 11 of the case 10 is formed of a conducting material, and an in-vehicle printed circuit board 20 for the radio communication is installed on the front side wall 11. On the printed circuit board 20, a micro strip printed antenna 21 is formed. The strip 22 of the antenna conductor of the antenna 21 has a circle shape.
Mitsuhiro Ozeki
Masako Nishimura