Patent ID: 11949154
Assignee: YOKOWO CO., LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An antenna device for vehicle, the antenna device comprising:
an antenna element;
an external connection terminal being connected with an external device;
a connection detection resistor having one end being grounded and having another end being connected with the external connection terminal, the connection detection resistor being connected in parallel with the antenna element;
a protection circuit having a capacitor, the capacitor having one end being grounded and having another end being connected with the external connection terminal, the capacitor being connected in parallel with the connection detection resistor, the protection circuit conducting a surge current from the external connection terminal to a ground side;
a matching circuit; and
a direct current cutting capacitor having one end being connected with the matching circuit and having another end being connected with the external connection terminal,
wherein the connection detection resistor is a resistor for detecting whether the external device is normally connected with the external connection terminal by a direct current voltage applied to the external connection terminal,
wherein the protection circuit is configured to conduct the surge current to the ground side, the surge current that occurs due to applying a surge voltage other than the direct current voltage to the external connection terminal, and
wherein the other end of the connection detection resistor and the other end of the capacitor are connected between the direct current cutting capacitor and the external connection terminal.