A vehicle-use electronic key system includes a control unit mounted on a real car, and an electronic key for sending a response signal on receiving a request signal sent from the control unit via a transmission antenna, the antenna being installed near the middle of the real car. Specifically, when a...http://www.google.fr/patents/US7304565?utm_source=gb-gplus-shareBrevet US7304565 - Vehicle-use electronic key system
