| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an antenna structure of an electronic key system capable of setting, for instance, outward communication and inward communication of the electronic key system at frequencies in the same band. <P>SOLUTION: A key operation-free system 3 where an electronic key 2 responds to inquiry from a vehicle 1 to transmit an ID code and ID verification is performed by the ID code is mounted on the vehicle 1. A leakage coaxial cable 17 is wired in the vehicle 1, and the leakage coaxial cable 17 is used as a transmission antenna of the vehicle 1. The leakage coaxial cable 17 transmits radio waves in the UHF band in a narrow band, and thereby a transmission area is formed only in the vicinity of the vehicle 1. Thereby, the radio waves in the UHF band are uniformly transmitted to the circumference of the vehicle, and the transmission area equivalent to the case where an LF antenna is used is formed by the radio waves in the UHF band. Thereby, the radio waves can be unified in the UHF band in the outward communication and the inward communication of the key operation-free system 3. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
