| 摘要 |
PROBLEM TO BE SOLVED: To provide an on-board antenna system using an array antenna which can detect the position of a key by one wireless communication device. SOLUTION: When the on-board antenna system 100 detects vehicle front areas (detection areas 501, 505, 507), a distributor 102 power-splits a transmission signal output from a transmitting/receiving circuit 101 into twelve signals which is the number of elements of a loop antenna and outputs the power split signals to a weight control part 103 to feed power only to the loop antenna elements 411, 412, 413, 414, 415. Then the direction of a beam is switched by adjusting the phase of an input signal to be fed to cover respective detection areas. COPYRIGHT: (C)2009,JPO&INPIT
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