To reduce a human body shielding effect and to reduce gain decline due to proximity of a human body, in a keyless entry system using only an UHF band.
An on-vehicle machine 2 includes: an on-vehicle antenna 21 capable of transmitting and receiving horizontally polarized waves; a transmission part 22 for transmitting signals to a portable machine 4; and a reception part 23 for permitting a keyless entry operation of a vehicle body 1 when it is determined that a distance between the on-vehicle machine 2 and the portable machine 4 is within a prescribed distance on the basis of a signal indicating the distance, which is received from the portable machine 4. The portable machine 4 includes: an antenna 41 for the portable machine, capable of transmitting and receiving the horizontally polarized waves; a reception part 42 for measuring the strength of the signals received from the on-vehicle machine 2 and measuring the distance between the on-vehicle machine 2 and the portable machine 4; and a transmission part 43 for transmitting the signal indicating the measured distance to the on-vehicle machine 2. At least one of the on-vehicle antenna 21 and the antenna 41 for the portable machine is capable of suppressing vertically polarized waves.
MIYASHITA HIROAKI
Hamada Hatsune
Kume Teruyo
Hideo Kawamura
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