| 摘要 |
PROBLEM TO BE SOLVED: To prevent communication from being disabled between an automobile and a reception tag by generating an omnidirectional magnetic field by providing a magnetic field generating part in the automobile, providing a magnetic receiving part in an identifying member, arranging a loop antenna in one of them, constituting the other by means of three coils which are wound around three axes constituting a three-faced body and permitting a current to flow with a deviated phase in a coil. SOLUTION: Low frequency communication equipment is provided with a magnetic field generating part arranged in the automobile, a magnetic field receiving part arrnaged in the identifying member and a loop antenna arranged in one of them. The others are constituted of three coils 1, 2 and 3 wound around mutually orthogonally crossed axes Ox, Oy and Oz constituting a three- faced body and the current with deviated phase of frequency by 60 deg. or 120 deg. are supplied to generate an omnidirectional magnetic field. Coil 1 is on vertical surface and has the axis Oy, coil 2 is on a horizontal surface and has the axis Oz ad the coil 3 is on the surface perpendicular to these two surfaces and has the axis Ox. The three axes Ox, Oy and Oz constitute the three-faced body.
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