RF tag, magnetic antenna, board mounted with the RF tag, and communication system

摘要

The present invention relates to a magnetic antenna for information communication using a magnetic field component which is a magnetic antenna or an RF tag capable of satisfying both reduction in size and improvement in communication sensitivity. More specifically, the present invention relates to an RF tag comprising a magnetic antenna for transmitting and receiving information using an electromagnetic induction method, and an IC mounted to the magnetic antenna, said magnetic antenna comprising a magnetic core and a plurality of coils formed on the magnetic core in which the coils each have an inductance L1 satisfying the specific relational formula, and are formed with bank winding when the coils are lap-wound so as to prevent increase in parasitic capacitance thereof, connected in parallel to each other in an electric circuit, and disposed in series on the magnetic core; and a combined inductance L0 of the magnetic antenna satisfies the specific relational formula.

主权项

1. An RF tag comprising a magnetic antenna for transmitting and receiving information using an electromagnetic induction method, and an IC mounted to the magnetic antenna, said magnetic antenna comprising a magnetic core and a plurality of coils formed on the magnetic core in which the coils each have an inductance L1 satisfying the following relational formula (1), and are formed with bank winding, connected in parallel to each other in an electric circuit, and disposed in series on the magnetic core; and a combined inductance L0 of the magnetic antenna satisfies the following relational formula (2):
L1≧1/(4π2×(operating frequency)2×(capacitance of IC+parasitic capacitance of antenna))   wherein L1 is an inductance per one coil;
L0≦1/(4π2×(operating frequency)2×(capacitance of IC+parasitic capacitance of antenna))   wherein L0 is a combined inductance of the magnetic antenna.