Antenna core and method of manufacturing the same, and antenna and detection system using the same
View Patent ↗An antenna core includes a laminate of a plurality of Co-based amorphous magnetic alloy thin strips in which a length ratio of a long axis to a short axis is greater than 1. 60% or more of the Co-based amorphous magnetic alloy thin strips in terms of the number of the thin strips as percentage have a line-shaped mark formed along the long axis on at least one surface thereof. An antenna includes the antenna core and a winding wound around the antenna core along the long axis.
1. A detection system, comprising:
a transmitter transmitting a specific radio signal; and
a receiver including an antenna receiving the radio signal to detect the transmitter,
wherein the antenna comprises,
an antenna core including a laminate of a plurality of Co-based amorphous magnetic alloy thin strips in which a length ratio of a long axis to a short axis is greater than 1, and
a winding wound around the antenna core along the long axis, and
wherein 60% or more of the plural Co-based amorphous magnetic alloy thin strips in terms of the number of the thin strips as percentage each have a line-shaped mark formed along the long axis on at least one surface thereof.
2. The detection system according to claim 1 ,
wherein a frequency of the radio signal is in a range of not lower than 40 kHz nor higher than 150 kHz.
3. The detection system according to claim 1 ,
wherein the system is mounted on an automobile.
4. The detection system according to claim 1 ,
wherein the system is an automobile keyless entry system.
5. The detection system according to claim 1 ,
wherein the receiver includes a card member and the antenna which is resin-sealed in the card member.
6. The detection system according to claim 1 ,
wherein the Co-based amorphous magnetic alloy thin strips located in outermost layers on both sides of the laminate each have the line-shaped mark.
7. The detection system according to claim 1 ,
wherein the length ratio of the long axis to the short axis of the Co-based amorphous magnetic alloy thin strips is in a range of not less than 2 nor more than 40.
8. The detection system according to claim 1 ,
wherein t 1 /t 2 ratio of the Co-based amorphous magnetic alloy thin strips is in a range of not less than 1 nor more than 1.4, where t 1 is a largest thickness of each of the Co-based amorphous magnetic alloy thin strips, and t 2 is an average thickness of each of the Co-based amorphous magnetic alloy thin strips.
9. The detection system according to claim 1 ,
wherein the Co-based amorphous magnetic alloy thin strips have an H-shape.
10. The detection system according to claim 2 ,
wherein the Co-based amorphous magnetic alloy thin strips have a composition expressed by a general formula:
Co a D b M c Si d B e
wherein D is at least one element selected from the group consisting of Fe and Ni, M is at least one element selected from the group consisting of Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta, and W, and a, b, c, d and e are a+b+c+d+e=100 atomic %, and 1 ≦b 10, 0.3≦c≦6.5, 5≦d≦12, 1≦e≦8.
11. The detection system according to claim 1 ,
wherein the line-shaped mark is a mark on a roll surface formed when the Co-based amorphous magnetic alloy thin strips are fabricated by a roll rapid cooling.
12. The detection system according to claim 1 ,
wherein the number of the stacked Co-based amorphous magnetic alloy thin strips is in a range of not less than 10 nor more than 50.
13. The detection system according to claim 1 ,
wherein the laminate has an insulating resin layer interposed between at least part of the Co-based amorphous magnetic alloy thin strips.
14. The detection system according to claim 1 ,
wherein a maximum magnetic flux density of the antenna core is in a range of not less than 0.35 T (tesla) nor more than 1.2 T (tesla).