Common mode choke coil and high-frequency component
A common mode choke coil includes a first coil element and a second coil element connected in series between a first port and a second port, and a third coil element and a fourth coil element connected in series between a third port and a fourth port. With normal mode current flow through the first and second transmission lines, a first closed magnetic circuit forms in which magnetic flux passing through the first and second coil elements forms a closed loop, and a second closed magnetic circuit forms in which a magnetic flux passing through the third coil element and the fourth coil element forms a closed loop. With common mode current flow in the first and second transmission lines, a third closed magnetic circuit forms in which a magnetic flux passing through the first through fourth coil elements forms a closed loop.
1. A common mode choke coil comprising:
a first transmission line;
a second transmission line paired with the first transmission line;
a first coil element connected in series to the first transmission line;
a second coil element connected in series to the first transmission line;
a third coil element connected in series to the second transmission line and coupled to the first coil element; and
a fourth coil element connected in series to the second transmission line and coupled to the second coil element, and
wherein winding directions and connection directions of the first coil element, the second coil element, the third coil element, and the fourth coil element are determined such that, with normal mode current flow through the first and second transmission lines, a first closed magnetic circuit forms in which a magnetic flux passing through the first coil element and the second coil element forms a closed loop and a second closed magnetic circuit forms in which a magnetic flux passing through the third coil element and the fourth coil element forms a closed loop, and, with common mode current flow through the first and second transmission lines, a third closed magnetic circuit forms in which a magnetic flux passing through the first coil element, the second coil element, the third coil element, and the fourth coil element forms a closed loop.
2. The common mode choke coil according to claim 1 ,
wherein the first coil element and the second coil element are disposed so that winding axes of the first coil element and the second coil element are substantially parallel to each other, and
wherein the third coil element and the fourth coil element are disposed so that winding axes of the third coil element and the fourth coil element are substantially parallel to each other.
3. The common mode choke coil according to claim 1 ,
wherein the first coil element and the third coil element are disposed adjacent to each other in a direction of the same winding axis shared by the first coil element and the third coil element, and
wherein the second coil element and the fourth coil element are disposed adjacent to each other in a direction of the same winding axis shared by the second coil element and the fourth coil element.
4. The common mode choke coil according to claim 2 ,
wherein the first coil element and the third coil element are disposed adjacent to each other in a direction of the same winding axis shared by the first coil element and the third coil element, and
wherein the second coil element and the fourth coil element are disposed adjacent to each other in a direction of the same winding axis shared by the second coil element and the fourth coil element.
5. The common mode choke coil according to claim 1 , wherein the first coil element, the second coil element, the third coil element, and the fourth coil element are formed of conductive patterns and via conductors for connecting layers which are placed in a laminate obtained by laminating a plurality of dielectric layers.
6. The common mode choke coil according to claim 5 , wherein a magnetic layer is placed between a conductive pattern forming the first coil element and the second coil element and a conductive pattern forming the third coil element and the fourth coil element.
7. The common mode choke coil according to claim 5 , wherein an ESD protection element is placed in the laminate and is connected to the first transmission line or the second transmission line.
8. The common mode choke coil according to claim 6 , wherein an ESD protection element is placed in the laminate and is connected to the first transmission line or the second transmission line.
9. A high-frequency component comprising a common mode choke coil that includes:
a first transmission line;
a second transmission line paired with the first transmission line;
a first coil element connected in series to the first transmission line;
a second coil element connected in series to the first transmission line;
a third coil element connected in series to the second transmission line and coupled to the first coil element; and
a fourth coil element connected in series to the second transmission line and coupled to the second coil element, and
wherein winding directions and connection directions of the first coil element, the second coil element, the third coil element, and the fourth coil element are determined such that, with normal mode current flow through the first and second transmission lines, a first closed magnetic circuit forms in which a magnetic flux passing through the first coil element and the second coil element forms a closed loop and a second closed magnetic circuit forms in which a magnetic flux passing through the third coil element and the fourth coil element forms a closed loop, and, with common mode current flow through the first and second transmission lines, a third closed magnetic circuit forms in which a magnetic flux passing through the first coil element, the second coil element, the third coil element, and the fourth coil element forms a closed loop.