COIL FOR RFID TAG

To provide a coil that has satisfactory characteristics even when the coil is used by being attached to or embedded in a tire, the coil forming an RFID tag in combination with a substrate on which an RF chip and a pattern coil connected to the RF chip are mounted.A coil 30 is held in a housing 75 accommodating a substrate 90 and is wound around the substrate 90. A first end of the coil 30 extends from the substrate 90 and forms a first element 50 of an antenna. A second end of the coil 30 extends from the substrate 90 and forms a second element 60 of the antenna. The first element 50 and the second element 60 are arranged in parallel to each other, and the first element 50 has a longer extension length than the second element 60. The coil 30 and a pattern coil 40 form a coupling transformer 20. The number of windings in the coil 30 is smaller than the number of windings in the pattern coil 40.