| abstract |
The present invention relates to a coil part and an antenna obtained by using the coil part. The coil part is composed of a coil, a ferrite core passing through a hollow portion of the coil, and a resin covering the same. As the core, a nickel-based ferrite core is used. The initial magnetic permeability μi of the nickel-based ferrite core at a frequency of 100 kHz and a temperature of 20 ° C. is 450 or more, and the average crystal grain size is 5 to 9 μm. The inductance change rates TLa and TLb with temperature change and the inductance change rates PLa and PLb with respect to stress change are both -0.6% to + 0.6%, and the total of TLa and PLa and the total of TLb and PLb exceed -1.0%. And less than + 1.0%. |