To obtain a target resonance frequency in a state such that an armor member is attached without changing the dimension of a coil even if the material and shape of the armor member change by providing a resonance frequency adjusting member in the coil and changing the dimension and the material of the resonance frequency adjusting member.
This antenna is provided with a coil 1 which helically molds a metal wire in a prescribed winding diameter and pitch and base part of the coil 1 is connected to a projecting part 2a of a feeding terminal 2 by caulking, soldering or the like. A resin made armor member 3 covers the coils so as to cover the outer circumferential part and the top part and the base part of the member 3 is fixed to the terminal 2 with an adhesion, etc. A cylindrical resonance frequency adjusting member 4 is inserted from the top of the member 3 in the coils 1. Thus, when the design of the member 3 is changed, it is possible to obtain a target resonance frequency and also to easily cope with it by deciding the length L and/or the external form D of the member 4 as the dimension of the coil 1 is remained as they are.
| WO/2021/045524 | ELECTRONIC DEVICE INCLUDING HELICAL ANTENNA |
MORIYAMA KAZUYUKI
NEGISHI KUNIO
