Patent ID: 7659858

Claim:
An electronic device comprising: a cylindrical case which has an inner space and both ends opened to the inner space and which is impermeable to a radio wave; a first cover which covers an opening in one end of the case and which is permeable to the radio wave; a second cover which covers an opening in the other end of the case and which is impermeable to the radio wave; a circuit board which is arranged between the first cover and the second cover in the inner space of the case; an antenna which is arranged between the first cover and the second cover in the inner space of the case, which is connected to the circuit board, and which includes an elongated core having end portions and an intermediate portion between the both end portions, and a coil wound around the intermediate portion of the core; a pair of magnetic flux introducing portions provided on the both end portions of the core of the antenna; a partition plate which is arranged between the first cover and the antenna in the inner space of the case and which is permeable to the radio wave; and a pair of flat and magnetic members which is arranged between the partition plate and the antenna in the inner space of the case and which is magnetically connected to the pair of magnetic flux introducing portions, wherein an electric signal entered into the inner space of the case from an outside of the case through the first cover and the partition plate is introduced into the magnetic flux introducing portions through the flat and magnetic members and then the electric signal is introduced into the intermediate portion of the core from the magnetic flux introducing portions through the both end portions of the core to act on the coil.