Patent ID: 8198960

Claim:
An electric field coupler comprising: a strip-like coil formed by bending a strip-like conductor which snakes along a plane perpendicular to a coupling direction in which electric field coupling occurs, such that coil axes are perpendicular to the coupling direction, the strip-like coil having an electrical length of one-half wavelength of a predetermined frequency of a radio-frequency signal and having a form in which the coil axes surround a central portion along the plane, a resonance portion that resonates with a radio-frequency signal having the predetermined frequency which is supplied from a feed end and that is connected to one end of the strip-like coil at a location corresponding to an antinode of a standing wave of a voltage by the resonance; and a ground provided on one side of the strip-like coil that is opposite to the coupling direction, wherein an other end of the strip-like coil is grounded, the strip-like coil produces coupling by a longitudinal wave electric field which vibrates in the coupling direction at the central portion, and a winding direction of the strip-like coil is reversed at the middle of the strip-like coil.