Patent ID: 9601831
Date: 2017-03-21
CPC Classifications: H01Q

Claim:
1. A radio device for attachment to a meter box having a planar obverse wall made of metal, the radio device comprising: a radiation conductor which converts a radio frequency signal into an electric wave and radiates the electric wave; a circuit board electrically connected to the radiation conductor and incorporating an electric circuit for supplying the radio frequency signal to the radiation conductor; a planar grounded conductor electrically connected to the electric circuit on the circuit board and placed such that the grounded conductor faces the radiation conductor and faces the planar obverse wall of the meter box upon attachment of the radio device to the meter box, the planar grounded conductor constituting a ground of the radiation conductor, the planar grounded conductor facing the planar obverse wall of the meter box to be spaced apart by a distance d from the surface of the meter box upon attachment of the radio device to the meter box such that the planar grounded conductor and the planar obverse wall of the meter box are electrically capacitively joined together and are substantially parallel, such that the planar grounded conductor and the planar obverse wall of the meter box cooperate as an enlarged ground plane of the radiation conductor to prevent or reduce increase in impedance between the radiation conductor and the planar grounded conductor upon attachment of the radio device to the meter box; and a resin-made casing sized to surroundingly contain the radiation conductor, the circuit board and the planar grounded conductor; wherein the planar grounded conductor, the circuit board and the radiation conductor are placed in this order along a linear axis in a thickness direction of the circuit board.