A known radio tag includes a RFID (Radio Frequency Identification) tag or the like. The radio tag performs radio communications with a reader/writer to read and write data. The radio tag is provided with an inlet inside it, and the inlet has an IC (Integrated Circuit) chip connected to an antenna pattern for performing radio communications. The IC chip sends and receives signals using the antenna pattern to perform radio communications or the like with the reader/writer.
There may be a case that the radio tag is attached to the metal surface of an attached subject where reflection, absorption, or the like of radio waves occurs. Also, there may be a case that the radio tag is attached to an attached subject containing liquid by which reflection, absorption, or the like of radio waves occurs. In these cases, there is a likelihood of reducing a radio communication distance that enables radio communications between the IC chip and the reader/writer. Therefore, a spacer for separating the inlet or the antenna pattern from the attached subject by a certain distance or more is provided between the inlet and the attached subject, thereby increasing the radio communication distance. Note that the following Patent Documents have been known as related art cases.
Patent Document 1: Japanese Laid-open Patent Publication No. 2006-338361
Patent Document 2: Japanese Laid-open Patent Publication No. 2008-9537
Since the spacer provided in the radio tag is manufactured so as to conform with the shape of the attached subject as evident from the Patent Documents, the size of the spacer is fixed. Accordingly, if the shape of the attached subject to which the radio tag having the spacer is attached is changed, the size of the spacer does not conform with the attached subject and thus the radio tag cannot be attached. In order to attach the radio tag to the attached subject whose shape is changed, it is required to redesign and remanufacture the spacer so as to conform with the shape of the attached subject. As a result, the cost of redesigning and remanufacturing the spacer is required.