RADIO TAG SYSTEM AND RADIO COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To securely perform communication between a radio tag of underground equipment and a reader on the ground, if a passive radio tag is used.SOLUTION: In a radio tag system performing transmission and reception of information by radio between the radio tag installed on the underground equipment and the reader on the ground, there is assumed a curve surface on which the radio tag and the reader are disposed at two focal points, and a configuration is made to dispose each reflector that reflects a radio wave having a shape constituted by a part of the curve surface, on each back face of the radio tag and the reader disposed opposite to each other. The reflectors are constituted by two ellipse curve surfaces formed of parts of the ellipse curve surface having two focal points at the positions of the radio tag and the reader.