Patent ID: 7777609

Claim:
A radio-frequency tag communication device arranged to transmit a transmitted signal toward a radio-frequency tag and to receive a reply signal transmitted from said radio-frequency tag in response to said transmitted signal, for thereby effecting radio communication with said radio-frequency tag, said radio-frequency tag communication device comprising: a receiver portion including a receiver antenna device which has a plurality of receiver antenna elements for receiving said reply signal from said radio-frequency tag; a reception-directivity control portion configured to control a directivity of reception of said receiver portion, by controlling a phase of a received signal which is received by each of said plurality of receiver antenna elements and which may include a leakage signal which is a part of said transmitted signal; a modulated-component extracting portion configured to extract a modulated component of said received signal which is modulated by said radio-frequency tag; and a direction detecting portion configured to detect a direction in which said radio-frequency tag is located, on the basis of said modulated component extracted by said modulated-component extracting portion.