Wireless tag communication device and method

A wireless tag communication device including an antenna configured to transmit a carrier wave and receive a response wave output from a wireless tag with respect to the carrier wave, and configured to specify a position of the wireless tag to be searched based on a radio wave intensity of the response wave received by the antenna, the wireless tag communication device further comprising:

• a radio wave controller configured to switch the carrier wave between a first carrier wave to be transmitted in a first polarization direction and a second carrier wave to be transmitted in a second polarization direction;
• and
• a comparator configured to compare a radio wave intensity of a first response wave output by the wireless tag with respect to the first carrier wave and a radio wave intensity of a second response wave output by the wireless tag with respect to the second carrier wave,
• the radio wave controller being configured to switch the carrier wave between the first carrier wave and the second carrier wave based on a comparison result of the comparator, wherein
• the radio wave controller is configured to control an output value of the carrier wave in a plurality of stages,
• the radio wave controller decreases the output value of the carrier wave by one stage when the wireless tag communication device receives the response wave from the wireless tag a first preset number of times, and
• the radio wave controller increases the output value of the carrier wave by one stage when the wireless tag communication device does not receive the response wave from the wireless tag for a second preset number of times.

A method for controlling a wireless tag communication device by a computer, the wireless tag communication device including an antenna configured to transmit a carrier wave and receive a response wave output from a wireless tag with respect to the carrier wave, and configured to specify a position of the wireless tag to be searched based on a radio wave intensity of the response wave received by the antenna, the method comprising:

• switching, by a radio wave controller, the carrier wave between a first carrier wave to be transmitted in a first polarization direction and a second carrier wave to be transmitted in a second polarization direction;
• comparing, by a comparator, a radio wave intensity of a first response wave output by the wireless tag with respect to the first carrier wave and a radio wave intensity of a second response wave output by the wireless tag with respect to the second carrier wave;
• switching, by the radio wave controller, the carrier wave between the first carrier wave and the second carrier wave based on a comparison result of the comparator;
• decreasing, by the radio wave controller, an output value of the carrier wave by one stage when the wireless tag communication device receives the response wave from the wireless tag a first preset number of times;
• and
• increasing, by the radio wave controller, the output value of the carrier wave by one stage when the wireless tag communication device does not receive the response wave from the wireless tag for a second preset number of times;
• wherein
• the radio wave controller is configured to control an output value of the carrier wave in a plurality of stages.

A method for controlling a wireless tag communication device by a computer, the wireless tag communication device including an antenna configured to transmit a carrier wave and receive a response wave output from a wireless tag with respect to the carrier wave, and configured to specify a position of the wireless tag to be searched based on a radio wave intensity of the response wave received by the antenna, the method comprising:

• switching, by a radio wave controller, the carrier wave between a first carrier wave to be transmitted in a first polarization direction and a second carrier wave to be transmitted in a second polarization direction;
• comparing, by a comparator, a radio wave intensity of a first response wave output by the wireless tag with respect to the first carrier wave and a radio wave intensity of a second response wave output by the wireless tag with respect to the second carrier wave;
• and
• switching, by the radio wave controller, the carrier wave between the first carrier wave and the second carrier wave based on a comparison result of the comparator;
• setting, by the radio wave controller, an output mode of the carrier wave transmitted from the antenna to a dual polarization mode, in which the first carrier wave and the second carrier wave are alternately transmitted, or to a single polarization mode in which only one of the first carrier wave and the second carrier wave is transmitted;
• switching, by the radio wave controller, the output mode to the dual polarization mode when the antenna does not receive the response wave in the single polarization mode;
• receiving, by a receiver, identification information that identifies the wireless tag to be searched;
• and
• setting, by the radio wave controller, the output mode to the single polarization mode when a search for the wireless tag identified by the identification information received by the receiver is started.