Wireless tag communication control device

1. A wireless tag communication control device that communicates with a wireless tag attached to a moving object, comprising:

a gate through which the object passes;

a sensor for sensing an existence position of the object, the sensor being arranged at the gate;

an antenna for transmitting an electric wave to the wireless tag, the antenna being arranged at the gate; and

an electric wave output adjustment unit that is connected to the antenna;

wherein an electric wave transmission output from the antenna is adjusted according to the existence position of the object in the gate so that said output is adjusted to a minimum electric wave transmission output for maintaining a communication with the wireless tag.

2. The wireless tag communication control device as set forth in claim 1 ,

wherein the sensor has a plurality of sensors, and the sensors sense the existence position of the object at different areas in the gate respectively.

3. The wireless tag communication control device as set forth in claim 1 or 2 ,

wherein the antenna has a plurality of antennas, and electric wave transmission outputs from the plural antennas are controlled according to the position of the object in the gate respectively.

4. A wireless tag communication control device that communicates with a wireless tag attached to a moving object, comprising:

a first sensor and a second sensor for sensing an existence position of the moving object, the first and second sensors facing each other;

a first antenna and a second antenna for transmitting an electric wave to the wireless tag, the first and second antennas facing each other;

a first electric wave output adjustment unit connected to the first antenna; and

a second electric wave output adjustment unit connected to the second antenna;

wherein electric wave transmission outputs from the first and second antennas are adjusted according to the existence position of the object so that said outputs are adjusted to minimum electric wave transmission outputs for maintaining a communication with the wireless tag.

5. A wireless tag communication control device that communicates with a wireless tag attached to a moving object, comprising:

a first partition wall and a second partition wall which face each other;

a first sensor and a second sensor for sensing an existence position of the object, the first and second sensors being arranged at one ends of the first and second partition walls respectively;

a third sensor and a fourth sensor for sensing the existence position of the object, the third and fourth sensors being arranged at the other ends of the first and second partition walls respectively;

a first antenna and a third antenna which are arranged at the first partition wall;

a second antenna and a fourth antenna which are arranged at the second partition wall, the second and fourth antennas facing the first and third antennas respectively; and

a first to a fourth electric wave output adjustment units which are connected to the first to fourth antennas;

wherein electric wave transmission outputs from the first to fourth antennas are adjusted according to the existence position of the object so that said outputs are adjusted to minimum electric wave transmission outputs for maintaining a communication with the wireless tag.

6. The wireless tag communication control device as set forth in claim 5 ,

wherein the first and third antennas are arranged between the first and third sensors, and the second and fourth antennas are arranged between the second and fourth sensors.