Tag communication system having a controlled antenna array to prevent interference
First Claim
1. A tag communication system comprising plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave,wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe;
- andsaid null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides a tag communication system, an interference preventing method and a tag communication controller suitable for prevention of a radio wave interference able to be caused by radio waves mutually emitted when plural tag communication devices are arranged. Plural reader-writers are oppositely arranged through a belt conveyer for conveying an article. A null of the reader-writer is opposed to a null of the reader-writer. A null of the reader-writer is opposed to a null of the reader-writer. Main lobes are directed to a direction causing no mutual interference.
16 Citations
9 Claims
-
1. A tag communication system comprising plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference. - View Dependent Claims (3)
- and
-
2. A tag communication system comprising plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave, and oppositely arranged through a moving path of this moving body,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference.
- and
-
4. An interference preventing method in plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference. - View Dependent Claims (6)
- and
-
5. An interference preventing method in plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave, and oppositely arranged through a moving path of this moving body,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference.
- and
-
7. A tag communication controller for controlling the operations of plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference. - View Dependent Claims (9)
- and
-
8. A tag communication controller for controlling the operations of plural tag communication devices for performing wireless communication with a RFID tag attached to a moving body through a radio wave, and oppositely arranged through a moving path of this moving body,
wherein each of said plural tag communication devices is constructed by plural antenna elements and has an array antenna able to form a null of directivity of the antenna and a main lobe; - and
said null is mutually opposed between one tag communication device and another tag communication device among said plural tag communication devices, and the directivity of each array antenna is controlled so as to direct said main lobe to a direction mutually causing no interference.
- and
Specification