The hottest reading distance is 10m. UHF can be pa

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UHF wireless tag with a reading distance of 10m can be attached to metal

Mitsubishi Electric recently developed a wireless tag (RFID tag) using UHF (950mhz) frequency band, which can be attached to the metal surface, and the reading distance is up to 10m (Figure 1). Previously, in terms of passive UHF wireless tags that do not use batteries, there has been a product that claims to be used on non-metallic surfaces with a reading distance of 8m, which has exceeded this distance this time. In terms of such labels that can be attached to the metal surface, previously "products with a reading distance of about 1m have been used in the empirical experiment of the Ministry of economy, industry and trade of Japan" (Mitsubishi Electric). If the UHF wireless tag is used to make the reading distance reach 10m, it will also become very convenient in the circulation management of metal containers and other operational fields

the reason why it can be pasted on the metal surface this time, so that the design of the refrigeration system uses energy conditioning technology, but also lies in its role in building brand image and improving flight experience, mainly because the wireless tag antenna adopts micro strip antenna (also known as patch antenna). The label is divided into three layers: a sponge like lining is placed on the aluminum alloy plate, and the positioning device: the landing height can be automatically controlled by the computer, and then the bottom plate for placing antenna elements and wireless IC chips is assembled on it (Figure 1). The aluminum alloy plate is separated from the antenna element by a lining of about 3mm. If the antenna adopts this structure, the metal body with aluminum alloy plate and wireless label can function as a part of the antenna base. However, ordinary wireless tags use dipole antenna or antenna using electromagnetic induction, so it is difficult to give full play to its function when pasted on the metal surface

Mitsubishi Electric said, "the price of wireless tags is expected to be around hundreds of yen per tag. It is envisaged that they will be posted on the containers in factories and warehouses and read by forklifts, or used in access management. We do not produce low-cost small tags." It said that it would never participate in the cost competition at a price of about 10 yen like ordinary labels. In the future, the company will take corresponding measures in the miniaturization and high-speed movement of readers and writers, so as to realize practicality in the middle of 2006

the reading distance of ordinary wireless tags can also reach 7m

according to Mitsubishi Electric, the reading distance of wireless tags this time can be increased to 10m due to two factors. One is that the wireless tag increases the antenna gain by increasing the antenna. As a result, the overall dimension of the wireless tag has reached 100mm × 200mm × 5mm, which is much larger and thicker than other passive wireless tags

another is that it greatly reduces the adverse effects on the sending circuit and receiving circuit of the reader writer. Specifically, (1) the transmitting and receiving parts are separated by setting the transmitting antenna and the receiving antenna separately; (2) By reducing the useless radiation of the transmission circuit, the interference between channels is reduced; (3) An electromagnetic shield is inserted between the transmitting circuit and the receiving circuit

the radio wave transmission power of the reader writer is about 1W. When the wireless tag distance is about 7m, the received power is only 1nW, with a difference of 1billion times. In the passive wireless tag system, how to achieve high power and high sensitivity is a problem that needs to be solved all the time. Mitsubishi Electric achieved a reading distance of 7m by using autonomous wireless tag technology in November 2004. With the solution to the reader writer problem, the reading distance of ordinary UHF wireless tags can also reach 7m

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