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Passive RFID vs active RFID vs semi-active RFID?

Radio frequency identification technology can be divided into three categories according to its tag power supply, namely passive RFID tags, active RFID, and semi-active RFID. then what are the differences and connections between active and passive tags?


1. Passive RFID. Passive RFID appeared the earliest, the most mature, its application is also the most widespread. In passive RFID, the electronic tag by accepting the microwave signal transmitted by the radio frequency identification reader, as well as through the electromagnetic induction coil to obtain energy to power itself briefly, so as to complete this information exchange. Because the power supply system is omitted, so the volume of passive RFID tags can reach the centimeter scale or even smaller, and its own structure is simple, low cost, low failure rate, and long service life. But as a price, passive RFID's effective recognition distance is usually shorter, generally used for close contact identification. Passive RFID mainly works in the lower frequency band 125KHz, 13.56MKHz, etc. Its typical applications include: bus cards, second generation ID cards, canteen meal cards, etc.

2. Active RFID. Active RFID emerged not long, but has been in various fields, especially in the highway electronic non-stop toll system plays an indispensable role. Active RFID through the external power supply, active to send signals to the radio frequency identification reader. Its volume is relatively large. But also therefore has a long transmission distance and high transmission speed. A typical active RFID tag can establish contact with the RFID reader from a hundred meters away, and the reading rate can reach 1,700read/sec. Active RFID mainly works in 900MHz, 2.45GHz, 5.8GHz and other higher frequency bands, and has the function that can identify multiple tags at the same time. Active RFID's long-range, high efficiency, making it in some need of high performance, a large range of radio frequency identification applications in essential.

3. Semi-active RFID. Passive RFID itself does not power, but the effective recognition distance is too short. Active RFID recognition distance is long enough, but need external power supply, the volume is larger. And semi-active RFID is for this contradiction and the product of compromise. Semi-active RFID is also called low-frequency activation trigger technology. Under normal circumstances, semi-active RFID products in a dormant state, only the tag to maintain data in the part of the power supply, so power consumption is small, can be maintained for a long time. When the tag enters the RFID reader recognition range, the reader first now with 125KHz low frequency signal in a small range of precise activation of the tag to make it enter the working state, and then through the 2.4GHz microwave and its information transmission. That is to say, the first use of low frequency signal precise positioning, and then use high frequency signal fast transmission data. The usual application scenario is: in a large area covered by a high-frequency signal, multiple low-frequency readers are placed in different locations for activating semi-active RFID products. This accomplishes both positioning and information collection and transmission.

The advantages and disadvantages of both

1. Active RFID tags

Active RFID tags are powered by a built-in battery, and different tags use different numbers and shapes of batteries.

Advantages: the role of distance, active RFID tags and RFID readers between the distance can reach dozens of meters, or even up to hundreds of meters.

Disadvantages: large size, high cost, the use of time is limited by the battery life.

2. Passive RFID tags

Passive RFID tags do not contain batteries, its electrical energy from the RFID reader to obtain. When the passive RFID tag near the RFID reader, passive RFID tag antenna will receive the electromagnetic wave energy into electricity, activating the RFID tag in the chip, and the RFID chip in the data sent out.

Advantages: small size, light weight, low cost, long life, can be made into different shapes such as thin sheets or lanyards, applied to different environments.

Disadvantages: because there is no internal power supply, so the distance between the passive RFID tag and RFID reader is limited, usually within a few meters, generally requires a larger power RFID reader.

Working principle

1. Active electronic tag is the tag work energy provided by the battery, the battery, memory and antenna together constitute the active electronic tag, different from the passive radio frequency activation method, before the battery replacement has been through the set frequency band outgoing information.

2. Passive rfid tag performance by the tag size, modulation form, circuit Q value, device power consumption and modulation depth of the great impact. Passive rfid tag 1024bits memory capacity, ultra-wide working band, both in line with relevant industry regulations, but also flexible development applications, can read and write multiple tags at the same time. Passive RF tag design, no battery, memory can be repeatedly erased more than 100,000 times.

Passive RFID technology warehousing applications

Passive RFID its internal is the antenna and chip composition, when the tag into the magnetic field, by the integrated circuit through the received electromagnetic waves to drive, these electromagnetic waves are issued by the RFID reader. When the tag receives a signal of sufficient strength, the RFID electronic tag is activated and can send data to the reader.

Passive RFID identifies and records information through the communication between the reader and the RFID electronic tag. The antenna can be installed anywhere to identify and record the tag information, RFID typical installation is installed to the warehouse door, or key nodes, we usually call the "throat".

Passive RFID technology warehouse applications passive RFID warehouse management Passive RFID can track or monitor the amount of pallets, boxes and goods shipped in and out of the warehouse. When entering the warehouse, the goods may already have RFID tags, or may first need to initialize the tags, enter the information about the goods, and then paste them onto the goods.

In the time of warehousing business, you can use fixed RFID reader, you can also use handheld RFID handheld data terminal, and forklift-type mobile reader, in the time of inbound and outbound, inventory, picking the key business, automatically record the goods associated with RFID tags, and can collect the information in real time to the data center management platform.

Active RFID technology warehousing applications

Active RFID is also known as active RFID tags, is based on the different ways of electronic tag power supply to divide the electronic tag a type, usually support long-distance identification. Active RFID electronic label, in accordance with the preset rules periodic signal emission, when the RFID label into the role of the read-write area, the reader to obtain the information emitted by the label, that is, the completion of the identification process of the label. Active RFID technology warehouse application Active RFID technology warehouse application

Active RFID reader is placed in the warehouse need to monitor and track the goods in the area, according to the site environment in accordance with the planning of the radio frequency, the deployment of active reader, to ensure the coverage of the range and signal strength, and wireless LAN wireless access point planning is the same reason.

There are different types of active tags, some active tags can set different signal emission period, can be in the specified time and rules, if the tag moves without permission or out of the warehouse will automatically alarm. For inventory counts, tags can automatically wake up and report their regular presence.

RFID Warehouse Management Software

RFID-based warehouse management software is focused on the characteristics and needs of warehouse management in various industries and developed to launch various industries and versions of warehouse management system products, also provide custom development of software, warehouse management business consulting services, to provide customers with integrated software, hardware and services for the overall solution, and it is simple and easy to use.

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