problems and disadvantages of an active RFID tag

The problems and disadvantages of an active RFID tag are:

• The tag cannot function without battery power, which limits the lifetime of the tag.
• The tag is typically more expensive, often costing $20 or more each
• The tag is physically larger, which may limit applications.
• The long-term maintenance costs for an active RFID tag can be greater than those of a passive tag if the batteries are replaced.
• Battery outages in an active tag can result in expensive misreads

Advantages of active RFID tags

The major advantages of an active rfid tag are:

• It can be read at distances of one hundred feet or more, greatly improving the utility of the device
• It may have other sensors that can use electricity for power
• Active RFID Tag has battery for generate power signal
• It has longevity up to 20 years

Features of active RFID tags:

Active RFID tags may have all or some of the following features:

• longest communication range of any tag
• the capability to perform independent monitoring and control
• the capability of initiating communications
• the capability of performing diagnostics
• the highest data bandwidth
• active RFID tags may even be equipped with autonomous networking; the tags autonomously determine the best communication path

Different Types of RFID Tags

There are mainly Three (03) different types of RFID Tags:

They are:

• Passive RFID tags
• Active RFID tags
• Semi-passive RFID tags

 Active RFID tags:

 Some Active Tags

Active RFID tags have their own internal source of power. This is used to power the circuits and   broadcast signals to the reader. These tags are usually more reliable than passive tags. They also have a  stronger signal because of their built-in power supply. This also allows them to work in places that  passive tags wouldn't be able to, such as in water(which would incluce humans and other animals),  metal, or from longer distances. They are however, larger and more expensive than passive tags. Today,  active tags can transmit from hundreds of meters and their batteries can last for about 10 years. Some  active tags contain different sensors that can read things like temperature, humidity, and radiation.

 Passive RFID tags:

Some Passive Tags

Passive RFID tags don't have an internal source of power. There is an electrical current that is created in the antenna by the incoming radio frequency signal from the reader. This means that the antenna has to be able to collect power from the incoming signal and also transmit the outbound signal to the reader. A passive tag can respond with identification numbers or non-volatile storage data. It can be read from about 10 cm to a couple of meters and since they don't have to have a power source on the device, they can be extremely small(they can be embedded in a sticker or under the skin).

In 2007, a company called RFIDsec created a passive tag that had many more privacy capabilities built into the device. These included built-in firewall acces controls, communication encryption, and a silent mode that would ensure that the soncumer at the point of sales can get exclusive control of the key to control the tag. In 2007, Hitachi,Ltd. developed a passive tag that was table to embedded in a sheet of paper. The problem with this is the antenna is 80 times bigger than the device. It can receive and send signals from as far away as a couple hundred meters. Companies are currently developing methods of production that will hopefully lower the prices of RFID tags dramatically.

Semi-passive RFID tags:

Semi Passive Tag

 Semi-passive tags have an internal power source like active tags, but it only powers the integrated circuit and doesn't broadcast a signal to the reader. The radiofrequency is used to broadcast a signal like a passive tag. These tags have a higher sensitivity than passive tags. This means that they can have a higher range and enhanced reliability. They also have a longer battery life than active tags. Information from www.wikipedia.org/wiki/RFID.