a. What is
RFID
RFID, short for Rradio Frequency IDentification, is a technology that
enables identification of a tag (that is normally attached with an entity) by
using electromagnetic waves. The function served by RFID is similar to bar code
identification, but line of sight signals are not required for operation of
RFID. Important components of an RFID system are:
- An RFID reader (also called transceiver) with an antenna and a transceiver,
- A transponder (Also called a tag) that includes an antenna and a chip)
Given below are the brief differences between the Barcode technology and
RFID:
|
Parameter
|
Bar Code
|
RFID
|
|
Frequencies used for tag reading
|
Optical frequencies
|
Radio frequencies
|
|
Type of communication
|
Line of sight communication
|
Non-Line of sight communication
|
|
Data Volume
|
Physical limitation exists. It is very difficult to read a very long
barcode.
|
Can carry relatively large volume of data.
|
|
Range of data readability
|
Very limited range, less than a feet or two.
|
Can be read up to several feet.
|
|
Cost
|
Cheap
|
Expensive, but likely to cost less as more industries adopt the
technology.
|
The following are the benefits of RFID Systems:
- Non-line of sight identification of tags.
- Unattended operations are possible, minimizing human errors and high cost.
- Ability to identify moving elements that have tags embedded.
- Larger area of coverage. Up to several feet.
- Can be used in diverse environments, including live stock, military, and scientific areas.
- RFID can be used in addition to Bar Code. These two technologies can be complementing each other.
- Automatic integration with back end software solutions provide end to end integration of data in real time.
- Expensive compared with Bar code
- Bulkier, due to embedding of electronic components in the tag. However, with advanced techniques, it is possible to reduce the size, and weight of the tags to a large extent.
- Prone to physical/electrical damage due to environmental conditions. For example, tags that are subjected to space exploration may encounter extreme temperatures. The tags required to be designed for a given application, and may be costly when designed for use under extreme environmental conditions.
·
Active and Passive RFID Tags:
·
There are primarily two types of RFID tags. One is active and the other is
passive. An active tag is powered using internal battery, where a passive tag
gets energized using a the power from a tag reader. A passive RFID tag will not
have a battery or any kind of power source by itself. It extracts the required
energy from a reader. Hence, a passive RFID tag reader must be able to emit
stronger electromagnetic signals, and in return, identify very weak signals
from the passive RFID tag.
·
Given below are the primary differences between a Passive and Active RFID
tags:
·
|
|
Passive RFID
|
Active RFID
|
|
Power Source
|
External (Reader provided)
|
Internal (Battery)
|
|
Tag Readability
|
Only within the area covered by the reader, typically up to 3 meters.
|
Can provide signals over an extended range, typically up to 100 meters..
|
|
Energization
|
A passive tag is energized only when there is a reader present.
|
An active tag is always energized.
|
|
Magnetic Field Strength
|
High, since the tag draws power from the electromagnetic field provided
by the reader.
|
Low, since the tag emits signals using internal battery source.
|
|
Shelf Life
|
Very high, ideally does not expire over a life time.
|
Limited to about 5 years, the life of a battery.
|
|
Data storage
|
Limited data storage, typically 128 bytes.
|
Can store larger amounts of data.
|
|
Cost
|
Cheap
|
Expensive
|
|
Size
|
Smaller
|
Slightly bulky (due to battery)
|
