As it happens, some technologies don’t instantly get their due recognition and commercial success and that is the case with Radio Frequency Identification, popularly known as RFID technology. The technology is so old that the early references go back to World War 2 era when allied forces used it to identify enemy aircrafts from the allied ones. But this is the time when this technology is getting its dues as the global RFID market soars to USD 14B in 2023 from 12.8 billion USD in 2022 and with a CAGR of 10.2% from 2022 to 2031, it is expected to hit $31.5 billion by 2031.
The RFID technology is essentially a wireless technology that uses radio frequency (RF) signals to communicate by transmitting and receiving data between an RFID tag and an RFID Reader. Based on the type of RFID tag used in the RFID system, it is divided into three categories, i.e Active RFID system, Passive RFID system and Battery Assisted Passive (BAP) or semi-active/passive RFID system.
As we understand, an RFID system is made of some crucial components known as RFID tags, RFID antenna and RFID reader in addition to an RF subsystem (a computer software system) that can record the data being transmitted and received.
In active RFID system, the RFID tag being used comes with internal batteries which act as the power source for the RFID tag, allowing it to constantly emit RF signals, like a beacon.
The active RFID system, though costly than passive RFID, are very much in use in supply chain and RTLS (Real Time Location Services) where constant RF signals are required to get the real-time location and improve the real-time visibility. The battery in active RFID tags allows for powerful signals that provide long read range and higher degree of accuracy and efficiency.
The cost of active RFID tags is generally $20 onwards and it depends on its durability in extreme environmental conditions. These tags provide a read range of up to 100m and emit periodical RF signals. The battery in active RFID tag lasts around 3-5 years and once the battery runs out, the active tag needs to be replaced. In future, as the technology matures, replaceable battery will make active RFID tags more cost-effective.
Since active RFID tags come with battery, these are also heavy in weight.
Passive RFID is the most popular RFID system that is driving the global retail and supply chain and logistics business. The passive RFID tags account for more than half the RFID market share and the UHF RFID labels in retail apparel sector alone account for 64% of tag volume and 72% of market value of UHF RFID.
Typically an RFID system is termed passive when the RFID tag used doesn’t consist of a battery. The passive UHF RFID tags provide a read range of 12-15m and high accuracy that too at low cost. These tags cost around .04-.05 USD or INR 3 onwards in India when acquired in bulk.
When a passive RFID tag is in the range of an RFID reader, the tag antenna uses the coming RF signal from the reader to energize the tag and the tag then sends the encoded data which is received and decoded by the RFID reader. The RAIN RFID (UHF Passive RFID) finds many applications in asset tracking, inventory control, supply chain and manufacturing, retail and healthcare amongst others.
Semi-Active RFID/ Semi-Passive RFID /Battery Assisted Passive RFID
The third type of RFID system is called Semi-Active or Semi-Passive RFID. It is also known as BAP (Battery Assisted Passive) RFID as the RFID tags used in this system come with internal batteries but power up only when the tag antenna receives an RF signal from the RFID reader in the zone.
BAP RFID uses the battery power to energize the IC unlike passive RFID which uses the RF signal energy coming from the RFID reader. The IC then modulates the Reader signal with relevant tag data and then backscatters the signal to the reader in the zone.
The semi-active or semi-passive RFID tags provide longer lifetime than active RFID tags since it does not emit signals constantly. It finds applications in asset management and supply chain and logistics operations. Apart from that BAP RFID tags allows for sensor incorporation. It helps with measuring temperature, humidity and other indicators and used in food transportation industry etc.
Besides, chipless RFID is also a new type of RFID that is a reality now as the Chipless RFID market size, in 2023 is valued at 1176.7m USD.
What are the different types of chipless RFID?
Chipless RFID is designed to work with no chip. As the name suggest, chipless RFID doesn’t come with silicon IC which is used to store information in chipped RFID tags. Instead, these tags use linear encoders to store information.
Lack of silicon chip saves a lot of cost on fabrication of these types of tags and it also allows it to function more efficiently in harsh environmental conditions such as heat, frost, moisture etc. With low fabrication cost, chipless RFID now costs around 10-20 euro cents (time domain technique, SAW, 256 bits) but it is expected to be available at 0.01$ per tag when bought in bulk in recent future.
Depending upon the type on encoding, chipless RFID is primarily of two types; time domain chipless RFID and frequency domain chipless RFID.
How does a chipless RFID work?
A chipless RFID tag works same as passive UHF RFID labels do except it stores the data on linear encoders and not on IC memory. When an RFID Reader sends an interrogating signal, the antenna in chipless RFID catches the signal which then reflects the surface of the chipless tag and captures the data encoded and backscatters it for the RFID reader in the read zone.
Difference between RFID and chipless RFID
The main difference between RFID and chipless RFID is the fact that chipless RFID doesn’t use a silicon chip to store data whereas chipped RFID does use a silicon IC for data storing purposes. Instead, the chipless RFID uses linear encoders on the surface of the chip to store the small amount of data like EPC information.
Apart from Active RFID, Semi-Active RFID, and Passive RFID system, RFID is also categorized based on the operating frequency of the RFID system. The RFID system typically operates over Low Frequency (LF, 128 KHz), High Frequency (HF, 13.56 MHz), and Ultra High Frequency (UHF, 860-960 MHz) and it is divided as such.
It is worth mentioning that the LF RFID system offers a read range of 3-10 cm, HF RFID system offers a read range of up to 1m (same as NFC) and UHF RFID system offer a read range of 12 to 15m.
To conclude, the three types of RFID are active RFID system, passive RFID and Semi-active/semi-passive or BAP RFID system depending upon the type of tag being used. Chipless RFID is a new advancement in the field of RFID which is now being proactively adopted to replace the barcode technology that was previously being used in retail and apparel and other businesses to identify items.