Radio Frequency Identification technology has become a huge part of the AIDC industry. Almost every medium to big business implements Long Range of Passive RFID Tags for the purposes of asset tracking, security, monitoring, etc. This is due to the impressive cost-benefit ratio of passive RFID technology.
Today, we will discuss what it is & more importantly, why is it so popular over other types of RFID solutions.
What is Passive RFID Technology?
There are two basic types of Radio Frequency Identification systems, namely – Passive & Active. A Passive RFID system consists of a tag that doesn’t have an internal power source. Unlike the NFC or active systems, these AIDC (Automatic Identification & Data Capture) systems work by using radio backscattering. An RFID system works by communicating data between two points (reader and tag) wirelessly by means of radio waves.
Radio backscattering refers to the phenomenon of reflecting a part of radio waves back to its source of origin. When a passive RFID tag enters the interrogation zone of a reader, it uses its antenna to capture the radio signal and power up. Then it backscatters the signal with the information programmed in it. These signals are then picked up by the antenna on the reader and converted into readable format.
Different Ranges of Passive RFID Tags
Passive RFID tags can have a wide spectrum of read ranges, depending on a couple of factors. These tags generally have small operational ranges when compared to active systems. This is because passive systems use a part of the reader’s signal to energize and broadcast a signal. This limits the amount of power their signals can have, therefore, limiting their range. Another important factor that affects the read range of a tag is its operational frequencies. Passive RFID systems operate in three different frequency ranges, namely – Low Frequency, High Frequency & Ultra-High Frequency.
Higher-frequency tags absorb and backscatter more energy than low-frequency tags, therefore, making the operation frequency directly proportional to the read range of a tag. So, let’s check out the average operational ranges of different passive tags.
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Type of Tags
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Frequency
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Read Range
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Low Frequency
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125 – 134.2 KHz
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10 to 20 cm
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High Frequency
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13.58 MHz
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1 m
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Ultra-High Frequency
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850 – 960 MHz
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18 – 20 m
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BAP RFID
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860 – 960 MHz
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100 m
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Active Tags
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100 KHz – 2.45 GHz
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150 – 180 m
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These are the average operational ranges of different types of RFID tags. As you can notice the last two tags have vastly superior range than the first three. This is because of the energy difference in the signal they broadcast, generally, ultra-high frequency tags work in most applications.
However. If you want a bigger range but still want to use a passive system, then you can look into the BAP system. BAP stands for Battery-Assisted Passive RFID, these tags have a small internal battery inside them. A BAP tag remains passive until it enters the interrogation zone of a reader. Once it receives a signal, it turns on and uses its battery to broadcast a signal to the reader.
Benefits of Choosing Passive RFID Tags for AIDC Solutions
The majority of businesses prefer using passive RFID systems, aside from a few items, passive is generally a good choice. Both active & passive systems have their advantages & disadvantages. However, today we will be focusing on the benefits of passive RFID tags.
Economical
The biggest advantage of passive systems is the cost of implementation and maintenance. Active tags can cost as much as 200 times more than an RFID tag. So, implementing in scale can easily make a very significant price difference between the two systems. With the combination of strategically placed readers and supply lines, passive tags can achieve almost the same functionality as an active one. Thus, making them a far more economical and popular choice of AIDC solution.
Good Read Range
Most retail stores are not very big and can easily be covered in the range of a passive tag. Even in large enterprises like warehouses and manufacturing plants, you can use a combination of external antennae to cover the entire area. With a read range of 18 to 20 meters, a passive RFID system can easily be applied in most industries.
Long Lifespan
Unlike active or BAP systems that use a battery to broadcast a signal, a passive RFID tag does not have an internal power supply. Therefore, you don’t have to worry about the tag becoming useless once the battery runs out. All you need to make a passive RFID tag work is a radio signal of the same frequency. In addition, there are no complex parts inside a passive tag, all it contains is a chip and a basic antenna. This allows a passive RFID tag to have a virtually infinite lifespan.
Scalable
Due to the small implementation and sustenance cost of long-range passive RFID tags, it is possible for them to be scalable. In short, even small firms can afford to invest more in passive tags as their business and product volume is growing without making the cost of AIDC unsustainable.
Applications of Passive RFID Tags
As discussed above, the combination of low cost, reliability, operational lifespan, and performance allows long-range passive RFID tags to have diverse applications. The low cost allows small businesses and even start-ups to easily implement an RFID system within their organizations. Being a reliable AIDC solution without any complex components allows businesses to cut costs on alternative security & asset tracking systems. Passive tags have virtually infinite lifespans, which makes them insanely cost-saving in the long term, especially in permanent applications.
So, below are some of the popular applications of long-range passive RFID tags:
(A). Retail Stores
(B). Warehouses
(C). Vehicle Tracking
(D). Parking Systems
(E). Jewellery Stores
(F). Manufacturing Plants
(G). File & Document Tracking
(H). Pallet Tracking
(I). Visitor Identification & Tracking
(J). Access Control Systems
These are just some popular industries/applications where passive tags are immensely popular and widely used. Now, let’s save you some time, and check out some popular long-range passive RFID tags.
Popular Passive RFID Tags
Frequently Asked Questions
Q1. What is the longest range of passive RFID tags?
Ans. Passive RFID tags are severely limited in their read ranges when compared to active systems. This is due to their signal having low power because of a lack of a power supply. On average, a passive RFID tag has a maximum read range of 18 – 20 meters.
Q2. What is the range of 125 kHz RFID?
Ans. 125 KHz is considered low frequency in the radio wave spectrum, similarly, the tag with this frequency is called Low-Frequency RFID Tags. These tags reflect only a small amount of power during backscattering, limiting their read range. They usually have a read range of up to 10 cm.
Q3. Which is better 13.56 MHz or 125 KHz RFID reader?
Ans. As discussed before, the operational frequency of an RFID reader is directly proportional to its read range. So, a high-frequency reader (13.56 MHz) will have a better range than a low-frequency tag (125 KHz). However, range is not the only factor that determines applications. Different systems have different applications. For example, in the case of billing, you only need to read tags that are present in a specified area, here, a 13.56 MHz reader would be useless.
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