Which one, Active or Passive?

Which one, Active or Passive?

Which one, Active or Passive? 405 212 Altis

Person can speak about passive and active tags for hours and hours when asked, especially when a person is verbalist like me,

Luckily, in the recent years, our job is getting easier and easier. With the execution of RFID projects of our government in the highways, without explaining hours, we do simply say; “Active tag is OGS and passive tag is HGS. Rather short, but effective. With the merits of this, people, who are distant to RFID technologies, people can understand that active tags are big and thick, passive tags are thinner and smaller. Of course, some can think OGS is a better technology and HGS is worse, because of the unreadable occassions in the gates of the highways. I am also thinking about to share a detailed article about this in the future.

Yes, I had given examples to the types of tags very shortly, but some may ask for more details. Here they are.

Passive RFID tags does not carry an energy source, it gets its power from the energy of electromagnetic waves ıf RFID readers. Frequently, passive RFID is used in the fields of Supply Chain Management Projects, Pass Systems, Parcel/Package or Product identification and tracking. Passive tags are more affordable than active RFID tags, since they do not include, battery or expensive circuit systems. This enables RFID projects affordable and economically procurable for plenty of sectors.

These tags are passive as the name implies. It is nominated as passive and they wait still. The energy, that is sent by RFID reader to the antenna, is converted to radio frequency wave by the antenna and it transmits signals to the air to form a reading field for RFID. This transmitted signal is pulled to itself by the internal antenna on the passive tag. This incoming ardio frequency wave works reversely and it is converted to energy to produce energy to the tiny chip on the tag. At this moment, the chip, which has electricity, produces an opposite signal and it transmits, radiates this. The reader catches this signal and transforms it to data.

There are various types of passive tags. The ones, who can stand high temperatures or hard tags that can endure hard conditions. 125 kHz, 13.56mHz ad 868 mHz are the frequently used ones as of frequency.

The advantages of passive tags in a few points;

  • They are smaller
  • They are cheaper
  • Thinner and more flexible
  • They can be produced in various different types
  • They can work years since they do not have a battery inside

Good News, in the recent years passive RFID tags can be produced with developed sensors. Values like humidity and temperature can be measured by sensors, which do not need batteries, starts to work with the energy of the RFID tag. After producing the data, these sensors sends the data to RFID readers. I am also preparing a detailed blog for these type of products to be posted.

When we come to active RFID tags, they get their power of signal sending from the batteries inside of the tags. This means usually they radiate signal constantly. In the real-time tracking projects, it is ideal to use active RFID tags. They have a longer range of reading comparing to passive tags, nevertheless they are more expensive due to their technology. They usually work with 433mHz and 915mHz frequencies. Generally, we, engineers prefer to use 433mHz models, yet 433mHz models has a longer wavelength and especially they work better in metal or liquid based environments than the other tags.

Active tags have a power source in them, so comparing to the passive models, they can send signal to wider ranges. Also they have larger memory than passive tags.

Their batteries can last 3 to 5 years. Some of the companies design the batteries of the tags to be changed after the end of the life of the batteries. This is an advantage, because the tags could be used after changing the battery. Yet, some of companies’ batteries in the active RFID tags could not be changed. You have to be careful with this criterion in the initial offers and first purchase.

The operation principle of active tags are 2. They expect signal from transponder type tag readers. As they are answering the signal, they transfer the data in the chip of the tag to the reader. So that, the tag does not send signals to the environment perpetually and uses the battery efficiently and effectively.
i.e. OGS (Otomatik Geçiş Sistemi-Automated Pass System) tags works under this principle with a little tiny Lithium battery for more than 10 years.

The second type tag, called Beacon, sends signals to the environment with particular time intervals.
Open space fixture tracking and mining are the sectors that Beacon is used frequently . This type of tags consumes the batteries loutishly. That is why the producers keep the signal power relatively low to ensure the extension of battery life. (Circa max. 100meters in general.)
Active tags has high-performance batteries, that’s why, they can produce a wide range of X with sensors . Only sensors? In the market, you can find tags with different features; with GPS, with External Memory, even adaptors with Wi-Fi features.

Active RFID tags are expensive to use, hense the objects, that the tags are attached, are more valuable products. e.g. Containers, expensive and valuable fixtures and inventory used in Mining and Civil Engineering Sector. Their sizes are bigger than the passive tags, that is why more durable models are produced, so in this classification they are more adventegous than the passive tags.

The advantages of active tags in some points;

  • Owning longer reading range/distance
  • Having the inner battery, they can integrate with different types of sensors, even with GPS!
  • Active tags are more durable and they can resist in hard conditions

Some of the tag companies produce BAP (Battery Assisted Passive) tags. These are the passive tags powered by battery. Usually they are produced with 868 mHz passive tags. Due to the battery inside, they have an important long range of reading distance. Like the active trasponders, they turn to active with the signals coming from RFID readers and their battery lives are quite long. As of passive tags, sensors can be embedded in those BAP tags. They are not widespread like the other tag types, but they in the leading role of some success stories.

After all these information flow, were you able to determine which tag is appropriate for you? No? Call us and let us determine together.

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