Free Trials

Download a free trial to find out which Altium software best suits your needs

How to Buy

Contact your local sales office to get started on improving your design environment

Downloads

Download the latest in PCB design and EDA software

  • PCB DESIGN SOFTWARE
  • Altium Designer

    Complete Environment for Schematic + Layout

  • CircuitStudio

    Entry Level, Professional PCB Design Tool

  • CircuitMaker

    Community Based PCB Design Tool

  • NEXUS

    Agile PCB Design For Teams

  • CLOUD PLATFORM
  • Altium 365

    Connecting PCB Design to the Manufacturing Floor

  • COMPONENT MANAGEMENT
  • Altium Concord Pro

    Complete Solution for Library Management

  • Octopart

    Extensive, Easy-to-Use Component Database

  • PRODUCT EXTENSIONS
  • PDN Analyzer

    Natural and Effortless Power Distribution Network Analysis

  • See All Extensions
  • EMBEDDED
  • TASKING

    World-Renowned Technology for Embedded Systems Development

  • TRAININGS
  • Live Courses

    Learn best practices with instructional training available worldwide

  • On-Demand Courses

    Gain comprehensive knowledge without leaving your home or office

  • ONLINE VIEWER
  • Altium 365 Viewer

    View & Share electronic designs in your browser

  • Altium Designer 20

    The most powerful, modern and easy-to-use PCB design tool for professional use

    ALTIUMLIVE

    Annual PCB Design Summit

    • Forum

      Where Altium users and enthusiasts can interact with each other

    • Blog

      Our blog about things that interest us and hopefully you too

    • Ideas

      Submit ideas and vote for new features you want in Altium tools

    • Bug Crunch

      Help make the software better by submitting bugs and voting on what's important

    • Wall

      A stream of events on AltiumLive you follow by participating in or subscribing to

    • Beta Program

      Information about participating in our Beta program and getting early access to Altium tools

    All Resources

    Explore the latest content from blog posts to social media and technical white papers gathered together for your convenience

    Downloads

    Take a look at what download options are available to best suit your needs

    How to Buy

    Contact your local sales office to get started improving your design environment

    • Documentation

      The documentation area is where you can find extensive, versioned information about our software online, for free.

    • Training & Events

      View the schedule and register for training events all around the world and online

    • Design Content

      Browse our vast library of free design content including components, templates and reference designs

    • Webinars

      Attend a live webinar online or get instant access to our on demand series of webinars

    • Support

      Get your questions answered with our variety of direct support and self-service options

    • Technical Papers

      Stay up to date with the latest technology and industry trends with our complete collection of technical white papers.

    • Video Library

      Quick and to-the-point video tutorials to get you started with Altium Designer

    The Advantages and Disadvantages of Active and Passive RFID Technologies

    November 20, 2017
    The Advantages and Disadvantages of Active and Passive RFID Technologies

    When I’m designing a new PCB or product one of the hardest parts for me is choosing exactly which components I should use. It seems like every technology out there now has a different configuration to achieve the best performance. Even when you’re dealing with a fairly straightforward technology like radio frequency identification (RFID) circuit board there are a lot of flavors to choose from. While every type of RFID design label uses an active RFID reader, also known as an interrogator, the tags for each arrangement are different. There are three main categories of RFID layout schematics that you can use based on these tag types: passive, semi-passive, and active. Each of the systems has its own pros and cons that can help you decide whether it’s right for your application.

    Passive RFID Technologies

    The simplest of the three RFID configurations is one that uses an active reader and passive tags. Passive RFID tags are made up of only two components: an integrated circuit (IC) schematic and an antenna. When combined these are sometimes called an inlay. Notably, passive RFID tags do not include a constant power source or a battery.

    Passive RFID system tags don’t need a battery because they collect their energy from the reader’s interrogation signal. To read tags in this arrangement, a reader will send out a powerful signal to all tags in its read frequency range. The tags then receive that signal on their antennas and use the energy from it to power up their ICs. After their processors have completed their tasks, the tags use inductive and backscatter coupling to communicate back to the reader. All of these characteristics mean that using a passive RFID tags system has a variety of pros and cons.

    Advantages of RFID Technology

    • Inexpensive - Since RFID system tags have a maximum of three components (IC, antenna, enclosure) they can be quite cheap.
    • Lightweight - The minimalist design of passive tags also means they don’t have much mass.
    • Lifetime - Other tags that use a battery may only have a lifetime of 3-5 years. The endurance of passive tags depends on the materials they’re made of and the environment they operate in. If they are placed in a gentle environment they could operate for up to 20 years.
    • Low Noise - Inductive and radiative coupling printed circuit board without an active antenna generates almost no noise.​

    ​​Disadvantages of RFID Technology

    • Short Range - The absence of an active antenna means that passive tags have an extremely short frequency range. Tags operating in low to a high frequency may have a maximum communication range of 2 feet. If they’re using a very high frequency they may get up to 20 feet, but that’s still a relatively short range.
    • Limited Storage - Even most non-volatile memory requires power to keep its contents from degrading. Without an onboard battery, passive tags can’t store much information.
    • Requires Reader - Passive types of RFID tags require a high-powered reader to even power on.
    • No Sensors - Most sensors require constant power to operate and possibly need memory to store data. This makes passive tags unsuitable for most sensing applications.
    Wireless tag used for RFID tracking purposes
    Passive tags can be nearly as thin as a piece of paper.

    Semi-Passive RFID Technology

    One step up from passive tags are semi-passive tags. In a semi-passive system, the tags will have some kind of onboard battery, but they won’t have an active transmitter. This means they still use an inductive or radiative coupling technology to communicate, leaving them with a shorter range than an active system. That battery can also support sensors and memory for power consumption.

    Advantages

    • Medium Range - One of the primary reasons passive tags have such a short read range is because they need to be close to a reader to power on. The power-on range is much shorter than the reflected communication range. Semi-passive tags can use their batteries to power their ICs, meaning they are limited by the high communication range rather than the shorter power range. A semi-passive system can read tags at 100 feet or more.
    • Active Components - Semi-passive tags are able to support sensors and memory because of their onboard battery. If you have an application that needs some sensors and memory but doesn’t need an extremely long range, you may be able to use semi-passive RFID printed circuit.
    • Medium Expense - Semi-passive tags are more expensive than passive tags but are certainly cheaper than active tags.
    • Low Noise - Just like in a passive system, semi-passive tags don’t add much noise to the environment.

    ​​Disadvantages

    • Requires Reader - Even though semi-passive tags don’t rely on a reader for power, they still need one to communicate.
    • Limited Lifetime - The presence of a battery automatically limits the lifetime of a tag. Instead of 20 years you might expect 2-7 years of operation. In addition, a tag with a battery will need a more gentle environment than a tag with just an IC and antenna.

    Active RFID Systems

    The most complex form of RFID is active RFID. In this scheme, the tag has a larger battery and uses an active transmitter instead of a passive one. An active transmitter necessitates a larger battery, which can also power a faster processor and other more energy intensive components.

    Advantages

    • Long Range - An active transmitter can communicate over longer distances. Active tags can have a read range of more than 300 feet, over 3 times that of semi-passive tags.
    • Low Power Readers - Since active tags use a powered antenna they don’t have to rely on a high-powered interrogator for all their signal strength.
    • More Components - When you add a larger battery you can also use a more powerful processor, more sensors, more memory—more components overall. If your tag needs to do a lot of different things, an active tag might be the best choice for you.

    ​​Disadvantages

    • Expensive - While passive tags may cost less than 10 cents per unit, active tags can cost as much as $20 per tag.
    • Limited Lifetime - Active RFID tags are generally designed so that they have 3-5 years of battery life. After the battery runs out, though, you’ll need to get a new tag.
    • Large and Heavy - Compared to a tag that’s as thin as a piece of paper, active tags are huge and weighty. Batteries are heavy and take up space. If you need your tags to fit between the pages of a book, active tags are probably not for you.
    • Noisy - Using an active transmitter will add noise to your environment. Be sure to see how active tag noise will affect your system.​
    Scanner and a warehouse
    You might want to use an active system if you need to scan an entire warehouse.

    Although there are many advantages and disadvantages for passive, semi-passive, and active RFID, these are the most important things to remember:

    • Passive tags can’t support sensors or memory and have a short range
    • Semi-passive have a medium range and can still be cheap
    • Active tags can do lots of things but are large, expensive, and heavy.

    ​​Armed with this knowledge you can choose the best type of RFID to use in your next project.

    You can choose from many varieties when using RFID tags, but when it comes to PCB design in general, the choices can become overwhelming. That’s why it’s important to use good software to help guide you through the process. CircuitStudio® has a wide variety of tools that can help you make the right design decisions.

    Have more questions about RFID design? Call an expert at Altium.

    most recent articles

    Back to Home