Admin posted on February 3, 2014 16:36

Over the last 6 months almost every leading passive RFID tag vendor has released new thinner metal-mount RFID tags. Metalcraft, Omni-ID, Confidex, XERAFY, and most other leading tag vendors all have flexible metal-mount tags that are .05" or less thick. Although all of them seem ideal for tracking laptops because they are metal-mount and very thin, their performance varies widely.

It may seem tempting to pick the one that will look best on your laptops, but choose wisely. Don't make your selection based on the read ranges documented by the vendor, because these were likely obtained on a solid metal object in an ideal lab environment. A lot of laptop cases are plastic or "metalic" at best, so the performance will not be the same as placing the tags on solid metal. We saw read range variances of more than 10 feet between the different tags we tested. It is also important to note that some tags may work better on different laptops, so it is important to test with the make(s)/model(s) of laptops you are using. Also test on a variety of locations on the laptop as the performance can vary significantly from one spot to another. Although most organizations would prefer to place the tag on the bottom of the laptop, this will typically significantly reduce the range of the tag. Generally placing tags somewhere on the lid will provide the best performance. Unfortunately there isn't a clear-cut best tag for laptops. It really depends on the make/model and where you want to place the tag.

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Admin posted on April 13, 2013 10:55

NOTE: Also read this updated post: RFID Laptop Tracking - Update

Tracking laptops with RFID can be a challenge, especially if the application is security-related. 


  • Metal
  • Tag placement
  • Ensuring good read rates

Because laptops contain a lot of metal, typical passive RFID tags will be pretty much useless.  Even though the laptop may have a plastic outer shell, the amount of metal in the screen and other components will generate interference.  Therefore a "metal mount" RFID tag will be required. 

Because "metal mount" RFID tags are thicker than a label, they cannot be mounted flush on the laptop.  Most people don't like the idea of a tag that is 1/8-1/4" or more thick stuck to a laptop.  Partially for aesthetic reasons, but also because they don't want the tag catching on something when going in/out of a laptop bag.  Tags with a tapered edge would be ideal to prevent the tag from catching, but the edges of most tags don't taper.  Sometimes placing a short metal mount tag along one of the sides will work, but most laptops have too many ports and no flat surface areas large enough to place a tag on the side.  Therefore placing a tag somewhere on the lid is usually the only option.

When placing the tag on the lid of the laptop is the only option, the thinner the tag the better.  However, thinner tags usually provide shorter read ranges, so a performance vs. aesthetic/usability decision will need to be made.

If security is a requirement, passive RFID typically won't be a good option.  Because passive UHF RFID cannot read through metal or liquid, something as simple as your hand covering the tag can prevent it from being read when moving past a reader.  Active RFID provides better read rates, has less interference issues, and provides options for motion and tamper detection making it a much better choice for securing laptops.  The only downside is that the size of the tag will be even larger than a passive RFID tag because it has a battery.  The larger more visible tag can act as a deterrent. 

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Admin posted on November 12, 2012 06:19

The primary difference betwee passive and active RFID tags is that active tags are powered by a battery and automatically broadcast their signal, whereas passive tags do not have a power source and only transmit a signal upon receiving RF energy emmited from a reader in proximity of the tag.

  Passive Active
Read Range Up to 40 feet (fixed readers)
Up to 20 feet (handheld readers)
Up to 300 feet or more
Power No power source Battery powered
Tag Life Up to 10 years depending upon the environment the tag is in 3-8 years depending upon the tag broadcast rate
Tag Costs $.10-4.00 or more depending upon quantity, durability, and form-factor $10-50 depending upon quantity, options (motion sensor, tamper detection, temperature sensor), and form-factor
Ideal Use For inventorying assets using handheld RFID readers (daily, weekly, monthly quarterly, annually). Can also be used with fixed RFID readers to track the movement of assets as long as security is not a requirement. For use with fixed RFID readers to perform real-time asset monitoring at choke-points or within zones. Typically necessary when security is a requirement.
Readers Typically higher cost Typically lower cost

When trying to determine whether active or passive RFID tags are better suited for your needs, there are a number of factors that should be considered.  Please consult an experienced vendor for assistance in evaluating the best option for your needs.

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Posted in: RFID Asset Tags  Tags:

Unfortunately there isn’t an easy answer to this question.  The short answer is that most handheld RFID readers can read most RFID tags anywhere from 1 to 20 feet.  Most fixed readers can read most RFID tags anywhere from several feet to 40 feet.  There are even a few very large tags designed for shipping containers that can achieve read ranges of well over 100 feet, but the size of these tags is not practical for most fixed assets.  These read ranges vary significantly, and don’t really answer the question sufficiently.  So let’s go into the details of the factors that will affect the range of an RFID tag.





It depends primarily on the following factors:

1.    The type of reader and antenna used (handheld or fixed reader)

2.    The type/size of tag used

3.    The type of asset being tagged

4.    The placement of the tag on the asset

5.    The environment

6.    The orientation of the tag in relation to the reader’s antenna



1.    Reader/Antenna Type

Generally fixed readers have more power and larger antennas than handheld RFID readers, so their effective read range is greater.  Although it depends on the vendor and model, fixed readers can often read 2-3 times the range of handheld RFID readers.


Another important variable that can affect the read range is the type of antenna on the reader.  The two most common types of antennas are circular and linear.  Linear antennas have a very focused wave propagation.  For maximum read range, the linear antenna and the antenna on an orientation sensitive tag need to be in the same orientation.  For example, if the linear antenna on the reader is in a horizontal position, the orientation sensitive tag also needs to be in a horizontal orientation.  If either the reader antenna or tag antenna orientation is changed, the read range can drop to a fraction of what it was when they were both at the same orientation. 


Circular antennas work well when the orientation of the tag will vary or cannot be controlled.  They have the ability to read a tag at almost any orientation, but the range is typically less than a linear antenna because the wave propagation is not focused in a particular orientation.



2. Type/Size of Tag

There is no “standard” passive RFID asset tag.  There are literally hundreds of types, sizes, and options to choose from.  Generally the larger the tag, the larger its antenna will be, so larger tags typically have greater read ranges than smaller tags.  However, there are exceptions to this rule.  A good example is tags that are specifically designed to mount on metal.  Many of these tags, although small, can achieve greater read ranges that larger tags when mounted on metal, because they are designed to use the metal to improve their performance.  Other specialty tags that are specifically designed for mounting on a particular type of material can also achieve greater read ranges than larger tags when attached to the type of material they are designed for. 


Many companies spend a lot of time and effort searching for the smallest tags they can find, thinking that all RFID tags have the same read range.  They don’t realize that these smaller tags are probably going to yield much shorter read ranges than larger tag options.


3.    Type of Asset being tagged

The material the asset is made of can have a significant effect on the read range of a tag.  Generally any asset with metal or liquid can cause interference.  Depending upon how close the tag is placed to the metal or liquid, the interference can be significant.  For instance, a tag that can be read by a handheld in “free air” at 20 feet, might only have a 6 inch read range when placed on a laptop.  Even though the outer shell of most laptops is plastic, there is a lot of metal underneath which causes a lot of interference.  For assets with metal and liquid, you will want to evaluate tags that are specifically designed to work on metal or liquid. 


4.    Tag Placement

The placement of the tag on the asset can affect the read range.  Some metal mount tags perform better if they have free-air on certain sides of the tag, so when they are placed dead center on an asset with a lot of metal, the performance can drop.  It is also sometimes difficult to tell if and where there might be metal on an asset.  PCs, laptops, printers, severs, digital projectors and similar assets that often have a plastic outer shell hide the underlying components.  Testing the tags in various areas of the asset will often result in varying read ranges.  Most assets have one or more “sweet spots”.  Finding these can improve the read range of a tag significantly.  Keep in mind that the “sweet spot” for one tag might not be the “sweet spot” for a different type of tag.



5. Environment

Different countries have different regulations and limitations on reader power and the frequency that they operate, which can affect read range.  Readers in Europe operate at a lower frequency and are limited to using less power than their counterparts in the U.S., so the read range for the same type of reader and tag is less in Europe than in the U.S.


Other environmental variables can be weather conditions.  Extreme cold or hot temperatures can affect read range. Humidity and rain can also cause unpredictable variations in read ranges.


In some cases, existing machinery or equipment being used can cause interference, especially equipment that might be operating at or near the same frequency.



6. Tag Orientation

Depending upon the design of the antenna in the tag, it may perform better at certain orientations (i.e. horizontal vs. vertical), depending upon the type of antenna on the reader.  Some tags are designed to be less sensitive to orientation and are usually symmetrical in size rather than long and thin. 


If the orientation of the tag will vary or cannot be controlled, consider using a circular polarized antenna (see number 1 above for more information on circular antennas). You could also consider using a tag that is not as sensitive to orientation.


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Posted in: RFID Asset Tags  Tags: ,

RFID is a great technology for tracking assets, but there are some exceptions.  Passive UHF RFID in particular should typically not be implemented to secure assets.  Because of the frequency that it operates at, it cannot penetrate metal or liquid. 

If you want to secure laptops for instance from leaving a building, there are too many ways to circumvent passive RFID.  The most obvious method to circumvent the technology is to just remove the tag.  Simply putting the laptop in a metal briefcase and walking past a reader would prevent the tag from being read.  Even in a nylon or leather laptop bag, there many environmental variables that can cause interference.  A cell phone, PDA, iPod or other electronic device with a lot of metal purposely or inadvertently being placed near or on the RFID tag on the laptop can prevent the tag from being read.  Even something as simple as placing your hand over the tag will typically prevent it from being seen by the reader.  There is enough saline (liquid) in the human hand to prevent the RF from penetrating.

Although there are numerous applications where Passive UHF RFID is well suited for tracking items, technologies like Active RFID are better suited for applications where security is a requirement.  Some of the Active RFID systems operate at frequencies that are less susceptible to interference from metal and liquid.  Because they have a battery, the signal is typically much stronger and more difficult to shield.  Many of the Active RFID tags also have tamper detection capabilities, so you know if someone tries to remove the tag from the asset.  These capabilities make Active RFID a much better choice for securing assets.

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Posted in: RFID Asset Tags , RFID Asset Tracking  Tags:


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