Rfid tags

RFID Tags

Friday, 2 November 12

RFID Tags

• Overview of RFID Based Systems


RFID Tags

• Examples of the types Tags available


RFID Tags

• How certain types of RFID Tags work


RFID Tags

• How certain types of RFID Tags work
• Examples of Applications of RFID systems


About Me


using Flash Remoting/BlazeDS with Coldfusion as the
middleware to database servers

manufactures RFID Tags and RFID readers

About Me

• Chris Velevitch




About Me

• Chris Velevitch
• Flex Developer




About Me

• Chris Velevitch
• Flex Developer
• Magellan Technology, Sydney




What are RFID
Systems?


Radio Frequency Identiﬁcation Systems use radio-
frequency electromagnetic ﬁelds to transfer data from a
device attached to an object. "

What are RFID
Systems?

• RFID - Radio Frequency Identiﬁcation



What are RFID
Systems?

• Uses Radio Waves to transfer Identity Data



What are RFID
Systems?

• Uses Radio Waves to transfer Identity Data
• Tags are physically attached to some object
that needs to be identiﬁed/tracked



Aspects of RFID Tags


There are many things to take into consideration when
designing an RFID based system.

There are quite a few of them, but some of them are
mutually exclusive.

• Active vs Passive


Active means it has it's own power source, whereas
passive gets its power from the interrogator

• Static vs Dynamic vs Updatable


Apart from it's unique ID, the data sent with ID is either:-

1) always the same
2) is different each time it is read
3) or it has been changed at some stage

• Long Range vs Short Range


The distance between the object and the interrogator.

Distances can range from 1 cm to 300 Km

• Proximity (of the tags)


If tagged objects are physically close together

This has an impact on how many tags per second can be
read which has an impact on the type of reader and type
of tag needed

this can range from < 1 a sec to 300 per sec

• Proximity Based (of the objects)
• Frequency


The frequency of the Radio Waves. They can range from
120kHz (HF) to 10 GHz (microwave)

the distance between the object and interrogator
determines the frequency at which the data is transmitted
before the RF signal is too weak to detect

Radio waves weaken at a rate inversely proportional to the
square of the distance (1/(d**2))

• Frequency
• Command and Control


There is the expectation that reading or listening for a tag
creates a side-effect in that something happens as a result

• Frequency
• Interrogator talks first vs device talks first


communication is initiated by the interrogator or the device

With passive tags, device talks first is no longer used
today because in the earlier techniques of design and
manufacturing of the IC’s used couldn’t packed into a
small enough space the complex circuits needed for the
sophisticated handshaking and control of the tags

Detailed reasons to follow

• Frequency
• Amount of Data Required


The amount of data the device needs to store is
dependent on the application requirements and data
capacities available

They range from 1-bit to 64kb

• Frequency
• Amount of Data Required
• Cost


of the tag and the interrogator/reader

The interrogators or readers are generally more expensive
than the tags and cost of tags start at few cents each to a
few 100 dollars

there are cases in which the tags can be 10’s of 1000’s of
dollars each

the cost of the readers can range from 100’s of dollars to
millions

The data


If tags are sourced from multiple manufacturers, the
manufacturer code is needed because it is possible have 2
or more tags with the same unique identiﬁer.

optional user written data such as serial numbers, part
numbers, locations, expiry dates, descriptions, lot
numbers, etc

The data

• Manufacturer Code



numbers, etc

The data

• Fixed unique identiﬁer



numbers, etc

The data

• Fixed unique identiﬁer
• Optionally, object speciﬁc information



numbers, etc

Examples of tags


So what to tags look like?

Active tag

Examples of tags


Semi-passive or battery assisted. On board battery is
used to power everything except the antenna so all
received power can be used for transmitting back the
signal which will be stronger than passive tags

Examples of tags


Implantable Passive tag

Examples of tags


1-bit passive tag

Examples of tags


This is a different type of 1-bit passive tag

Examples of tags


Passive tag

Examples of tags


Examples of tags


These chips are designed to be extremely low power
and contain control logic to control power
consumption, to send data and how much, to be
silent

Examples of tags

Tag Type GPT8 GPL5 MDT3 LMP7 MAG5 DIA4 DOC3 CC2.5 CC5
Specifications
Nominal Label Dimensions 26.9mm dia 16 x 50mm - 42 x 47mm 19 x 51mm 30 x 76mm 26 x 66mm 54 x 85mm 50 x 80mm
Antenna Dimensions 25 dia 14 x 48mm 31 x 41mm 39.45 x 44.40mm 16 x 48mm 27 x 73mm 20 x 60mm 45 x 76mm 45 x 76mm
Turns 8 5 3 7 5 4 3 2.5 5
Minimum Separation
1.5mm 1.0mm 0.1mm 3.0mm 1.0mm 1.8mm 0.1mm 1.0mm 4.0mm
Field Strength
A/m RMS 3.10 3.50 3.00 0.91 3.00 1.50 3.30 1.30 0.54
Applications Gaming Gaming Document Tracking Multi-purpose Insight maga- Diamond Document Document Tracking Multi-Purpose
Tokens Plaques Paper zine reader Tracking Tracking Paper Folders

Reader compatibility
MARS-AT * * * * * * * * *
Tunnel Readers:
MSTRP-6464 - - - x - - - x** x
MSTRP-5050 - - - x - - - x x
MSTRP-4040 x - x x x x x x x
Stand-alone Readers:
MDR-3021 - - - x - - - - x
MDR-1109 x x x x x x x x x
MDocR-2505 - - x - - - x x -
3D Readers:
M3DR-4330 x - x x x x x x x

Magellan has a range of PJM RFID StackTags as detailed below. Tags can be supplied as bare inlets, transparent or paper labels. If required, Magellan can produce custom tags.

Note: not all tag types are held in stock. Minimum order quantities, design and set-up costs may apply.

* = Antenna Dependent
** = Not full 3D range
Copyright Magellan Technology 2012

How passive Tags work?


They work on the same principles as transformers


• How do passive tags get their power?


They work on the same principles as transformers



The ratio of the voltages is equal to the ratio of the
number of turns in each coil.


• How is the data sent and received?


The coils also act as antennas



The coils act as antennas


• How is the radio frequency generated




Tuned Resonate circuit


• Radio frequency interference


If 2 tags are next to each other, their radio signals will interfere
and cancel each other out effectively making the 2 tags invisible
to the reader because the tag’s signal is weaker.



If 2 tags are next to each other, their radio signals will interfere
and cancel each other out effectively making the 2 tags invisible
to the reader because the tags are transmitting a strong enough
signal.



As the distance between 2 tags decreases the amplitude of the
each tags radio signal decreases

Proximity handling


Tuned vs untuned circuits
Handled by the tag chip
readers can simultaneously listen all 8 channels
read rates are 300 tags/sec

Proximity handling

• Controlling the tag frequency



Proximity handling

• Controlling the tag frequency
• 8 Channels



Readers


Readers


Small tunnel reader

Readers


Document tray reader

Readers


Large desktop reader

Readers

Frige and 3D cabinets

Readers

3D reading illustration

Applications


All commercial aircraft have RFID tags installed, the
reader/interrogator is located at Sydney airport (off
screen). Air traffic control radar triggers the aircraft
to send it’s ID along with altitude, speed, heading
and GPS location (and maybe some other data).

The tag is integrated with the aircraft avionics in
order to get the dynamic data

This is a speciﬁcally designed use case $$$

Applications


Car remotes - command/control

also garage door opens

home alarm sysems

Applications


eToll tag - command/control

Applications


• chris.velevitch@gmail.com


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