external power supply or data
cables are needed for testing, these
may affect the measured radiation
pattern and give a false report. The
undesirable radiation caused by
any common mode current will
interact with the intended antenna
radiation and give a distorted
measurement.
NPL has therefore developed a
wireless RF-to-optical link using an
Electro-Optic transducer, the
OEFS-PR-7G — the result of a
collaboration between NPL and
Japan’s NEC-Tokin Corporation.
This can receive RF signals up to
7GHz and creates an RF-to-optical
transducer link that allows the RF
cable to be replaced by a minimally
perturbing optical fibre that will
barely interfere with the signal of
the device being measured.
The antennas using the facility
are expected to operate primarily
over the frequency range 400MHz
to 11GHz.
The chamber also uses a TDK
radio wave absorber material with
very low reflection to cover its walls.
‘Normally, foam with carbon is
used,’ said Miller. ‘Unfortunately
the carbon leaks from this, creating
a coal dust-style problem. The TDK
doesn’t do this so we now have a
very clean environment, too. There
is no other facility like this in the UK,
especially one using RF-to-optical
transducers.’
Research at NPL’s previous
antenna facility helped with the
development of O2’s 3G network.
The company used NPL’s measurement
chamber to ensure it
chose the right equipment before
investing in a multi-million pound
infrastructure upgrade.
To support the increased data
transmission needs of 3G and meet
the terms of its licence, O2 had to
install a new network of antennas,
capable of handling larger data volumes
and higher network
transmission speeds. By moving
from older fixed-tilt antennas to
new variable tilt models, the reliability
and access to the network
could be improved.
But to do this, the company had
to choose between various types of
antennas whose specifications
were provided by their makers
rather than an independent body,
making their likely performance
hard to judge. NPL therefore provided
testing services to verify the
manufacturers claims and compare
the devices on offer, confirming
their gain and directivity.
Julia Pierce
FOR THE LATEST NEWS GO TO www.theengineer.co.uk
the EnGIneeR 1–14 SEPTEMBER 2008 7
Foiling ID theft
Portable shield could help stop credit card cloning
A SIMPLE foil envelope that costs the same as a postage stamp could
prevent the cloning of credit cards and passports during transit and
use.
Recently there have been repeated concerns about the security
of biometric passports and the vulnerability of their radio frequency
identification (RFID) microchips to skimming — copying its contents by
readily-available hand-held scanning devices.
The shield from BioCert iQBio Metrics, the UK arm of global
technology company Artemis Solutions Group, takes its inspiration from
19th century physicist Michael Faraday, who discovered that lining
an object with a conducting material shielded the contents from the
influence of external electric fields.
Called the IdlokR envelope, it is a non-ferrous foil lined pocket that
shields the item from incoming radio signals, isolating the transmitter
from the receiver and so preventing a scanner from activating the chip.
The envelope is available for passports, travel passes and credit/debit
cards. Radio signals from the scanner simply bounce off the foil lining
of the cover, never reaching the chip. When the device is needed it can
be removed easily from its cover to be read.
Microchip technology is now used routinely by many industries as a
method of storing personal data. Aside from passports and credit cards
RFID technology is also being incorporated into store cards, travel
passes, parking permits and entry passes for sites or buildings.
However, devices employing RFID chips are vulnerable to
skimming. During this process, the chip is duped into surrendering information
after responding to the radio frequency waves emitted by a
hacker’s scanner.
This can be used to subsequently access an individual’s personal
data without their knowledge and without leaving evidence of the crime.
Even if the data is encrypted, hackers can access the chip as many
times as they need until the code is broken.
‘When the passport office sends passports out in the post or by
courier, or credit card issuers do the same, they are taking a big risk in
terms of allowing people to access the data within them,’ said Duncan
Preen, managing director of BioCert iQBio Metrics.
‘It is easy to identify these documents while they are on the move if
you know what you are looking for, so all someone would have to do is
to infiltrate the handling company before skimming the envelopes as
they move through. Normal envelopes do not protect the data at all.’
Skimmers beware: IdlokR envelopes aim to shield data on credit cards
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