<s>
Chipless	B-Device
RFID	I-Device
tags	I-Device
are	O
RFID	B-Application
tags	I-Application
that	O
do	O
not	O
require	O
a	O
microchip	O
in	O
the	O
transponder	O
.	O
</s>
<s>
RFIDs	B-Application
offer	O
longer	O
range	O
and	O
ability	O
to	O
be	O
automated	O
,	O
unlike	O
barcodes	O
that	O
require	O
a	O
human	O
operator	O
for	O
interrogation	O
.	O
</s>
<s>
The	O
main	O
challenge	O
to	O
their	O
adoption	O
is	O
the	O
cost	O
of	O
RFIDs	B-Application
.	O
</s>
<s>
The	O
design	O
and	O
fabrication	O
of	O
ASICs	O
needed	O
for	O
RFID	B-Application
are	O
the	O
major	O
component	O
of	O
their	O
cost	O
,	O
so	O
removing	O
ICs	O
altogether	O
can	O
significantly	O
reduce	O
its	O
cost	O
.	O
</s>
<s>
The	O
major	O
challenges	O
in	O
designing	O
chipless	B-Device
RFID	I-Device
is	O
data	O
encoding	O
and	O
transmission	O
.	O
</s>
<s>
To	O
understand	O
the	O
development	O
of	O
chipless	B-Device
RFID	I-Device
tags	I-Device
,	O
it	O
is	O
important	O
to	O
view	O
it	O
in	O
comparison	O
to	O
classic	O
RFID	B-Application
and	O
barcode	O
.	O
</s>
<s>
RFID	B-Application
benefits	O
from	O
a	O
very	O
wide	O
spectrum	O
of	O
functionalities	O
,	O
related	O
to	O
the	O
use	O
of	O
radio-frequency	O
(	O
RF	O
)	O
waves	O
for	O
data	O
exchange	O
.	O
</s>
<s>
It	O
is	O
also	O
true	O
that	O
RFID	B-Application
contributes	O
other	O
significant	O
functionalities	O
,	O
and	O
the	O
question	O
is	O
therefore	O
one	O
of	O
imagining	O
a	O
technology	O
based	O
on	O
RF	O
waves	O
as	O
a	O
communication	O
vector	O
that	O
would	O
retain	O
some	O
of	O
the	O
advantages	O
of	O
barcodes	O
.	O
</s>
<s>
The	O
high	O
cost	O
of	O
RFID	B-Application
tags	I-Application
is	O
actually	O
one	O
of	O
the	O
principal	O
reasons	O
that	O
chipped	O
RFID	B-Application
is	O
rare	O
in	O
the	O
market	O
for	O
tags	O
for	O
widely	O
distributed	O
products	O
,	O
a	O
market	O
that	O
numbers	O
in	O
the	O
tens	O
of	O
thousands	O
of	O
billions	O
of	O
units	O
sold	O
per	O
year	O
.	O
</s>
<s>
However	O
,	O
technically	O
speaking	O
,	O
chipped	O
RFID	B-Application
offers	O
significant	O
advantages	O
including	O
increased	O
reading	O
distance	O
and	O
the	O
ability	O
to	O
detect	O
a	O
target	O
outside	O
the	O
field	O
of	O
vision	O
,	O
whatever	O
its	O
position	O
.	O
</s>
<s>
RFID	B-Application
has	O
many	O
arguments	O
in	O
its	O
favor	O
in	O
terms	O
of	O
functionality	O
,	O
the	O
only	O
problem	O
remaining	O
being	O
the	O
price	O
.	O
</s>
<s>
Chipless	B-Device
RFID	I-Device
has	O
also	O
good	O
arguments	O
in	O
terms	O
of	O
functionality	O
.	O
</s>
<s>
Some	O
functionalities	O
are	O
degraded	O
versions	O
of	O
what	O
RFID	B-Application
can	O
do	O
(	O
read	O
range	O
/	O
reading	O
flexibility	O
are	O
reduced	O
...	O
)	O
,	O
others	O
seem	O
to	O
be	O
even	O
more	O
relevant	O
in	O
chipless	O
(	O
discretion	O
,	O
product	O
integrity	O
of	O
the	O
tag	O
)	O
.	O
</s>
<s>
Like	O
various	O
existing	O
RFID	B-Application
technologies	O
,	O
chipless	B-Device
RFID	I-Device
tags	I-Device
are	O
associated	O
with	O
a	O
specific	O
RF	O
reader	O
,	O
which	O
questions	O
the	O
tag	O
and	O
recovers	O
the	O
information	O
contained	O
in	O
it	O
.	O
</s>
<s>
However	O
,	O
chipless	B-Device
RFID	I-Device
tags	I-Device
are	O
fundamentally	O
different	O
from	O
RFID	B-Application
tags	I-Application
.	O
</s>
<s>
Chipless	B-Device
RFID	I-Device
tags	I-Device
,	O
on	O
the	O
other	O
hand	O
,	O
function	O
without	O
a	O
communication	O
protocol	O
.	O
</s>
<s>
The	O
detection	O
of	O
a	O
chipless	O
tag	O
in	O
noisy	O
environments	O
is	O
much	O
more	O
difficult	O
in	O
chipless	O
than	O
in	O
UHF	O
RFID	B-Application
due	O
to	O
the	O
absence	O
of	O
modulation	O
in	O
time	O
,	O
that	O
is	O
,	O
the	O
absence	O
of	O
two	O
different	O
states	O
in	O
the	O
backscattering	O
signal	O
.	O
</s>
<s>
In	O
2004	O
,	O
Tapemark	O
announced	O
a	O
chipless	B-Device
RFID	I-Device
that	O
will	O
have	O
only	O
a	O
passive	O
antenna	O
with	O
a	O
diameter	O
as	O
small	O
as	O
5µm	O
.	O
</s>
<s>
Surface	O
acoustic	O
wave	O
devices	O
consists	O
of	O
a	O
piezoelectric	O
crystal-like	O
lithium	O
niobate	O
on	O
which	O
transducers	O
are	O
made	O
by	O
single-metal-layer	O
photolithographic	B-Algorithm
technology	O
.	O
</s>
<s>
Data	O
is	O
encoded	O
using	O
Pulse	B-Device
Position	I-Device
Modulation	I-Device
(	O
PPM	O
)	O
.	O
</s>
<s>
The	O
democratization	O
of	O
these	O
chipped	O
based	O
systems	O
like	O
the	O
RFID	B-Application
one	O
have	O
however	O
given	O
rise	O
to	O
environmental	O
issues	O
.	O
</s>
