Mojix
®
STAR 1000 System User Manual
43
Appendix F: Glossary
AIDC:
Automatic identification and data collection.
Active Tag:
RFID tags with their own internal power
source, which is used to power the integrated circuits and
to broadcast the response signal to the reader. Active tags
typically beacon their identifier at fixed intervals and can
feature sensor information and extended memory. (See
also “passive tag” and “semi-passive tag.”)
Air Interface:
The means used to wirelessly enable tag-
reader communications.
Antenna Polarization:
The orientation of the antenna’s
electromagnetic (EM) field. Polarization often implies a
preferred tag-antenna orientation which optimizes the
antenna’s ability to acquire tag signal and data. Technically,
polarization relates to the orientation of EM fields at
specific antenna components. In user-level discussions,
however, polarization is typically referenced to the ground
and assumes the antenna is in its normal mounting
position. If, for example, a horizontally polarized (parallel
to the ground) antenna that is normally mounted upright
on a beam or wall were mounted on its side instead, it
would then be thought of as being vertically polarized
(perpendicular to the ground) from the user’s perspective,
though the antenna’s inherent polarization never changes.
Anti-collision:
The ability of a reader to read multiple tags
in the field (read window) virtually simultaneously. (See
“discrimination.”)
Attenuate:
To decrease the broadcasting range of an
antenna’s signal.
Backscatter (backscatter modulation):
A method
of tag-reader communication that uses radio frequency
(RF) energy broadcast from a reader/antenna to
essentially bounce the RF signal off the tag and back
to the reader. The tag encodes its own identification
data on the original signal and reflects (backscatters) the
modified (modulated) signal back to the reader’s receiver.
The alternative to backscatter technology is transmitter
technology (see “active tag 1”). Backscatter tags may
be powered solely by the reader’s signal or may include
a battery for increased read range or to power an
onboard processor.
Beam-Powered Tag:
A tag whose internal circuitry is
energized by converting a portion of the reader’s RF signal
(“beam”) to power that enables it to modulate and reflect
(backscatter) that signal to the reader. (See “passive tag 2.”)
Beamforming:
A signal processing technique used
in sensor arrays for directional signal transmission
or reception. This spatial selectivity is achieved by
using adaptive or fixed receive/transmit beampattern.
Beamforming takes advantage of interference to change
the directionality of the array. When receiving, information
from different sensors is combined in such a way that the
expected pattern of radiation is preferentially observed.
Beam steering:
Changing the direction of the main lobe
of a radiation pattern. In radio systems, beam steering
may be accomplished by switching antenna elements or
by changing the relative phases of the rf signals driving
the elements.
Chip:
(See “integrated circuit.”)
Coax:
Coaxial Cable.
DepCon:
(See “Master Controller.”)
Deployment Controller:
(“See Master Controller.”)
Discrimination:
The ability of a reader to read individual
tags in a field containing multiple tags, or the ability
of the system to determine efficiently what to report.
Discrimination with regards to tags uses anti-collision
algorithms (See “anti-collision.”) Discrimination with
respect to interrogation zones uses information to
determine how best to report in which interrogation zone
a tag is located (See “interrogation zone.”)
Electronic Product Code (EPC):
An ultra-low-cost RFID
tag containing a 64-bit or 96-bit unique ID codes—the
equivalent of the bar-coded UPC (Universal Product Code)
plus additional data not accommodated by UPCs. The EPC
tag falls under AIDC Class 1.
eGroup
™
:
Electronic manifest of a targeted population
of tags that enable true electronic proof of delivery and
heightened levels of anti-counterfeiting, security and
authentication.
EM:
Electromagnetic.
eMux:
eNodes frequently are deployed with multiplexers
(eMux’s) that can connect up to ten eNodes to a STAR
or to another (upstream) eMux. The eMux amplifies and
conditions RF signals from the STAR and provides DC
power to eNodes.
