There are 3 channels located lower in frequency than the normal
10 channels, which can only be operated below 100 mW ERP, whereas there are 2 channels
higher in frequency than the normal 10 channels, which can be operated below 500 mW
ERP. The complete frequency range for RFID operation with respective regulated power
level is as shown in Figure 7.12.
The channel numbering system shown in Figure 7.7 is included in Figure 7.12 along with
a new channel numbering systemto simplify the discussion hereon. Channels 4, 7, 10, and 13
RF absorbing materials
2 8 4 10 6 2 8 4 10 6 2 8
Truck
Truck
TruckTruck
Truck
Truck
FIGURE 7.10
Use of RF absorbing materials. The antennas
facing each other at the same door are at least
four channels away. (From Leong, K.S., M.L. Ng,
and P.H. Cole. 2006a. Synchronization of RFID
readers for dense RFID reader environments. International
Symposium on Applications and the Internet.
SAINT, Phoenix, Arizona, USA, # 2006 by IEEE.
With permission; Leong, K.S., M.L. Ng, A. Grasso,
and P.H. Cole. 2006d. J. Commun., 1, 9, # 2006 by
IEEE. With permission.)
Channel
Channel
2 8 4 10 6 2 8 4 10 6 2 8
8 2 6 10 4 8 2 6 10 4 8 2
FIGURE 7.11
Channel switching within antennas. (From Leong,
K.S., M.L. Ng, and P.H. Cole. 2006a. Synchronization
of RFID readers for dense RFID reader environments.
International Symposium on Applications and
the Internet.
Pages:
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273