Figure 1 shows that for flat polarization antenna,
as electronic waves radiate as straight polarized
waves, it is not easy to recognize a few of tags
simultaneously according to locations of tags or
directionality of tag antenna, and it may cause
malfunction due to multi-channels. However, as seen
in figure 2, as circular polarization wave radiate
electronic waves in circular form, it is very effective
to recognize a few tags regardless of locations of tags
and direction of antenna.