38
2 RFID System Physical Anti-Collision Experimental Verification
Fig. 2.4 Tagformance system schematic diagram
(3) Observe the error between the test result curve and the reference curve. If the
error is within ± 0.5 dBm, it is considered to meet the calibration requirements.
Click “clear screen” to prepare for the formal test.
(4) Set the frequency range and step of the test, place the test tag above the
instrument according to the polarization direction of the antenna, and click
“STARTSWEEP” to start the test.
(5) After the test is completed, save the data and turn off the power.
In this test, the frequency range is set between 800 and 1000 MHz, and the
frequency step is 20 MHz. The maximum values of the sensitivity of the five tags
in the frequency range were –11.184 dBm, –15.276 dBm, –16.657 dBm, –20.029
dBm, and –20.347 dBm, respectively. The values measured by the instrument are
compared with those calculated by the experiment, as shown in Fig. 2.5.
Figure 2.5 shows the comparison results of tag sensitivity obtained by the two
methods. Among them, the broken lines of the square mark represent the sensitivity
value directly measured by the instrument, the broken lines of the triangle mark
represent the sensitivity value calculated according to the reading distance measured
by the experiment, the x-coordinate represents the serial number of the tag, and the
y-coordinate represents the sensitivity value.
It can be seen that the trends of the two curves in Fig. 2.5 are roughly the same, and
the difference between the two curves is the error interference in the experimental
environment. Calculate the difference between the two methods of each tag to get the
data, and take its average value to get the average error of the tag test environment
is 1.891dBm. The error value can be used to correct the test results of tag group
sensitivity and eliminate the environmental error to obtain more accurate results.
2 RFID System Physical Anti-Collision Experimental Verification
Fig. 2.4 Tagformance system schematic diagram
(3) Observe the error between the test result curve and the reference curve. If the
error is within ± 0.5 dBm, it is considered to meet the calibration requirements.
Click “clear screen” to prepare for the formal test.
(4) Set the frequency range and step of the test, place the test tag above the
instrument according to the polarization direction of the antenna, and click
“STARTSWEEP” to start the test.
(5) After the test is completed, save the data and turn off the power.
In this test, the frequency range is set between 800 and 1000 MHz, and the
frequency step is 20 MHz. The maximum values of the sensitivity of the five tags
in the frequency range were –11.184 dBm, –15.276 dBm, –16.657 dBm, –20.029
dBm, and –20.347 dBm, respectively. The values measured by the instrument are
compared with those calculated by the experiment, as shown in Fig. 2.5.
Figure 2.5 shows the comparison results of tag sensitivity obtained by the two
methods. Among them, the broken lines of the square mark represent the sensitivity
value directly measured by the instrument, the broken lines of the triangle mark
represent the sensitivity value calculated according to the reading distance measured
by the experiment, the x-coordinate represents the serial number of the tag, and the
y-coordinate represents the sensitivity value.
It can be seen that the trends of the two curves in Fig. 2.5 are roughly the same, and
the difference between the two curves is the error interference in the experimental
environment. Calculate the difference between the two methods of each tag to get the
data, and take its average value to get the average error of the tag test environment
is 1.891dBm. The error value can be used to correct the test results of tag group
sensitivity and eliminate the environmental error to obtain more accurate results.