Antenna Measurement - Deepace KC901M User Manual

ones if necessary. If the screws need to get inside very deep, duplexer's Q value will
reduce. If needed, user can lengthen solenoid by taking apart the duplexer.
If the insertion loss can't be reduced to a reasonable level, user might consider
using S11 (connect the dummy load to the untested port and it's not preferred to
connect it to instrument's port) to try different adjustments. Also balance it with
other parameters and make SWR stay within 1.5.
During the adjustment, user should lock the screw to fix the parameters.
NOTice
Port matching has a great influence on duplexer's attenuation. There will be
some tiny differences of the results by using different instruments. There also will be
differences after changing the connections between instrument and duplexer. There
are differences too for different repeaters and antennas' impedance which may cause
gap between its actual performance and the expected performance. In the initial
testing, after putting the repeater in, users should be accumulating operating
experiences from each actual performance .
Concatenate the attenuator (about 10dB) with instrument's input port to
improve the matching. Increase the output attenuation (SHIFT+Po. ATT) to 10dB.

4.2 Antenna Measurement

WARNING
The maximum output generated from the output port of KC901M is
10dBm(10mW). The output will be transmitted to the air via the antenna during
testing. To diminish the transmission, users can increase the output attenuation
(Po.ATT). A recalibration (Re CAL) is imperative in this case.
4.2.1 SWR Measurement
When measuring SWR, set the instrument to S11 and select the Format as VSWR.
Connect the antenna to Port 1, Using adapter if necessary. User must stay away from
the antenna after setting the center and span.
Antenna's standing wave ratio is related with the field environment. So users
should choose a capacious open-air, such as the roof. The cable should be as short as
it can be; if the RF cable is too long, disconnect the end from the antenna, and then
do the user calibration at the end of cable.
The 13.56 MHz antenna, which RFID usually uses, almost can't connect to the
instrument directly. In this case, users can make a small ring-type antenna by
themselves to measure its SWR. When leaning that small antenna close to the RFID
antenna, the standing wave will change. This gives valuable experiences for judging
the performance of the tested antenna as the standing wave changes.
4.2.2 Cable canceling
When measuring antennas, users may not be able to calibrate on the antenna's
port due to the limitation of the field environment, therefore, there exists the
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