User Manual

Antenna Tuning
Figure 26: Antenna Tuning (Impedance) using an Impedance Analyzer
EAS Pedestal
Network Impedance Analyzer
Top
Antenna
Center
Antenna
B ottom
Antenna
Calibration Plane
(50 Ohms + 0j)
BARRF Out
Transmission/Reflexion Set
RG-58 Cables
Adjust the trimmer capacitor (Figure 24) of each antenna for best impedance until the impedance
reaches 50±5 + 0j±5 Ω at 13.560 MHz.
Continue the tuning process by checking the antenna isolation (see
section 6.4, “Adjusting the
Antenna Isolation
”).
Figure 27: Impedance Values using an Impedance Analyzer
Poor Impedance
Good Impedance
6.4 Adjusting the Antenna Isolation
Once each antenna is tuned for optimal impedance (see section 6.3, “Adjusting the Antenna
Impedance
”), it is necessary to verify the isolation of each antenna.
Correct antenna isolation is not greater than –25 dB or 300-mVpp residual peak-to-peak voltages
collected on either the top or bottom antenna when the center antenna is powered by the tuning kit
December 2004 Revision 1.0 37/50