NXP Semiconductors
AN11740
PN5180 Antenna design
AN11740
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Application note
COMPANY PUBLIC
Rev. 1.1 — 19 June 2018
345311
25 of 62
11. Calculate the matching components
12. Simulate the matching
13. Assembly and measurement
14. Adaptation of simulation
15. Correction and assembly
The details of those steps are described in with an example, using the PN512 Bueboard
antenna together with the PN5180. The blocks and components are used as shown in
Fig 21.
(1) This circuit only covers the Tx part.
Fig 21. PN5180 Reader only antenna matching circuit
4.2.1.1 Measure the antenna coil
The antenna coil must be designed as described in section 3 and be measured. The
measurement is required to derive the inductance L, the resistance R
Coil
and the
capacitance C
pa
as accurate as possible.
The easiest even though not most accurate way is to use the VNA to measure the
impedance Z of the antenna coil at 13.56MHz and to calculate L and R out of it:
Typically, the VNA directly can show the L and R, as shown in Fig 22 and Fig 23.
Coil
L
j
R
Z
ω
+
=
(4)
