NXP Semiconductors
AN11740
PN5180 Antenna design
AN11740
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Application note
COMPANY PUBLIC
Rev. 1.1 — 19 June 2018
345311
32 of 62
The schematic are shown in Fig 26, the simulation result in Fig 27. The normal simulation
is done with ideal components, which is accurate enough for the capacitors. However,
the antenna coil as well as the EMC filter inductors L0 are far from being ideal. RFSIM99
allows to use physical models, which requires to enter e.g. the self-resonant frequency
and the Q-factor measured at a certain frequency. With these models the simulation
already becomes more accurate (see Fig 27b).
With these values the first assembly can be done, even though the reality still might be
slightly different due to inaccurate values for the antenna coil itself and due to the slightly
different component values (e.g. C1
simulation
= 41.6pF versus C1
real
= 33pF + 8.2pF =
41.2pF).
(1) The “measurement GND” (= simulation GND) is
not
the PN5180 and evaluation board GND!
Fig 26. RFSIM99 Schematic
