NXP Semiconductors
AN11740
PN5180 Antenna design
AN11740
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2018. All rights reserved.
Application note
COMPANY PUBLIC
Rev. 1.1 — 19 June 2018
345311
19 of 62
(1) Operating distance = 1cm, X and Y = horizontal distance from antenna center.
(2) These simulation results do neither take any specific environment nor loading effects into account
Fig 15. Magnitude of field strength in 1 cm distance
Note:
The field strength is not the same for all three antennas, but has been adjusted
individually to achieve the maximum allowed field strength for each antenna.
3.2 Layout recommendations
The connection between the TX output pins (TX1 and TX2) and the EMC low pass filter
has to be as short as possible. The GND connection especially between TVSS and the
C0A and C0B (see Fig 18) capacitors must be as short as possible.
The connection between the block capacitors and the VDD pins need to be as short as
possible. This holds especially for the TVDD and its block capacitor.
The PN5180 evaluation board and its related description (see [9]) can be taken as a
reference.
The Fig 16 and Fig 17 show a part of the top and bottom layer structure around the
PN5180 as reference. The GND layer is a complete area of one of the middle layers (not
shown).