SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11
Design-in
Page 91 of 157
2.4.2.2
Guidelines for ANT_DET layout design
describes the recommended layout for the antenna detection circuit to be provided on the
application board to achieve antenna detection functionality, implementing the recommended schematic
described in the previous
and
The
ANT
pin must be connected to the antenna connector by means of a 50
transmission line,
implementing the design guidelines described in section
and the recommendations of the SMA
connector manufacturer.
DC blocking capacitor at
ANT
pin (C2) must be placed in series to the 50
RF line.
The
ANT_DET
pin must be connected to the 50
transmission line by means of a sense line.
Choke inductor in series at the
ANT_DET
pin (L1) must be placed so that one pad is on the 50
transmission line and the other pad represents the start of the sense line to the
ANT_DET
pin.
The additional components (R1, C1 and D1) on the
ANT_DET
line must be placed as ESD protection.
The additional high pass filter (C3 and L2) on the
ANT
line are placed as ESD immunity improvement
SARA m odule
C2
R1
D1
C1
L1
J 1
C3 L2
Figure 36: Suggested layout for antenna detection circuit on application board