Data Sheet

R8002 Datasheet
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9.2 Layout Guidelines(Internal Antenna)
It is strongly recommended to use good layout practices to ensure proper operation of the module. Placing copper or
any metal near antenna deteriorates its operation by having effect on the matching properties. Metal shield around the
antenna will prevent the radiation and thus metal case should not be used with the module. Use grounding vias
separated max 3 mm apart at the edge of grounding areas to prevent RF penetrating inside the PCB and causing an
unintentional resonator. Use GND vias all around the PCB edges.
The mother board should have no bare conductors or vias in this restricted area, because it is not covered by stop mask
print. Also no copper (planes, traces or vias) are allowed in this area, because of mismatching the on-board antenna.
5
26.9
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20
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4
3
.
5
1
3
1
8
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a
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.
0
.
5
1
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2
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Applic. PCB
no bare copper(exept solder pads for module)
no copper and components on any layer
no components on any layer
do not place any conductive parts in this area
Provide solid ground plane(s) as large as possible around area
Figure 9: FSC-BT986 Restricted Area
Following recommendations helps to avoid EMC problems arising in the design. Note that each design is unique and the
following list do not consider all basic design rules such as avoiding capacitive coupling between signal lines. Following
list is aimed to avoid EMC problems caused by RF part of the module. Use good consideration to avoid problems arising
from digital signals in the design.
Ensure that signal lines have return paths as short as possible. For example if a signal goes to an inner layer through a
via, always use ground vias around it. Locate them tightly and symmetrically around the signal vias. Routing of any
sensitive signals should be done in the inner layers of the PCB. Sensitive traces should have a ground area above and
under the line. If this is not possible, make sure that the return path is short by other means (for example using a
ground line next to the signal line).
9.3 Layout Guidelines(External Antenna)
Placement and PCB layout are critical to optimize the performances of a module without on-board antenna designs.
The trace from the antenna port of the module to an external antenna should be 50Ω and must be as short as possible
to avoid any interference into the transceiver of the module. The location of the external antenna and RF-IN port of
the module should be kept away from any noise sources and digital traces. A matching network might be needed in
between the external antenna and RF-IN port to better match the impedance to minimize the return loss.
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