GEM Module Hardware Integration Guide
Version 0.3
Wahoo Fitness
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90 West Wieuca Road, Suite 110
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Module Layout Considerations
General Considerations
1.
Locate the GEM Module close to the edge of your circuit board for best RF
performance.
2.
A solid ground plane should be used except for the antenna keep-‐out area.
3.
All module GND pins must be connected to your circuit ground.
4.
Place GND vias close to the module GND pads
5.
Route traces to avoid noise being picked up on VCC or I/O lines
6.
Ensure no exposed copper is located underneath the GEM module
Top-‐side area directly under the module should be kept clear of copper, silkscreen and
vias
Antenna Considerations
The GEM antenna was characterized using the GEM development board. Similar
performance can be obtained by following the following layout guidelines:
1.
Locate the GEMSRB01 on the edge of the host PCB in the right corner to allow the
antenna to radiate properly.
2.
Keep all mounting hardware and metal clear of the keep out area for proper
antenna radiation.
3.
Metal close to the GEMSRB01antenna will have degradation on the antenna
performance. Suggested clearances are 20mm top/bottom and 20mm left or
right.
4.
It is best that the customer test with an actual prototype or final design to see
the effects of any enclosure.
5.
The antenna keep-‐out area and dimensions are shown in the figure below.
Antenna Characteristics
The GEM module includes an integrated monopole chip antenna. Antenna performance will
depend on host PCB layout. The following plots show antenna radiation pattern of the GEM
antenna.
