7.2 Best Design Practices
The design of a good RF system relies on thoughtful placement and routing of the RF signals. The following guidelines are recommen-
ded:
• Place the BGM220S and antenna close to the center of the longest edge of the application board.
• Do not place any circuitry between the board edge and the antenna.
• Make sure to tie all GND planes in the application board together with as many vias as can be fitted.
• Generally ground planes are recommended in all areas of the application board except in the antenna keep-out area shown in
ure 7.3 Antenna Clearance in Inner and Bottom Layers on page 34
• Open-ended stubs of copper in the outer layer ground planes must be removed if they are more than 5 mm long to avoid radiation of
spurious emissions.
• The width of the GND plane to the sides of the BGM220S will impact the efficiency of the on-board chip antenna.
• To achieve optimal performance, a GND plane width of 50 mm for BGM220S12A or 55 mm for BGM220S22A is recommended
as seen on
Figure 7.4 Illustration of Recommended Board Width on page 35
.
• See
4.16.1 Antenna Typical Characteristics
Figure 7.5 Non-Optimal Layout Examples on page 36
illustrates layout scenarios that will lead to severely degraded RF performance
for the application board.
Figure 7.4. Illustration of Recommended Board Width
BGM220S Wireless Gecko Bluetooth
®
Module Data Sheet
Design Guidelines
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