Design Note DN033
Figure 7: Recommended PCB Design with Larger GND
Figure 8. CC-Antenna-DK Board 3 - Mitsubishi Chip Antenna for 868/915/955 MHz
Bandwidth and power gain can be improved by increasing the distance between the ground plane and the antenna. On the other hand, the performance can also be improved by increasing the dimensions of ground plane. Therefore, improved performance can be expected by increasing the distance and the GND plane dimension simultaneously, as long as the layout is allowed.
It is important that no components, ground plane or other metallic objects are positioned in the open area around the antenna. Ground planes on the back and inner layers under the antenna should also be removed.
Since metallic objects in vicinity of the antenna decrease the gain, be sure to keep these objects away from the antenna area.
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