It is critical that the RF section be laid out correctly to ensure optimal module performance. A poor layout can cause low-output power and sensitivity degradation. Figure 10-8 shows the RF placement and routing of the CC2651R3SIPA module with the 2.4-GHz integrated antenna.

Figure 10-4 Module Layout Guidelines

Follow these RF layout recommendations for the CC2651R3SIPA module when using the integrated Antenna:

• Dimensions A thru G in Figure 10-8 must be strictly adhered to for optimal RF performance
• The module must have a minimum 10-mm ground plane on either side of the module on all layers as shown with dimension G in Figure 10-8
• There must be at least on ground-reference plane under the module on the main PCB

For the CC2651R3SIPA it is recommended to use 4-layer PCB board with the dimensions A thru G copied on all 4 layers. This will provided for the best antenna bandwidth in the 2.4GHz band. In addition, it s recommended for optimal antenna RF performance that:

• L1 to L2 layer thickness of 0.175 mm,
• Overall 4-layer board thickness of 1.6 mm as per the reference design
• The 4-layer dielectric constant of 4.0 +/- 0.2.

Deviation from this will cause a potential detuning of the integrated antenna.