4 Circuit Design
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The impedance simulation tool should be used to accurately control the RF signal
cable at 50Ω impedance.
The GND pin adjacent to the RF pin should not have thermal welding plate and should
be in full contact with the ground.
The distance between the RF pin and the RF connector should be as short as possible.
At the same time, avoid the right-angle route. The recommended route angle is 135°.
Attention should be paid to the establishment of the connection component package
and the signal pin should be kept at a certain distance from the ground.
The reference ground plane of the RF signal cable should be kept intact; adding a
certain amount of ground holes around the signal and the reference ground can
improve the RF performance; the distance between the ground hole and the signal
cable should be at least 2 times the cable width (2*W).
The equivalent capacitance of the TVS should be less than 0.5 pF.
Add a π-type circuit (two parallel component grounding pins are connected directly to the
main GND) between the module and antenna connector (or feeding point) for antenna
debugging. Two parallel components are directly connected across the RF cable, and the
branch must not be pulled out.
Module
ANT_DIV
ANT_MAIN
NC
NC
0R
Main
antenna
NC
NC
0R
Diversity
antenna
Figure 32. Antenna reference design
