User's Manual

DT0237A page14of24 Rev:1.0
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Figure 9: Micro-strip trace parameters
H1 and T1 are taken from the stack-up parameter of the host’s PCB as shown in Figure 10, the relative dielectric constant depend on the
material used.
Figure 10: Example stack-up
An example stack-up, copper thickness, RF traces width and traces to copper clearance in order to get 50 ohms is presented below. The
calculation toll is then used to find the remaining parameters of the micro-strip traces as shown in Figure 11.
Figure 11: 50 ohms calculation (mm) Trace width: 0.7mm Copper clearance: 0.1445mm
The resulting parameters can then be used to define the trace width and copper clearance on RF traces of the host’s PCB. The RF traces
must be surrounded by copper all along the path of undefined length; the path should be as short as possible to reduce losses. Vias must
be added all along the RF traces. See reference trace design in Figure 7 for an example.
Note: a new trace design is subject to validation, additional testing and authorization through a Class II Permissive change on
the FCC and IC grants.