Impedance control in antenna line - PLS62-W | Thales IoT Developer Community
July 25, 2019 - 4:56pm, 1848 views
I am developing a new application board to fit in our requirements, and I am stuck in the antenna impedance.
I was using the PLS8-US_HD_v01.000c given in https://iot-developer.thalesgroup.com/documentation/pls8-us-technical-documentation, which seems to be the same family of PLS62-W.
In section 18.104.22.168 recommends to use a Stripline (50 Ohms) under the module, and out of the module it recomends a Microstrip (50 Ohms). It makes sense once the module and the reference ground makes a ground "sandwich" in the antenna line.
Analysing the Figure 17 (PLS8-US evaluation board layer table), the third layer seems to be the reference, so:
- Substrate Height 1: 798 (708+25+65)um,
- Trace Thickness: 25 um,
- Substrate Height 2*: +/- 40um (two green coat),
- Trace Width: 330 um,
-Substrate Dielectric: 4.4 (it was considered that substrate 2 has the same dielectric as substrate 1 - probably wrong).
With this considerations and values, I could get 50 Ohms strip line, but I do not feel safe to use it in my application board, because the layer table is different.
I would like to know what parameters (Substrate Height 2 and Substrate Dielectric2) were used to calculate the stripline 50 Ohms?