Gemalto is now part of the Thales Group, find out more.

You are here

Impedance control in antenna line - PLS62-W | Thales IoT Developer Community

williankataoka

July 25, 2019 - 4:56pm, 1083 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://developer.gemalto.com/documentation/pls8-us-technical-documentation, which seems to be the same family of  PLS62-W.

In section 4.1.2.2 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?