QUESTION

Question

We have a couple of options re placement of the antenna – basically on either side of the PCB.

Say for the Lucida SR4L002, or the Inversa SR4L034 devices.

I appreciate the preference is to have the matching components on the same side as the antenna, as shown in application notes etc., however is it feasible to place the antenna on the other side to the matching components ?

 

If so are there any design guidelines, and / or are there any components that must be the same side as the antenna ?

 

Just looking to confirm what the feasible options are ?

 

Kind regards,

Mark.

Answer 1

Hi Mark,
Your question in regardless of the type of antenna. If the antenna and radio module is on the top and bottom of the PCB then a through hole must be made in the 50 Ohm line. This through-hole represents RF-technically a coil and a capacitor. That you even can calculate. I would do the matching so that the radio module sees a good 50 Ohm. In matching with many components energy is lost and the unwanted coil and capacitor become part of your matching. If the radio module does not see a good 50 ohms, this can lead to harmonics. If you like, we can match for you and measure the antenna in 3 axes on the radiation pattern.
Regards from Germany
Harald