Feed Line

RE: Feed Line

Zsolesz — Mon, 30 Mar 2020 12:52:49 GMT

Hi,

Thank you for the all answer helped a lot!
I am looking for 'end mount' chip antenna and change it.

Best wishes!

RE: Feed Line

Andreas — Mon, 30 Mar 2020 12:42:25 GMT

Hi,

This antenna is 'corner mount' (see the datasheet), while you have mounted it as 'end mount' (see this guide by Johanson). It will probably still work, just not optimally, varying between different models. It probably causes the antenna to detune quite a bit though, you should add another component to the antenna matching network to make sure you can match any antenna impedance. Either a parallel component between L3 and the antenna, or a series component between L4 and C28.

Best regards,

Andreas

RE: Feed Line

Zsolesz — Mon, 30 Mar 2020 11:55:43 GMT

Hi,
Thank for answer!
I made version 2.0 PCB, Can you check this too?

I used (JOHANSON TECHNOLOGY 2450AT43B100E) chip antenna.
2450AT43B100 Datasheet

RE: Feed Line

Andreas — Mon, 30 Mar 2020 09:39:16 GMT

Hi,

You are short one component in the RF matching network. You need to add C4

You should also replicate the reference RF matching network PCB layout:

Except for that you can move the other components around as you wish (within reason) to minimize the size of the design. The feed can be made much more straight, just re-organize the components a bit. If you are not able to fit a wide trace in this area it is not critical if it is not 50 ohms. E.g.

Best regards,

Andreas