PCB antenna in 20mm circle PCB

RE: PCB antenna in 20mm circle PCB

tamojit — Tue, 30 Oct 2018 07:55:48 GMT

I am also designing a board based on nrf51822 and I am pretty much confused about my design. I cannot set my mind on something that I would like to share with you.
Firstly, is using a balun like this any better than discrete matching network as given in the reference design ?
Secondly, is a chip antenna like this with the balun be viable and effective solution than inverted F antenna have already designed ?

Please have a look at this thread .

RE: PCB antenna in 20mm circle PCB

Oleh — Wed, 23 Jul 2014 11:08:29 GMT

May I ask what was the motivation to use PCB antenna? Have you considered a chip antenna?

RE: PCB antenna in 20mm circle PCB

Reinier Gerritsen — Wed, 23 Jul 2014 09:24:16 GMT

Hi,

Your feed point is extended by the vertical pcb trace. It is not a 50 Ohm transmission line because there is no GND plane underneath. So in effect, you have a series inductance to your intended antenna feed point. Was that intentional?

RE: PCB antenna in 20mm circle PCB

Håkon Alseth — Tue, 22 Jul 2014 17:17:53 GMT

Hi,

I would always recommend adding an additional antenna tuner in form of a PI-network: en.wikipedia.org/.../Antenna_tuner

You're using an inverted F-antenna, which has a tap to ground (basically a shunt inductor), but this does not mean that it's guaranteed 50 ohm for this design.

I've posted an answer here why each different design must be tuned, regardless of antenna used.

Best regards, Håkon