Their datasheets are pretty terrible on electrical specifications and characteristics compared to other vendors. The documentation is highly targeted towards software engineers.

Regarding the suggested ground clearance below the inductor: where do you have this Information from? From several reference designs I could not see this …

The sample kit she was using looked like one I have from Johanson P/N C402

I don't know, but I guess it's probably easier with a capacitor for tolerances and one can use a cheaper pcb material with less impedance control

She seem to didn't mention it at the same time she did that, but I believe she was shortening the antenna to help move the markers into the centre of the resonant frequency shown on the SWR chart on the right. She was trying to avoid adding another unnecessary component.

Adding excessive C can be malicious from efficiency point of view, even high Q capacitors have their losses. It is better to hand-tune antenna on prototypes and move forward with new design.

Those calculations apply to dimensions of a microstrip line, a transmission line that has a line on top and a reference plane beneath a given dielectric material. The electrical length of the signal propagating in said dielectric is therefore affected by the permittivity as you well said. The antenna has no reference ground, it's just a metallic strip in the air (and a bit of the PCB dielectric, but no other reference beneath), so the length is more approximate to the free-space length - but still a little affected by the presence of a higher dielectric material in the vicinity of the conductor plus the fact that a monopole (as well as a dipole) should be slightly smaller than a free-space quarter/half of the wavelength, plus the fact that it is bent which adds inductance and thus further reduces the effective length to have the same resonance. There's no calculation that gives a precise value for it, the way to go is to make it the free-space quarter wavelength and then "tune it", by slicing at the antenna, arriving at the correct length for the desired frequency. That's why, unless you have simulation software, you can either build some prototypes with copper tape (and a lot of cutting skills), or otherwise follow the recommended designs. Hope that helped.

@@magictwister8439 Ohk, Thanks for the explanation! I got it now!!

SWF port for antenna testing that is on the Development kit. She shows the part number so you can look at the component. The part works in a way that it disconnects the PCB antenna if you plug in a cable to measure

it is on my to do list

@@RobertFeranec Cant wait ❤️

Yes, depends on your trace dimensions, the distance to reference and the used materials.

I used to do it, but ... I am curious, what do you think why I don't do that anymore?

@@RobertFeranec To be honest, I don't know the reason why! But I would like to know for sure?

The short video formats (tiktok, shorts, etc) changed behavior and expectations of people from videos. If it's not interesting from second 1, they just move to a different video. That is what is unfortunately happening. PS: Kaja explains what she does later in the video.

@@RobertFeranec thanks for the explanation, Robert!

Tbh, it's never relevant. If the presenter is competent, the audience will know.

custom design wont fit pre-certified module(s)