I’ve been thinking in another idea: What if I put a via exactly below the pad K1 of the HE910? So in this way, I could trace in the another layer a line of whatever the width I want. That could be possible? What about the characteristic impedance that has the via? It maybe could has a worse impedance that the line of 0.7mm and definitely that’s what I don’t want.
What do you think about this? How do I calculate the impedance of the via?
I usually use the follow page to calculate line inpedance:
On this page I tried to evaluate your case as per attached doc. I think you can do the job on the same layer where module is, without the use ov a via, which need a bit to calculation to be evaluated.
Try to modify the values on the on line tool to see the effect, but don’t worry a lot if the line you are designing is 0,7mm large.
You have to prefer a 0,7mm track than a via.
Excuse me if I didn’t thank you, what you said was really useful.
But I’ve some doubts yet. Using a "Coplanar Wageguide" line could help me making the 50 ohm impedance that I need, but that would need that the width of the gap be like 0.1mm. This is extremely thin in my opinnion, what do you think about this?
I’m worried about something can go wrong. For example, what if dust drops exactly in the gap, that would make the gaps width even more thinner. Could this affect the opperation of the antenna?
I was thinking in making the gap around 0.2mm, so the characteristic impedance would be around 59ohm. That would make a VSWR around 1.18. Is this a good VSWR? Could I take the chance of making my line of around 60ohm? Or is preferable to make the gap of 0.1mm width, so the impedance matches the 50ohm?
Thank you a lot!
even if it’s a good practice to design a antenna line with impedance higher than 50Ohm to
take into account impedance reduction due to process, 60 ùOhm could be a bit too high.
But it is also a fact that 0,1 mm could be a small size, even if I think you can do it.
The best idea should be to modify PCB style,, something likedielectric height and/or er.
This is the reason why it is always suggestged a 4 layers design.
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