The microstrip track with all the via fencing looks too narrow. I assume this is supposed to be a 50 ohm line? You might check this- I assume this is on FR4 at 1.5 mm (.062”), if so, a 50 ohm track is about 3 mm wide (.125”). A narrower track will give you a higher impedance line, this line looks more like a 100 ohm line. If it’s a matching section, ignore my comment, but if its supposed to be 50 ohms, check it. You might also consider putting some via stitches around the perimeter of the planes- they’re kind of floating RF wise at the edges except perhaps at the top and at the fencing. I’m sure your initial design will work as is- but the narrow track will create some mismatch loss (range) and the lack of perimeter stitching can cause RF leakage- kind of a slot antenna that will radiate in the plane of the board- could give a squirrelly radiation pattern. If the module vendor has a recommended layout, I would study it carefully and use it as much as possible. Also, is any local bypassing recommended external to the module on power lines, etc.? Something like a 10 nF 0805 and a bulk 1 uF ceramic would seem wise and cheap. That 3.3v line is an inductor- not so bad really but dying to have a shunt C at the module end to make a proper “bias T” kind of structure. Have fun. Regards, John M. Wettroth (984) 329-5420 (home) (919) 349-9875 (cell) From: TriEmbed <[email protected]> On Behalf Of Scott Hall via TriEmbed Sent: Friday, October 29, 2021 3:35 AM To: Triangle Embedded Computing Interest Group <[email protected]> Cc: Adam Novak <[email protected]> Subject: [TriEmbed] Does my Raspberry Pi LoRa modem board look ready to send off to OSHPark? Question from Adam Novak <[email protected] <mailto:[email protected]> >, posed at 9:26pm 28-Oct-21: Anybody here know PCB design? Does my Raspberry Pi LoRa modem board look ready to send off to OSHPark?
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