QUESTION

asked by
Board size vs Grandis Right
I'm looking into designing a LORA 868MHz (sf12) product. Ideally, we want the PCB to be 22mm wide, and 80mm high. Antenna on top right. The Grandis arrived to our attention, as a candidate.

According to datasheet, and demo board, 35mm width is recommended, but someone suggested maybe 22 is fine. Can you advice?

Also, we do realize that 80mm is too little, it should ideally be at least ~100mm, right? Is there a general rule on bad this reduction would be?

And thirdly, if we do create prototype boards that are 100mm height, is there a downside on placing all the components closer to the antenna, rather than on the opposite end (as low/far away as possible)? Our thoughts are, that if we can just have a ground plan at the lower half of the board, we could cut the PCB to find out how small we can make it, before it getting too bad.

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1 Answer

answered by
Hi,

80mm is indeed bit too short, ~100mm as you have said would be better. If you create a 100mm board just have the large components atleast 10-15mm distance from the antenna so it doesn't block the radiation or couple with it.

Best regards,

Yu Kai Yeung
commented by
Hi,

Thank you for your answers.

Do you have any thoughts on how much of a problem the reduced PCB width is?
commented by
Hi,

Reducing the width will have some slight effect but the performance drop won't be as drastic as reducing the length. If the design requires reducing the width or the length of the PCB, reducing the width would be the better choice.

Best regards,

Yu Kai Yeung

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Yu Kai Yeung

Antenna Engineer at Antenova Yu Kai is an antenna expert with over 10 years of experience in the design and testing of antennas. He has experience helping customers with certification testing, combined with his knowledge of RF measurement procedures.

Raymond Lee

Senior Antenna Engineer at Antenova Raymond has a wealth of experience in RF and antennas across many industry sectors. He has over 20 years of experience in electronics design and manufacturing.

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