We lay out the RF trace for below model.

GSM 900MHz

RF trace maintain at 50Ω impedance. As I know, the RF trace needs to be as short as possible for better signal. Do we need to bend RF trace when tuning component comes in between? See attached image for a better understanding of my question.

enter image description here

Do I need to follow curved traces at interaction of L3 and C67?

  • \$\begingroup\$ I believe you're supposed to use a 45 degree chamfer but don't quote me on that. \$\endgroup\$ – τεκ Oct 24 '18 at 13:32
  • \$\begingroup\$ @τεκ As always, Microwaves101 has you covered! \$\endgroup\$ – Shamtam Oct 24 '18 at 13:59

Yes, a smooth bend would be better for signal integrity than the square corner. All other things being equal, that corner sticking out represents an unnecessary impedance "bump" in the transmission line. Although in this case, the dimensions are so short that you'd probably never be able to measure the difference. The solder fillets on the nearby components also create impedance changes of about the same order of magnitude. And making the turn within a component pad makes the question moot anyway.


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