I am trying to connect W3113 antenna to my RFID UHF reader. The datasheet of the reader requires me to use 50 ohm microstrip line. However, I do not find where I can draw microstrip. Is it still the regular routing? If not, how do I draw the microstrip line in EAGLE? Thanks!


Microstrip simply means a controlled-impedance trace on one of the surface layers. A stripline is the same, except on an internal layer.

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A Microstrip is just a regular track but you determine its required width in order to have a specific characteristic impedance (50 ohms in your case) based on the copper weight and distance between it and the ground plane beneath it on an internal layer (or bottom layer, if you only have a two-layer board). This is one of the most accurate online calculators I know of that will help you determine the correct width of your trace: https://www.eeweb.com/tools/microstrip-impedance

  • \$\begingroup\$ Thank your for your detailed reply. For the substrate, does it refer to the material of my PCB, such as FR-4? \$\endgroup\$ – LFJY Jun 21 '18 at 19:28
  • \$\begingroup\$ @LFJY Yes, "substrate" means the material to which the copper is adhered, so in your case, FR-4 \$\endgroup\$ – DerStrom8 Jun 21 '18 at 20:03

There are no special provisions for that in Eagle.

You have to calculate the necessary trace width and gap yourself, it depends on your stackup. There are various calculators for this, e.g. this one.

  • \$\begingroup\$ Thank you! So I will just use the regular routing in Eagle. \$\endgroup\$ – LFJY Jun 21 '18 at 19:28

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