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I am trying to design a microstrip Wilkinson power divider in ADS for 2.4GHz. My schematic is shown below: enter image description here

The calculations all check out but I am not getting the best RL at 2.4GHz: enter image description here

If anyone could help figure out what is going on that would be great

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  • \$\begingroup\$ Given you seem to have got pretty good performance at 4.8 GHz, try doubling the length of all the transmission line elements in your design. \$\endgroup\$
    – The Photon
    Commented Oct 30, 2020 at 5:20
  • \$\begingroup\$ If you want us to show where you went wrong, show the calculations you did to choose the transmission line lengths. \$\endgroup\$
    – The Photon
    Commented Oct 30, 2020 at 5:21

2 Answers 2

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Looks like you have calculated quarter wavelength at 4.7 GHz. You need to double the length of microstrip for 2.4 GHz. Check out the simulation and schematic. (I have use the same substrate and values you used)

I have doubled the length

Here is the plot

Try to do EM simulation in ADS with the layout for better and accurate results.

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  • \$\begingroup\$ This worked thank you!! \$\endgroup\$
    – user267451
    Commented Oct 30, 2020 at 16:07
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Your microstrip lines are shown as 0.348" long, which is 8.84 mm. Given the speed of light in FR4 is roughly c/2 1, this corresponds to an electrical length of about 16 mm. As a Wilkinson is built with λ/4 line, it's tuned to a wavelength of about 64 mm, or a frequency of c/λ = 300e6 / 64e-3 = roughly 4.7 GHz, which is what your plot shows.

Double the length of the lines.

1 Very approximate, depends on geometry and frequency, especially with a horrible substrate like FR4, but it's good enough for gross back-of-envelope calculations like this.

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