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I have inductor to block RF. My signal is between 1 and 2 GhZ.

How should I choose the value of this inductor ? 1µH is enough ??

What are the other parameters to take care about ?

enter image description here

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    \$\begingroup\$ If you target 500 ohms reactance at 1 GHz, you get 80 nH. And get about 10% impedance discontinuity. If you need to deliver a lot of current, you might need to use a lower value to get low ESR. If you need to only deliver a little current, you might use a higher value to get less discontinuity with some added cost and board area. \$\endgroup\$ – The Photon Nov 30 '19 at 20:52
  • \$\begingroup\$ The current is about 150mA \$\endgroup\$ – doom Nov 30 '19 at 21:01
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    \$\begingroup\$ So do some engineering. What inductors are available on the market? What's the balance between ESR and how much reflection they'll cause in your design? Which ones meet your needs for price, availability, reliability and vendor support? It's your design, you need to design it. \$\endgroup\$ – The Photon Nov 30 '19 at 21:07
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    \$\begingroup\$ Also remember you need an SRF above 2 GHz. You might end up using two inductors in series to get that and as high of a value as you need. \$\endgroup\$ – The Photon Nov 30 '19 at 21:11
  • \$\begingroup\$ I found LQW04CA90NK00D from Murata that is 90nH, 520mA, 240mOhms max, SRF 2,5GHz and 0302 package (0805 metric). It is unshielded. Think this is a good choice taking in account all given advice. Thanks all for your help. D. \$\endgroup\$ – doom Dec 3 '19 at 11:11
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Your proposed 1 micro H coil has more than enough inductive reactance at 1 GHz to not affect the 50 ohm match.

Problem is when it comes to real coils that have parasitic capacitance. This parasitic capacitance along with your labled inductance gives rise to a parallel resonant frequency. If this resonance is below in your case 2 GHz then the coil is really a capacitor at the top end of your frequency range.

These days coil manufacturers are more likely to state resonant frequencies. When you select your production coil you will be in nH and not micro H because the larger inductances have much lower resonant frequencies.

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