high self resonance frequency of capacitor
SRF depends very much by the value of the capacitance. Very small value capacitors, even if they are from cheap manufacturers, have high SRF.
AVX have some good capacitors for microwave frequencies.
Many capacitors have 0,5-0,7 nH parasitic inductance and 0,5 Ohm parasitic resistance. Using these values you can calculate SRF of capacitor which vakue is given. High SRF capacitors have parasitic inductance two times smaller.
actually i want a capacitor 12pF, 9 and 6 pF that will operate at maximum 3 GHz. my supervisor tell me to find a capacitor whose Q is higher and look for SRF of 5 GHz. im very tired of searching. mostly i find is that SRF is at 3 GHz.
i really need ur help gys
You need high Q and SRF or high Q and SRF is not necessary? Look at AVX Accu-P series. 12 pF 0402 capacitor has 2.2 GHz and Q 52 at 1168 MHz.
Or look at SLC Dielectric Labs, ATC and other. They have much larger SRF and Q but are not for solder.
yes i need the one with high q and high srf also. as i said earlier
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You can find ATC or Murata microwave capacitor.
I used Murata microwave capacitor 10pF/0402, and its insertion loss is less than 0.1dB at X band. If I remember correctly, the 1pF SRF can reach 10GHz.
PS.
There are several capacitors, not only 1pF, which SRF reach 12G, or even 40GHz.
Would you like to tell us about application of capacitors which you need? Perhaps Accu-P AVX or GQM Murata series are suitable.