UHF bandpass filter

  1. tuyoleni
    tuyoleni
    Hi guys

    I am struggling with a UHF band pass filter. Here are the specs:

    Passband frequency range: 416 - 458 MHz
    Center frequency: 436.5 MHz
    Stopband attenuation: 60 dB
    Loss: 1 dB or better
    Filter order: 3

    I have done the simulation in Filter solutions and when I buid it it doesnt work. I please want if somebody can do the simulation in MWO office and see how it looks like. I am not experienced with MWO. Any suggestions are welcome.

    Your comments and help will be highly appreciated.

    Thanks in advance
  2. kalbun
    kalbun
    Hello, this message is quite old, but I'll post an aswer nonetheless.
    I passed your filter data to Elsie, the software we use for this kind of work.
    Here are the resulting components. It's a Cauer filter, 3rd order, that meets your specifications, and the components' values seem reasonable.

    1st parallel LC: 68pF, 2nH
    1st series LC: 1pF, 54 nH
    2nd series LC: 2p4, 136nH
    2nd parallel LC: 68 pF, 2nH
    Zi=Zo=50R

    Hope this helps...
    Giuseppe
  3. feilong87
    feilong87
    Can you give a circuit diagram and some pictures about that?
    And Stopband frequency range?
    thanks.
  4. Tomas1707
    Tomas1707
    feilong87, when you write, it doesnt work, you mean in the device which it is designed for, or you measured it by scalar or spectral analyzer?
  5. sv1437
    sv1437
    Hi feilong87, did you get your UWB filter to work ?

    And kalbun (Giuseppe), I used the inductor and capacitor given by you in the earlier post , I don't see a UWB response.

    See the attached schematic and the frequency response.


  6. chaitanya4
    chaitanya4
    please...provide the formulae you have used to find inductor and capacitor values
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