+ Post New Thread
Results 1 to 3 of 3
  1. #1
    Full Member level 1
    Points: 1,371, Level: 8

    Join Date
    Sep 2010
    Posts
    107
    Helped
    17 / 17
    Points
    1,371
    Level
    8

    component dimension selection for RF circuits

    Hi,

    Got two questions,

    1. Is there a general rule for selecting dimensions of components for RF circuits?
    I've heard lumped component dimensions should be less than lambda/10 at the operating frequency... is that true?

    2. Can we have holes in a metal package of a microwave circuit which will not allow to leak RF signals?
    dimensions of the holes in terms of lamda? < lambda/10, <lambda/20 etc?

    cheers,
    per_lube

    •   AltAdvertisement

        
       

  2. #2
    Advanced Member level 1
    Points: 2,811, Level: 12

    Join Date
    Sep 2012
    Location
    Pakistan
    Posts
    414
    Helped
    80 / 80
    Points
    2,811
    Level
    12

    Re: component selection for RF circuits

    i think size of component depends on the power they can handle 1/4Watt resistor must be smaller than 1Watt one. with same freq. but high Power requirement you will have to use a bigger one no matter how it effects lamda/10 or else!!
    as a general rule use smallest package component that at the same time can handle required power, it is good for space minichrization point of view.
    If you Believe everything you Read, Better Don't Read!


    1 members found this post helpful.

    •   AltAdvertisement

        
       

  3. #3
    Advanced Member level 5
    Points: 20,661, Level: 34
    Achievements:
    7 years registered

    Join Date
    Jan 2011
    Posts
    3,382
    Helped
    1208 / 1208
    Points
    20,661
    Level
    34

    Re: component selection for RF circuits

    Power dissipation is one concern, but with regards to component sizing I'm usually concerned about how size effects signal losses and circuit accuracy. For example if I'm at 500MHz are 1008 packages still okay, or should I move down to 0805 or smaller? On one hand my components will probably behave more like they should with their marked values, but on the other hand they will have lower Q and more loss. So how do you know when to make the switch?



--[[ ]]--