# implementation of a band-pass filter

1. ## Re: implementation of a band-pass filter

Originally Posted by CataM
The attenuation will be given by the filter's components. ADS will show what is the attenuation if you use the Filter Design guide...
I am using that but ... I can't even set my filter order ...
When I choose a low-pass filter I can set the filter order easily but for a band-pass filter, it doesn't work...
so I have 2 problems now!
1- I can't set filter order using Filter Design Guide (N=5, e-r,bans-pass)
2- then attenuation

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Originally Posted by FvM
If you give the known specifications for your filter, we can possibly clarify how far the remaining parameters are already determined by it. Or implement a design example.
sure, an equal ripple band-pass with a center frequency of 3.5GH and FBW=20%...for 5dB, N=5

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2. ## Re: implementation of a band-pass filter

Originally Posted by MAHYAR239
1- I can't set filter order using Filter Design Guide (N=5, e-r,bans-pass)
2- then attenuation
Filter's order gives the attenuation.
sure, an equal ripple band-pass with a center frequency of 3.5GH and FBW=20%...for 5dB, N=5
Try with Maximally flat with following parameters:
Ap=5 dB
As= 122 dB
Fs1=0.28 GHz
Fp1=2.8 GHz
Fp2=4.2 GHz
Fs2=42 GHz

That gives a 5th order Band Pass filter.

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3. ## Re: implementation of a band-pass filter

Originally Posted by CataM
Filter's order gives the attenuation.

Try with Maximally flat with following parameters:
Ap=5 dB
As= 122 dB
Fs1=0.28 GHz
Fp1=2.8 GHz
Fp2=4.2 GHz
Fs2=42 GHz

That gives a 5th order Band Pass filter.
but it's an equal-ripple one

4. ## Re: implementation of a band-pass filter

Do you want 5 dB pass band ripple?

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5. ## Re: implementation of a band-pass filter

Originally Posted by FvM
Do you want 5 dB pass band ripple?

yes, that's what I want

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Now, I'm trying to design it using "Passive Circuit DG - Microstrip Circuits" feature of ADS...when click the "design "it shows the following warning ..how can I modify it?

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6. ## Re: implementation of a band-pass filter

5 dB ripple is quite high, that's true. It involves particularly a high Q of individual LC sections and respective sensitivity against parameter variations, also possibly extreme L and C values.

I don't know if it's an exercise or a real hardware design problem.

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7. ## Re: implementation of a band-pass filter

I wonder why my manual values of capacitors and inductors are not even close to the values ADS gives ...

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and
but I have these values from manual calculations:
for example : C1 = 0.1066 pF , L1= 19.3919 nH
What's wrong?

8. ## Re: implementation of a band-pass filter

I got similar values as ADS with Nuhertz Filter Solutions. How did you calculate the filter? Same topology, same parameters?

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9. ## Re: implementation of a band-pass filter

It is very difficult to implement a 5th order band pass filter with only 1 pair of capacitor and inductor..

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10. ## Re: implementation of a band-pass filter

I see C1 = 0.1066 pF , L1= 19.3919 nH if you design the filter for 0.5 dB pass band ripple.

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11. ## Re: implementation of a band-pass filter

I guess I had some mistakes in the manual calculation ...thanks all

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