optimization for a flat S21 in ADS

[shanmei]

In ADS optimization function, I would like to have a flat S21 over 1GHz-2GHz. How can I set an arbitrary magnitude? The following only allows me to set a specific magnitude. I just need a very constant magnitude over the frequency, regardsless of the magnitude.

For example, if the magnitude is around 20dB, then the region is around 18-20dB.
if the magnitude is around 10dB, then the region is around 8-10dB.
Thanks.

 

[BigBoss]

If you change Type ">" to "Inside", the optimizer will do it.

 

[shanmei]

Thank you. "Inside" helps to define a region. However, it still requires to enter the specific "max" and "min" value. For example, I have to define the "max" to be 20, and the "min" to be "18".

Is there a way that I don't need to define the exact value of the "max" and "min"? I only need to the deviation region of the S21 to be 2dB. Whatever 10dB-12dB or 20dB-22dB.

 

[volker@muehlhaus]

I never tried that, but maybe you can use a composite goal like

max(db(S21))-min(db(S21))

The difficulty is the result is a single number only, not a vector of values over frequency. It would be possible to limit the frequency using index values.

Example:

max(db(S21[COLOR="#FF0000"][5::11][/COLOR]))-min(db(S21[COLOR="#FF0000"][5::11][/COLOR]))

for frequency point 5 to 11

 

[vivekroy]

I think what you are trying to do is to reduce the ripple within a band.

Why not try the ripple function of ADS? See page 370 of https://literature.cdn.keysight.com/litweb/pdf/ads2005a/pdf/expmeas.pdf

 

[shanmei]

The function ripple works. Thanks.