microstrip bandpass filter at 2.4 GHz

[SAWW]

hi,
i m designing microstrip bandpass filter at 2.4 GHz in ads 2011 using FR4 substrate.. my schematic is giving good results but layout results are completely different from the schematic.. can u tell what could be the possible errors ?

 

[BigBoss]

What type of schematic do you use ?? What is your simulation tool ?? What are your EM settings ??What kind of MS model have been implemented accurately in this tool ??

 

[SAWW]

i m using parallel coupled lines.. EM simulation(dielectric constant-4.4, height-1.58 mm,conductor thickness-0.035,tand=0.002, conductivity-4.1E+7)

 

[volker@muehlhaus]

my schematic is giving good results but layout results are completely different from the schematic.. can u tell what could be the possible errors ?

The schematic simulation can miss some effect (coupling) or the EM setup can be wrong. From experience in EM support, 95% of these problems are from wrong setup in EM. Wrong materials, bad mesh setup, bad port configuration.

Typical mistake in couple line filters is that users forget to enable edge mesh. Without edge mesh, coupling is underestimated.