The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Sep 17th, 2019, 3:56pm
Pages: 1
Send Topic Print
SAW filter insert loss (Read 4124 times)
cybq
Junior Member
**
Offline



Posts: 16

SAW filter insert loss
Jul 03rd, 2006, 1:10am
 
Hi friends,
A problem was found that the insert loss of SAW filter synthesized by ADS is not agreed with the specified value if the input and load impedance are different. Isn't a bug in ADS?  There is several dB difference.

That is to the insert  loss ( measured by the output of SAW filter load divided by the voltage when source and load are direct conected) is agreed with the specified value when in/out impedance are the same.


But, when I simulated the S parameters, setting up the Term1 and Term2 are the source and load impedances respectively, I get the result that the S21 is the same as the specified value. Why?

Thanks in advance.

cybq
Back to top
 
 
View Profile   IP Logged
pancho_hideboo
Senior Fellow
******
Offline



Posts: 1424
Real Homeless
Re: SAW filter insert loss
Reply #1 - Jul 3rd, 2006, 8:23am
 
Hi.

What do you mean by "SAW filter synthesized by ADS" ?
You synthesized the equivalent LCR circuits from measured S-parameter of SAW filter ?

S-parameters are defined by port impedances.
So it is natural that S21 is changed when you use different port impedances from vaules in S-parameter measurement.

ADS have following function.

stos()
Changes the normalizing impedance of a scattering matrix
Syntax
y = stos(S, zRef, zNew, zy)
Back to top
 
 
View Profile WWW Top+Secret Top+Secret   IP Logged
cybq
Junior Member
**
Offline



Posts: 16

Re: SAW filter insert loss
Reply #2 - Jul 3rd, 2006, 6:29pm
 
I have tried to synthesized the SAW filter with LCR, but failed. Because it is not possible to synthesie the SAW high selection characteristics with electronical components, instead of using a SAW (which uses the piezoelectric effect to turn the input signal into vibrations that are turned back into electrical signals in the desired frequency range).  


Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2019 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.