Microstrip Tapped Line filter Design - RF Cafe Forums
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Post subject: Microstrip Tapped Line filter Design Posted:
Fri Jun 29, 2007 5:31 am
Joined: Sat Jun
16, 2007 12:26 am
Can you tell me how
to find out the tapped point and tapped length in a Edge coupled tapped
line filter design?
I am trying to design a band pass filter
using Edge coupled tapped line structure.
The inputs I have
are impedances, Er, substrate information. I am not able to find out
the way to calculate tapped point and tapped length using all these
Is there any way to find out the tapped length and tapped
point using ADS tool? If it is then how?
Post subject: Posted: Sat Jan 03, 2009 1:39 pm
Joined: Fri Jan 02, 2009 12:27 pm
Search for an
IEEE article titled "Microstrip Tapped-Line Filter Design" by Joseph
S. Wong. That article gives the design procedure and all the math behind
selecting the tap point.
Posted: Tue Jan 06, 2009 12:09 pm
Fri Feb 17, 2006 12:07 pm
Location: London UK
you cannot locate that, a simple high-level approach is to set the internal
impedance level of the filter (say 200 ohms or whatever), which can
improve the design process. Then the tapping point is simply derived
from the ratio of internal and external (50 ohm) impedance, the end-line
characteristic Z, and the loaded Q of the input/output resonators. The
tap point = Len * ASIN(SQRT(PI*Zs/(4*Z0*Ql)))
where len is the length of the end resonator,
Zs is the internal
impedance (100 ohm, 200 ohm or whatever)
Z0 is the characteristic
impedance of the end resonator in its geometric environment
Ql is the loaded Q of the end resonator, derived from graphs.
process is described in the RSGB Microwave Handbook, a 3 volume set.
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