Upload
goeksenin-bozdag
View
204
Download
11
Embed Size (px)
DESCRIPTION
filters
Citation preview
EE522 Numerical Methods for EM
-Final Project-
Microstrip Notch Filter
Goksenin Bozdag
December 30, 2014
Goksenin Bozdag 30 December 2014 2/22
Outline
MS Filter Design
MS Notch Filter Design
OpenEMS Simulation
HFSS Simulation
QUCS Simulation
Fabrication and Measurement
Comparison of the Results
Goksenin Bozdag 30 December 2014 3/22
Microstrip Filter Design
A filter two-port network used to control the frequency response at a certain point
Low-pass, high-pass, band-pass, and band-reject
Communication, radar and measurement systems
Goksenin Bozdag 30 December 2014 4/22
The image parameter method in WW II
Today, CAD packages by the insertion loss method
The methods lead to circuits using lumped elements
In RF, distributed elements such as microstrip lines needed to use
Limited range of lumped inductors and capacitors
Difficult implementation at microwave frequencies
Richards Transformation and Kurodas Identities
Microstrip Filter Design
Goksenin Bozdag 30 December 2014 5/22
Image parameter method
cascade of simpler two port filter sections
the procedure is relatively simple
Iterated many times
Microstrip Filter Design
low-pass filter
half section
low-pass response,
single half-section
low-pass response with
four (half) sections
Goksenin Bozdag 30 December 2014 6/22
Microstrip Notch Filter Design
Insertion loss method
Uses network synthesis techniques
Ideally, no power loss in the passband
Bases normalized low-pass filter
2dB 10log 10log 1 ( )inL
PIL
P
2
1
1 ( )LRP
2
2
M( )1
N( )LRP
where M and N are
real polynomials.
Goksenin Bozdag 30 December 2014 7/22
Richards transformation converts lumped elements to transmission lines
Microstrip Filter Design
tan( l)LjX jL
tan( l)CjX jC
Reactance of
Inductance Short-stub
Susceptance
of Capacitance Open-stub
Goksenin Bozdag 30 December 2014 8/22
Microstrip Filter Design
Kurodos identities use redundant transmission lines
Separete transmission line stubs
Series stubs into shunt stubs, vice versa
Impractical impedances to practical impedances
where n2= 1 + Z2/Z1
Goksenin Bozdag 30 December 2014 9/22
Microstrip Filter Design
Low-pass
equivalent circuit
Richards Transf. & Freq. Mapping
Adding Matched
Unit Elements
Applying Kurodas Identities
Goksenin Bozdag 30 December 2014 10/22
Notch filter rejects the band sharply, band-stopping
Avoiding interference or unwanted signals
More optimum filter structures
Employing quarter-wave open and short stubs in series and parallel as resonant circuits
Microstrip Notch Filter Design
Lumped element
band-stop filter
Equivalent circuit with
addmittance inverters
Goksenin Bozdag 30 December 2014 11/22
Microstrip Notch Filter Design
Admittance inverter
O.C. for LC Res.
All of the elements represents by distributed elements
Avoided reduntant elements
Characteristic impedance of open stubs
4 oon
n
ZZ
g
Zo1 = Zo = 50 and = 12.5 mm for g1 = 0.7 and = 1.8 at 3.2 GHz
where g coefficient of 0.5 dB equal ripple
and =
Goksenin Bozdag 30 December 2014 12/22
Finite Difference Time Domain (FDTD) Solver
Open and Free, requires MatLab or Octave
The code separeted into six parts
Setup geometrical parameters
Setup FDTD paramters (e.g. Boundary cond.)
Setup FDTD mesh (resoulution, thin metal)
Assiging Substrate Material
Assisgning ports and open-stub
Post processing (reading voltages and currents)
OpenEMS Simulation
Goksenin Bozdag 30 December 2014 13/22
OpenEMS Simulation
Goksenin Bozdag 30 December 2014 14/22
High Frequency Structure Simulator, Ansys Inc.
Finite Element Method (FEM)
Frequency Domain Solver
Filter modeling includes the parts:
Draw the geometry
Assigin the materials
Assign the ports and boundaries
Setup solution frequency and convergence
Setup sweep frequencies
Post Processing
HFSS Simulation
Goksenin Bozdag 30 December 2014 15/22
HFSS Simulation
0.50 1.50 2.50 3.50 4.50 5.50Freq [GHz]
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
Y1
HFSSDesign1MSL NF HFSS ANSOFT
m1
m6 m7
m2Curve Info
dB(S(1,1))Setup1 : Sw eep
dB(S(2,1))Setup1 : Sw eep
Name X Y
m1 3.2650 -28.3810
m2 3.2650 -1.0139
m6 2.4500 -3.0028
m7 4.0000 -3.0114
Goksenin Bozdag 30 December 2014 16/22
Quite Universal Circuit Simulator, open and free
Mathematical formulations for calculation
Includes many library and tools including
MS lines, stubs, lumped elements and
transmission line calculators eg. rectangular wg
Filter modeled by following the steps
Draw the circuit diagram using library
Assigin the substrate
Setup sweep frequencies
Post Processing
QUCS Simulation
Goksenin Bozdag 30 December 2014 17/22
QUCS Simulation
Goksenin Bozdag 30 December 2014 18/22
Fabrication and Measurement
Goksenin Bozdag 30 December 2014 19/22
Mesh Number Duration (sec) Res.Frq. (GHz)
OpenEMS 55514 150.2 3.217 0.5176
HFSS 14240 144 3.265 0.4747
QUCS X 2 3.220 0.5559
Realized Filter X X 3.250 0.4077
Comparison of the Results
Error Rates (%)
Resonance Freq.
OpenEMS 1.0154 34.3144
HFSS 0.4615 16.4337
QUCS 0.9231 36.3503
HFSS the most accurrate
QUCS results almost the same with openEMS
QUCS the most practical and fast
Goksenin Bozdag 30 December 2014 20/22
References
Pozar, David M., Microwave Engineering, John Wiley & Sons, USA, 2012.
Hong, J. S. and Lancaster M. S., Microstrip Filters for RF and Microwave Applications, John Wiley & Sons, New York, 2001.
Ludwig R. and Bretchko P., RF Circuit Design: Theory and Applications, Prentice-Hall Inc., New Jersey, 2000.
Goksenin Bozdag 30 December 2014 21/22
References for Softwares
OpenEMS, www.openems.de
HFSS v13, www.ansys.com/Products
QUCS, www.qucs.sourceforge.net
Goksenin Bozdag 30 December 2014 22/22
Thanks for your
participation.
Questions ?