Introduction to High
Frequency Structure Simulator
Pengcheng Jia
Background
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Introduced from 90s
Simulation tool for complex 3 D geometries
Using Finite Element Method
Adaptive Mesh generation & refinement
2 Main Vendors—Agilent & Ansoft
Merger from May 1
Transfer to Ansoft HFSS after Nov. 1, 2001
Requirement & Resources
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HFSS consume tremendous memory if fine
result is needed
300M+ Memory and 400M+ processor is
recommended
Floating License Key within ECEWIN2K
subnet
Remote access to new Scully which has 1 G
RAMBUS400 Memory and 1.7G P4 processor
Agilent HFSS
Ansoft HFSS
Features(1)
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Computes s-parameters and full-wave fields
for arbitrarily-shaped 3D passive structures
Powerful drawing capabilities to simplify
design entry
Field solving engine with accuracy-driven
adaptive solutions
Powerful post-processor for unprecedented
insight into electrical performance
Features(2)
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Advanced materials
Model Library-including spiral inductors
Model half, quarter, or octet symmetry
Calculate far-field patterns
Wideband fast frequency sweep
Create parameterized cross section models2D models
Applications
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Antennas
Microwave transitions
Waveguide components
RF filters
Three-dimensional discontinuities
Passive circuit elements
Procedure to simulate
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Open or Make new project
Draw objects
Assign material property
Define boundary conditions
Solve
Display result
New project
Project Preferences
Drawing basics
Drawing Lines & 2 D objects
Drawing 3 D objects
Object Library
Editing Objects
Materials
Metal & Resistor
Boundaries
Boundary Conditions
Add A Boundary
Display Boundary
Calibrating Ports
Solve
Frequency & Meshing
Displaying Results
S Matrix
Plot Field
Result Comparison
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r=8.5; Hsub=625 um; W=150um; G=75 um
Z L  jZ 0Tan  L
Z  Z0
Z 0  jZ LTan  L
---Theoretical Equation
@10G
Theoretical HFSS
L=100 um
0.04 nH
0.05 nH
L=300 um
0.12 nH
0.13 nH
L=600 um
0.24 nH
0.24 nH
L=800 um
0.33 nH
0.31 nH
Finite Element Method
Tetrahedron
Impedance Concept
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Zpi, Zpv & Zvi
Microstrips use Zpi impedance
2P
1
Zpi 
;P 
*
I I
2
 ExHds; I   Hdl
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Slot-type (CPW) use Zpv impedance
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TEM waves use Zvi impedance
V V *
Zpv 
2P
Zvi  Zpi  Zpv
Projects with HFSS
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Microstrip Line to Waveguide Transition
EM Field of the transition
Waveguide Combiner System
Slotline Antenna
Bonding Wire Discontinuity
Packaging for CPW Lines
Field Plot
Useful links
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http://www.ansoft.com
http://dutettq.et.tudelft.nl/~hfss/welcome.html
http://wwwinfo.cern.ch/ce/ae/Maxwell/index.html
Documents for HP HFSS is in “Scully”
c:/Otherprg/hfss/doc
References
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HP High-Frequency Structure Simulator
User’s Reference
HP High-Frequency Structure Simulator
Tutorial