HFSS

1. Introduction to High
Frequency Structure Simulator
Pengcheng Jia

2. Background
 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

3. Requirement & Resources
 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

4. Agilent HFSS

5. Ansoft HFSS

6. Features(1)
 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

7. Features(2)
 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 models-
2D models

8. Applications
 Antennas
 Microwave transitions
 Waveguide components
 RF filters
 Three-dimensional discontinuities
 Passive circuit elements

9. Procedure to simulate
1. Open or Make new project
2. Draw objects
3. Assign material property
4. Define boundary conditions
5. Solve
6. Display result

10. New project

11. Project Preferences

12. Drawing basics

13. Drawing Lines & 2 D objects

14. Drawing 3 D objects

15. Object Library

16. Editing Objects

17. Materials

18. Metal & Resistor

19. Boundaries

20. Boundary Conditions

21. Add A Boundary

22. Display Boundary

23. Calibrating Ports

24. Solve

25. Frequency & Meshing

26. Displaying Results

27. S Matrix

28. Plot Field

29. Result Comparison
 r=8.5; Hsub=625 um; W=150um; G=75 um
@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
0
0
0
L
L
Z jZ Tan L
Z Z
Z jZ Tan L





---Theoretical Equation

30. Finite Element Method
Tetrahedron

31. Impedance Concept
 Zpi, Zpv & Zvi
 Microstrips use Zpi impedance
 Slot-type (CPW) use Zpv impedance
 TEM waves use Zvi impedance
*
2 1
; ;
2
P
Zpi P ExHds I Hdl
I I
  
  
*
2
V V
Zpv
P


Zvi Zpi Zpv
 

32. Projects with HFSS
 Microstrip Line to Waveguide Transition

33. EM Field of the transition

34. Waveguide Combiner System

35. Slotline Antenna

36. Bonding Wire Discontinuity

37. Packaging for CPW Lines

38. Field Plot

39. Useful links
 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

40. References
 HP High-Frequency Structure Simulator
User’s Reference
 HP High-Frequency Structure Simulator
Tutorial