1 / 40

Introduction to Time Domain Electromagnetic Methods

Introduction to Time Domain Electromagnetic Methods. Yanjie Zhu Yinchao Chen Paul G. Huray 12/03/2004. Outline. Comparison of different numerical methods Introduction to Finite Difference Time Domain (FDTD) Method Applications of FDTD to electrical engineering

brigham
Download Presentation

Introduction to Time Domain Electromagnetic Methods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Time Domain Electromagnetic Methods Yanjie Zhu Yinchao Chen Paul G. Huray 12/03/2004

  2. Outline • Comparison of different numerical methods • Introduction to Finite Difference Time Domain (FDTD) Method • Applications of FDTD to electrical engineering • Initial study of CFDTD to the detection of PCB impurities and surface roughness

  3. Frequency Domain Methods MoM (Method of Moment) Zeland IE3DTM Agilent ADSTM (Advanced Design System) Ansoft EnsembleTM FEM (Finite Element Method) Ansoft HFSSTM UGS FEMAPTM Time Domain Methods FDTD Remcom XFDTDTM Zeland FidelityTM RM Associate CFDTDTM MRTD (Multi-Resolution Time Domain) PSTD (Pseudo-Spectral Time Domain) Comparison of different numerical methods

  4. Advantages & Disadvantages

  5. Principle of Finite Difference Derivative of f(x) at point P using finite difference approximations

  6. Mesh Structure for FDTD Algorithm A standard Yee’s lattice

  7. Implementation of FDTD Algorithm Starting point is Maxwell’s differential equations.

  8. Updating Equations-Hz

  9. Updating Equations-Ez

  10. Selection of the parameters ★ Cell size criterion ★ Excitation choices Gaussian pulse: Blackman-Harris pulse:

  11. Boundary Conditions Shielded boundary: Perfect Electric Conductor (PEC) Perfect Magnetic Conductor (PMC) Open boundary: Absorbing Boundary Condition (ABC) Perfectly Matched Layer (PML)

  12. Sequence of an FDTD Iteration Cycle

  13. Calculation of MMICs Parameters

  14. Calculation of MMICs Parameters The characteristic impedance Z0 is calculated by For a transmission line, the effective dielectric constant εeff is defined as: with: For a two-port network, S11 and S21 can be defined as: Input Impedance:

  15. Near-to-Far Field Transformation

  16. Using integral equation Conformal FDTD When the object to be simulated has curved surfaces and edges, the stair casing approximation of conventional FDTD technique can produce significant errors. Stair case: Conformal:

  17. Applications of FDTD in Electrical Engineering • Simulation of Wave Propagation Problems • Microwave Engineering Problems • Antenna Problems • Scattering Problems • Signal Integrity Problems

  18. Simulation of Wave Propagation I will show a simple 1dfdtd matlab code to clarify the wave propagation problem.

  19. Microstrip Low-pass filter

  20. Result

  21. Conical Horn Antenna d1=0.71, d2=1.86, lt=1.08, l=3.75, =28degree

  22. CFDTD ------------ Result

  23. Result

  24. z y x Scattering Problems

  25. Debye sphere 22.5 degree incidence dispersive, theoretical dispersive, FDTD Result

  26. T1 T2 Port1 Port2 T3 T4 Signal Integrity Problem Structure Stack-up: Top View: 100mil*100mil Cell size: 0.7mil*0.7mil*0.35mil Frequency range: 10GHz-60GHz

  27. Result

  28. Result Sig GND Sig GND Sig GND

  29. Result Sig GND Sig GND Sig GND

  30. Result Sig GND Sig GND

  31. Initial study of CFDTD to the detection of PCB impurities

  32. Time domain field distribution

  33. Time domain current distribution

  34. Initial study of CFDTD to the detection of PCB impurity

  35. Time domain field distribution

  36. Time Domain current distribution

  37. Comparison of field distribution

  38. Comparison of current distribution

  39. Comparison of field distribution on yz plane Without impurity With air bubble

  40. Comparison of field distribution on yz plane With dielectric bubble εr=10 With PEC bubble

More Related