a glimpse into multiphysic-analyses | cst eumw 2010 presentations| september 2010 | 1 a glimpse into

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  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 1

    A Glimpse into Multiphysic-Analyses

    using

    CST STUDIO SUITE™

    Accounting for thermal heating effects and mechanical

    deformation in the electrical design

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 2

    EM-field computation

    Thermal

    analysis

    Stress analysis /

    deformation

    EM-properties of deformed geometry

    can be fed into sensitivity analysis

    The Motivation …

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 3

     Thermal Simulation

     Mechanical Stress Simulation

    CST MPHYSICS STUDIOTM

    Courtesy of Spinner GmbH, Germany

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 4

    Online Demo

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 5

    Example : 2-Post Bandpass Filter

    Rel Bandwidth:0.9 %

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 6

    1) EM (FD tet)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 7

    1D Results > |S| dB

    Tchebychev Filter

    ===================

    Order = 2

    Bandwidth = 5 MHz

    Center Frequency = 570 MHz

    Passband ripple = 0,01 dB (1,100747 VSWR)

    Return loss = -26,3828 dB

    Normed g values:

    -------------------------------------------

    g1 = 0,4489

    g2 = 0,4078

    g3 = 1,1008

    Corresponding coupling coefficients in MHz / (rel):

    -------------------------------------------

    k_E = 11,14 (0,0195413)

    k1_2 = 11,69 (0,0205021)

    k_out = 11,14 (0,0195413)

    Group Delay Time

    ----------------

    t_d1 = 57,153 ns

    t_d2 = 51,922 ns

    t_d3 = 0, ns

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 8

    Power Loss Dens. > loss (f=0.575)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 9

    Power Loss Dens. > loss (f=0.575)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 10

    Current Density (f=0.575)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 11

    Export the Thermal losses

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 12

    2) Thermal Solver

    Import the losses from EM FD

    5000

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 13

    Thermal boundaries Thermal volume losses as sourceThermal boundaries

    Temperature Heat flow

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 14

    3) Mechanical Solver

    FxKxBxM 

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 15

    http://www.engineeringtoolbox.com/young-modulus-d_417.html

    1 GPa = 1kN/mm2 σ=ε.E

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 16

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 17

    Displacements > displacement1 Define a displacement eg at a face (xyz) directly at the WG-Port

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 18

    Import a field source (from therm),

    and activate it

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 19

    2D/3D Results > Displacement Temperature change as source Mech. Displacements

    Von Mises Stress Deformed Mesh

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 20

    Matrix to solve: QEK

    [K]: symmetric, complex, contains geometry, material, frequency

    xi, yi

    Example: Linear Shape functions for a 2D element in xy

    jkijkkjijkkjkjijk

    kji

    kji

    kji

    xxcyybxyyxa

    ccc

    bbb

    aaa

    yxN ;;;.,,1 2

    1

    xj, yj

    xk, yk

    k

    j

    i

    kji

    z

    z

    z

    NNNz ],,[

    zi

    [E]: unkowns z

    [Q]: Sources

    kjinmdxdy x

    N

    x

    N

    x

    N

    x

    N k nmy

    nm

    xy

    xnm ,,,;)(,

    Example: electrostatic

    4) Sensitivity ( Introduction)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 21

    ),(),(),( 1

    ),( 0

    pEpKpE j

    pS TT

    Introduction to Sensitivity

    S-Parameters:

    [K] …left hand side, E (Fields at ports, p… any parameter

    E p

    K E

    p

    S j T0

    Sensitivity of S-parameter vs. parameter change:

    Direct analytical derivation of

    K-matrix elements via e.g. [N]

    3D Fieldsolution

    Same 3D Fieldsolution

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 22

    Numerical calculation of gradients is expensive and unstable

    Here: Sensitivity of S-parameter vs. parameter change

    no additional 3D solution required (only another S-Parameter computation)

    Very efficient computation of sensitivities

    Result: S-parameter ranges for tolerant parameters

    Currently available for FD-Tet solver

    Introduction to Sensitivity

    E p

    K E

    p

    S j T0

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 23

    p p

    S SS

    p

    MWSDnmnm .)3(

    What is it good for?

    The sensitivity helps estimate „new“ S-parameters due to the (small) change

    of the parameter, at no extra cost

    Suppose the parameter p changes by a quantity ∆p :

    exact computation of the Sensitivity

    (Approximated by 1st order Taylor expansion)

    Introduction to Sensitivity

    The various sensitivities are used in an optimizer to solve for ∆p as variables to

    best fit the S-parameter goals.

    ∆p … face constraints

    p p

    S xSpxS

    p

    .)()(

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 24

    For every product, there are: Technical specifications

    Fabrication tolerances

    The fabrication tolerances will lead to some

    products not fulfilling the specifications

    Yield:

    What is the Yield Analysis

    Total

    Passed yield

    #

    #

    Gaussian

    Uniform

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 25

    How is yield calculated typically?

    Parameters vary according to a known probability curve

    Repeat

    Change the value of all parameters

    Simulate

    Check if specification (in our case for S-params.) is met

    Until the number of simulations is statistically relevant

    This is a large number of EM simulations - typicaly hundreds or thousands!!!

    Knowing the sensitivity, there is no need to perform 3D simulations, at least if the parameters vary in a small range.

    The efficiency of this new sensitivity analysis approach makes Monte-Carlo based yield analysis feasible even for complex multi-parametrical three- dimensional structures

    Typical Approach vs. CST Approach

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 26

    Import the displacements

    4) Sensitivity (based on mech. Displacements)

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 27

    Setup Sensitivity Analysis

    4) Sensitivity

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 28

    Display S-parameter Sensitivity

    4) Sensitivity

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 29

    Summary

    Integrated workflow with

    CST MPHYSICS STUDIO™

    Ease-of-use: New solvers within

    well known frontend

    Accuracy of integrated solution and

    solver technology

    Wide application range due to tight

    integration within CST STUDIO SUITE™

    Thermal

    Structural Mechanics

    EM

  • www.cst.com | CST EuMW 2010 Presentations| September 2010 | 30

    Thank you for your attention!