Introduction. HFSS 3D EM Analysis S-parameter. Q3D R/L/C/G Extraction Model. magnitude [db] Frequency [GHz] S11 S21 -30

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Moris Griffith
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1 ANSOFT Q3D TRANING

2 Introduction HFSS 3D EM Analysis S-parameter Q3D R/L/C/G Extraction Model magnitude [db] S11 S Frequency [GHz]

3 Quasi-static or full-wave techniques Measure the size of the interconnect in units of wavelength! Size < λ/10, use quasi-static solvers. Output circuit model in RLGC. Size > λ/10, and/or radiation important, use full-wave solvers. Output S, Y, and Z parameters and fields.

4 Wavelength issues low frequencies (lump model) : λ/10 wavelengths >> wire length ν p = λ f

5 Q3D Extractor 1. 3D Fast Quasi-static EM solver 2. 2D Fast R/L/C/G EM solver Arbitrary 3D structure

Capacitance matrix The equation relating the total charge on a capacitor with the potential difference relative to a ground at zero volts is : Q=CV In a three-conductor system, matrix

6 Capacitance matrix The equation relating the total charge on a capacitor with the potential difference relative to a ground at zero volts is : Q=CV In a three-conductor system, matrix notation is used: Q1 C11 C12 C13 V1 Q C C C V Q3 C31 C32 C33 V3 The off diagonals are always negative, which accounts for the sign of the charge on each of the conductors.

7 Q3D and circuit capacitance Q3D solution: s s Q1 C C V s s Q 2 C C V circuit solution: Q C V C V V k k Q C V V C V k k C C C C s k k C s k 12 12

8 Self-inductance

9 Mutual-inductance A voltage is induced across a conductor when the number of field lines around it changes. di dt a V Ls Lab di dt b

10 Partial inductance Partial self inductance: number of field lines per amp around just the conductor segment. Partial mutual inductance: number of field lines per amp around both the conductor segment.

11 Partial inductance matrix Defined for any collection of conductors di k Vj Ljk k dt di di di di V L L L L dt dt dt dt Partial self inductance Partial mutual inductance

12 Loop inductance V2 L22 I2 L21 I1 L23 I3 L2g I g V L I L I L I L I gnd gg g g1 1 g 2 2 g3 3 V V V ' 2 2 gnd V I ( L L L L ) ' g g1 gg I ( L L L L ) g g 2 gg I ( L L L L ) g g3 gg

13 Inductance matrix The individual elements of the inductance matrix are computed in the same way as the elements of the capacitance matrix. For a three-conductor system with a well-defined ground return path, the relationship between the magnetic flux in each loop and the current loop I in each is given by: 1 L11 L12 L13 I1 L L L I L31 L32 L33 I3 The diagonal elements are self-inductances and the symmetric off diagonal elements are the mutual inductances of the loops.

14 Solve setup Capacitance matrix DC Resistance and inductance matrix AC Resistance and inductance matrix

15 Solve setup Number of conduction passes to refine FEM mesh % total error as stopping criteria % with the largest error, changed per pass

16 Solve setup Conduction passes. C: optimizes DC mesh Difference between the n and n-1 iteration M: calculate the R, L and optimizes the large scale structure of the mesh

17 Mesh of DC and AC solution DC AC

18 Reduced matrix operation Move sink Add sink Join in series Join in parallel Float net Return path Ground net Float terminal Float at infinity Change frequency

19 Move sink Let you switch the placement of sink terminals in a conductor without having to change the terminal assignment and generate a new solution. i i i i out 1 2 3

20 Add sink Allow user to add current sinks to a model without having to change the setup and generate a new solution. Allows user to simulate the presence of multiple current sinks in a conductor. While actually solving the model, only a single sink is allowed for conduction simplicity.

21 Join in series and parallel This feature allows you to connect two or more conductors in series and parallel. Series Parallel

22 Ground net and Return path Grounded net reduce feature allows you to add grounded conductors to your model. Return path lets you select a conductor that is identified as a return path enabling you to model the effects of return currents on the inductance and resistance matrices. Notice that the negative reference node for defining the branch voltages has also been changed.

23 Q3D extractor processes

24 Reference A. E. Ruehli, Inductance calculations in a complex integrated circuit environment, IBM J. Res. Develop., vol. 16, pp , Sept A. E. Ruehli and P. A. Brennan, Capacitance models for integrated circuit metallization wires, IEEE J. Solid-State Cir., vol. SC-10, pp , Dec

Do not fill out the information below until instructed to do so! Name: Signature: Section Number:

Do not fill out the information below until instructed to do so! Name: Signature: E-mail: Section Number: No calculators are allowed in the test. Be sure to put a box around your final answers and clearly