How to Analyze the EMC of a Complete Server System?

How to Analyze the EMC of a Complete Server System? Christian Schuster and Xiaomin Duan Institut für Hamburg, Germany Workshop on Hybrid Computational Electromagnetic Methods for EMC/EMI (WS10) EMC Europe, September 17-21, 2012, Rome, Italy

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 2

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 3

Typical High-End Server System IBM Blue Gene/L Supercomputer System (2006) Rack 32 node cards 1,024 chips System 64 Racks 65,536 chips Compute node 2 chips Node card 32 chips 16 compute nodes, IO cards 2.8/5.6 TF/s 512 GB 180/360 TF/s 32 TB Chip 2 processors 2.8/5.6 GF/s 5.6/11.2 GF/s 1.0 GB 90/180 GF/s 16 GB Image: A. Peters and J. Budnik, High throughput computing on Blue Gene, IBM Systems and Technology Group, 2007 4

Challenges for EMC A. Vogt, H.-D. Bruens, S. Connor, B. Archambeault, C. Schuster, Applicability of the Thin Sheet Approximation to the Analysis of EM Emission from Coated PCBs, 2012 IEEE EMC International Symposium on Electromagnetic Compatibility 5

Challenges for Modeling Typical Size 10-6 m Typical Size 1 m Factor 1'000'000! Images: IBM Online Photo Gallery 6

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 7

Elements of a Server Unit Slots Holes Chassis Daughter cards Motherboard ICs Heat sink Cables SMT devices Microstrips 8

Elements of a Server Unit Slots Holes Chassis Daughter cards What would it Heat take sink to simulate this? Cables ICs Motherboard SMT devices Microstrips 9

Problem Sizing Using MoM 8 inch Daughter card Discretization @ 5GHz Driver 50 Δl Signal pin Driver 10 inch 2 inch Motherboard 1.5 inch Ground pin 1 cm 1.5 inch 2 inch 8 inch Connector pins 10 inch Receiver 50 Receiver 18 000 patch elements 5 GB memory 8 core parallel solver 28 minutes per frequency point 10

Problem Sizing Using MoM Slots Holes Chassis Daughter cards MoM: 10-10010 Heat 6 sink patches / days to weeks Cables ICs Motherboard SMT devices Microstrips 11

Problem Sizing Using FEM Discretization @ 50GHz 50 000 mesh cells 1.8 GB memory 8 core parallel solver 35 minutes per frequency 12

Problem Sizing Using FEM Slots Holes Chassis Daughter cards FEM: 10-100 10 Heat sink 6 cells / days to weeks Cables ICs Motherboard SMT devices Microstrips 13

Challenges for EMC A. Vogt, H.-D. Bruens, S. Connor, B. Archambeault, C. Schuster, Applicability of the Thin Sheet Approximation to the Analysis of EM Emission from Coated PCBs, 2012 IEEE EMC International Symposium on Electromagnetic Compatibility 14

Joining Forces for the Attack A. Vogt, H.-D. Bruens, S. Connor, B. Archambeault, C. Schuster, Applicability of the Thin Sheet Approximation to the Analysis of EM Emission from Coated PCBs, 2012 IEEE EMC International Symposium on Electromagnetic Compatibility 15

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 16

Basics of the Method of Moments (1) Incident electromagnetic fields cause surface currents (2) Surface currents generate scattered fields (3) Scattered and incident fields superpose and form the total fields (harmonic time dependency assumed) (4) On all surfaces the total fields have to fulfill the corresponding boundary conditions 17

Basics of the Method of Moments (5) For PEC surfaces: n E tot 0 (6) For dielectric interfaces: n E tot,0 n E tot,1 n H tot,0 n H tot,1 (7) The fields are calculated from electric and magnetic integral equations 18

Basics of the Method of Moments A 4 J e R jkr da j 4 J e R jkr da E ja H 1 A E inc L E ( J ) H inc L H ( J ) R.F. Harrington: Field Computation by Moment Methods, The Macmillan Co., New York, 1968 19

Surface & Current Discretization RWG basis functions Rooftop basis functions S. M. Rao, D. R. Wilton, A. W. Glisson: Electromagnetic Scattering by Surfaces of Arbitrary Shape, IEEE Trans. Antennas Propagat., vol. 32, 1984 20

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 21

The Contour Integral Method Boundary ports (q) Observation y r Rˆ tˆ r r r r n ˆ r C n ˆ Source Via ports (p) n ˆ Cutout area C C z x V k 2 j (2) j d H k r r nˆ J r ds r Rˆ (2) nˆ H k r r V r C C 1 0 (2) H 0 (2) H 1 : Zero-order and first-order Hankel function of the second kind k, η, d: wavenumber, wave impedance and thickness of the substrate T. Okoshi, Planar Circuits for Microwaves and Lightwaves, Berlin, Germany: Springer-Verlag, 1985, ch. 3. 22

Discretization of the Contour(s) N j1 N uij Vj hiji j i 1, 2,..., j1 N 23

Discretization of the Contour(s) 24 p q pp pq qp qq p q pp pq qp qq I I H H H H V V U U U U

Discretization of the Contour(s) Z Z qq pq Z Z qp pp U U qq pq U U qp pp 1 H H qq pq H H qp pp The parallel-plate impedance matrix 25

Calculation of Fields from Currents The boundary field distribution can be obtained by: q I qp V q Z 0 I p Cavity field distribution Far-field radiation 26

Application to Complex Board y (0,6330) (670,6330) (5390,6214) (6615,6214) (0,0) (670,5230) (930,5230) (930,3265) (4156,4980) (4340,4980) (4340,4100) (3800,4100) (3800,3515) (3135,3515) Port 2 (2693,2609) Decaps (3135,3265) Port 1 (5100, 1412) (6615,4980) (5390,4980) (5660,4533) (5660,4100) (5390,4533) (5900,2335) (5900,610) (6910,2335) (6910,2020)(8430,2020) (9240,1630) (8930,610) (10230,4100) (11470,3626) (11470,3405) (12550,3405) (12550,1766) (10230,1630) (8430,1630) (9240,900) (10750,1630) (8930,900) (8930,900) (9240,900) (10750,822) (12420,822) (12550,3626) (12550,3578) (14162, 3578) (13360,1766) (13360,1333) (12420,1333) (14162, 2950) (15338, 2950) (15338, 0) x X. Duan, R. Rimolo-Donadio, H.-D. Brüns, B. Archambeault, and C. Schuster, Special session on power integrity techniques: contour integral method for rapid computation of power/ground plane impedance, in Proc. IEC DesignCon Conference, Santa Clara, USA, February 1-4, 2010. 27

Transfer Impedance Z12 (Magnitude) [db ] Input Impedance Z11 (Magnitude) [db ] 60 40 20 Application to Complex Board no decaps measured no decaps CIM 18 decaps measured 18 decaps CIM 0-20 FEM CIM -40-60 0.1 1 10 100 1000 Frequency [MHz] 60 40 20 0 no decaps measured no decaps CIM 18 decaps measured 18 decaps CIM x -20-40 @ 100 MHz y -60 0.1 1 10 100 1000 Frequency [MHz] 28

Combination with Physics Based Via Model Electrolyte capactors Pitch: 40-80 mil 100 mil SMT capactors Power planes Signal via Ground via 29

Combination with Physics Based Via Model vu C j u V j u I j pp Z ij u I i u V i vu C i C v : via capacitance Z pp : parallel-plate impedance vl C j vl C i Decap L interc. l V j l Ij l I i l V i Cavity 1 vu C j vu C i u I Y V u cu Cavity 2 vl C j Z pp vl C i l I Y Y v cl V l Cavity N X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A combined method for fast analysis of signal propagation, ground noise, and radiated emission of multilayer printed circuit boards, IEEE Transactions on Electromagnetic Compatibility, vol. 52, no. 2, pp. 487-495, May 2010. 30

Electric Field (Magnitude) [kv/m] Combination with Physics Based Via Model Field distribution at 2.4 GHz 0.12 0.1 : Proposed method ------: FEM simulation 2.4 GHz y 0.08 Cavity 3 Cavity 1 z x FEM simulation 0.06 E max 636 V/m E min 4.6 V/m 0.04 0.02 Cavity 5 y 0 0 0.5 1 1.5 2 2.5 3 x-coordinate [inch] Along the observation path z x Proposed method 31

Radiated Power [W] Combination with Physics Based Via Model 120 90 Electric Far Field [V/m] 60 0.006 10 0 150 30 0.002 180 0 [Degree] 10-2 210 330 240 300 270 Horizontal Diagram (xy-plane) FEM simulation Proposed method 10-4 Proposed method FEM simulation 10-6 0 5 10 15 20 Frequency [GHz] Electric far field radiation diagrams at 2.4 GHz and a distance of 10 meter Radiated power X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A combined method for fast analysis of signal propagation, ground noise, and radiated emission of multilayer printed circuit boards, IEEE Transactions on Electromagnetic Compatibility, vol. 52, no. 2, pp. 487-495, May 2010. 32

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 33

Hybridizing CIM and MoM: Part One C Internal ports p Exterior subdomain External ports r Internal: (CIM) Z Z pp qp Z Z pq qq I I p q U U p q y z x Interior subdomain I p Internal ports q I q I r External: (MoM) Y rr U Boundary condition: U r U, q r I r I r I q Port p Z pp Z pq Z pq Z qq Z pq Port q Port r rr Z Yield the parallel-plate impedance including randiation effect: Z p Z pp Z pq 1 1 Yrr Zqq Zqp Z pp Zcorr X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 34

Equivalent Magnetic Current Electric field lines z Power Planes y x Equivalent Magnetic Current Equivalent Magnetic Current z x y Symmetric Plane Electric field lines X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 35

Real Part of Input Impedance [ ] Full MoM vs. Hybrid CIM-MoM 10 3 (4, 3 ) 10 2 10 1 CIM + radiation loss Concept II Port 1 (2,1 ) 10 0 y z z (0, 0 ) x x Port radius: 10 mil c r = 1, tan = 0, d = 10 mil d 10-1 10-2 10-3 Numerical error Simulation time: Concept-II: 22 s/freq Hybrid method: 0.1 s/freq 10-4 0 1 2 3 4 5 Frequency [GHz] Loss is only from radiation, corresponding to the real part of the input impedance. X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 36

Full MoM vs. Hybrid CIM-MoM z y x y z x Full MoM Hybrid CIM-MoM X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 37

Magnitude of Input Impedance [ ] FEM vs. Hybrid CIM-MoM 10 3 (1, 3 ) (4, 3 ) 10 2 (0, 2 ) (1, 2 ) Port 1 (3, 2 ) (2, 1 ) (4, 1 ) 10 1 y z z (0, 0 ) x (2, 0 ) Port radius: 5 mil Antipad Port radius: radius: 10 10 mil mil c 5.810 7 d 10 0 x r = 3.8, tan = 0, d = 60 mil Simulation time: FEM: > 4 min/freq Hybrid method: 0.6 s/freq 10-1 10-2 Proposed Method FEM Solver (airbox) 0 1 2 3 4 5 Frequency [GHz] X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 38

FEM vs. Hybrid CIM-MoM FEM solver: CIM/MoM: Z corr Z corr Z in Z airbox Z PMC pq in Y rr qq 1 1 Z Zqp X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 39

Radiated Power [W] FEM vs. Hybrid CIM-MoM 10 1 10 0 10-1 10-2 10-3 10-4 Input Power: 1W 0 1 2 3 4 5 Frequency [GHz] CIM (PMC) Proposed Method FEM Solver (airbox) X. Duan, R. Rimolo-Donadio, H.-D. Brüns, and C. Schuster, A hybrid CIM/MoM approach for power plane analysis including radiation loss, Asia-Pacific Symposium on Electromagnetic Compatibility APEMC, Jeju Island, South Korea, May 16-19, 2011. 40

Hybridizing CIM and MoM: Part Two Magnetic currents M s z y External domain x Induced electric currents J s External structures Internal domain Via R u R l Power Plane Surface S Step 1: a magnetic current distribution around the board is obtained by CIM. Step 2: the magnetic current is used as excitation to compute EMI considering scattering of external structures. The board can be simplyfied as one plate. J s J s Solve by CIM Solve by MoM M Use as excitation Step 1 Step 2 J s X. Duan, A. Vogt, H. Brüns, C. Schuster, Progress Towards a Combined CIM/MoM,, Approach for EMI Analysis of Electronic Systems, IEEE EMC Europe 2012 41

Application to Two Board Set Up Region for field plots z Excitation: 1mV y x The virtual plane for the MoM step 0.3 mm d 5 cm Radiated power @ observation point X. Duan, A. Vogt, H. Brüns, C. Schuster, Progress Towards a Combined CIM/MoM,, Approach for EMI Analysis of Electronic Systems, IEEE EMC Europe 2012 42

Application to Two Board Set Up Electric field distribution between boards X. Duan, A. Vogt, H. Brüns, C. Schuster, Progress Towards a Combined CIM/MoM,, Approach for EMI Analysis of Electronic Systems, IEEE EMC Europe 2012 43

Induced noise voltage at input port [ V] Application to Two Board Set Up 3.5 @ observation point 3 2.5 2 d = 2cm d = 1cm d = 0.5cm d = 0.2cm 1.5 1 0.5 After the two Step calculation, the scattered field around the cavity boundary by MoM. The scattered field is then translated to noise at the input via ports by CIM 0 0 1 2 3 4 5 6 7 8 9 10 Frequency [GHz] Estimation of noise voltage caused by the scattered field for the two board case. X. Duan, A. Vogt, H. Brüns, C. Schuster, Progress Towards a Combined CIM/MoM,, Approach for EMI Analysis of Electronic Systems, IEEE EMC Europe 2012 44

Application to Single Board in Chassis @2.4 GHz 45 @2.4 GHz

Application to Single Board in Chassis X. Duan, A. Vogt, H. Brüns, C. Schuster, Progress Towards a Combined CIM/MoM,, Approach for EMI Analysis of Electronic Systems, IEEE EMC Europe 2012 46

Content Introduction Problem Sizing MoM - The Method of Moments CIM - The Contour Integral Method Hybridization of CIM and MoM Conclusions & Outlook 47

Conclusions & Outlook There is no single method suited for the EMC analysis of complete server systems (of course) Hybridization of special pupose solvers in a full-wave solver framework show some potential On top of that parallelization and acceleration methods will have to be employed.. plenty of room for innovations! 48