G93427.1

Modeling and Simulation of Conducted and Radiated EMI from HPM and UWB Sources

on Printed Circuit Boards and Integrated Circuits

A. C. Cangellaris and E. MichielssenECE Department

University of Illinois at Urbana-Champaign

D. YangEECS Department

University of Illinois at Chicago

G93427.2

Objective

Characterize accurately the spurious signal (noise) propagation through the packaging hierarchy (printed circuit boards, cards, connectors, interposer, package…) to the die.

HPM/UWBSources

AntennasCracks

AperturesCables

Propagationto interior

InternalCoupling

EMI to connectors &

packages

Internal fields as radiated EMI

Circuits

Spuriousbehavior

G93427.3

Successful fulfillment of this objective is dependent on our ability to tackle the EM complexity and abstract it

EM Complexity– Geometric complexity and distributed nature of the packaging

hierarchy (“coupling path”)– Broad frequency bandwidth of the interfering signal– Non-linearity of the terminations

Tackling Complexity– Hierarchical approach to the modeling of electromagnetic

interactions– From lumped models to transmission-line models to full-wave models

Abstracting Complexity– Systematic order reduction of numerical models of the coupling

path– Equivalent circuit representation of the coupling path for its

seamless incorporation in network-oriented non-linear circuit simulation

G93427.4

From the physical structure to the network representation of the EMI effect

Integrating Substrate

(PCB, MCM, …)

Packageddigital & analogdevices

Conducted& radiated

EMI

Radiated EMIVirtual couplingports

Physical coupling ports (e.g., connectors, cables…)

EM Modeling & Simulation

Model Order ReductionSynthesis

V

V

Network representation

of thecoupling

path

Sourcerepresentationof conductednoise at thephysical ports

Equivalent sourcerepresentation ofradiated EMI coupling

Non-linearlumped circuits

G93427.5

Specific subtasks

Task 1. Development of a coupling path modeling methodology

Task 2. Development of a (EMI) source modeling methodology

Task 3. Non-linear Transient Simulation of the hybrid lumped-distributed non-linear network

G93427.6

Task 1. Modeling of the Coupling Path

Our modeling approach is hierarchical– Domain decomposition– Use suitable EM modeling approach for individual blocks

– Multi-conductor Transmission Lines (MTL)– Full-wave modeling (FEM, integral equation). Use fast

frequency- and time-domain solvers from Task 1

Y(s)

Y(s)

MTL

MTL

MTL

MTL

Y(s)

Integrating Substrate (e.g. PCB)

G93427.7

Task 1. Modeling of the Coupling Path

For each individual block develop a frequency-dependent multi-port representation in terms of a matrix transfer (e.g. admittance) function

– Directly, through model order reduction– SVD-based & Krylov methods

– Indirectly, from the discrete time or frequency responses

The Indirect Approach:

1 1 1

2 2 2

3 3 3

( ) ( ) ( )1 11 12

( ) ( ) ( )2 11 12

( ) ( ) ( )3 11 12

( ) ( ) ( )11 12

M M M

f f fNN

f f fNN

f f fNN

f f fM NN

f Y Y Y

f Y Y Y

f Y Y Y

f Y Y Y

VectorFitting 0 0( ) k

kk k

as s

s p

Y G C G

G93427.8

Task 1. Modeling of the Coupling Path

Curve fitting constrained to produce stable representations

Subsequent post-processing to render the representation passive

Foster canonical representations of passive, reciprocal, linear multi-ports of finite order

lead to strictly passive equivalent circuit synthesis

– Direct compatibility with general-purpose, non-linear, network analysis-oriented circuit simulators

0 0( ) kk

k k

as s

s p

Y G C G

G93427.9

Example Study: SPICE-based transient simulation of switching noise in digital systems

Objective: Through simulation select appropriate decoupling capacitors to control voltage reference disturbances during switching

Modeling & Simulation Strategy1. EM modeling of the power distribution network2. Synthesis of SPICE-compatible equivalent circuit3. SPICE-based transient simulation

EM modeling of power & ground plane pair

Circuit models forvoltage regulatorand switching driver

G93427.10

Example Study: SPICE-based transient simulation of switching noise in digital systems

11 12

1 1

21

1

FDTD modeling of power &

ground plane pair

Development of pole-residue

representation of a two-port macromodel

through passive model order reductio

nM M

k k

k kk k

Mk

k k

R R

s P s P

R

s P

Step 1 :

Step 2 :

Y22

1

Mk

k k

R

s P

Step 3: Equivalent Circuit synthesis

G93427.11

Example Study: SPICE-based transient simulation of switching noise in digital systems

Synthesized equivalent circuit

Circuit models forvoltage regulatorand switching driver

Decoupling capacitor

Supply voltage disturbancewithout decoupling capacitor

Supply voltage disturbancesuppressed due to the presencedecoupling capacitor

G93427.12

Task 2. Modeling of the (EMI) Source

Radiated EMI most challenging– Procedure: Given the excitation and the physical

description of the coupling path, calculated the induced currents at the short-circuited ports where non-linear circuitry is connected

Once again, our approach is hierarchical– When valid, use known EM field to MTL coupling

models– Extensive use of UIUC PWTD fast solver– Deterministic approach of limited use

– Develop statistics for the attributes of the induced current waveforms

G93427.13

Example Study: EMI of a Stacked-Card Configuration

2mm

30 cm

20 cm

NA

60 cm

60 cm

Geometry

Excitation fmax = 1 GHz at fmax = 0.3 m, ds at fmax = /300 /10

use Adaptive LF-PWTD (ALF-PWTD)

2707SN Discretization

ObjectiveCompute Compute

common mode common mode current on the current on the coax cablecoax cable

50| 21| cm

exc

IS

V

G93427.14

Example Study: EMI of a Stacked-Card Configuration

Comparison of computed |S21| Comparison of computed |S21| to the measured resultto the measured result**

* www.emcs.org/tc9

-90

-80

-70

-60

-50

-40

-30

-20

-10

0.1 1

ALF-PWTDmeasurement

|S21

| (dB

)

frequency (GHz)

G93427.15

Task 3. Non-Linear Transient Simulation

Two Approaches:1. Physics-oriented Non-linear Transient

Simulation– Physical (distributed) model for the coupling path– Circuit models for non-linear electronics– Most rigorous and exact; yet, computationally

intensive (small-scale applications)– UIUC’s Fast PWTD Solver is the work horse– Interfacing with non-linear circuit solver with

models for the semiconductor devices– “Standard” SPICE not the optimal choice because its

architecture is biased by applications involving, lumped (primarily RC) passive circuitry

Example Study: A Hybrid Cross-talk/EMI problem (TC9 Challenge Problem)

DiscretizationDiscretization

Excitation fmax Excitation fmax = 3 GHz= 3 GHz at fmax at fmax = 0.1 m= 0.1 m ds at fmaxds at fmax = = /500 /500 /8/8

5400SN

Point 1

(Excitation)

Point 2Point 3

Point 4

15 cm

80 cm

Geometry mesh

Example Study: A Hybrid Cross-talk/EMI problem

Voltage responses (comparison with PEEC solver)Voltage at Load Point 2Voltage at Load Point 2

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 2 4 6 8 10

PEECPWTD

volta

ge (

V)

time (ns)

-0.3

-0.2

-0.1

0

0.1

0.2

0 2 4 6 8 10

PEECPWTD

volta

ge (

V)

time (ns)

Voltage at the upper wireVoltage at the upper wire Voltage at the left wireVoltage at the left wire

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0 2 4 6 8 10

PEECPWTD

volta

ge (

V)

time (ns)

Excitation PulseExcitation Pulse

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 2 4 6 8 10

volta

ge (

V)

time (ns)

G93427.18

Task 3. Non-linear Transient Simulation

2. Network-oriented Non-linear Transient Simulation– In the spirit of traditional SPICE; however, enhanced with

capabilities relevant to the primarily distributed RLC nature of the passive circuitry

– Better convergence than “standard” SPICE– Versatility in the “black-box” representation of blocks of the

coupling path– TRANSIM is such a simulator

– Under development at North Carolina State University (NCSU) in Prof. M. B. Steer’s group

– On-going enhancement of its EM modeling capabilities through a collaborative effort between UIUC (A. Cangellaris) and NCSU

– In addition to its use as the primary engine of the network-oriented non-linear transient simulation, TRANSIM will be interfaced with the fast solver PWTD

G93427.19

Summary

The objective is to characterize through modeling and simulation the EMI signals propagating through the packaging hierarchy to the digital/analog circuitry

To accomplish this, the following subtasks will be undertaken:

– Modeling of the coupling path and its reduction into an equivalent network representation

– Modeling of the (EMI) sources– Development of a robust and versatile non-linear

transient simulation environment that combines SPICE-like lumped-circuit simulation capability with distributed-circuit simulation capability