HFSS 14 Update for SI and RF Applications - · PDF fileWhen HFSS is used for package and PCB extraction a 2D Electrical CAD layout editor is better suited ... HFSS 14 Update for SI

© 2011 ANSYS, Inc. September 6, 20111

HFSS 14 Update for SI and RF Applications

Presenter:Senior Application EngineerJeff Tharp, Ph.D.


• Advanced Integrated Solver Technologies– Finite Arrays with Domain Decomposition– Hybrid solving

• FEBI• IE Regions

• Physical Optics Solver in HFSS‐IE• New Layout interface for HFSS: Solver on Demand in Designer

• Usability Enhancements• CAD Integration in Workbench

– Improved Multiphysics flow

Overview


Advanced Solvers:Finite Arrays with DDM


Finite Arrays with Domain DecompositionEfficient solution for repeating geometries (array) with domain decomposition technique (DDM)


Finite ArraysSolve large finite array designsEfficient setup and solutionDefine unit cell and array dimensions• Efficient geometry creation and representation

Efficient Domain Decomposition solution

• Leverages repeating nature of array geometries

• Only mesh unit cell• Virtually repeat mesh throughout array

Post‐process full S‐parameter• Couplings included• Edge effects included3D field visualizationFar field patterns for full array

Memory efficient Enabled with the HFSS HPC product


Finite Arrays by Domain Decomposition• Each element in array treated as solution domain

• One compute engine can solve multiple element/domain in series

Distributes element sub-domainsto networked processors and memory


Example: Skewed Waveguide Array• 16X16 (256 elements and excitations)

• Skewed Rectangular Waveguide (WR90) Array– 1.3M Matrix Size

• Using 8 cores– 3 hrs. solution time– 0.4GB Memory total

• Using 16 cores– 2 hrs. solution time– 0.8GB Memory total

• Additional Cores– Faster solution time– More memory.

Unit cell shown with wireframe view of virtual array


Skewed Waveguide Array

• Patterns from 8X8 Array– Dashed is

idealized infinite array analysis

– Solid from finite array analysis

• Two simulations use identical mesh

• Note edge effects due to finite array size


Efficiency Example: 8X8 Array Patch Array

Direct solver with 12 cores• 5:05:14• 60.8 GB RAM

Finite Array DDM with 12 cores

• 00:44:53• 1.8 GB

6.8X faster33.8X less memory


HPC: Faster with additional coresLinux cluster• 16X Dell PowerEdge R610

– Dual six‐core Xeon X5760, 8GB per core

Same 8X8 array of probe feed patch antennas

3M+ Matrix size, 64 excitations

Study performed using 101, 51 ,26, 11, 6 and 3 engines.*• 101 simulation time = 17 min., 20X faster than direct solver• *Three engines used as baseline

1

2

3

4

5

6

7

0 50 100 150

speed factor

speed factor

Number of cores


Hybrid Solving: Finite Element‐Boundary Integral


• Antenna Placement Study: UHF Antenna on Apache UH64 airframe– Finite Elements with DDM– Boundary Integral (3D Method of Moments)– Hybrid Finite Element‐Boundary Integral (FE‐BI)

Finite Element‐Boundary IntegralSolving Larger Problems with Rigor


Hybrid Solving: Finite Element‐ Boundary Integral

Apache helicopter• UHF antenna placement study @ 900 MHz

Solution volume• 1,250 m3

• 33,750 λ3

Solution Specs• 72 engines• Matrix size = 47M• 6 adaptive passes• 300 GB RAM• 5 hr 30 min

Finite Elements with DDM




Solution surface• 173 m2

• 1557 λ2

Solution Specs• 12 core MP• 680k unknowns• 9 adaptive passes• 83 GB RAM• 5 hr 28 min

Boundary Integral, 3D MoM with HFSS‐IE




FEM solution volume• 69 m3

• 1863 λ3

IE solution surface• 236 m2

• 2124 λ2

Solution Specs• 12 cores total using DDM with MP

• Matrix Size = 2.9M• 6 adaptive passes• 21 GB RAM• 1 hr 3 min

Hybrid Finite Element – Boundary Integral

Compared to 72 core FEM solution14X less memory5.5 times faster


Hybrid Solving: IE Regions


FEBI and Physically Separate “Domains”

1meter10λ

1meter20λ

1meter30λ

Frequency Memory Required

3 GHz 2GB


6 GHz 10GB


9GHz 30GB

Reflector with multiple FE‐BI domains• Conducting reflector and feed horn each surrounded by air with FEBI applied to surface of air volumes– Provides integral equation “link” between FEM domains

• But 3D MoM solution from integral equations could be applied directly to conducting surface only


HFSS Hybrid Solving – IE Regions

• Parallelized– IE regions solved in parallel.

– Analogous to FEM domains

• Rigorous– Multiple reflection

• Automated


IE Dielectric Regions• Solve “large homogeneous blocks of dielectric” with a “boundary condition”– Replace enclosed arbitrary dielectrics– Solve with multiple open or enclosed IE regions– Conducting IE regions may be inside dielectric IE regions

FEM

Conducting IE

Enclosed IE

Ground Penetrating RadarAntenna

Air

Surface

Soil

Mine

Different solution domains may be solved in parallel with DDM


HFSS IE Regions ‐ Example


Physical Optics


HFSS‐IE PO

Asymptotic solver for extremely large problems• In HFSS‐IE• Solves electrically huge problems

– And provides first pass “quick solution” for IE• Currents are approximated in illuminated regions

– Set to zero in shadow regions• No ray tracing or multiple “bounces”

Target applications:• Large reflector antennas• RCS of large objects such as a windmill

Option in solution setup for HFSS‐IE.

Sourced by incident wave excitations• Plane waves or linked HFSS designs as a source


PO Examples

Notice the shadowing of the gun barrel on the tank and the tank on the ground.


HFSS‐IE PO ‐ Example

Offset reflector 50 λ0 in diameter fed by a horn (far-field link)

Simulated with 8 coresIE: 48.3min and 11.9GBPO: 23S and 286MBNote > 120x speedup


Solver on Demand


Solver on Demand: An ECAD Interface for HFSS

Problem Description:

1. Converting package and printed circuit board layout data to 3D mechanical CAD models creates a large amount of unnecessary overhead in the geometry database

2. A key capability needed for wide‐spread use of HFSS as an extraction tool is to make it accessible to non experts

Solution:

1. When HFSS is used for package and PCB extraction a 2D Electrical CAD layout editor is better suited for model creation and setup

2. The Designer Layout editor with Solver on Demand improves HFSS accessibility for non‐expert engineers who need to use HFSS for package and PCB extraction

– It provides an EMI solution for 2 layer pkg and board design with HFSS and PlanarEM

3. The Designer Layout editor with Solver on Demand significantly reduces the engineering time required to set up package and pcb models for extraction with HFSS

4. Cadence design flows allows a user to solve with HFSS from within the Cadence environment using Cadence Extracta and an IPC link


Designer RF with HFSS ‐ Solver on Demand

HFSS ‐ Solver on Demand• Intuitive PCB design entry for HFSS• Chips, packages, channels, modules, …• Designer layouts simulated with HFSS– Automated boundary and port setups– Finite dielectrics and ground supported

• Wave and Lumped Gap Port– Single ended and Differential– Vertical and Horizontal– Coaxial, CPW and Grounded CPW


“HFSS for ECAD”

Two Design Flows for Electrical Design• Mechanical CAD– Connectors, Waveguides– HFSS

• Electric CAD (layout)– PCBs, Packages, On‐chip Passives– HFSS ‐ Solver on Demand


Highly automated for in layout design environment– Primitives = traces, pads, bondwires, vias– Net name definition

Significantly reduce engineering time interacting with software

Lightweight interface for geometrically complex structures

Direct import of Cadence products using Cadence Extracta– Allegro, APD, and SiP

Direct HFSS solve from within the Cadence environment – Virtuoso, Allegro, APD, and SiP

“HFSS for ECAD”


Cadence SPB Integration

Cadence integration enables engineers to create an HFSS model that is ready to simulate directly from the Cadence user interface.

Advanced settings can be pre‐defined in an XML‐based control file to simplify setup for non‐expert users.

Other features:• Critical net selection for extraction.• Cut out and select critical geometry• Manual or automatic extent definition.• Port definition based on component pins or cutout edges. Definine wave ports at cutout extends

• Uses 3D information such as bondwire, ball and bump information from SiP to HFSS.• Support for package, PCB and SiP flows.• IPC interface enables real time feedback from HFSS to Cadence


HFSS within Cadence SPB & Virtuoso

• Dynamic ECAD Flow• Create and Solvemodels with HFSS from within Cadence SPB & Virtuoso

HFSS Solution Progress


HFSS ECAD Layout Editor• HFSS Solver Technology is embedded in Designer as “Solver on Demand”

Export 3D HFSS Model

Solve in Designer using HFSS


HFSS Solve for PKG merged to PCB

Lumped ports on package bumps


HFSS ECAD Layout Editor

Adapt HFSS mesh at multiple frequencies:



Surface roughness and etch factor can be defined in the stackup editor:


Parameterized Padstacks

Enables parametric investigation of via geometry, or optimization.

Applied to global padstack definition. Therefore, project variables are used:


Parameterized Differential Vias



ParameterizableEtch Factor

Parameterizable Surface Roughness

Automatic Causal Djordjevic Sarkar Dielectric Models


Show Nets in HFSS for MCAD

“Show Nets” identifies 3D conducting paths between terminals


Huray Surface Roughness: Modeled vs. Measured

Nodule Radius; a = 0.5 um

Hall-Huray Surface Ratio: low = 1, mid = 3, high = 6

Surface Roughness Reference: P.G. Huray, O. Oluwafemi, J. Loyer, E. Bogatin, and X. Ye; "Impact of Copper Surface Texture on Loss: A Model That Works", DesignCon 2010, February 1 ‐ 4, 2010.

Resonance Reference: P. Pathmanathan, C.M. Jones, S.G. Pytel, D.L. Edgar, P.G. Huray, “Power Loss due to Periodic Structures in High‐Speed Packages and Printed Circuit Boards”, European Microelectronics Packaging Conference – IMAPS 2011, Brighton, England, September 12 – 15, 2011


Passivity Enforcement: Interpolating Sweeps

Additional criteria to determine convergence

Passivity violations used as new basis points

Improves reliability of models in transient SPICE simulations


De‐embedding Lump Port (Calibration)

Physical dimensions of lump port carries current• “intrinsic inductance”

Analytic inductance is de‐embedded from port S‐parameters

“Calibrating” the “test fixture” of the measurement

Implementation analogous to wave port de‐embedding


Transient Network Analysis• Separate Frequency and Time domain “Edit Source“ settings

• Specify delay of TDR to synchronize rise times

• Handling of partial S due to passive ports

Transient• Scaling and delay of individual sources

General• Support for general frequency dependent materials

HFSS Transient


Usability Enhancements


General Enhancements• Save Radiated field data only

– Reduced the amount of stored data

• Import list for Edit Sources– Can include parametric variables

• Network Installation for clusters– Improved reliability on Linux

• Non‐graphical solves without product‐links• Solves are independent of Mainwin registry

– Installations on Windows• Non‐graphical solves without product‐links

• New Registry Configurations– Installation: Lowest precedence

– Defaults applicable to all users– Machine:

• Defaults applicable to all users on a machine.– User :

• Machine independent user specific default– User and machine: Highest precedence

• Defaults specific to user + machine

~10X Reduction


3D Modeler Enhancements

View customization.

• 64‐bit user interface• Post process larger simulations

• Z‐stretch• Speed Improvements

• Faster geometry loading• Improved solid modeler speed.• Improvements for selecting complex

objects.


CAD Integration on WB Improvements

• CAD integration in ANSYS Workbench provides direct link to 3rd party CAD tools

• Such as ProEngineer, Catia, SpaceClaim• Added support for parametric analysis and distributed solving of CAD parameter


Ansoft to ANSYS Geometry Transfer• Geometry and material assignment transfer from Ansoft to ANSYS • Consume geometry from multiple upstream CAD sources – Source can be any of CAD, DesignModeler or Ansoft products– Further geometry edits are possible in ANSYS Design Modeler

• Creates User Defined Model (UDM) for each geometry input.


Conclusions• Advanced Integrated Solver Technologies• Physical Optics Solver in HFSS‐IE• New Layout interface for HFSS: Solver on Demand in Designer

• Improved Multiphysics flow• Usability Enhancement


HFSS 14 Update for SI and RF Applications

Presenter:Senior Application EngineerJeff Tharp, Ph.D.


Save Radiated Field Data Only• Reduced the amount of data stored on hard drive for large antenna problems• Setting for Solution setup, discrete and fast sweeps

~10X Reduction


Import List Entry for Edit Sources

Easy input for magnitude and phase from source list• Can include parametric variables


Ansoft HPC Enhancements: Network Installation on clusters

• Improved reliability on Linux– Non‐graphical batch solves without product‐links– Solves are independent of Mainwin registry

• No hung mainwin services or corrupt mainwinregistry

• Network installations on Windows for Non‐graphical batch solves without product‐links– Need to install VC redistributables on nodes

ANSYS Registry XML file


Registry ConfigurationSoftware settings can be defined at various levels (all operating systems):• Installation: Lowest precedence– Installation level defaults applicable to all users

• Machine:– Machine specific defaults applicable to all users on a given machine.

• User :– Machine independent user specific default

• User and machine: specific value – Highest precedence– Most specific value: Specific to user and machine

Run:

from the product installation directory for usage details.

UpdateRegistry -help


IronPythonTo get started using IronPython (from any Desktop Product):• Set the environment variable ANSOFT_ENABLE_COMMANDWINDOW_UI=1

• From the user interface:Tools>Open Command Window


Physical Optics (PO)

Currents approximated as J≈ 2nxHinc

• Handles object scattering using asymptotically derived currents.

• There is an edge effect but it does not yield the true diffracted fields.

Source

Recieve

Scatterer


HFSS Setup & Solve in Virtuoso


Port assignment by pad

Select pad ‐> RT Click ‐> Create Port

Port name is derived from pad name


Remove port definition

Remove the port definition• This does NOT delete the pad, just removes the port definition.


Virtuoso IntegrationHFSS within Virtuoso• Lumped ports (vertical and horizontal)• Simulation Setup & Solve

Improve storage of database for use with other designs in the same CDN lib.

Simplify layer stackup

Clustering of via arrays

Virtuoso Layout

Solver on Demand


A Review: Domain Decomposition

Distributed memory parallel solver technique

Distributes mesh sub‐domains to network of processors

Significantly increases simulation capacity

Highly scalable to large numbers of processors

Automatic generation of domains by mesh partitioning

• User friendly• Load balance

Hybrid iterative & direct solver• Multi‐frontal direct solver for each sub‐

domain• Sub‐domains exchange information

iteratively via Robin’s transmission conditions (RTC)

Distributes mesh sub-domainsto networked processors and memory


Running Finite Array

Use Master/Slave unit cell design to adapt the mesh

• Called “Unit Cell for Adaptive Meshing” in image

Copy/Paste Design• Called “8X8 Array” in image

Create a single pass setup in finite array design

On “Advanced” tab use “Setup Link” to link mesh from unit cell design

Doing adaptive meshing in finite array design will be time consuming and not as efficient


PO Solver in HFSS-IE 14

• PO assumes the fields on all illuminated surface are the incident fields• Effects of the scatterers are included by assuming the incident fields are

scattered at each point on the body as if it were reflected from an infinite tangent plane at that point; J~2(n x Hinc ) for PEC.

• For non‐illuminated surfaces the J are set to zero.

Where: JPO = 2(n x Hinc )

PEC


PO Solver in HFSS-IE 14

•For objects that fit the approximations mentioned previously the simulation is •Incredibly efficient in both time and memory

•However,•No diffraction (edge, corner, tip,…) from edges, corners or tips•No higher order interaction –

•No scattered fields from the other objects, e.g. the reflected‐reflected terms.

•Sources must be exterior to the PO objects•Incident plane waves•Far field links from other simulations.

•Only good conductors – no dielectrics.


Design Description

• Balanced Amplifier• MMIC amplifiers in parallel

Power = 30dBmP1dB = 11dBm

F=10GHz

Gain = 22dB



• Combined layout editor for 2D and 3D views

<ALT> left mouse (rotate)

Documents

HFSS 14 Update for SI and RF Applications - · PDF fileWhen HFSS is used for package and PCB extraction a 2D Electrical CAD layout editor is better suited ... HFSS 14 Update for SI