open EMS What is openEMS? Interfacing Tools Status & Outlook - - PowerPoint PPT Presentation

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open EMS What is openEMS? Interfacing Tools Status & Outlook - - PowerPoint PPT Presentation

Oct 08, 2022 133 likes •329 views

openEMS - An Introduction and Overview Using an EM field solver to design antennas and PCBs Thorsten Liebig FOSDEM19 03.02.2019 open EMS What is openEMS? Interfacing Tools Status & Outlook Outline What is openEMS? 1 Interfacing

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  • penEMS - An Introduction and

Overview

Using an EM field solver to design antennas and PCBs

Thorsten Liebig

FOSDEM’19

03.02.2019

EMS

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What is openEMS? Interfacing Tools Status & Outlook

Outline

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What is openEMS?

2

Interfacing Tools

3

Status & Outlook

Thorsten Liebig –

http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

What is openEMS?

free and open source electromagnetic field solver can be used to simulate/evaluate RF and optical devices (e.g. antennas, filters, waveguides, transmission lines, RCS1, ...) uses the FDTD2 method to iteratively solve Maxwell’s equations in time domain Octave/Matlab (or Python3) are used as scripting interface Linux and Windows fully supported the user has full control over every aspect of the simulation comes with a lot of tutorials and examples

1Radar cross section 2Finite Difference Time Domain 3Python interface is not feature complete yet

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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

List of Features

Full 3D EC-FDTD in Cartesian and cylindrical coordinates Many geometrical primitives: e.g. cubes, cylinder, wires, polygons... Import/Export CAD models (e.g. STL or PLY files) Lumped elements like SMD resistors, capacitors and inductances Builtin simple circuit simulation or touchstone export Coordinate dependent material and excitation definition Support for multi-polar dispersive material model Include human body models (e.g. Virtual Family) Access and process raw or interpolated field dumps in TD or FD Fast multi-threading, near-to-far-field transformation Simple graphical user interface to review the defined structures FDTD engine utilizing SSE, multi-threading and operator compression Support for remote/cloud or cluster (MPI) computing ...

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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

A typical openEMS Simulation Script

Header part with constants and defines General FDTD setup like:

TD pulse setup (typically Gaussian pulse) Boundary conditions

CAD Part:

Define substrates/materials and metallic objects Define lumped elements & (lumped) ports (active and passive)

Setup the FDTD mesh:

Most important step Needs the most experience!

Setup field dumps (near- or far-field) Run the simulation Post-processing and figure creation

Time for an example!

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http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

Simple Patch Antenna Examples

Tutorial: Wifi (2.4 GHz) patch antenna example

(a) Conventional / Cartesian Patch Antenna (b) Conformal / Cylindrical Patch Antenna

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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

Helical Antenna Examples

Tutorial: Wifi helical antenna example:

(a) Helical Antenna using a Cartesian or Cylindrical grid (b) Helical Antenna Array using a Cartesian grid

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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

MRI: Multi Transmit SAR Calculation Example I

6 Loop Coils

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MRI: Multi Transmit SAR Calculation Example II

Multi transmit local SAR examples:

(a) Vn = 1; ∀n = 1..6 (b) Vn = exp(j n 2π

N ); ∀n = 1..6 Thorsten Liebig –

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What is openEMS? Interfacing Tools Status & Outlook What is openEMS? Workflow Show Cases

Small Size Wifi PCB Antenna Example

(a) CC2511 USB Dongle 4 (b) openEMS Model

Simulation Results: Target frequency of ≈ 2.45

GHz is confirmed

Antenna matching strongly depends on the PCB size RF simulation is important to adept to PCB size, material & thickness

4Source:

http://www.ti. om/lit/an /swr a117 d/s wra1 17d .pdf

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http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook Overview Examples Ultimate Interfacing Goal

Outline

1

What is openEMS?

2

Interfacing Tools

3

Status & Outlook

Thorsten Liebig –

http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook Overview Examples Ultimate Interfacing Goal

Interfacing Tools - Why do we want them?

Free & open source EM solver exists Free & open source PCB editors exists Nice to have: RF-Simulation of PCB

PCB trace antenna (wifi, bluetooth, NFC) PCB trace filters and transmission lines (hairpin, notch, stub, ...)

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But: Weak open source link between both worlds ... Both worlds should be more connected & interfaced!?

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https:// ommons.wikimedia.org/wiki/File:Mi rostrip_Distributed_Element_Filter_Te hnology.jpg

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Interfacing Tools - Overview

There are some tools to interface with openEMS: hyp2mat

Reads commercial Hyperlynx format, writes openEMS solver script (Matlab/Octave) Already included in openEMS package, including examples

https://github. om/koendv/hyp 2mat

pcb-rnd

Graphical, point and click PCB editor Many import and export formats (kicad, eagle, protel, hyperlynx, hp-gl) exporter to openEMS

http://repo.hu/proje ts/p b- rnd

pcbmodelgen

Convert KiCAD PCB files to models for import in openEMS

https://github. om/j yrax/p b mode lgen

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What is openEMS? Interfacing Tools Status & Outlook Overview Examples Ultimate Interfacing Goal

Interfacing Tools - hyp2mat - Hairpin Filter Example

Hairpin filter imported from Eagle with hyp2mat:

(a) Model in openEMS (b) S-Parameter Result from openEMS

Source: Example included in hyp2mat

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What is openEMS? Interfacing Tools Status & Outlook Overview Examples Ultimate Interfacing Goal

Interfacing Tools - pcb-rnd - Hairpin Filter Example

Hairpin filter from pcb-rnd:

(a) Layout in pcb-rnd (b) S-Parameter Result from openEMS

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What is openEMS? Interfacing Tools Status & Outlook Overview Examples Ultimate Interfacing Goal

What would be the Ultimate Interfacing Goal?

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Design your PCB with your favorite (free) PCB editor/designer

2

Design your 3D CAD models (e.g. housing, connector) with your favorite (free) CAD tool (e.g. FreeCad)

3

Import to openEMS and do your RF simulation

4

Import the touchstone results into your favorite (free) circuit simulation software (e.g. Qucs) PCB Design

(e.g. KiCAD, pcb-rnd)

3D CAD Model

(e.g. FreeCAD)

RF Simulation

(openEMS)

Circuit Simulation

(e.g. Qucs)

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What is openEMS? Interfacing Tools Status & Outlook Status & Outlook Further Reading

Outline

1

What is openEMS?

2

Interfacing Tools

3

Status & Outlook

Thorsten Liebig –

http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook Status & Outlook Further Reading

Status & Outlook

Project-Status:

  • penEMS is a mature EM simulation package

many (advanced) FDTD features already available There is still a lot to do: Improve and expand the documentation Complete the python interface Continue efforts to interface with other EDA & CAD tools Add new FDTD features ...

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http://openEMS.de
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What is openEMS? Interfacing Tools Status & Outlook Status & Outlook Further Reading

Further Reading

For further information:

www.ate.uni- due.de
  • penEMS Website:
http://openEMS.de
  • penEMS Forum:
http://openEMS.de/forum
  • penEMS Development:
https://github. om/thliebig
  • penEMS is a free and open source software

⇒ Feel free to download, evaluate and contribute

Thank you for your attention!

Thorsten Liebig –

http://openEMS.de
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