The Future of Computational Electromagnetics: Science ... - IEEE Xplore

EurAAP Corner

Juan R. Mosig Laboratory of Electromagnetics and Acoustics (LEMA) Ecole Polytechnique Federale de Lausanne (EPFL) LEMA-ELB, EPFL-5tation 11 CH-1015 Lausanne, Switzerland Tel: +41216934628 Fax: +41216932673 E-maH: [email protected]

The Future of Computational Electromagnetics: Science or Product Guy A. E. Vandenbosch

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Department of Electrical Engineering ESAT-TELEMIC Katholieke Universiteit Leuven Kasteelpark Arenberg 10, 8-3001 Leuven, 8elgium E-mail: [email protected]

Abstract As in every year, the EurAAP Working Group on Software organized a convened session on numerical techniques/software at the 2011 EuCAP conference. This year, the goal was to have a more industrially oriented session, with the theme, "The Future of Computational Electromagnetics: Science or Product." The idea was that 25 years ago, all development in this area was done in pure research environments. Nowadays, quite a lot of development is done on the research and development premises of tool vendors. Many strategic questions can be raised concerning this theme. These questions were addressed in this session, both from the perspective of academia and of industry. The last slot in the session was completely reserved for discussion. The session was attended by about 70 people.

1. Introduction

D

uring the last 25 years, the computational electromagnetics (CEM) community has seen drastic changes. In the 1980s,

very few commercial solvers existed, and university research groups were not really concerned with formats and the technicali ties of the software, as such. They just wanted properly working software to design their antennas. Nowadays, the situation is totally different. First of all, dozens of tools are on the market. It could be expected that in the coming 10 years a consolidation phase is going to take place. Only a few major players are expected to grasp and maintain a substantial market share. Second, since nowadays mainstream practical antenna design is already being

embed it within a real tool. Of course,this is a consequence of the fact that the proper implementation of a software tool requires a considerable amount of time and effort. There

is

thus

a

real

danger

that

the

computational

electromagnetics community as a whole is getting polarized. On the one hand,there are the research groups at universities and insti tutes whose first target is to produce new, more-efficient algo rithms. This "science" is then published to the benefit of the whole community. On the other hand, there are the commercial software vendors. Their first target is not to produce science,but to deliver a good "prod4�t" to their customers, simultaneously maintaining the financial and commercial health of the company.

dominated by the commercial tools,the university groups involved in modeling tend to loose the incentive to build really coherent software. Instead, there is a tendency to concentrate on the pure

The

EurAAP

Working

Group

on

Software

session

at

EuCAP 2011 was about this polarization, and the way the parties

scientific output: the modeling techniques themselves, without

involved are looking at the issue. More information on this work

going the necessary "next mile" to transform the technique and

ing group can be found in [1,2].

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IEEE Antennas and Propagation Magazine, Vol. 53, No.3, June 2011

To initiate a discussion on the theme in order to see

2. Strategy

what the EurAAP Working Group on Software can do to smooth any consultation and cooperation processes.

When convening a session at EuCAP, the tradition is to find a proper co-convener from outside Europe. With his overwhelming expertise in this area, Prof. R. Mittra was certainly qualified. I am very thankful that he accepted to help me convene this session.

At the end of the session, a full slot was reserved for discus sion on the topics raised during the session.

Since the intention was to have an industrially oriented ses

3. The Session

sion, the second challenge was to convince the important software vendors to contribute with papers. After a few weeks of inviting and explaining, I am proud to say that we were able to present a

3. 1 The " Academic" View

program with the following software vendors: CST (Computer Simulation Technology), with the CST

After a brief introduction [II], the session started with an

Studio software tools [3],

"academic" paper by Prof. Mittra [12] (Figure I),entitled "Making

IDS (Ingegneria Dei Sistemi), with the Antenna Design

Commercial Software for EM Modeling." The basic message of

Framework (ADF) [4], WIPL-D, with the WIPL-D software [5],

a Transition from University Research Lab to the World of Prof. Mittra was threefold: 1.

MIG (Microwave Innovation Group), with WASP-NET

Although the commercial EM simulators nowadays are

[6],

essential tools for microwave and antenna design engi neers, most of the software modules are based upon

Ansoft - Ansys, with the HFSS software, represented

well-known algorithms, which inevitably have a unique

by Prof. Jin-Fa Lee from the Ohio State University [7],

flavor. This makes them especially suited for a class of problems for which they offer a distinct advantage. For

IMST,with the Empire software [8],

example, a Method of Moments (MoM) code is very fast for perfectly conducting

Agilent, with the EDA software, featuring Momentum

Time-Domain (FDTD) technique can handle arbitrary geometries and material parameters with greater ease.

TICRA,with the GRASP software [10].

For some applications, it is more interesting to analyze in the frequency domain, whereas for others a direct

During the preparation phase, several important questions were

analysis in the time domain is more appropriate. For

raised to the software vendors:

general-purpose solvers, the natural trend is thus to go for a combination of techniques and algorithms in a sin

How does your company see the development process

gle framework.

within the computational electromagnetics community?

research at universities and research institutes? How is the cooperation, if any, between industry and academia organized in general within your company? Is this the most optimal way or can it be better organ

objects, whereas the

Finite-Element Method (FEM) or the Finite-Difference

[9],

Is it still useful to do computational electromagnetics

The criteria used to judge a code are generality, accu racy, and speed. However, there is no "best" solution.

2.

The commercial tools as they are today are not able to handle all topologies of interest to the designers. This goes from sometimes even very simple shapes (a fully surface-meshed very thin wire, for example) up to very large problems (the Square Kilometre Array, for exam ple, the chief protagonist of the 21st century antenna world). The academic world is mainly focusing on

ized? How does "your" software tool cooperate with universi ties,institutes, and other software vendors? What will the result be of the mix of university research - tool development? What is the roadmap that is followed when a new tech nique is going to be incorporated in your tool? What about interfaces between different tools? Are there things that can be developed out of a competi tive environment? Summarizing,the main goals of the session were: To give an overview of how the software vendors work internally,in view of all these issues;


Figure 1. Prof. Mittra explaining his "academic" view.

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Sandwich Honeycomb configurations

Figure 2. Sample problems that remain elusive beyond the current capabilities of CEM technologies: a SAR image of land vehicles on lossy rough ground with vegetation; multiple antennas, operating frequency bands from UHF to Ku band, instaUed on large platforms; organic LED modeling with three-dimensional layers of random media; a UAV with multilayer complex thin coating; and system analyses of signal and power integrities of real-life integrated circuits.

these aspects. CEM researchers are continuously look ing for better and more-suited algorithms. More recent

3.2 The "Commercial" View

developments in the CEM world clearly illustrate this, for example, the Fast Multipole Method (FMM), the Discontinuous Galerkin (DG) method, and the Dipole Moment (OM) method.

Most of the electromagnetic-simulation tool vendors started as spin-offs from groups at research institutions. [n the beginning, research was mainly done off-site, in the research environment, and the companies focused on user-interface development, testing,

3.

The integration into the commercial codes of new algo

marketing, and supporting the software. In many cases, over the

rithms resulting from cutting-edge academic research in

years the vendors have kept their unique relationship with the

many cases is not trivial. This "transfer path" is not

original research groups. Examples are WIPL-D, the Empire soft

always paved very smoothly or in a timely manner. Any

ware, FEKO,

acceleration of this process would certainly be of great

planned in cooperation with and executed by these research

benefit to the user,who is often frustrated by the limita

groups. For example, in the case of WIPL-D the research group

tions "here and now" of the commercial codes.

WASP-NET, etc. The scientific innovations are

involved is the electromagnetics group at the

University of

Belgrade. MiG ( WASP-NET) has a research cooperation with the This view was shared by Prof. J.-F. Lee [17]. He gave a more

University of Bremen. Basic research, of which results are some

detailed view of the types of problems that are still "unsolvable"

times published, is done in cooperation with the university. The

by commercial tools. The reader can get a taste of these types of

development of some of the software modules in some cases is stiII

problems from Figure 2. Prof. Lee also addressed the issue of

fully performed within the university group. More often, ideas

multi-physics co-simulations. Research topics of today are in many

originate at universities, while final development of the product is

cases multi-disciplinary. Of crucial importance are,for example:

done in the company.

Electromagnetic and thermal effects, and their mutual interaction, within ICs and complete packages;

Some vendors,like CST and Agilent,have loosened the ties a bit. Since the size of the software tools has grown quite signifi cantly over the years - consisting of hundreds of modules contain

266

In high-power microwave applications, the modeling of

ing over millions of source-code lines - dedicated development

the plasma and the nonlinear charge distributions and

departments within the companies have been established, focusing

their coupling.

on the needs of industrial applications, and software development


is done in-house. In some cases,the distinct interests of a commer

some cases, even several conceptually different approaches might

cial software vendor and a university or research institute make a

be investigated by different groups, before the most promising

partnership even difficult. Protection of the intellectual property

result can be selected for implementation into the commercial tool

conflicts with the university researcher's aim to publish results.

framework. In some cases, where proprietary technology needs to be improved, only in-house research may be possible, due to

In order to explain how a development cycle works,the flow

confidentiality requirements. However, cooperation with external

chart as explained by Peter Thoma from CST was quite revealing.

partners can still help in solving specific subtasks of the larger pro

It is based on the idea of "Agile Software Development." Another

ject.

important aspect, touched on by Filip Demuynck from Agilent Technologies, was the integration within the customer's design

Commercial

tool

vendors

accumulate

extensions

and

flow. A third very important aspect is related to the educational

improvements over a long period of time. Therefore,advancing the

task of universities.

state of the art of their simulation capabilities often requires quite sophisticated technology as the starting point for further investiga tion. Although this may not be an issue for larger research groups,

3.2.1 Agile Software Development [13]

this often limits the options for new and smaller teams, as well as the ability for interdisciplinary research. The commercial tool ven10rs can help to overcome this problem by providing an open

The concept of Agile Software Development has become a widely accepted approach for customer-oriented software develop ment [21]. There exists a multitude of flavors of such agile tech niques, with

a

very

lightweight

representative

being

architecture with APIs as part of their software. This approach enables research groups to use commercial software tools as an efficient framework for further research,if needed.

called

SCRUM [22]. One of the latter's main concepts is to subdivide the development timeline into rather short intervals: so-called Sprints. For each Sprint, a number of projects is selected. Larger projects

3. 2.2 Design Flow Integration [19]

have to be subdivided into subprojects that fit into a single Sprint. After each Sprint, a review step takes place, which allows adjust

A key factor to product success is the integration of software

ing the goals and resources for the next Sprint. This procedure

within the customer's design flow. Seamless links into a design

allows making use of experience gained from previous Sprints, as

platform open up the solution to a broader set of users. The addi

well as respecting changing project priorities. The overall goal is to

tional investment to tum an algorithm into a software product inte

use the available development time as efficiently as possible, in

grated in a design flow is considerable. However, it makes the

order to maximize the benefit perceived by the users.

product less vulnerable,as opposed to a point-tool solution that can

As a starting point, it is essential to collect and properly prioritize project ideas, which will then be fed into the develop ment process. With many thousands of users of the software focus ing on quite different types of electromagnetic problems, the proper selection of projects becomes a rather challenging task.

Feature Requests

S&S Feature Ideas

R&D

Typical sources for projects in a commercial software-develop ment environment are as follows (Figure 3): Requests for new or enhanced functionality to better address existing or new market requirements, Infrastructure enhancements that are necessary in order to improve the software's architecture,

Backlog Items

Re-Engineering

Problem-Reports

Figure 3.

Sources for projects in a commercial software

development environment.

New research achievements that significantly extend the simulator's capabilities for particular applications. The projects can be categorized by the level of research required to accomplish the task. No special care has to be taken for projects that are rather straightforward extensions of existing functionality, without the need for additional research. These pro jects can be handled in a rather straightforward way by the development process. Other projects may require varying amounts of additional research. This research can then either be done in house, by members of the research and development team, or can also be done in cooperation with external partners, including research institutions. Such projects are generally difficult to plan, since it is typically difficult or impossible to provide reliable time estimates. Nevertheless, even for these rather unpredictable pro jects, SCRUM can be helpful in order to better structure the research process and to maximize the rate of success [23]. In general, the more risk is involved in a particular research activity, the more sense it makes for the simulation-tool vendor to

Figure 4. F. Demuynck from Agilent, making a strong case for

carry out this project together with external research institutions. In

Design Flow Integration.


267

There is also a reason why in many cases the software ven dors make their tools available for universities at drastically reduced costs, or sometimes even free of charge. The motivation for that is obviously getting many future engineers accommodated to their tools, in this way raising future potential customers. How ever, this poses an extra threat. Most of the universities are nowa days forced to increase their small research budgets by third-party funds. Such third parties are more interested in getting concretely working antennas, rather than supporting basic research activities. Of course, these designs are based on the readily available commercial tools. This increases the threat sketched above. A last point is that the cooperation with universities within the framework of smaller projects enables the software vendors to attract the talent: talent that may eventually choose to pursue a career in their midst.

Figure 5. A group photo of the conveners and presenters: (I-r) An "accidental" representative from the audience, Prof. B. Kolundzija from WIPL-D, Dr. P. Thoma from CST, Prof. R. MiUra (co-convener), Dr. F. Demuynck from Agilent, Prof. J. F. Lee from Ohio State University, Prof. F. Arndt from MIG,

W. Simon'from IMST, Prof. G. Vandenbosch (convener). The presenters from IDS and TICRA were excused.

3. 3 "Academic" Software/EDXlEDI [20] Some software vendors put forth a pretty strong view: "There is no longer a justifiable need to develop [one's] own software tools at universities,in industry,and at research institutions." Let it be clear that is not the view (and I might add "at all") of the EurAAP Working Group on Software. It is the experience of the members of this working group that in-house-developed software

easily be replaced, F. Demuynck (Figure

4)

argued that the fact

that Agilent's Momentum is integrated in multiple platforms - in Agilent's Genesys and Advanced Design System for the RF and microwave designer, and in Cadence Virtuoso for the RF-mixed signal IC designer - is a very important asset. Also, within this design

flow, the

EM

product portfolio can be strategically

extended with other solvers. A MoM solver can be accompanied by a Finite-Element Solver (FEM) and a Finite-Difference Time Domain (FTDT) solver.

has two major assets: its complete transparency and its "to-the core" flexibility. There have been many occasions where this has proven fruitful,also for pure research purposes. The adaptation and modification of an in-house-developed tool may suddenly open new fields of research, where no commercial software vendor is active (yet...). This explains the continuous support of the working group for the development of the Electromagnetic Data eXchange stan dard (EDX/EDI). TICRA, the Danish company developing the

GRASP software framework, is closely linked to this. This effort was initiated as a joint effort in the Antenna Centre of Excellence

3. 2. 3 From Student, Over Researcher, to Employee

(ACE) and the European Antenna Modelling Library (EAML) pro ject, respectively funded under EU-FP6 and ESA-TRP budgets. Since the end of ACE, the development has continued under the umbrella of the Working Group on Software EurAAP, the Euro

A crucial factor in the debate, mentioned by several software vendors, is the educational task of universities. The employees working within industry - and, of course, also within the compa nies themselves - once were students at these universities. This means that they still have to be educated and trained in computa tional electromagnetics, and, even better, maybe even complete a PhD in this area. It is of no interest to the software vendors that C EM would disappear from the curricula, It is dramatically bad and dangerous to the community that there is a trend in some

pean Association on Antennas and Propagation, in close coopera tion with the EAML partners [I]. The EDX/EDI is seen by the Working Group on Software as one of the pillars of a community wide research strategy. It is our sincere hope that the existence of the EDX framework may again stimulate researchers to contribute to real software development, without having to compromise their scientific output by spending too much time on formats and interfacing. The last paper in the session presented the latest developments in this area [20].

places that this is not done any more. There,students are no longer educated in important basic research topics in (computational) electromagnetics, including fundamentals, advantages, disadvan tages of all numerical methods. [f there are no longer students edu

4. Conclusion

cated in such fundamentals,this will [16]: The goal of this session was to get an overview of the birth Drastically reduce the number of engineers in industry

and evolution of several CEM software vendors,to inventory their

who are capable of designing components and appropri ately applying the adequate software tools,

relationships with academia, and to initiate a discussion on the future of computationafelectromagnetics. It was clear at the end

Hinder the education of researchers able to make the

many of them with a preferred partner, some of them on a more

that most of the vendors cooperate with the academic community:

268

required basic research developments, which are the

global scale. All of them recognize the importance to their compa

basis for efficient designs and also for developing soft

nies of education in CEM at universities. A point of discussion

ware tools.

with some vendors was the usefulness of the development of soft-


ware at universities. The EurAAP Working Group on Software

12. R. Mittra, "Making a Transition From University Research Lab

hopes that this event may lead to further common initiatives, sup

to the World of Commercial Software for EM Modeling," Euro

ported both by the academic and the commercial CEM community.

pean Conference on Antennas and Propagation, Rome, Italy, April 11-15,2011.

5. Acknowledgements

13. P. Thoma, "How Does Research Fit Into the Commercial EM Tool Development Process?," European Conference on Antennas and Propagation, Rome, Italy, April 11-15,2011.

I would like to thank Prof. R. Mittra. I am convinced that his reputation considerably helped to convince some of the software vendors to support this initiative. I also would like to thank the per ' sons I had contact with: Dr. Peter Thoma from CST, Ing. M. Bandinelli from IDS, Prof. B. Kolundzija from WIPL-D, Prof. F. Arndt from MIG, Prof. Jin-Fa Lee from Ohio State University, W. Simon and Dr. R. Baggen from IMST, Dr. F. Demuynck from Agilent, P. E. Frandsen from TICRA, and M. Sabbadini from ESA-ESTEC.

14. M. Bandinelli, "Antenna Design Framework: Solving the Eda Antinomy," European Conference on Antennas and Propagation, Rome, Italy, April 11-15,2011. IS. B. Kolundzija, "W IPL-D: From University Software to Com pany Product," European Conference on Antennas and Propaga tion, Rome, Italy, April 11-15,2011. 16. F. Arndt, "WASP-NET®: Recent Advances in Fast EM CAD and Optimization of Waveguide Feeding Networks, Aperture Antennas and Slot-Arrays by Efficient Hybrid MM/FE/MoM , FE

6. References I. G. A. E. Vandenbosch, R. Gillard, and M. Sabbadini, "The

Antenna Software Initiative (AS I): ACE Results and EurAAP Con

tinuation," IEEE Antennas and Propagation Magazine, 51, 3, June 2009,pp. 85-92. 2. http://www.antennasvce.org/Public/WGSoftware. 3. http://www.cst.com. 4. http:// www.idscompany.it. 5. http://www.wipl-d.com.

BI and MoMIPTD Techniques," European Conference on Anten nas and Propagation, Rome, Italy, April 11-15,2011. 17. J.-F. Lee, "The Maturity of Computational Electromagnetics: Are We There Yet?," European Conference on Antennas and Propagation, Rome, Italy, April 11-15,2011. 18. W. Simon, A. Lauer, A. Wien, and L. Baggen, "Solving Large Scale EM Problems Using FDTD Analysis," European Conference on Antennas and Propagation, Rome, Italy, April 11-15,2011. 19. F. Demuynck, "Innovation in Computational Electromagnetics at Agilent," European Conference on Antennas and Propagation, Rome, Italy, April II-IS,20 II. 20. M. Sabbadini, J. Friden, P. E. Frandsen, M. Ghilardi, and G. A.

6. http://www.mig-germany.com.

E. Vandenbosch," New Developments of the Electromagnetic Data

7. http://www.ansoft.com.

Rome, Italy, April 11-15,2011.

8. http://www.imst.com.

21. A. Cockburn, Agile Software Development: Software Through

Exchange," European Conference on Antennas and Propagation,

People, Amsterdam, Addison-Wesley Longman, 2001. 9. http://www. agiIent.com. 22. M. Beedle and K. Schwaber, Agile Software Development with 10. http://www.ticra.com.

Serum, Upper Saddle River, NJ, Prentice Hall, 2002.

II. G. A. E. Vandenbosch and R. Mittra, "The Future of Computa

23. M. Marchesi, K. Mannaro, S. Uras, and M. Locci, Distributed

tional Electromagnetics: Science or Product," European Confer

Serum in Research Project Management, Agile Processes in Soft

ence on Antennas and Propagation, Rome, Italy, April I I-IS,

ware Engineering and Extreme Programming, Lecture Notes in

2011.

Computer Science, 2007, Volume 453612007, pp. 240-244.


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