Metasurfaces for Antennas: Canonical surfaces, EBG surfaces, soft and hard surfaces, gap waveguide technology

Transcription

1 Metasurfaces for Antennas: Canonical surfaces, EBG surfaces, soft and hard surfaces, gap waveguide technology Valencia, Spain, September 2012 Organizers Involved institutions P.-S. KILDAL CHALMERS Alejandro Valero UPV SUMMARY In recent years there has been significant research on synthesizing new materials that can enable new and better antennas. These metamaterials are designed by making use of periodic structures, and often it is the surface characteristics of them that are of interest, in particular in antenna design. Special attention has been given to designing surfaces with high surface impedance in order to obtain an artificial magnetic conductor. These surfaces turn out to have frequency bands (bandgaps) inside which no surface waves can propagate along the surface, and they are therefore also referred to as electromagnetic bandgap (EBG) surfaces. This stop characteristic of the EBG surface makes it similar to the transversely corrugated surface that already in 1987 was the basis for introducing a concept of soft and hard surfaces, based on a terminology used in acoustics and diffraction theory. The EBG surface is equivalent to a soft surface. During 2006 metamaterials were used to design RF cloaks for making objects invisible to EM waves. The invention got attention in media due to the pictorial resemblance with Harry Potter s cloak. Similar cloaks were realized already in 1996 by making use of the go characteristics of the hard surface. During this course the background and theory of ideal magnetic conductors and soft and hard surfaces will be explained, as well as how to implement these theoretical models in existing software based on different numerical methods. The course covers also how magnetic conductors and soft and hard surfaces can be designed and practically realized, and how to analyze them without having to model each detail of the periodic structure. The limitations of the different analysis models as well as of the surface realizations themselves will be discussed with particular attention to diffraction effects, dispersion, surface waves, leaky waves, local quasi-tem gap waves, and bandgap properties. The work will be presented in relation to specific applications such as: ground planes, low-profile antennas, miniaturization, reduction of coupling, removal of parallel-plate noise in multilayer circuit boards, gap waveguides for millimetre waves, waveguide slot arrays, packaging of microstrip circuits, packaging of MMICs, filters, reduction of far out sidelobes, directivity enhancement, high-efficiency hard horns, quasi-tem waveguides, compact horn antennas, reduction of blockage from cylindrical objects, grid amplifiers, and infinite array simulators. The last two days will be devoted to gap waveguides of different types for different applications including realization by micromachining above 100 GHz. Speakers Name Organization Title Per-Simon Kildal CHALMERS Prof., Fellow IEEE Stefano Maci UNISI Prof., Fellow IEEE Zvonimir Sipus University of Zagreb Prof. Eva Rajo Iglesias University Carlos III of Madrid, affiliated prof at Chalmers Prof., Senior Member IEEE Alejandro Valero Polytechnic University of Valencia (UPV) Prof., Senior Member IEEE Erik Lier Lockheed Martin, PA, USA Lockheed Martin Fellow Petrie Meyer Stellenbosch University, South Africa Professor

2 Preliminary lecture program Day 1: Introduction, surface concepts and cloaking Introduction to the course Kildal, Valero Historical background, DNG materials, artificial surfaces. Maci Coffee break Introduction to canonical surfaces (PEC, PMC, PEC/PMC strip grids, soft-hard Kildal surfaces, EBG surfaces, ideal EBG surfaces, ideal gap waveguides) Metasurface wave antennas Maci Hand out group assignments, self study, group work Kildal, Rajo, Plenary discussion Valero, Maci Day 2: Applications, and how to design the surfaces The soft and hard surfaces and their applications (bandgap, sidelobe reduction, soft corrugated horns, cloaking, hard horns) Kildal Designing the stop surfaces (EBG, soft surfaces) Rajo Analytical and numerical approaches for waveguides, horns and more using asymptotic boundary conditions (Moment methods, FDTD&FEM) Kildal (Kishk) The canonical EBG surface, a numerical approach Sipus Self study and work with group assignments Kildal, Rajo, Plenary discussion Day 3: Novel wideband approaches: metamaterials hard horns and gap waveguides Novel metamaterial soft and hard horn antennas, metamaterial waveguides and isolation surfaces Lier Gap waveguides between parallel plates Kildal Designing the stopband and application to packaging Rajo Losses in gap waveguide compared to other structures Pucci Self study and work with group assignments Kildal, Rajo, Plenary discussion Day 4: Numerical techniques, packaging of active components and microstrip gap waveguides Numerical spectral domain approaches for planar radiating metasurface Sipus structures (approximations & full wave) The microstrip gap waveguide Valero Gap waveguide slot arrays Valero High gain gap antenna proposals and estimated performance at 60 GHz Kildal Self study and work with group Parallel workshop presentations, see Kildal, Rajo, assignments program below Plenary discussion

3 Gap waveguide components, and workshop Concept of PMC packaging & application to MMIC packaging at 38 GHz Zaman Equivalence between hollow waveguides and gap waveguides, characteristic impedances Raza Tutorial on designing filters using metasurfaces, how does losses affect Meyer performance To be determined Completion of group assignments Completion of group assignments Presentation of group assignments Parallel workshop presentations, see program below Parallel workshop presentations, see program below Kildal, Rajo, Kildal, Rajo, Program in parallel workshop (time slots are marked green above): Day 4: General numerical approach for gap waveguides Maaskant Day 4: Alfonso, Designing filters with gap waveguides (two 30 min talks) Zaman Day 4: Designing filters with gap waveguides (two 30 min talks) Baquero, Meyer Rotman lens using ridge gap waveguide technology-baquero Baquero Progress report on gap waveguide and DB surface research in Zagreb Sipus, Bosiljevac To be determined Micromachining of gap waveguides using SU-8 Martinez Micromaching gap waveguides at 260 and 100 GHz Rahiminejad Pucci

4 Group assignments and computer exercises The students will be divided in four groups, according to their interest, and each group will the first day receive an assignment and associated copies of journal articles to be solved by working a little on them every afternoon. They were asked to structure their work as follows: Day 1 Monday afternoon: Read 1-2 articles about basics of canonical surfaces, and propose solution to assignment using these. (Conceptual design) Day 2 Tuesday afternoon: Read 1-2 articles about designing the artificial surfaces, or how to formulate them, and design the surfaces for the chosen application. Day 3 Wednesday afternoon: Design the device (antenna or waveguide) Day 4 Thursday afternoon: Complete the assignment and make powerpoint slides. Day 5 Friday afternoon: Complete slides and present them for everybody. The characteristics of the four different assignments are shown in the table below. There will be one supervisor allocated to each group (Kildal, Kishk, Rajo and Sipus). Examples of assignments: Title of assignment 1. Slot array with gap waveguides 2. Patch antenna with low sidelobes 3. Modal solutions of cylindrical metasurface waveguides 4. Modal solutions of gap waveguides Supervisor Alejandro Valero Eva Rajo Per-Simon Kildal Zvonimir Sipus Antenna design Antenna design Type of Waveguide Theory of gap using gap using EBG assignment theory waveguides waveguides surfaces Background / skills needed Basic antenna design and theory Basic antenna design and theory Additional interest in field theory Additional interest in field theory Credits, exams and their outcome We arranged an exam via the week after the course was over. The course represents the equivalent of 1 week of study, so we recommend that they get 2 credit units including the work with the exam. CVs of Lecturers: Per-Simon Kildal (IEEE M 82-SM 84-F 95) has been Professor at Chalmers University of Technology, Gothenburg, Sweden since He has authored an antenna texbook, and more than 110 journal articles and letters in IEEE or IET journals. He has designed two very large antennas, including the Gregorian dual-reflector feed of Arecibo radiotelescope. He has invented several reflector antenna feeds that has been used in successful industrial products such as Ericsson s MINILINK. The latest feed invention is the so-called Eleven antenna for use in future radio telescopes. He is the originator of the concept of soft and hard surfaces, recently resulting in the gap waveguide, a new low-loss metamaterial-based transmission line advantageous in particular above 30 GHz. His research group has pioneered the reverberation chamber into an accurate measurement tool for antennas and wireless terminals subject to Rayleigh fading, being commercialized in the spinoff company Bluetest AB. Prof Kildal received two best paper awards for articles published in the IEEE Transaction on Antennas and Propagation, and he is the recipient of the 2011 Distinguished Achievements Award of the IEEE Antennas and Propagation Society.

5 Alejandro Valero-Nogueira (IEEE M 95,SM 2010 ) received the M.S. degree in electrical engineering from Universidad Politécnica de Madrid, Madrid, Spain in 1991 and the Ph.D. degree in electrical engineering from Universidad Politécnica de Valencia, Valencia, Spain in In 1992 he joined the Departamento de Comunicaciones, Universidad Politécnica de Valencia, where he is currently an Associate Professor. During 1999 he was on leave at the ElectroScience Laboratory, The Ohio State University, Columbus, where he was involved in fast solution methods in electromagnetics and conformal antenna arrays. He has published 25 journal articles, over 100 conference papers and 3 patents. He has supervised 3 Ph.D. students and participated in more than 20 research projects financed by the Spanish government or the industry. His current research interests include computational electromagnetics, Green s functions, waveguide slot arrays and Gap waveguides. Erik Lier received his M.S. and Ph.D. degrees in electrical engineering in 1976 and 1982, respectively, from the Norwegian University of Science and Technology, Trondheim, Norway. In 1977 he joined the faculty as a scientific assistant. From 1978 to 1990 he was a research scientist at the Electronics Laboratory at the same University, where he carried out national and international projects in the area of microwave antennas, direct broadcasting satellite (DBS) technology, digital beamforming networks and phased array antennas. In 1989 he spent one year as a scholar at UCLA. Since 1990 he has been with Lockheed Martin Commercial Space Systems (former RCA and GE Aerospace) as a principal antenna engineer. He has been involved in the design of various satellite antenna components and systems, and has been a technical consultant and reviewer on various satellite programs. Erik was instrumental in bringing shaped reflector technology to the company in 1992, resulting in winning ASIASAT-2. He lead the antenna element development that was a discriminator for winning GPS IIRM and later GPS III satellite programs. His main research interest is in active phased array antennas, and since 1993 he has been a main contributor and leader in the development of this technology within the company. He has been involved in phased array antenna system trades and has been leading the development of array antenna hardware as well as software for array analysis, synthesis and calibration. In 2008 Erik initiated and has since been heading up the internal metamaterials research collaboration effort within LM. Dr. Lier has authored and co-authored more than 100 journal and conference papers and holds 21 patents with multiple patents pending. He is currently authoring a chapter in Reflector Antenna Handbook (Artech House) on Hybrid Mode Horn Antennas. He received the 1993 GE technical excellence award, and the LM Company Publications award in 2004, 2011 and He is a Lockheed Martin Technical Fellow, a Fellow of the IEEE, and was recently nominated to become an IET Fellow. Stefano MACI (S 98, F 2004) received his laurea degree (cum laude) in Electronic Engineering from the University of Florence, Italy. Since 98 he is with the University of Siena (UNISI), Italy, where he presently is a Full Professor. At UNISI, he is the Director of the PhD School of Engineering, head of the Laboratory of Electromagnetic Applications (LEA), Faculty representative of the International Affair Board, and member nominated by the Rector of the Board for the UNISI Research Program. His research interests include EM theory, antennas, high-frequency methods, computational electromagnetics, and! metamaterials. He was a co-author of an Incremental Theory of Diffraction for the description of a wide class of electromagnetic scattering phenomena at high frequency, and of a diffraction theory

6 for the analysis of large truncated periodic structures. He was responsible and international coordinator of several research projects funded by the European Union (EU), by the European Space Agency (ESA-ESTEC), by the European Defence Agency, and by various European industries. He was the founder and presently is the Director of the European School of Antennas (ESoA), a post-graduate school that comprises 30 courses on antennas, propagation, and EM modelling though by 150 teachers coming from 30 European research centres. He is member of the Finmeccanica Stefano Maci was Associate Editor of IEEE Transactions on EMC, two times Guest Editor of IEEE Transaction on Antennas and Propagation (IEEE-TAP), Associate Editor of IEEE-TAP. He is presently a member of the IEEE AP-Society AdCom, a member of the Board of Directors of the European Association on Antennas and Propagation (EuRAAP), a member of the Executive Team of the IET Antennas and Propagation Network, a member of the Technical Advisory Board of the URSI Commission B, a member of the Italian Society of Electromagnetism. He was recipient of several national and international prizes and best paper awards, and he is principal author or coauthor of 110 papers published in international journals, (among which 70 on IEEE journals), 10 book chapters, and about 350 papers in proceedings of international conferences. Zvonimir Sipus (S 95-M 98) was born in Zagreb, Croatia, in He received the B.Sc. and M.Sc. degrees in electrical engineering from the University of Zagreb, Croatia, in 1988 and 1991, respectively, and the Ph.D. degree in electrical engineering from Chalmers University of Technology, Gothenburg, Sweden, in From 1988 to 1994, he worked at Rudjer Boskovic Institute, Zagreb, Croatia, as Research Assistant, involved in the development of detectors for explosive gases. In 1994, he joined the Antenna Group at Chalmers University of Technology, where he was involved in research projects concerning conformal antennas and soft and hard surfaces. In 1997 he joined the Faculty of Electrical Engineering and Computing, University of Zagreb, where he is now a Professor. Since 2008 he is the Head of the Department of Wireless Communications there. From he was also an adjunct researcher at the Department of Electromagnetics, Chalmers University of Technology. His main research interests include numerical electromagnetics with application to antennas, microwaves, and optical communications. Eva Rajo-Iglesias (SM 08) received the Telecommunication Engineering degree from University of Vigo, Vigo, Spain, in 1996 and the Ph.D. degree in telecommunication from University Carlos III of Madrid, Madrid, Spain, in From 1997 to 2001, she was a Teacher Assistant at the University Carlos III of Madrid. In 2001, she joined the University Polytechnic of Cartagena as Teacher Assistant for a year. She came back to University Carlos III as a Visiting Lecturer in 2002 and since 2004, she is an Associate Professor with the Department of Signal Theory and Communications, University Carlos III of Madrid. After visiting Chalmers University of Technology (Sweden) as a Guest Researcher, during autumn 2004, 2005, 2006, 2007 and 2008, she is, since 2009, an Affiliate Professor in the Antenna Group, Signals and Systems Department. She is in charge of the Electromagnetic Field and Antenna courses in the Degree Communication Systems Engineering. Her main research interests include microstrip patch antennas and arrays, metamaterials and periodic structures and optimization methods applied to Electromagnetism. She has (co)authored more than 40 contributions in international journals and more than 80 in international conferences. Dr. Rajo-Iglesias received the Loughborough Antennas and Propagation Conference (LAPC) 2007 Best Paper Award and Best Poster Award in the field of Metamaterial Applications in Antennas sponsored by the IET Antennas and Propagation Network, at Metamaterials 2009: 3rd International Congress on Advanced Electromagnetic Materials in Microwaves and Optics. She presently serves

7 as Associate Editor for the IEEE Antennas and Propagation Magazine and for IEEE Antennas and Wireless Propagation Letters. Petrie Meyer was born in 1965 in Bellville, South Africa. He enrolled for a BEng at Stellenbosch University in 1983, and completed his Master's degree in At that time he was appointed as Junior Lecturer at the Department of Electrical and Electronic Engineering at the University of Stellenbosch, where he received his PhD in 1995 on numerical analysis of microstrip circuits using the Method-of-Lines. In 2003 he was appointed Professor in the field of Microwaves and Electromagnetics, and in 2009 became Head of Department. His research field is that of microwave devices, including CEM and mathematical modelling. He has authored or co-authored more than 80 technical journal and conference papers. His current focus is on microwave filters and ultra low-noise amplifiers for the planned Square Kilometre Array (SKA) radio astronomy antenna. In 2004, he was awarded the South African THRIP prize for human resource development, and in 2007 the international CST prize for a published journal paper making use of CST. In both 2009 and 2010, he was awarded the University of Stellenbosch Rector s award for research. He has served as chairman for the local IEEE AP/MTT conferences since 2005 and as technical chair for the 1999 IEEE Africon conference, as well as chairman of the IEEE South Africa Section during He serves as regular reviewer for IEEE, IET and Wiley microwave journals. In 2009, he was elected Fellow of the South African institute for Engineers.