In the framework of the European School of Antennas, the course "Metasurfaces for Antennas" will be be held at the Faculty of Electrical Engineering and Computing in Zagreb, Croatia, from 5th to 9th October 2015. The European School of Antennas (ESoA) is a geographically distributed post graduate school that has the objective to reinforce the European training and research in antennas and relevant applications. The Summary of the course is given below, and the detailed description of the course is given at the course web page.
Mladen Vukomanovic and Zvonimir Sipus had presentations at the European Conference on Antennas and Propagation (EuCAP), named: "Efficient Analysis of Gap Waveguide Structures through a Mode Matching Approach" and "Analysis of Canonical Curved Metasurfaces". Conference was held at Lisbon, Portugal, from 12th to 17th April 2015.
As a part of the project prof. Anthnony Grbic visited the electromagnetic group at FER in Zagreb (14th -22nd October 2014). During the visit, partners defined forthcoming activities in modeling of metastructures and their experimental characterization. Prof. Grbic also gave an IEEE talk with the title “Metasurfaces for Manipulating Electromagnetic Waves.” The summary of the talk is given below.
Dr.sc. Davor Zaluški and Dario Bojanjac, dipl. ing. will spend six months visiting the research group of Prof. Anthony Grbic at University of Michigan. They will work on practical realization of a DB surface and of a curved metasurface.
Prof. Zvonimir Šipuš attended the 8th Workshop on Integral Techniques for Electromagnetics," Ovronnaz, Switzerland and delivered a talk about recent results in implementing integral methods in the analysis of periodic waveguide structures.
Mladen Vukomanović, M. Eng. and Prof. Zvonimir Šipuš attended the 56th International Symposium ELMAR-2014, 10-12 September 2013, Zadar, Croatia. Mladen delivered a talk about the analysis of gap-waveguide structures:
- Mladen Vukomanović, Marko Bosiljevac, Zvonimir Šipuš, “Efficient analysis of gap-waveguide structures through a rigorous mode-matching approach.”
In September 2014 Josip Lončar, M. Ing. joined the UKF PAMS team as a PhD. Student. Josip got his first degree two years back and he was working in industry, in the field of electronic systems. However, he decided to enhance his knowledge, enrolled the PhD, came back to Uni, and joined the UKF PAMS team. He will be working on active metamaterials.
Prof. Silvio Hrabar attends the 8th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics 2014 (Copenhagen, August 25-30, 2014) and delivers one invited and one regular talk that report recent results in active MTMs and scaled RF experiments that mimic metatronic devices:
- Silvio Hrabar, ‘Is Stable Dispersionless Non-Foster DNG Metamaterial Indeed Impossible? (invited)
- Silvio Hrabar, Boris Okorn, ‘Application of D-dot Wire Concept in Optical Scattering and Radiating Systems’.
Prof. Silvio Hrabar attends the 2014 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (Memphis, July 6–11, 2014) and delivers three talks with the newest results achieved within the UKF PAMS project:
- Boris Okorn, Silvio Hrabar, ‘Verification of concepts of D-dot wire and D-dot loop in RF regime’
- Silvio Hrabar, Boris Okorn, Vedran Ciganović, Igor Koris, ‘Ideal versus Realistic non-Foster Elements in Active Metamaterials’
- Silvio Hrabar, Petar Kolar, Antonija Peric,’ Broadband Negative-capacitor-based Enhanced Transmission through Subwavelength Aperture’
Davor Zaluški, in collaboration with Prof. Silvio Hrabar and Damir Muha, developed fully functional artificial DB surface. The performed experiments clearly showed that this surface behaves as a PEC for one polarization of impinging EM wave, while for other polarization it has the PMC properties. To the best of our knowledge, this is the first experimental realization of a fully functional DB surface and it is reported in June issue of Applied Physics Letters (http://dx.doi.org/10.1063/1.4883405).
In May 2014, three new researchers joined the UKF PAMS team:
- Dr. Davor Zaluški
Davor recently obtained his Ph.D. in Electromagnetic Metamaterials at FER. He currently holds a postdoc position and he is working in metamaterial-based waveguides and antenna as well as in artificial EM surfaces.
- Dario Bojanjac, Dipl. Ing.
Dario is a Ph.D. student at FER. He is working in analytical and numerical methods in electromagnetics in general, and their applications to metamaterials, in particular.
- Zoran Ereš, M.S.E.E.
Zoran is a research associate at Rudjer Boskovic Institute and a part-time Ph.D. student at FER. He is working in graphene physics and technology and their applications in metamaterials.
The low-frequency (1 kHz-25 kHz) negative capacitor demonstrator based on a commercial integrated audio amplifier was designed and prototyped by Prof. Silvio Hrabar and P.h. D. student Boris Okorn. This low-frequency demonstrator generates a large negative capacitance (-1.2 mikroF). Such a large value of negative capacitance enables direct measurements of both voltage and current waveforms in the time-domain, which could help in understanding of the counter-intuitive basic physic. All the measurements clearly show that a negative capacitor could be interpreted as a three-pole generator/sink.
Prof. Silvio Hrabar and prof. Zvonimir Sipus visited UKF partner group at the University of Michigan (headed by prof. Anthony Grbic). During the visit, Partners defined forthcoming activities in modeling of metasurfaces and their experimental characterization. Furthermore, the experts from University of Zagreb delivered two research seminars at Radiation Laboratory, University of Michigan:
- Prof. Silvio Hrabar ‘From RF Metamaterials to Nanophotonics and back- Is it possible to bridge the gap between engineers and physicists?’
- prof. Zvonimir Sipus ‘Design of Metamaterial and Metasurface Devices’.
Prof. Zvonimir Sipus had presentation at the European Conference on Antennas and Propagation (EuCAP), named: "Simplifying the Design of Complex Electromagnetic Structures Using Green's Functions Based on Asymptotic Boundary Conditions". Conference was held at The Hague, The Netherlands, from 6th to 11th April 2014.
Professor Hrabar and his collaborators (Dr.sc. I. Krois and Ph.D. students I. Bonić, A. Kiričenko and D. Muha) designed and tested the first prototype of broadband volumetric ENZ non-Foster metamaterial operating in RF regime. The prototype comprises a 2x2 array of short electric dipole loaded with negative capacitors. The measurements revealed relative effective permittivity of 0.67 +- 10% within, the bandwidth 10 MHz-20 MHz (one octave). As far as our knowledge goes, this is the first experimental demonstration of stable volumetric ENZ non-Foster metamaterial.
Prof. Zvonimir Šipuš presented a seminar on analysis methods that can lead to fast and accurate computer program for designing gap-waveguide components.
Prof. Zvonimir Šipuš presented the project at Workshop on Gap-waveguide technology, Gothenburg, Sweden, 21 - 22 November 2013. The cooperation with Chalmers University of Technology (group of Prof. Per-Simon Kildal) on development of fast analysis tools of gap-waveguide components has been established.