PROJECTS
   

Project
Acronym: CMETA 
Name: Analysis and design of curved metamaterial structures 
Project status: From: 2015-06-01 To: 2017-05-31 (Completed)
Contract number: FA9550-15-1-0121 
Action line: EOARD - European Office of Aerospace Research and Development  
Type (Programme): Ostali 
Instrument: Ostalo 
Project cost: 100.000,00 USD
Project funding: 100.000,00 USD
Project coordinator
Organisation Name: Sveučilište u Zagrebu Fakultet elektrotehnike i računarstva 
Organisation adress: Unska 3, 10000 Zagreb 
Organisation country: Hrvatska 
Contact person name: prof.dr.sc. Zvonimir Šipuš 
Contact person email: Email 
Croatian partner
Organisation name: Fakultet elektrotehnike i računarstva 
Organisation address: Unska 3, 10000 Zagreb, Hrvatska 
Contact person name: prof.dr.sc. Zvonimir Šipuš
Contact person tel:
6129-798   Contact person fax:  
Contact person e-mail:  
Partners
Organisation nameCountry
Short description of project
Curved multilayered dielectric structures with embedded metallic patterns can act as electromagnetic devices that direct waves, change the polarization of transmitted or reflected waves, or influence the spectrum properties of those waves. Recently, it was shown that metasurfaces can be successfully used for building various electromagnetic structures and this technology could be implemented in many applications that vary from smart radomes for airplane or missile applications (in particular nose radomes) to subreflectors for multi-frequency antenna reflector systems. Till now most of the attention was focused on the development of planar metasurface structures. However, many demanding electromagnetic applications require the implementation of curved structures. In order to successfully design curved metasurface structures one needs to develop a specialized algorithm since the considered structures are very large in terms of wavelengths and they contain a lot of small metallic details within each of the metasurface layers (by definition, the unit cell of the metasurface pattern is much smaller than a wavelength). The need for a specialized program lies in the fact that these large finite structures with numerous small cells cannot be efficiently designed using general electromagnetic solvers since memory requirements would be extremely large and the successful optimization would simply be too slow. We propose a 24-month effort to develop a systematic approach and algorithm for designing curved multilayer structures containing metasurface layers. First part of the project will be focused on the development of an efficient and accurate program for designing such structures. Second part of the project will be focused on the development of experimental prototypes that will demonstrate the abilities of these newly developed electromagnetic structures. The analysis method will connect several approaches that show superior properties when designing specific electromagnetic structures. The considered structure will first be divided into a part with strongly curved parts (such as a tip region of nose radome) and into a weakly curved part. The strongly curved part will be rigorously analyzed using the moment method approach that combines surface and volume integral formulations. The weakly curved part will be analyzed using physical optics (PO) approach which was previously successfully applied to the analysis of large reflector and radome structures. In order to accelerate the program the analysis method will be focused on Body-Of-Revolution (BOR) class of electromagnetic structures. We believe that this assumption will not cause any loss in the generality of the analysis approach since most of the practical applications possess rotational symmetry, i.e. they belong to the BOR class of structures. The metasurface itself will be analyzed using the sheet admittance boundary conditions that were successfully implemented in the analysis of planar multilayer metasurface structures. In order to apply the sheet model we will generalize the sheet impedance analysis approach to include curved metasurface structures. In the second part of the project the focus will be on the realization of several practical curved metasurface prototypes that will answer two questions – is it possible to successfully use the developed program for the design of realistic components, and which technology can be used for making such structures. The planar structures can be easily built using the printed circuit board technology. The same technology can be used for singly-curved structures. However, the double-curved structures cannot be built in such a way and some alternative technology should be implemented. In recent years, there is an expansion of 3D printing methods and we propose to test if such technology can be used for building double-curved metasurface structures. The main problem in this realization will be to obtain accurate metallization of desired pattern, and as a part of the project we will investigate different metallization approaches. This task is planned to be realized together with researchers from AFRL/RYMH since recently they put a lot of efforts in developing 3D printing methods of electromagnetic structures, in particular of metalized patterns on arbitrarily-shaped dielectric supporting structures. The best solution will be selected for experimental realization of the considered doubly-curved metasurface device.  
Short description of the task performed by Croatian partner
 


   

Design by: M. Mačinković

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