Self Complementary Structure with Low Signature – SAFAS

The innovative nature of this project is based on the very special properties of self-complementary structures that have a theoretically unlimited operating bandwidth. When these structures are associated with one or more metasurfaces, they allow achieving compact directive wideband antennas or thin absorbing materials. These composite structures can be used to design an antenna array if they are lossless or absorbing material if they are with or without loss.
The sizing of structures was achieved using analytical models that have been developed and optimized with the help of softwares such as HFSS and CST.
More efficient tools (FACTOPO), adapted to the calculation of bi-periodic structures of finite and large dimensions, have been developed and implemented in order to assert the validity of concepts. The realization and measurement of a directive antenna array and an absorbing material were carried out during the project to obtain experimental validation of the theoretical results.

Conception of analytical models allowing nearly instantaneous design of multilayer structures.
Design of a metamaterial based antenna with a thickness less than ? / 4 at the lowest operating frequency and having in the two principal polarizations, a bandwidth of 6: 1 at 45° and from 5: 1 at 60°. Realization and measurements of two prototypes. Design of a metamaterial absorber with a thickness less than ? / 6 at the lowest operating frequency and having: a bandwidth of 5: 1 (<-15dB) at normal incidence and 4: 1 (<-10dB) at 60 °. Realization and measurements of two prototypes.

Confidential

Part of the results of SAFAS project was disseminated both nationally (Forum DGA, JNM, Colloque National Métamatériaux, Atelier ONERA-CNES, GDR Ondes, Journée Thématique Matériaux pour la Furtivité Radar & Optique, Journées d’études Electromagnétisme et Guerre Electronique) and internationally (Eucap2014, ISAP 2014 IEEE CAMA2014, META'15). The other part of the results will be submitted to international journals (IEEE TAP, Applied Physics A) and conferences (IEEE CAMA2016, META'16).

The project SAFAS (Self Complementary Structure with Low Signature) is proposed by a consortium composed of Telecom ParisTech, ONERA and SART. Objective is the study and development of a planar multilayer structure to achieve a low profile directive antenna array with low SER and frequency agile thin absorbent material.
The novelty of this project is based on very specific properties of self-complementary structures that have a theoretical bandwidth unlimited and which, together with one or more high impedance surfaces, may give compact wideband directive antennas or thin and frequency agile absorbent materials.
These composite absorbent structures can be used as ground plane for antenna when they’re without losses or as an absorbent material they’re with or without losses. In addition, the introduction of discrete elements and controllable in the high-impedance surface moves its resonant frequency and thus lead to the production of a reconfigurable absorbent material.