Electromagnetic Tools for Precise Ceramic Radome and Antenna Characterization Cynthia Junqueira*, Mario A. R. Canto**, Ediana Gambin*, Daniela Ronsó Lima*, Diovana de Moura Silva*, Maurício Weber B. da Silva*, Gustavo R. Silvério*, Francisco C. L. de Melo*, Francisco Piorino Neto*, João M. Kruszynski de Assis*, Marcelo B. Perotoni***, Marcelo Antonio Santos da Silva ****, Antonio Sérgio B. Sombra**** *Institute of Aeronautics and Space, IAE, Brazil {cyjunqueira@uol.com.br, edigambin@gmail.com, dronsolima@yahoo.com, dbms10@gmail.com, mauricio.weber@gmail.com, gustavorsilverio@hotmail.com, franciscofclm, franciscofpn, joaojmka@iae.cta.br} **Industrial Fostering and Coordination Institute, IFI, Brazil, {marioafonsomarc@ifi.cta.br} ***Federal University of ABC, UFABC, Brazil{marcelo.perotoni@ufabc.edu.br} ****Federal University of Ceará, LOCEM, UFC, Brazil {marceloassilva@yahoo.com.br, sombra@ufc.br} Résumé Les applications aérospatiales requièrent l'emploi de matériaux supportant des ambiances extrêmes et les céramiques sont un des candidats possibles. Ici le focus porte sur la caractérisation par des méthodes électromagnétiques d'échantillons de radome réalisés en céramique. Cette contribution décrit la méthodologie de développement d'une antenne de transpondeur en bande C recouverte d'un radome en céramique et destiné à un vol spatial. La céramique retenue est de type aluminium-silicate (Mullite) pour laquelle trois compositions différentes sont analysées et les tests standards accomplis. L'évaluation électromagnétique des échantillons (permittivité) a été effectuée avec des méthodes non-destructives telles que Hakki-Colleman ou de type espace-libre. Un ensemble radome-antenne en bande C a été conçu en technologie microstrip et employant une céramique Mullite d'épaisseur 5 mm, le prototype a été construit puis évalué au laboratoire. Enfin, des mesures effectuées dans une chambre anéchoïde ont indiqué un excellent accord entre simulations et résultats pratiques. Mots-clefs: méthodes en électromagnétisme, radome céramique, méthodes non destructives, antenne. Abstract Aerospace applications demand materials that support critical environmental conditions and ceramics are one of the candidates. Here, the focus is the application of electromagnetic methods to precisely characterize ceramic radome samples. This work describes a steady methodology in development of a C band transponder antenna covered with ceramic radome for flight applications. The chosen ceramic was the aluminum silicate (Mullite) and three different compositions were analyzed and the ceramic standard tests were accomplished. Electromagnetic samples evaluation (electrical permittivity) was performed with the application of non destructive methods as Hakki-Colleman and Free- Space. A C band set radome-antenna was designed with microstrip technology and employing a Mullite ceramic with 5 mm thickness, the prototype was build and evaluated at the laboratory. Finally, measurements in anechoic chamber indicates excellent conformance between the simulations and practical results. Index Terms: electromagnetic methods, ceramic radome, nondestructive methods, antenna. Introduction In aerospace applications, ceramic radomes play an important role and deserve special attention. Aerospace applications demand materials that support critical environmental conditions and ceramics are one of the best candidates due to their characteristics. This kind of component works together with a communications system and contributes decisively for the resultant array pattern, so its proper characterization is very important. In this scenario, it is important to have a holistic view over all the parameters involved in the project, because, altogether with the material electromagnetic characterization, it is necessary that the used materials follow the aerodynamic, structural, environmental and mechanical constraints. The chosen ceramic was the aluminum silicate (Mullite) [1-2] mainly due to the low specific mass, good resistance to thermal shock and low dielectric loss properties. The development was based in three different compositions and sintering temperatures. The designed Mullite material was checked by X-ray diffraction. During the samples development several tests were performed: Vickers hardness, bulk density, shrinkage rate and fracture toughness. The micro structural characterization was done by electron microscopy scanning (SEM). The best observed results for density and formation of the Mullite phase were presented for samples sintered at 1650°C. Journées scientifiques 24/25 mars 2015 URSI-France 117