Abstract. The miniaturization of devices and the increase of operating frequencies are two important issues for communication system development. This requires a high degree of integration, higher performance and lower cost. Isolator is an important non-reciprocal passive component for source protection. In most cases, the non-reciprocal effect is based on field displacement phenomenon induced by a magnetized ferrite material. In this paper we propose a new design of a coplanar isolator based on field displacement, composed of a non symmetrical coplanar transmission line, made from a ferrite layer and ground plane below.Simulations were performed using HFSS software. Measurements were made on a first 1000 µm-thick YIG film sample giving 1 dB of insertion losses and 17 dB isolation and on a second sample made from a 150 µm-thick YIG ferrite sample giving an insertion loss lower than 2 dB. Interesting applications of this isolator structure are considered.

International audienceThis article deals with the modeling, practical implementation, and characterization of an azimuthal directive antenna around 10 GHz. The design of the antenna is based on transformation optics concept by transforming the radiation of a plane source into an azimuthal radiation. This coordinate transformation procedure is achieved by modifying the electromagnetic properties of the space around the plane source. Metamaterials presenting electric and magnetic resonances are used to produce the effective material parameters necessary for the transformation. S11 parameter and direct far-field measurements are performed on a fabricated prototype to experimentally demonstrate the narrow beam profile and the beam deflection. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2536-2540, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.2712

Abstract-The non reciprocal effect of such devices as microstrip and coplanar isolators can be based on the field displacement phenomenon induced by a magnetized ferrite material. The structure under study is made from a ferrite thin-film deposited on a alumina substrate. A non symmetrical coplanar line is put on the ferrite film and the absorber is made from either a graphite film or a Tantalum Nitride film or a copper slab. In order to work in millimeter wave range the barium ferrite was selected. Moreover, the size of the component could be less than the circulator one. The small size and simple shape are the principal advantages of a coplanar isolator structure.