Bruno Sauviac

NUMERICAL STUDY OF A CIRCULATOR USING YIG THIN FILM WITH A COPLANAR STRUCTURE

This paper deals with the field of passive microwave components. Coming from the requirements of mobile communication devices, miniaturization of microwave components is needed. The DIOM laboratory is using the RF sputtering to realize magnetic thin films. The use of these magnetic thin films for a circulator design enables to develop a new manufacturing technique compatible with the miniaturization of these devices. These components are devoted to future wireless applications in the 8–12 GHz frequency range. The advantages of these components lie in using YIG thin film and in the fact that accesses to the device are coplanar waveguide (CPW). The CPW structure has a signal line and a ground in the same plane. Therefore, the circulator with a CPW structure will be easily fabricated using low cost lithography. Moreover, connections with other devices will be easier.

Modelling Resonance Frequencies of a Multi-Turn Spiral for Metamaterial Applications

The planar metal particles, consisting of a multi-turn spirals, are studied with the aim of using them to realize high impedance surfaces or as an elementary cell to create an artiflcial material. These spirals present a resonant behaviour in a certain frequency band. To obtain miniature devices, a compromise between the surface and the e-ciency of the resonance must be found. The compactness of the particles can be increased by using s spirals. However, the accuracy on resonant frequency of existing models is not su-cient for our applications. We present a simple analytical model that determines the resonant frequency from the geometric dimensions of the approximated model. This model is verifled by electromagnetic simulations and by measurements.

Modeling and Measurement of a Zeroth-Order Resonator and a Composite Right-Left-Handed Transmission Line in Coplanar Technology

This paper presents a coplanar composite right-left handed zeroth-order resonator (CRLH CPW ZOR) and a coplanar composite right-left handed transmission line (CRLH CPW TL). These devices are realized using an elementary cell designed in a coplanar waveguide conflguration on alumina substrate. Additional lumped elements are carried out with an interdigital series capacitor and a short-circuited stub inductor as a shunt. The CRLH CPW ZOR is fabricated and analyzed using equivalent circuit modeling and three dimensional flnite element method. The proposed devices are fabricated and measured. The resonator has a measured insertion loss of 2.7dB and a return loss better than 13dB. The length of the proposed device is only 5.2mm; this very small size compared with a traditional half wave resonator, shows the interest of this kind of approach.

COPLANAR METAMATERIAL MICRO-RESONATOR

We propose a metamaterial coplanar stop-band fllter made of multi-turn rectangular spiral particles. Numerical and experimental results show the feasibility of devices with dimensions more than 10 times smaller than those in the literature and with good performances.

Marrying Heterogeneous Circles of Trust: No Silver Bullet Yet

Numerous business and state‐owned entities assert the need of secured information exchanges on digital identities based on trusted third parties. Entities trusting each other create a federation. At first, it is necessary for them to formalize this alliance with legal documents. In a second time, an architecture of identity federation will allow them to establish technical trust links, creating a circle of trust, most often with a public key infrastructure. The real challenge for the identity federation domain is the interoperability of information systems thanks to normalized and standardized protocols, that is to say, realize interconnection of circles of trust.