Design of a new coplanar isolator made from YIG film operating in the X-frequency band

¹ LT2C, Université Jean Monnet, 42000 Saint-Étienne, France
² Laboratoire des semi-conducteurs et des hyperfréquences, Université Mentouri de Constantine, Route Ain el Bey, Constantine 25000, Algeria

^a e-mail: didier.vincent@univ-st-etienne.fr

Received: 1 March 2011
Revised: 22 July 2011
Accepted: 26 September 2011
Published online: 28 November 2011

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.