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Design of a Coplanar Circulator Based on Thick and Thin Ferrite Film
This paper takes place in the field of passive microwave components. Coming from the requirements of mobile
communication devices, miniaturization of microwave components is needed. Aimed at this objective, for several years we
have been working on the development of a miniature planar circulator. The main aim of this paper is to show the circulator
with different ferrite thickness and then to present a method to reduce the insertion loss of the circulator in function of the
thickness of the ferrite film. The circulator is designed with new topology coplanar/microstrip. The analytical structure based
on stripline circulator and analysed by using a three dimensional finite-element method. The circulator is then fabricated, and
its properties in the microwave range are characterised using a network analyser and a probing system. An additional part for
the isolator with non-symmetrical was designed in order to reduce the insertion loss in the conductor and to obtain a large
bandwidth compared to the existing devices.