Nonreciprocal Distributed Structures using Coupled Ferrite Lines with Vertical Magnetization (original) (raw)
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Study of Nonreciprocal Devices Using Three-Strip Ferrite Coupled Line
Progress In Electromagnetics Research, 2011
This paper presents the investigations of nonreciprocal devices employing a novel ferrite coupled line junction. The structure is designed using coplanar line technology with the ground half-planes reduced to the strips. The investigated junction is composed of one ferrite section placed in between of two dielectric sections. In the ferrite section the longitudinally magnetized ferrite slab is located at the top or the bottom of the strips and is covered with the dielectric layers. In the dielectric sections the ports of the junctions are located. The wave parameters and field distributions of the modes propagated in the dielectric and ferrite sections are obtained from spectral domain approach. In order to determine the scattering matrix of the junction the mode matching method is utilized. The investigation of the circulator and isolator designed based on the Smatrix of the junction are presented. The obtained results are verified by comparing them with HFSS simulations and own measurements of the fabricated devices. In both cases a very good agreement is observed.
Nonreciprocal left handed coplanar waveguide over ferrite substrate with only shunt inductive load
Microwave and Optical Technology Letters, 2007
A novel ferrite nonreciprocal left-handed (LH) transmission line is presented. The proposed structure is composed of a coplanar waveguide over a ferrite substrate, horizontally magnetized and periodically loaded with only shunt inductors. The line has a nonreciprocal LH propagation with transmission level better than −5 dB with isolation level up to 20 dB over a moderate bandwidth. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2810–2814, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22848
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IEEE Transactions on Microwave Theory and Techniques, 1993
A full-wave analysis is applied to a nonradiative dielectric waveguide where the isotropic dielectric slab is replaced by a transversely magnetized ferrite. The characteristic equation is obtained and the corresponding effects are discussed. The above structure exhibits reciprocal propagation characteristics. Nonreciprocal effects are also possible with a proper dielectric loading. Several numerical results are presented in the form of dispersion curves and operational diagram, as function of several ferrite and guide parameters. Electronically tuned and nonreciprocal devices can be implemented using this simple structure.
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Progress In Electromagnetics Research Letters, 2009
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.
Ferrite-Coupled Line Circulator Simulations For Application at X-Band Frequency
IEEE Transactions on Magnetics, 2000
We have designed and simulated a circulator circuit in which the magnetization aligns along the plane of an yttrium iron garnet (YIG) film. For an X-band frequency (8-12 GHz) circulator we have utilized a YIG slab ( 200 m thick) with saturation magnetization (4 ) and ferrimagnetic resonance (FMR) linewidth (1 ) of 139.26 kA/m and 10 Oe, respectively. Broadband circulator operation was realized for frequencies above FMR, = 5 GHz. The applied FMR field was 79.58 kA/m. The Ansoft HFSS software suite was used to simulate the circulator response. The insertion loss 21 and the isolation 12 were calculated to be 0.9 dB and 52 dB, respectively, with 15% bandwidth at the center frequency of 10.1 GHz. We believe that this in-plane circulator design may enable high performance with significant volume and weight reduction.
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International Journal of Bifurcation and Chaos, 2011
Power transmission in one-dimensional nonlinear magnetic metamaterials driven at one end is investigated numerically and analytically in a wide frequency range. The nonlinear magnetic metamaterials are composed of varactor-loaded split-ring resonators which are coupled magnetically through their mutual inductances, forming thus a magnetoiductive transmission line. In the linear limit, significant power transmission along the array only appears for frequencies inside the linear magnetoinductive wave band. We present analytical, closed form solutions for the magnetoinductive waves transmitting the power in this regime, and their discrete frequency dispersion. When nonlinearity is important, more frequency bands with significant power transmission along the array may appear. In the equivalent circuit picture, the nonlinear magnetoiductive transmission line driven at one end by a relatively weak electromotive force, can be modeled by coupled resistive-inductive-capacitive (RLC) circuits...
Influence of nonuniform magnetic field on a ferrite junction circulator
IEEE Transactions on Microwave Theory and Techniques, 1999
We have analytically formulated the problem that a ferrite circulator junction is biased by a nonuniform magnetic field. Interport impedances of the junction can, therefore, be solved numerically. Nonuniform-bias field will reduce the transmission bandwidth, and the circulation condition is apt to be altered if the bias field shows nonuniformity near the center of the junction. Our calculation compares very well with measurements
IEEE Transactions on Magnetics, 2000
The electromagnetic analysis of a Y-junction circulator proposed here is more realistic than the conventional one, as it accounts for two aspects that are usually neglected despite their frequent occurrence in practice: 1) the nonuniformity of the dc-bias field met in planar technology and 2) the introduction of a tensor to take into account all the magnetization states of the ferrite material. Slicing the ferrite sample into concentric zones allows us to consider the radial variation of the bias field in the electromagnetic calculation. A magnetostatic calculation of the internal field provides the true internal field within each region of the ferrite disk. We replace the Polder tensor, which describes only one specific magnetization state of the material, with another tensor that allows the true magnetization of the ferrite rings to be taken into account.
Strip-line ferrite junction circulator†
International Journal of Electronics, 1973
A Y-junction circulator based on empty substrate integrated coaxial line (ESICL) technology is proposed in this paper. As ESICL is a novel transmission line, many of the common waveguide devices have not yet been developed in this technology, i. e. only filters, a power divider, a 90 • hybrid directional coupler or transition structures have been presented but no non-reciprocal devices. In this paper, a ferrite based circulator has been designed and fabricated to operate at a central frequency of 12 GHz. Measurements performed with the help of an electromagnet confirms the stability of the circulator response under different DC biasing fields. Also, measurements with magnets have been done to integrate the circulator in communication systems. In addition, different temperature tests from 20 • C to 90 • C have been carried out with the aim of checking the scattering parameters variations. The experimental results confirm the results obtained by the full wave simulations: insertion loss better than-1 dB isolation and return loss below-10 dB from 10 GHz to 14 GHz. INDEX TERMS Empty substrate integrated coaxial line (ESICL), non-reciprocal device, ferrite, Y-junction circulator.