The development and current status of microwave ferrite technology is reviewed in this paper. An introduction to the physics and fundamentals of key ferrite devices is provided, followed by a historical account of the development of ferrimagnetic spinel and garnet (YIG) materials. Key ferrite components, i.e., circulators and isolators, phase shifters, tunable filters, and nonlinear devices are also discussed separately.

Ferrite devices and materials

A systematic method to obtain the bidimensional spectral dyadic Green's function of stratified planar structures with arbitrary complex bianisotropic layers is developed The method is based on the uniqueness and equivalence electromagnetic theorems A first-order partial differential formulation for the electromagnetic field inside each layer is used An explicit algorithm makes it possible to go from the single-layer formulas to the general multilayer matrix formulation The perturbative nature of the method provides good numerical efficiency and straightforward determination of asymptotic behavior >

A general algorithm for computing the bidimensional spectral Green's dyad in multilayered complex bianisotropic media: the equivalent boundary method

Davidenko's method is a reduction of Newton's method for the numerical solution of n-coupled nonlinear algebraic equations into n-coupled first-order differential equations in a dummy variable. This algorithm is useful for the solution of dispersion relations of electromagnetic waves propagating in lossy waveguiding structures, particularly layered geometries containing one or more gyrotropic layers. In this class of problems, Newton-based numerical techniques are not always satisfactory and Davidenko offers an altenative which is efficient and reliable and which relaxes the extent of the restriction placed on the initial guess to be sufficiently close to the solution. Presented are Davidenko's method, its application to lossy-waveguide dispersion relations, and an example where the algorithm was applied successfully.

Application of Davidenko's Method to the Solution of Dispersion Relations in Lossy Waveguiding Systems

Nonreciprocal microstrip lines based on magnetic nanowired substrates were fabricated for the characterization of microwave differential phase shifts. We provide a fully integrated solution for the nonreciprocal edge guided mode, which is achieved by asymmetrically loading the width of the microstrip with nanowires of different heights. An analytical model explaining the microwave nonreciprocal propagation, which takes into account the substrate permittivity and the microstrip memductance, is validated with the experiment.

Differential phase shift in nonreciprocal microstrip lines on magnetic nanowired substrates

An analytical and numerical study is presented for a five region planar canonical structure modeling quasi-optical integrated surface magnetoplasmon based nonreciprocal devices for the near-millimeter wave range. The model includes a slab of a high quality semiconducting material, such as n-GaAs, magnetized parallel to its surfaces and perpendicular to the direction of propagation. The analysis performed is exact. Sample results show the possibility of acceptable performance for isolators over a bandwidth of 45 GHz in the 500-GHz range and of differential phase shifter design over a bandwidth of 65 GHz in the 380-GHz range.

Performance Predictions For Isolators And Differential Phase Shifters For The Near-Millimeter Wave Range

Results of a theoretical study are presented for a four-region model of a nonreciprocal dielectric-ferrite loaded stripline phase shifter employing the edge-guided dynamic mode. The behavior of our model in terms of the differential phase shift, the insertion loss, and the effective bandwidth is explored as a function of the various parameters involved.

D.M. Bolle

Papers

The Edge-Guided Mode Nonreciprocal Phase Shifter