A Study of Nonreciprocal Coupled Ferrite-Dielectric Image Guide Structure for Ka-band

The nonreciprocal coupled ferrite-dielectric image guide structure with the same geometry as in our previous experimental investigation has been studied numerically by finite element method in the frequency range 26–40 GHz. The ferrite element in the experiment has been inhomogeneously magnetized by using a disk-shaped permanent magnet, whose diameter is comparable with the length of the ferrite bar. Recently, we have modelled the ferrite element as homogeneously magnetized perpendicularly to the ground plane and the direction of propagation. This homogeneous magnetization represents first approximation of the real inhomogeneous one. Here we have extended the numerical examination of the nonreciprocity and as a result we have proposed a procedure for designing isolators with inhomogeneous magnetization. Also, we have investigated the influence of several parameters – permanent magnetic field strength and three ferrite material parameters (saturation magnetization, relative dielectric permittivity and dielectric loss tangent) on the nonreciprocal behavior of the coupled ferrite-dielectric structure.

Asymptotic Stability Analysis for Sheet Metal Forming—Part II: Application

The general asymptotic method proposed in Part I is applied to the investigation of the puckering instability in the hemispherical cup test. Both a membrane and a shell stress state for the principal axisymmetric solution have been considered. Due to the possibility of strong deviations from proportional loading in some cases, a corner theory of plasticity is also employed, in addition to the standard J2 deformation theory which is often used in plastic buckling calculations. Results are compared to a previous experimental investigation for brass specimens. [S0021-8936(00)00904-1]