Investigations of Cylindrical Ferrite Coupled Line Junction Using Hybrid Technique

Abstract

Abstract-In this paper, a novel longitudinally magnetized cylindrical ferrite coupled line (CFCL) junction is proposed. In comparison to planar ferrite coupled line (FCL) configurations, which are well known in literature, in such structure the higher gyromagnetic coupling occurs. This allows to obtain the required in FCL devices Faraday rotation angle π/4 for the ferrite with shorter length and lower value of magnetization. As a result the total insertion losses in the ferrite section can be reduced using the proposed topology. In the analysis of the proposed CFCL junction a hybrid technique combining method of moments and coupled mode method (MoM/CMM) is applied. The results are compared with the ones obtained from commercial software HFSS and a good agreement is obtained.

Nonreciprocal Devices Utilizing Longitudinally Magnetized Ferrite Coupled Lines

“…where matrix Q, diagonal matrix of eigenvalues k, and matrix of eigenvectors K are defined in [10]. The solutions of (14) are the eigenvalues k 1 and k 2 , defining propagation coefficients of two fundamental modes in ferrite guide which take the following form:…”

“…The better performance in comparison to currently proposed planar configurations was obtained for nonreciprocal devices utilizing cylindrical ferrite coupled line (CFCL) junction [10]. Due to the similar geometry to the circular waveguide with coaxially located ferrite rod, such structure allows to obtain close-to-optimal Faraday rotation effect.…”

Investigations of Four-Port Circulator Utilizing Cylindrical Ferrite Coupled Line Junction

“…This is done by determining impedance representation of an artificial cylinder enclosing inner dielectric/ferrite rod with the use of FDFD technique. Then the obtained discrete solution is combined with the analytical fields in the outer region of the artificial cylinder using MoM [23]. As a result a set of homogenous equations is obtained which solution are propagation coefficients and field distributions of modes occurring in the investigated guide.…”

“…In the proposed approach we define artificial cylindrical surface S surrounding the centrally situated dielectric/ferrite rod in the guide, which divides the structure into inner and outer region. In the outer region the fields are expressed using analytical relations [23]. In the inner region the analytical solution is difficult to find due to the complexity of structure, hence the more universal discrete FDFD technique is applied.…”

“…Combining impedance matrix with the analytical solution in the outer region the propagation coefficients and field distributions of the modes occurring in the considered guide can be easily determined [23]. For the considered problem Z matrix is determined with the use of FDFD technique.…”