Analysis of the Radiation Characteristics of a Primary-Feed Waveguide in a Quasi-Optical Antenna for Circular TE(On) Mode

Are calculated the radiation characteristics of two types of primary-feed waveguides of millimeter wave quasi-optical antennas, which transform circular TE(On) mode into a linearly polarized beam. These antennas are utilized for heating and diagnostics of fusion plasma. Analysis is based on the Huygens-Fresnel principle, which takes the diffraction effect into account. For Convenience in analysis, a feed waveguide is divided into two sections, an uniform waveguide section and a visor section. Assuming that the diameter of the waveguide is several times as large as the wavelength and that the structure of the visor is open, the radiation field is approximated by superposition of direct radiation, and first and second reflection on the visor. Numerical results are presented and compared with experimental results. In these types of waveguides, the shadow section on the visor has a great influence on the radiation field. The results of calculation show that the length of the visor should be longer than that obtained by the geometrical optics, and the longer visor reduces the side-lobe level in the direction of the waveguide axis. The results agree well with those in experiments

Orbit decomposition of Jordan matrix algebras of order three under the automorphism groups

The orbit decomposition is given under the automorphism group on the real split Jordan algebra of all hermitian matrices of order three corresponding to any real split composition algebra, or the automorphism group on the complexification, explicitly, in terms of the cross product of H. Freudenthal and the characteristic polynomial.Comment: v2, 32 pages, presentation improved, minor errors corrected, and the title changed as appeared in J. Math. Sci. Univ. Toky

Modeling of gapped power bus structures for isolation using cavity modes

Power bus resonance characteristics of a gapped power-plane with a slit and a split power-plane with a gap were studied, using a fast algorithm based on a full cavity-mode resonator model and the segmentation method. Inductance and capacitance models were used to account for a field coupling along the slit and across the gap, respectively. Good agreements between the calculated and measured results were found to demonstrate the effectiveness and accuracy of our fast algorithm and the segmentation method, as well as the inductance model for the slit and the capacitance model for the gap. </p

El conocimiento que sobre el Japón tenían los europeos en los siglos XVI y XVII (II): los japoneses destinatarios de la evangelización

Continuando con el estudio sobre el encuentro entre el cristianismo y la cultura japonesa el estudio intenta explicar la estructura social del Japón en aquella época: la existencia de los samurais, la institución familiar y otras instituciones y la presencia de un pueblo cristiano tras la misión.Continuing with the topic of the junction between Christianity and Japanese culture, the study aims at explaining the social structure of Japan at that time: the existence of samurais, the family as an institution and the presence of a Christian folk after the mission was finished

Hamiltonian homogeneity on a complex contact manifold

The notion of c-manifolds is introduced as a generalization of complex contact manifolds as well as the degree of symplectifications. And the condition of infinitesimal Hamiltonian homogeneity on a c-manifold is established by means of a moment map defined on the symplectification.Comment: 26 pages; v4: major conceptual changes from v3 by deleting the section 3 because Theorem 3.2 (ii) is wrong

Convergence acceleration and accuracy improvement in power bus impedance calculation with a fast algorithm using cavity modes

Based on the cavity-mode model, we have developed a fast algorithm for calculating power bus impedance in multilayer printed circuit boards. The fast algorithm is based on a closed-form expression for the impedance Z matrix of a rectangular power bus structure; this expression was obtained by reducing the original double infinite series into a single infinite series under an approximation. The convergence of the single series is further accelerated analytically. The accelerated single summation enables much faster computation, since use of only a few terms is enough to obtain good accuracy. In addition, we propose two ways to compensate for the error due to the approximation involved in the process of reducing the double series to the single series, and have demonstrated that these two techniques are almost equivalent