基于单平面双螺旋谐振单元左手传输线研究

单平面双螺旋谐振单元是一种左手单元,具有不需缺陷地结构和小型化的特点。该文主要对由单平面双螺旋单元组成的对称和非对称两种传输线形式进行了仿真研究。利用电磁仿真工具,仿真分析了两种形式传输线的回波损耗和插入损耗特性。由仿真结果可知,非对称形式传输线的电磁性能较好。该文设计了两组对比仿真实验,即对称和非对称形式传输线结构相位特性对比,一、四单元非对称传输线相位特性对比,对传输线结构的相位特性进行了分析。结果表明,基于单平面双螺旋结构的非对称形式传输线具有左手效应。

A Cheeger-Mller theorem for symmetric bilinear torsions on manifolds with boundary

In this paper,we extend Su-Zhang’s Cheeger-Mller type theorem for symmetric bilinear torsions to manifolds with boundary in the case that the Riemannian metric and the non-degenerate symmetric bilinear form are of product structure near the boundary.Our result also extends Brning-Ma’s Cheeger-Mller type theorem for Ray-Singer metric on manifolds with boundary to symmetric bilinear torsions in product case.We also compare it with the Ray-Singer analytic torsion on manifolds with boundary.