公开(公告)号：JPH08102602A

公开(公告)日：1996-04-16

申请号：JP16680495

申请日：1995-06-08

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： JIYORUJIYO BERUCHIN ,  RUCHIANO ATSUKACHIINO

IPC: H01P1/208 ,  H01P7/06

Abstract: PURPOSE: To provide a narrow band filter that does not have so much loss by tilting the side of a middle part consisting of rectangular waveguides against planes of polarization including an iris at an appropriate angle and cascading them. CONSTITUTION: Each cavity resonator consists of three waveguide parts which are cascaded and arranged on the same axis, that is, a circular cross-section waveguide whose one end is closed with a circular bottom plane, a rectangular cross-section waveguide and further a circular cross-section waveguide whose one end is closed with a circular bottom plane. In such cases, two terminating parts CC1 to CC4 maintain two modes which have linear polarization that is in parallel with or vertical to planes including irises IR1 to IR3, and the sides of middle parts CR1 and CR2 which consist of waveguides having a rectangular cross-section are tilted against planes that include the irises IR1 to IR3 at an appropriate angle. Two orthogonal modes in each cavity resonators are directly connected through rectangular waveguide parts CR1 and CR2. Then, it is possible to obtain a filter that has an elliptic transfer function.