公开(公告)号：WO1993010584A1

公开(公告)日：1993-05-27

申请号：PCT/US1992009966

申请日：1992-11-18

Applicant: HUGHES AIRCRAFT COMPANY

Inventor： HUGHES AIRCRAFT COMPANY ,  DOLEZAL, Franklin, A. ,  GREGOIRE, Daniel, J. ,  HARVEY, Robin, J.

IPC: H01S03/09

CPC classification number: H01S3/0903 ,  H01P7/06

Abstract: A waveguide filter (22, 24) is incorporated into a cavity resonator (20) for a free-electron laser or the like by coating a material layer (24) on the inner peripheral surface of a hollow waveguide member (22). A high pass filter configuration is provided when the conductivity of the material layer (24) is higher than that of the waveguide member (22), such that electromagnetic signals having wavelengths longer than the skin depth of the material layer (24) pass into and are affected by the lower conductivity waveguide member (22). Reversing the conductivities produces a low pass filter configuration in which signals having wavelengths shorter than the skin depth are affected by the material layer (24). A bandpass filter configuration is provided by adding an additional material layer (32) of low conductivity to a high pass filter, whereas a band exclusion filter configuration is produced by adding an additional material layer (32) of high conductivity to a low pass filter.