Dichroic diplexer design for millimeter waves

Metallic plates of finite thickness perforated periodically with circular holes can be used as diplexers, called "dichroic", as part of quasioptical multiplexers in the millimetric range. The purpose of this work is to investigate their filtering properties, to provide a method to design dichroic filters in an efficient way and to draw conclusions about their field of application. Computed results are compared to measurements and the design of a diplexer for the breadboard of an atmospheric radiometer is presented.