Microwave band-splitting filters consisting of quasi-optical rectangular waveguides

The employment of a waveguide data transmission system based on the use of millimeter waves requires band-splitting filters which divide a transmission band of more than one octave into two or more subbands. A filter design utilizing quasi-optical waveguides makes it possible to keep losses, particularly at high frequencies, at a low level. The reported investigation shows that band-splitting filter designs employing quasi-optical rectangular waveguides have significant advantages in comparison to corresponding filters with circular waveguides, if the band-splitting filter network is followed by channel filters consisting of single-wave rectangular waveguides. The relations obtained in a theoretical analysis are supplemented with the results of an experimental study.