Transmission of dominant transverse electric mode in large rectangular waveguide, with polarization parallel to width, by use of mode absorber

Claim 1

A WAVEGUIDE SYSTEM FOR THE TRANSMISSION OF MICROWAVE SIGNALS OF A GIVEN FREQUENCY COMPRISING A RECTANGULAR METAL WAVEGUIDE WITH MEANS FOR LAUNCHING THE SIGNALS TO BE PROPAGATED IN TO WAVEGUIDE AS A PLANE POLARIZED WAVE WITH THE ELECTRIC VECTOR PARALLEL TO THE LONGER SIDE OF THE GUIDE, THE GUIDE HAVING THE DIMENSIONS OF ITS LONGER SIDE SUCH THAT THE GUIDE CAN TRANSMIT THE SIGNALS AT SAID GIVEN FREQUENCY IN MORE THAN ONE MODE, AND A MODE FILTER IN THE GUIDE COMPRISING A NUMBER OF RESISTIVE FILMS IN PLANES PARALLEL TO THE SHORTER SIDE WALL OF THE GUIDE TO SUPPRESS THE TRANSMISSION OF MODES IN WHICH THE ELECTRIC VECTOR IS NOT PARALLEL TO THE LONGER SICE, THE GUIDE HAVING DIMENSIONS OF THE SHORTER SIDE SUCH THAT THE GUIDE CAN TRANSMIT MODES AT SAID GIVEN FREQUENCY HAVING MORE THAN ONE HALF PERIOD OF VARIATION IN THE ELECTRIC VECTOR AND HAVING A MODE SUPPRESSION FILTER COMPRISING AT LEAST ONE SLOT IN AT LEAST ONE OF THE SHORTER FACES OF THE GUIDE ALONG THE AXIAL DIRECTION THEREOF TO SUPPRESS THE TRANSMISSION OF MODES HAVING MORE THAN ONE HALF PERIOD OF VARIATION IN THE ELECTRIC VECTOR ACROSS THE SHORTER DIMENSION OF THE WAVEGUIDE.