EQUIVALENCE BETWEEN PHYSICAL OPTICS AND APERTURE INTEGRATION FOR RADIATION FROM OPEN-ENDED WAVE-GUIDES

The eigen-mode radiation from an open-ended waveguide of arbitrary cro ss section is considered. The following theorem is demonstrated: the K irchhoff-Kottler aperture integration for the radiated field is equiva lent to the physical-optics (PO) approach applied to the wall currents . This theorem allows one to resort to aperture integration for those structures involving complicated PO integration. On the other hand, ba sed on the same theorem the aperture integration may be reduced to a l ine integral along the edge of the waveguide for those configurations that allow a simple PO integration. It can also be useful in developin g more efficient solutions in the framework of incremental theories.