Quasi-optical polarization diplexing of microwaves

The feasibility of a microwave quasi-optical polarization diplexer has been demonstrated using photo-etched copper strips with thin mylar backing as a practical example. The insertion losses of the principal polarization and the cross polarization have been calculated and measured. The conducting strips must be aligned in a preferred direction, namely, perpendicular to the plane of incidence, to minimize cross-polarized radiation, whereas orientation of the plane of the grid with respect to the beam direction is not restricted. The measured cross-polarized radiation agrees with predictions from simple theoretical models of a magnetic current sheet for the transmission mode and an electric current sheet for the reflection mode. This type of diplexer has been successfully employed in studying the polarization properties of the 20-GHz signal from the ATS-6 satellite.