A set of boundary conditions requiring vanishing of the normal components of the D and B vectors at theboundary surface is introduced and labeled as that of DB boundary. Basic properties of the DB boundary arestudied in this paper. Reflection of an arbitrary plane wave, incident with a complex propagation vector, isanalyzed for the planar DB boundary. It is shown that waves polarized transverse electric TE and transversemagnetic TM with respect to the normal of the boundary are reflected as from respective perfect electricconductor and perfect magnetic conductor planes. The basic problem of current source above the planar DBboundary is solved by applying TE and TM decomposition for the source. Realization of the DB boundary interms of an interface of uniaxially anisotropic metamaterial half-space with zero axial medium parameters isconsidered. It is also shown that such a medium with small axial parameters acts as a spatial filter for wavesincident at the interface which could be used for narrowing the beam of a directive antenna. Application of DBboundary as an isotropic soft surface with low interaction between antenna apertures also appears possible.Peer reviewe
