Multi-beam Radiation by Line Sources Embedded in an Electromagnetic Band-Gap Material

Electromagnetic Band-Gap (EBG) materials can be used in antenna applications to enhance the gain of a low-directivity antenna, with two possible strategies: i) in an assembly of the EBG as a superstrate of a primary source, in the so-called Resonant-Cavity Antennas; ii) with the embedded-source method, in which a source positioned in the EBG couples with the lattice modes. The mechanism of coupling of the source with the EBG modes has been discussed in [1], [2]. As shown in [1], a suitable excitation from a line source in a square lattice EBG, that couples with the lattice mode, excites a broadside beam, if the embedded-source antenna ends on PEC plate. A layout for two-beam excitation has been proposed in [2], through the excitation from two line-sources in a rotated EBG lattice.