Enhancing the directivity of a short-length horn by an EBG cavity

In the millimeter frequency range, horn antennas are widespread components in high-directivity applications, but with the drawback of being heavy and bulky. To limit size and weight of such antennas, a lower gain must be accepted, as the radiative properties are dependent on the aperture extension and on the length. A cavity made from an Electromagnetic Band-Gap material can be successfully employed to overcome these limitations, when used as a superstrate of a shorter horn antenna. The new radiator has a wider extension but it is more suitable for low-profile applications.