Abstract: An antenna apparatus includes: a parabolic reflector; a dielectric support pedestal; a sub-reflector connected to an upper part of the dielectric support pedestal; and a waveguide connected to a lower part of the dielectric support pedestal, wherein the parabolic reflector has a curved surface in which a ratio of a focal length to a diameter is greater than a preset value, and at least one corrugation configured to suppress a cross polarization is formed in a region of the dielectric support pedestal.

Abstract: Disclosed in the present invention is a floating hologram system. The floating hologram system includes a diffuser configured to form a projection image using light beams transmitted from an image transmitter and diffuse the formed image, and a holographic optical element on which the image diffused from the diffuser is incident and which generates a virtual image floating at a position a predetermined distance therefrom and has a convex lens characteristic. A distance between the diffuser and the holographic optical element is determined based on a focal length of the holographic optical element and a distance from the holographic optical element to the virtual image.

Abstract: A structure of a dry heating system, and a method for constructing the same are disclosed. An upper board stacked on a heat radiator has a double-layer structure comprising first upper board elements and second upper board elements in order to prevent steps from being formed at seaming portions formed on the upper portion of the dry heating system, thereby maintaining flatness of the upper board, and reducing any bending of the upper board, in which the first upper board elements constitute a lower portion of the double-layer structure, and serve to protect the heat radiator while supporting a weight load, and the second upper board elements constitute an upper portion of the double-layer structure, and serve to maintain the flatness of the upper board by removing the steps, thereby ensuring excellent quality in construction of the dry heating system.

Abstract: A structure of a dry heating system, and a method for constructing the same are disclosed. An upper board stacked on a heat radiator has a double-layer structure comprising first upper board elements and second upper board elements in order to prevent steps from being formed at seaming portions formed on the upper portion of the dry heating system, thereby maintaining flatness of the upper board, and reducing any bending of the upper board, in which the first upper board elements constitute a lower portion of the double-layer structure, and serve to protect the heat radiator while supporting a weight load, and the second upper board elements constitute an upper portion of the double-layer structure, and serve to maintain the flatness of the upper board by removing the steps, thereby ensuring excellent quality in construction of the dry heating system.