## 1 Introduction  
Antennae designed to exhibit multiple beam coverage over sizable angular range and over a wide band is needed in satellite communication. Mostly, electrical beam steering is realized through the use of phased array, reflector and switching network [1]. The transformation optics concept is investigated to design a beam steering lens [2, 3] and a similar approach for deviation of the beam is shown by the reflecclive array surface [4] and transmit array structure [5], which are relatively larger in dimension and are costly in manufacturing. The Ku-band frequency of operation has been the interest in research fields especially to analyze the signal attenuation levels [6, 7]. In order to have effective radio wave propagation, low profile flat Luneburg lens of multilayer gradient index metamaterials is studied in [8], which requires the materials which have permittivities of higher values that will increase the cost of lens fabrication. Most recently, Luneburg lenses have been the choice of interest [9], where 3D printing is used for the design of lenses however the lens shows higher profile and complexity in the design concept. In order to make lower profile and light weight Luneburg lens, flat Luneburg lens concept has been proposed. The transformation of point excitation on the circumference into a directional beam that ultimately steers the radiated beam direction is depicted by the Luneburg lens. To realize such lens behavior,several approaches are studied as defined printed circuit board patches [10], patches with step change in waveguide [11], meandering crossed microstrip lines with variation in their widths [12], periodic structure of metallic post [13], air filled cylindrical modified parallel plate [14], parallel plates filled with polymer material [15], dielectric slab of concentric rings which shows various permittivity values [16], cylindrical lens sandwiched between two parallel plates made from Teflon material [17], modified Luneburg lens antenna with two identical machined parallel metal plates of planar slot radiator as a feed source [18], cylindrical Luneburg lens obtained through hole drilling process [19] and parallel plates with epoxy posts in between that are fed by an E-shaped patch [20]. Focusing on these aspects, this article proposes a 3D printable structure that is kept in between the two parallel plates with fundamental separation distance of a half wavelength. Additive manufacturing (AM) shows vast design freedom for complex geometrical structures, which are preferred to traditional micromachining due to the advantages such as low cost, light weight and ability to revise a design quickly [21; 22; 23; 24]. The recent works on 3D printed Luneburg lens antenna and antenna performance, as suggested in [25; 26], are helpful to understand the microwave dielectric properties of antenna structure. In this article, the approach is described to place 3D printable cylindrical posts for defined radial distance from center that shall show the method to steer the radiated beam direction. Section 2, describes the concept for the cylindrical unit cell of various diameters, which correspond particular relative permittivity values. Similarly, Section 3, highlights the facts about design procedure and the placement of cylindrical units' cells. Additionally, Section 4, points the results and discussion thus obtained as well as comparison with other design aspects. Finally, Section 5, concludes the article with concluding remarks.