# Generation of Beam Tilt through Three-Dimensional Printed Surface
## 3 Phase Plots for the Generation of CRS and BDS  
As described in the above section, the step starts with the generation of a BDS surface whereby a more uniform phase is required above the horn aperture. In order to maintain a uniform phase, we have chosen a suitable value above the maximum normalized phase value for the feed horn only condition through multiple simulation runs from the CST software. The five-layer database was used to maintain uniformity in the phase distribution. Here, the respective phase value towards the end of aperture positions particularly for 41.25, 48.75 and 56.25 mm are fine tuned in order to achieve more uniformity in the overall phase variation. Thus, the phase values in degree arranged across the aperture are shown in Figure 6, where the minimum and maximum values of 70\({}^{\circ}\) and 330\({}^{\circ}\) are noted, respectively. Additionally, the obtained phase variation in degree at 6.25 mm (\(\lambda/4\)) above the top surface of the designed five-layer prototype is shown in Figure 7. Here, it is observed that the phase values become more uniform towards the center position and are mostly below 30\({}^{\circ}\), and slightly higher values are seen towards the end of aperture and are relatively greater than 200\({}^{\circ}\). Additionally, the obtained five layer's pictorial outlooks with its top and perspective views are depicted in Figure 8a,b, respectively. Since the cubes that are placed in the top and bottom of the five-layer prototype are the same, we have mentioned only the top view. Figure 6: Arrangement of phase throughout the aperture distribution for the generation of the five-layer prototype. Figure 7: Phase distribution noted in 6.25 mm (\(\lambda/4\)) above the top surface of the designed five-layer prototype. In the next step, we have designed the CRS with a phase increment of 40\({}^{\circ}\) from the left of the aperture toward the right side. In each column of the phase distribution, the phase values will be the same, and it will be incremented as we move towards the next column. These phase values in degrees are highlighted in Figure 9. The minimum phase value of 0\({}^{\circ}\) and the maximum phase value of 320\({}^{\circ}\) are thus maintained. The 0\({}^{\circ}\) phase is kept in the fourth column starting from the left side and this 0\({}^{\circ}\) phase column is shifted right for each column, i.e., fifth, sixth, etc., to the sixteenth column and again shifting back to the first column, which is performed so as to obtain minimum side lobe level for the broadside condition. The increasing phase gradient is maintained from the bottom towards the upper side, which is along the E-plane. The phase distribution as noted in Figure 6 is added to the phase shown in Figure 9, so the combined phase in degrees is obtained, as shown in Figure 10, which will generate the BDS surface and be able to deflect the beam to a particular elevation angle. This four-layer cube arrangement is able to show the minimum side lobe level in combination with CRS for broadside direction. Since, the cubes defined for each layer of this four-layer BDS structure are not symmetrical, we have interlinked CST software with Matlab so that the systematically generated code is run for the proper placement of these cubes. The  
Figure 8: Five-layer prototype: (**a**) top view, (**b**) perspective view. Figure 9: Phase distribution of CRS for the designed four-layer prototype. top, bottom and perspective views are shown in Figure 11a-c, respectively. The relative dimensions in terms of footprint and height of the fabricated BDS prototype, as shown in Figure 11, are of 120 \(\times\) 120 mm and 30 mm, respectively.