## 4 Results and Discussion
### Characteristic Plots and Comparison Table  
The simulated pattern of peak directivity and gain plots as well as the side lobe level variation after the placement of cylindrical rods in defined circular ring regions are shown in Figure 9a,b, respectively. As noticed, in the design operation frequency of 12 GHz, simulated peak directivity and gain values are 11.9, 11.2, 10.8, 10.6, 10.1 dBi and 11.7, 10.9, 10.4, 10.3, 9.87 dBi, respectively for \(0^{\circ}\), \(30^{\circ}\), \(45^{\circ}\), \(75^{\circ}\) and \(90^{\circ}\) of WR-75 waveguide counter clockwise direction, which shows the decreasing trend in its values. Similarly, side lobe levels are \(-11.2\) dB, \(-8.4\) dB, \(-8.1.6\) dB, \(-9.2\) dB and \(-8.3\) dB for the rotation of the WR-75 waveguide in \(0^{\circ}\), \(30^{\circ}\), \(45^{\circ}\), \(75^{\circ}\) and \(90^{\circ}\) in the counter clockwise direction. In addition, we have plotted the measured directivity and gain plots against the simulated values for \(0^{\circ}\), \(45^{\circ}\) angles of rotation of WR-75 waveguide, which is shown in Figure 10a. This figure highlights the matching trends for simulated and measured directivity and gain patterns. The measured values of directivity and gain in \(0^{\circ}\) condition at 11, 12 and 14 GHz are 11.5, 11.01 dBi; 12.5, 12.08 dBi; and 12.6, 12.33 dBi, respectively. Similarly measured directivity and gain values in \(45^{\circ}\) condition at 11, 12 and 14 GHz are 10.84, 10.56 dBi; 11.16, 10.98 dBi; and 12.23, 11.59 dBi, respectively. Interestingly, these are comparable to the simulated values and are less than 3 dB in difference between directivity and gain margin. This signifies the lower loss behavior of the material under consideration. Similarly, Figure 10b shows the simulated and measured return loss plot for rotation angles of \(0^{\circ}\), \(30^{\circ}\), \(45^{\circ}\), \(75^{\circ}\) and \(90^{\circ}\) for WR-75 waveguide. This plot signifies the matching of proposed antenna structure throughout the operating frequency band where its values are less than 2.2, expect for the measured \(75^{\circ}\) case which might be due to the arrangement of cylinders within the defined circular regions of the proposed prototype. Moreover, we have analyzed the cross polarization values for both \(0^{\circ}\), \(45^{\circ}\) angles of rotation of WR-75 waveguide, which are shown in Figure 11a,b. In the \(0^{\circ}\) angles of rotation case, the observed cross polarization values are below \(-7\) dBi where as in the \(45^{\circ}\) case, its values are below -12 dBi. However, most of the values lie in between \(-15\) dBi to \(-35\) dBi, which signifies the better matching behavior in operating frequency ranging from \(10\) GHz to \(15\) GHz with respect to lower cross polarization with the minimum loss of signals at the receiver end. Figure 8: Measurement system setup in anechoic chamber. Attached index figures shows fabricated prototype and assembled system with parallel plates and waveguide. Similarly, the comparison of proposed antenna prototype with other structures is shown in Table 1. This shows the proposed antenna prototype gives wideband beam deviation that is observed across the frequency range from 10 GHz to 15 GHz. Additionally, the side lobe levels are lower than \(-\)6 dB for operating Ku-band frequency range, and the proposed prototype is 100 mm in diameter, which is comparatively smaller as compared with other proposed antenna structures. The design goal of proposed structure is to show beam deviating characteristics from 10 GHz to 15 GHz maintaining higher values of \(\theta\). Figure 11: Noted cross polarized values, (**a**) \(0^{\circ}\) (**b**) 45\({}^{\circ}\) angles of rotation of WR-75 waveguide. Figure 9: (**a**) Distribution of simulated peak directivity and gain values. (**b**) Side lobe levels plot in 10 GHz, 11 GHz, 12 GHz, 13 GHz, 14 GHz and 15 GHz frequencies.