## 5 Final Simulated and Measured Results  
The simulated results of the proposed model are varified with the help of the fabricated design. As shown in fabricated design, the rectangular slot is carved on the ground plane. The DR is positioned on the Roger substrate. A copper strip is piled on the top surface of the DR. Meanwhile the coaxial probe is used to excite the DR from the edge. The reflection coefficient of the design is assesed with the help of the Vector Network Analyser (VNA). The simulated and measured reflection coefficient of the design is depicted in Figure 10. For \(-10\) dB reference value of the reflection coeffcient, the simulated operating bandwidth of the design is from \(8.45\) GHz to \(14.09\) GHz. The simulated resonance frequencies are \(9.44\) GHz and \(13.13\) GHz, respectively. The measured reflection coefficient follows the simulated values. The measured operating band starts from \(8.58\) GHz and ends on \(14.09\) GHz. The measured resonance frequncies are the same with better impedance matching. Figure 11 depicts the simulated and measured axial ratios of the design. For \(3\) dB reference value, the simulated axial ratio bandwidth is from \(10.085\) GHz to \(11.10\) GHz. The max dip of the axial ratio is at \(10.5\) GHz. Measured axial ratio bandwidth is slightly right  
Figure 8: Effect of variation in the copper strip on the axial ratio. Figure 9: Electric field distribution on the top surface of the DR at (**a**) T = 0, and (**b**) T = t/4. shifted, and ranges from 9.8 GHz to 10.8 GHz. This shift and slight degredation in axial ratio performance is due to fabrication inaccuracies and surrounding noise in the chamber. The proposed design has a good, measured gain, efficiency and radiation pattern. All the measured values are close to the simulated values. The measured peak gain of the design is shown in Figure 12. The measured peak gain of the design is 6.5 dBic, i.e. is less than the simulated value. The measured gain of the design over the axial ratio bandwidth is between 6 to 6.5 dBic. The minor deviation in the measured values is due to imperfect fabrication of the prototype. Figure 13 illustrate the simulated and measured radiation efficiencies of the design. Their values over the entire axial ratio bandwidth are more than 96%. Figure 14 depicts the simulated and measured RH (Right Hand) CP and LH (Left Hand) CP far field patterns at 10.5 GHz central frequency of the AR. The electric fields distribution on the DR top surface show that the design is dominantly RHCP by 37 dB in the main direction of the radiation. The direction of radiation at 10.5 GHz is boresight and focused towards 15\({}^{\circ}\). The radiation pattern of the design in terms of E-field and H-field at 9.44 GHz and 13.13 GHz is depicted in Figures 15 and 16, respectively. The radiation pattern  
Figure 11: Simulated and measured axial ratios of the design. Figure 10: Simulated and measured reflection coefficients of the proposed design. at 9.44 GHz is broadside with 6.5 dBic radiation gain. Both the simulated and measured radiation pattern at 9.44 GHz are quite close to each other. At 13.13 GHz, the main radiation lobe is now focused at 330\({}^{\circ}\) with a relatively narrow beam width. The design has a good radiation gain of more than 5 dBic. The simulated and measured radiation pattern gain at 13.13 GHz are also in close matching. Figure 17a,b show the top and bottom views of the fabricated design while c shows the radiation pattern measurement setup. Figure 12: Simulated and measured realized gain of the design. Figure 13: Simulated and measured radiation efficiencies of the design. A comparison of the proposed design with the recently published work is presented in Table 2. From the Table 2 it is clear that the proposed design in comparison with the published work is very simple with good gain, very high efficiency, simple architecture and compact size. Column 1 of Table 2 shows that the proposed design has size comparison both in physical lengths and electrical lengths.