# Circularly Polarized Broadband Printed Antenna for Wireless Applications
## 2 Antenna Design Structure
### Various Parameter Optimization  
To investigate the consequences of the corresponding structural variables on the impedance and AR bandwidth, parametric research has been completed in this section. Figure 5 portrays the simulated S\({}_{11}\) and AR with dissimilar parameter values of \(R1\), \(R2\), \(R3\), \(L1\), and angle \(\alpha\). Initial values were fixed of all the parameters during optimization. (a) Effect of ground plane circular slot radius \(R1\)  
Figure 5 depicts the antenna functionality against the bottom circular slot radius \(R1\). As displayed in Figure 5, \(R1\) includes a nominal influence on the impedance bandwidth of higher frequencies when its radius decreases. On the other hand, increasing its radius from an optimum value of 17 mm improves the S\({}_{11}\) in the higher frequency range but upshifts, the lower frequencies. However, the variations in \(R1\) have a nominal influence upon CP procedure in the higher frequency range. Nevertheless, when \(R1\) is varying with regards to the 17 mm radius, the antenna seems to lose its CP property in the low and middle of the targeted frequency range. (b) Effect of patch circular radius \(R2\)  
The proposed antenna functionality is also examined when the patch circle radius \(R2\) is diversified as depicted in Figure 5. The impedance bandwidth is relatively susceptible to the deviation of \(R2\). From Figure 5, it can be noticed that reducing \(R2\) with esteem to the ideal 11.2 mm causes the antenna to reduce its \(-10\) dB bandwidth while raising it causes the antenna S\({}_{11}\) to reduce in the upper rate of the recurrence range. However, the variants of \(R2\) have a nominal influence on the CP radiation in the larger frequency range. Nevertheless, when \(R2\) is reduced with regard to the most effective worth, the antenna seems to lose its CP procedure in the low operating frequency range. (c) Effect of patch circular slot radius \(R3\)  
Figure 5 describes the overall antenna performance against the circle slot patch radius \(R3\). As demonstrated in Figure 5, \(R3\) includes a less significant influence on the impedance bandwidth when its size decreases. Nevertheless, increasing its size decreases the S\({}_{11}\) in the center frequency range. However, all the CP settings are sensitive to the patch slot radius \(R3\). The circular slot radius \(R3\) can influence the relative placement of the sickled slot patch strips. Therefore, the CP behavior is usually influenced because of the coupling capacitance between the sickle from the patch and the copper in the bottom plane. Seen from the graph that reducing \(R3\) with regard to 7.7 mm triggers the antenna to drop its CP property completely within in the entire bandwidth while increasing it triggers the antenna to reduce its CP features in the low-frequency range. Seen from Figure 5 that the broadest 3 dB ARBW is definitely accomplished when \(R3\) is 7.7 mm. * Effect of patch circular slot radius \(L1\)  
Figure 5d displays the overall antenna performance versus the antenna feed placement size \(L1\). The monopole feed line is the primary radiator of the antenna. Thus, the semicircle slotted patch mounted on it plays an essential role in the antenna linear radiation design for CP radiation features. As demonstrated in Figure 5d, \(L1\) has a nominal influence upon impedance bandwidth when \(L1\) decreases from its optimum value. However, increasing the space improved the S\({}_{11}\) in the upper rate of the recurrence but decreases the low-frequency range. However, the variants of \(L1\) have minimal influence on the CP procedure in the desired working band. * Effect of \(<\)AOB angle \(\alpha\)  
Figure 5e depicts the antenna performance versus the \(<\)AOB angle \(\alpha\). From this figure, the S\({}_{11}\) is sensitive to the variation of the three-circle angle \(\alpha\). The S\({}_{11}\) at the lower frequency bands tends to decrease as \(\alpha\) increase, while very small changes are found at the higher frequencies.