# A Two-Port Dual-Band Dual-Circularly-Polarized Dielectric Resonator Antenna
## 2 Antenna Design and Analysis
### Parametric Study  
The parametric analysis of the proposed DBDCP DRA is performed using the ANSYS High Frequency Structure Simulator (HFSS) software version 19.2. The parameters of interest are the width of the corner truncation \(b\), the height of the longitudinal groove \(h_{1}\), and width of the ground plane \(w_{sub}\), and their effects on the simulated reflection coefficients  
Figure 6: Simulated \(E\)-field distributions inside proposed DRA at 4.0 GHz when excited by P1.  
Figure 7: Simulated \(E\)-field distributions inside proposed DRA at 5.5 GHz when excited by P2.  
and ARs are analyzed. During this analysis, one design parameter is studied at a time, while the others remain at optimized values.  
Figure 8 shows the effects of varying the width of the corner truncation \(b\) on both reflection coefficients and ARs. As shown in Figure 8a, an increment in \(b\) shifts the impedance matching of the UB (P2 excited) toward higher frequencies, but this does not have much impact on the impedance matching of the LB (P1 excited). However, by changing the value of \(b\), it is found that the AR performances at both the LB and the UB change dramatically. As indicated in Figure 8b, the 3 dB AR bandwidth of the LB shift toward higher frequencies as \(b\) increases. Meanwhile, increasing \(b\) from 14.06 mm to 15.06 mm enhance the 3 dB AR bandwidth of the UB, but the AR value increases again to higher than 3 dB as the value of \(b\) exceeds 16.06 mm (see Figure 8c).  
The impact of variations in the height of the longitudinal groove \(h_{1}\) in the simulated reflection coefficients and ARs are depicted in Figure 9. The performances of the LB and UB are not very sensitive to the variation of the \(h_{1}\). Increasing the value of \(h_{1}\) slightly shifts the impedance and AR bandwidths of both LB and UB toward higher frequencies. So, an appropriate choice of \(h_{1}\) leads to a maximum overlapped impedance/3 dB AR bandwidths at each band.  
The effects of variations in the ground plane size \(w_{sub}\) on reflection coefficients and ARs are plotted in Figure 10. It is observed that the impedance matching and 3 dB AR bandwidth move toward lower frequencies with the increase in the value of \(w_{sub}\). Conversely, impedance matching and AR performance of the UB are not very sensitive to the  
Figure 8: Simulated results of (**a**) reflection coefficient, (**b**) AR when P1 excited and (**c**) AR when P2 excited for the proposed DBDCP in terms of \(b\).  
Figure 9: Simulated results of (**a**) reflection coefficient, (**b**) AR when P1 excited and (**c**) AR when P2 excited for the proposed DBDCP in terms of \(h_{1}\).  
alteration in \(w_{sub}\). This is due to the difference in the feeding configurations from two ports. The feeding configuration in P1 is asymmetrical, and therefore, it is more sensitive with the changing in the ground plane size. Meanwhile, the feeding configuration in P2 is symmetrical.  
Based on the parametric study, the optimized values of \(b\), \(h_{1}\), and \(w_{sub}\) are 15.06 mm, 6 mm, and 41 mm, respectively.