# A Dual-Polarized Omnidirectional Rectenna Array for RF Energy Harvesting Harvesting
## 4 Discussion of the Proposed Rectenna Array
To describe the performance of the proposed rectenna array more intuitively, the maximum PCEs and their corresponding power densities obtained during simulations and measurements at different polarization direction angles are listed in Table 4. Meanwhile, Table 5 lists the simulated and measured maximum PCEs and PCE fluctuations of the rectenna array at different EM wave incidence angles. According to the data in Tables 4 and 5, the proposed rectenna array has good omnidirectional RF energy harvesting capability, and the PCE fluctuations in different harvesting scenarios are below 10%. Table 6 below gives the comparison between the rectenna array in this work and the existing related works. It can be found that the proposed rectenna array can maintain good stability when receiving EM waves with varying incident directions and polarizations. It is competitive with the existing arts in terms of spatial coverage, polarization mode, and PCE fluctuation when used for RF energy harvesting (REH) applications. \begin{table}
\begin{tabular}{c c c c} \hline \hline \begin{tabular}{c} **Polarization** \\ **Direction Angle** \\ \end{tabular} & **Incident Angle** & \
\begin{tabular}{c} **Maximum PCE for** \\ **Simulation/Measurement (\%)** \\ \end{tabular} &
\begin{tabular}{c} **Power Density Corresponding to** \\ **Simulation/Measurement (\(\mu\)iW/cm\({}^{2}\))** \\ \end{tabular} \\ \hline \(0^{\circ}\) & \(0^{\circ}\) & \(60.51/58.73\) & \(85.33/128.12\) \\ \(0^{\circ}\) & \(45^{\circ}\) & \(60.51/59.04\) & \(78.33/105.35\) \\ \hline \(90^{\circ}\) & \(0^{\circ}\) & \(49.4/48.35\) & \(259.62/377.26\) \\ \(45^{\circ}\) & \(45^{\circ}\) & \(44.9/44.04\) & \(263.78/275.83\) \\ \hline \(45^{\circ}\) & \(0^{\circ}\) & \(56.81/55.52\) & \(120.27/165.45\) \\ \(45^{\circ}\) & \(45^{\circ}\) & \(57.8/55.80\) & \(123.25/130.75\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Maximum PCEs and their corresponding power densities at different polarization direction angles. Figure 19: Simulated and measured results of the rectenna array when the polarization direction angle is \(45^{\circ}\): (**a**) PCEs versus input power density; (**b**) PCEs versus incident angle. \begin{table}
\begin{tabular}{c c c c} \hline \hline \begin{tabular}{c} **Polarization** \\ **Direction Angle** \\ \end{tabular} & \begin{tabular}{c} **Power Density** \\ **(\(\mu\)iW/cm\({}^{2}\))** \\ \end{tabular} & \
\begin{tabular}{c} **Maximum PCE for** \\ **Simulation/Measurement (\%)** \\ \end{tabular} &
\begin{tabular}{c} **PCE Fluctuation for** \\ **Simulation/Measurement (\%)** \\ \end{tabular} \\ \hline \(0^{\circ}\) & \(100.3\) & \(60.97/59.10\) & \(1.73/0.99\) \\ \(251.9\) & \(30.47/45.99\) & \(2.37/3.15\) \\ \hline \(90^{\circ}\) & \(287.2\) & \(49.73/47.51\) & \(5.67/4.82\) \\ \(555.1\) & \(31.82/42.23\) & \(5.96/8.55\) \\ \hline \(45^{\circ}\) & \(133.5\) & \(58.9/55.92\) & \(1.64/0.58\) \\ \(305.7\) & \(32.47/46.12\) & \(2.6/3.69\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Maximum PCEs and PCE fluctuations at different EM wave incidence angles.