## 6 Experimental Results  
We fabricated the metasurface and measured it to verify the simulated results. Figure 10a illustrates the fabrication of 20 \(\times\) 20 elements totaling 120 \(\times\) 120 mm\({}^{2}\) to practically verify the attributes of the proposed metasurface. Metallic copper designs are etched onto the thin layer of PTFE (\(\epsilon_{r}=2.1\)), using printing circuit technology. The metal layer has a thickness of 0.035 mm, whereas the PTFE layer has a thickness of 1.6 mm. A metallic copper plate is used on the back side of the substrate to achieve complete reflection. As shown in Figure 10b, the experiments are performed in an anechoic chamber to eliminate reflections and background noise, for accurate results. With the aid of two different sets of LP horn antennas, the reflected waves in two frequency sweeps (8-18 GHz and 18-40 GHz) are measured. These horn antennas are associated with the Agilent vector network analyzer N5230.  
To collect the reflected waves from the metasurface, wideband two-horn antennas are employed. To calculate the LP-CP conversion, both the co- and cross-polarized reflection coefficients need to be measured. In order to measure the reflected co-polarized components, both antennas are oriented horizontally (vertically) in the same direction. On the other hand, the receiving antenna is placed horizontally, while the transmitting antenna is positioned vertically, in order to measure the cross-polarized reflection coefficients. Figure 11a displays the simulated and measured results of the co- and cross-polarization conversion. Also, the PCR is measured and depicted in Figure 11b for LP-LP verification. We also measured the LP-CP performance of the proposed structure. Figure 11c shows the measured AR of the proposed metasurface. With slight discrepancies caused by fabrication tolerances, the agreement between the simulation and measurement is considered satisfactory. Notably, the measured resonant frequencies correspond with the values predicted by the simulations for a typically incident \(y\)-polarized wave. Performance comparisons between the newly  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Reference**} & **Substrate** & **Periodic Unit** & **3 dB AR** & \multirow{2}{*}{**PCR (\%)**} & **Substrate** & **Performance** & **No. of Bands** \\  & **Height h (mm)** & **Cell p (mm)** & **(\%)** & & & **Layer** & **Polarization** & **No. of Bands** \\ \hline Ref. [9] & 1.6 & 6.0 & 50.8 & 90 & Single layer & LP–CP & 1 \\ Ref. [17] & 1.6 & 6.0 & 35.23/ & NG & Single layer & LP–CP & 2 \\ Ref. [18] & 3.5 & 9.5 & 69.51 & NG & Single layer & LP–CP & 1 \\ Ref. [30] & 1.0 & 8.0 & 23.9 & NG & Single layer & LP–CP & 3 \\ Ref. [37] & 1.57 & 10.0 & 0.9/1.6/ & NG & Bi-layer & LP–CP & 4 \\  & & & 1.7/1.72 & & & & LP–CP & 5 \\ This paper & 1.6 & 6.0 & 40.15/14.6/ & 95 & Single layer & LP–CP & 5 \\  & & & 13.76/2.7/0.2 & & & & LP–LP & 4 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The proposed design in comparison with polarizers in recently cited papers.  
Figure 10: (a) Prototype metasurface array, (b) experimental setup in an anechoic chamber.  
developed LP-CP and reflective CPC metasurface and previously published studies, in multiple frequency bands, are shown in Table 2. Thus, the anticipated LP-CP conversion and CPC are realized in multiple frequency bands, between 10 GHz and 40 GHz. As discussed above, the angular stability of the design is analyzed over a wide range of incident angles. The results of the AR are shown in Figure 6b, with \(\theta\) varying from 0 deg to 30 deg. Figure 6b demonstrates the effect of oblique incidence on the dip in 3 dB resonance. The third resonance 3 dB dip is sensitive to the incident angle, with the bandwidth shrinking at a higher frequency. It can be reasonably concluded from the 3 dB dip resonances that the designed metasurface is angularly stable over a wide range of incident angles, making it suitable for various applications.