## 2 Unit Cell Design
The simulation results of the uniform unit cell, including magnitude and phase reflection as a function of frequency, are shown in Figure 3. The simulations were repeated for three capacitance values: _Cdiode min_ = 0.032 pF (red), _Cdiode max_ = 0.216 pF (green), and _Cdiode res_ (28 GHz). This provided a dynamic reflection phase range of 311\({}^{\circ}\), marked by a continuous black crosser, as shown in Figure 3a. The magnitude of the reflected beam for capacitance is shown in Figure 3b. The maximum loss value for _Cdiode res_ (28 GHz) = 0.0815 pF was 5.5 dB, marked by a continuous black crosser, as shown in Figure 3b. The via was used for the DC bias for the varactor diode. The standard via diameter for manufacturing is 0.25 mm-0.30 mm, which had no effect on the MS's performance. Figure 3c describes the influence of the via diameter on the resonance frequency and the absorption, where no significant influence was found. The simulation results of type A and type B unit cell phase reflection and magnitude are shown in Figure 4 as a function of frequency for three capacitance values: _Cdiode min_ = 0.032 pF (green), _Cdiode max_ = 0.216 (red) pF, and the 28 GHz resonance capacitance _Cdiode res_. Type A provided a dynamic reflection phase range of 236\({}^{\circ}\) and type B provided a dynamic reflection phase range of 150\({}^{\circ}\), marked by the dashed black crossers shown in Figure 4a,c, respectively. The maximum loss value of type A _Cdiode res_ (28 GHz) = 0.05 pF was 1.6 dB, and the maximum loss value of type B _Cdiode res_ (28 GHz) = 0.04 pF was 0.8 dB, marked by continuous black crossers in Figure 4b,d, respectively. The resonance frequency is related to the inductance and capacitance of the unit cell. The thickness, h, of the dielectric substrate is proportional to the inductance [25]; thus, the change of h affects the resonance frequency and the dynamic phase range of the unit cell. The motivation to design an MS based on the stripes method was to reduce the total absorption of the proposed MS compared to the uniform type (one stripe). Changing h is advantageous since it reduces the \"transition effects\" (or \"edge effects\"), yielding \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Parameter** & **Description** & **Value (mm) Uniform Unit Cell** & **Value (mm) Type A** & **Value (mm) Type B** \\ \hline P & Unit cell length & 3.4 & 3.4 & 3.4 \\ W & Unit cell width & 2.55 & 2.55 & 2.55 \\ S\({}_{\rm L}\) & Pad/Line(strip) length & 2.45 & 2.45 & 2.45 \\ S\({}_{w}\) & Pad/Line(strip) width & 0.9 & 0.9 & 0.9 \\ D\({}_{\rm L}\) & Varactor diode length & 0.7615 & 0.7615 & 0.7615 \\ D\({}_{\rm W}\) & Varactor diode width & 0.406 & 0.406 & 0.406 \\ D\({}_{\rm H}\) & Varactor diode height & 0.203 & 0.203 & 0.203 \\ D\({}_{\rm i}\) & Distance between external line & 0.686 & 0.686 & 0.686 \\ D\({}_{\rm o}\) & Distance between internal line & 0.94 & 0.94 & 0.94 \\ h & Dielectric substrate thickness & 0.381 & 0.6 & 0.75 \\ t & Copper thickness & 0.035 & 0.035 & 0.035 \\ Pd & Pad diameter & 0.6 & 0.6 & 0.6 \\ VD & Via diameter & 0.3 & 0.3 & 0.3 \\ CD & Clearness diameter & 0.6 & 0.6 & 0.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Geometric unit cell parameters. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Description** & **Value** \\ \hline _Rdiode_ & Diode resistance & 4 \(\Omega\) \\ _Cdiode max_ & Max diode capacitance & 0.216 pF \\ _Cdiode min_ & Min diode capacitance & 0.032 pF \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Electrical unit cell parameters. a better beam-steering performance. Any differences between two adjacent stripes would disturb the periodicity of the unit cells of the whole MS, causing transition effects or edge effects, degrading the reflected beam. The advantage of changing h (the dielectric substrate thickness) eliminates this problem. In this realization, the incident wave \"sees\" the same geometry but with a different phase reflection, significantly decreasing the transition effects.