# A Wideband Metal-Only Patch Antenna for CubeSat
## 2 Antenna Configuration and Simulation Results
### Parametric Analysis  
This section outlines a parametric study that aims to identify factors that affect antenna performance, i.e., reflection coefficient (\(\left.\left|\mathrm{S}_{11}\right.\right|\)), \(-10\) dB bandwidth and total gain. HFSS is used to obtain the simulation results. The value of \(\mathrm{W}_{1}\) is a vital factor to adjust the resonant frequency of the proposed antenna as it is the main radiating element. Figure 3 shows the simulated \(\left.\left|\mathrm{S}_{11}\right.\right|\) with width \(\mathrm{W}_{1}\) varied from 18.8 to 22.8 mm with 2 mm steps in the range. Other parameters are fixed. We can see that the second (fundamental) resonant frequency shifts downwards (decreases) when increasing width \(\mathrm{W}_{1}\), while the first resonant frequency is barely affected. This is because of the increase of the width of the radiating element. The reason that the lower resonant frequency is barely affected is because it was generated by the shorting pins. Therefore, the width of \(\mathrm{W}_{1}\) has a significant effect on resonant frequency and reflection coefficient of the proposed antenna. To achieve a wide bandwidth and meet the required resonant frequency of 2.45 GHz, \(\mathrm{W}_{1}\) = 22.8 mm is selected. It provides a simulated \(-10\) bandwidth of 1.12 GHz (1.60-2.72 GHz), and small \(\left.\left|\mathrm{S}_{11}\right.\right|\) of \(-32.8\) dB at resonant frequency 2.45 GHz. Figure 4 shows the simulated \(\left.\left|\mathrm{S}_{11}\right.\right|\) with different slot length values when \(\mathrm{W}_{1}\) = 20.8 mm. The length \(\mathrm{L}_{2}\) is varied from 8.6 to 22.6 mm with 7 mm steps in the range. Other parameters are fixed. We see that the slot length \(\mathrm{L}_{2}\) has no effect on the resonant frequency of the proposed antenna. However, \(\left.\left|\mathrm{S}_{11}\right.\right|\) improves (decreases) when increasing the slot length \(\mathrm{L}_{2}\). In addition, when \(\mathrm{L}_{2}\) is set to 22.6 and 29.6 mm, a dual band resonant mode is obtained instead of only one wide band. The most suitable slot length is \(\mathrm{L}_{2}\) = 15.6 mm as it provides a small \(\left.\left|\mathrm{S}_{11}\right.\right|\) of \(-32.85\) dB at 2.45 GHz and a wide \(-10\) dB bandwidth of 1.12 GHz (1.606 GHz-2.727 GHz). As shown in Figure 5, the width (\(\mathrm{W}_{3}\)) of the lower folded patch influences the bandwidth and the operating frequency. We see that when \(\mathrm{W}_{3}\) increases, the operating frequency decreases. For example, when changing \(\mathrm{W}_{3}\) is changed from 7 mm to 16 mm, the operating frequency shifts from 2.62 GHz to 2.37 GHz. Moreover, when \(\mathrm{W}_{3}\) is decreased, e.g., \(\mathrm{W}_{3}\) = 7 mm, the proposed antenna starts providing a dual band instead of a wideband. The optimal width is when \(\mathrm{W}_{3}\) = 15.6 mm, as it provides a \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values (mm)** \\ \hline W & 33.8 \\ L & 88.4 \\ \(\mathrm{W}_{1}\) & 20.8 \\ \(\mathrm{W}_{2}\) & 10.4 \\ \(\mathrm{W}_{3}\) & 13 \\ \(\mathrm{L}_{1}\) & 15.6 \\ \(\mathrm{L}_{2}\) & 15.6 \\ \(\mathrm{L}_{3}\) & 20.8 \\ \(\mathrm{L}_{4}\) & 36.4 \\ \(\mathrm{h}_{1}\) & 18.4 \\ \(\mathrm{h}_{2}\) & 9.5 \\ x & 0 \\ y & 10.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Optimal parameters of the proposed antenna. Figure 2: Wideband mechanism of the proposed F-shaped patch: (a) RLC resonance for 2.45 GHz and (b) dual RLC resonance including the effect of the slot. Figure 6 depicts the simulated reflection coefficients of the proposed antenna versus a frequency with different values of L\({}_{1}\) (e.g., 10.6 mm, 15.6.8 mm, 20.6 and 30.6 mm). We can see that the change in the L\({}_{1}\) has almost no effect on the \(-10\) dB bandwidth; however, it has a slight effect on the reflection coefficient \(\mid\)S\({}_{11}\)\(\mid\). We observe that the \(\mid\)S\({}_{11}\)\(\mid\) increases when the L\({}_{1}\) increases.