## 4 Results
#### 4.1.2 Correlation Between Antenna Geometry and Performance Metrics
Rectangular antennas exhibit a mean operating frequency around 2.4 GHz, accompanied by a relatively wide distribution with high outliers. This suggests significant variability, potentially beneficial for broadband applications but also indicative of increased susceptibility to interference. Similarly, array antennas operate around the same mean frequency but present a narrower distribution, with both high and low outliers. This pattern reflects reduced variability and a tendency toward more stable frequency behavior, making them suitable for applications that require consistent operation with limited spectral drift. Circular antennas demonstrate a slightly higher mean frequency (\(\approx\)2.5 GHz) and a generally narrow distribution, although a few high outliers and a lower median suggest moderate variability and potential for operation in slightly lower bands. Bow-tie antennas operate at a lower mean frequency (\(\approx\)2.0 GHz) and exhibit a very tight distribution with low outliers, indicating low variability and stable performance at lower frequencies. Such characteristics make them well-suited for short-range or low-frequency communication applications. Figure 7: Boxplot showing frequency distribution of different antenna designs for energy harvesting. The \"other\" category presents a broader distribution centered around 2.5 GHz, with pronounced outliers on both ends. This reflects the diversity of antenna types included in this group and suggests high spectral variability, allowing operation across a wider frequency range. Slot antennas, with a mean frequency near 2.0 GHz, show a narrow distribution and a single high outlier, implying relatively stable performance and suitability for moderate-frequency applications. Spiral antennas stand out with a lower mean frequency (\(\approx\)1.8 GHz) and a narrow distribution, though a few extreme values at both ends point to a degree of flexibility in frequency tuning. This makes them valuable in contexts requiring both stability and adaptability. Lastly, fractal antennas exhibit a mean frequency close to 2.5 GHz and a tightly clustered distribution, interrupted by high outliers. These results suggest that fractal designs offer stable operation at elevated frequencies, ideal for systems targeting higher-frequency ambient RF sources. * Gain vs. antenna design  
This subsection investigates the relationship between antenna design and gain, a key performance metric in energy harvesting systems as it directly influences the amount of captured ambient electromagnetic energy. By analyzing gain distributions across different antenna categories through boxplot visualization, this section highlights variations in amplification capacity and design-dependent trade-offs. Understanding these differences provides valuable insights for selecting appropriate antenna geometries based on application-specific gain requirements and deployment environments. Figure 8 elucidates distinct gain distribution patterns among antenna designs, underscoring the influence of geometry on amplification performance. Array antennas, for instance, typically exhibit a mean gain of approximately 6 dBi, coupled with a relatively narrow distribution; however, both high and low outliers are discernible. This observation implies moderate variability and consistent performance within their practical operational range. Rectangular antennas, conversely, present a lower mean gain of around 3 dBi and a wider distribution marked by substantial positive and negative outliers, indicative of considerable variability and a broad spectrum of achievable gain values. Circular antennas present a mean gain of 4 dBi and a distribution similar to that of rectangular designs, although with more pronounced low outliers. This reflects comparable variability and a tendency toward lower gain in certain implementations. Bow-tie antennas maintain a mean gain near 5 dBi and exhibit a notably narrow distribution with limited outliers, suggesting low variability and consistently modest gain performance.