## 4 Results
#### 4.3.2 Correlation Between Rectifiers and Performance Metrics
Half-wave rectifiers stand out with the largest average area (\(\approx\)6000 mm\({}^{2}\)) and a broad range of values, reflecting their association with high-energy collection needs but also demanding more robust designs to accommodate spatial variability. Microwave rectifiers show the smallest median area (\(\approx\)2500 mm\({}^{2}\)) and a remarkably narrow distribution, suggesting consistent miniaturization, though this limited size inherently constrains their  
Figure 20: Boxplot showing area distribution of different rectifier designs for energy harvesting. energy harvesting capacity--making them ideal for ultra-compact systems where spatial economy is prioritized over power density. This subsection investigates the relationship between rectifier topology and antenna surface area in RF energy harvesting systems. Since rectifier design may impose specific impedance-matching and integration requirements, it can indirectly influence the overall size of antenna structure. By analyzing the distribution of antenna areas across different rectifier types, this section aims to identify whether certain topologies are more frequently associated with compact or large-scale configurations, providing insight into spatial constraints and design compatibility in integrated energy harvesting architectures. These findings highlight the influence of rectifier topology on antenna area and system integration. While compact designs such as full-wave and microwave rectifiers are well-suited for miniaturized or embedded applications, larger-area configurations like half-wave or single-step rectifiers may be more appropriate for systems targeting higher energy output, provided that spatial flexibility is permitted. * Efficiency vs. rectifier  
This subsection examines the relationship between rectifier topology and overall system efficiency in RF energy harvesting applications. As the rectifying stage directly governs the conversion of RF signals into usable DC power, its architecture and component characteristics play a central role in determining energy conversion efficiency. By analyzing the distribution of efficiency values across different rectifier types, this section aims to identify which configurations offer more consistent or higher conversion performance, and how these patterns inform rectifier selection based on application-specific energy requirements and design constraints. Figure 21 illustrates the distribution of efficiency across different rectifier topologies used in RF energy harvesting systems. The Schottky rectifier exhibits a mean efficiency of approximately 60%, with a relatively wide distribution and the presence of low outliers. This pattern indicates moderate to high variability, suggesting that while high efficiency is achievable, performance may degrade under certain conditions. Nevertheless, the Schottky configuration remains a favorable choice when high conversion efficiency is prioritized, provided that some fluctuation can be tolerated. Multi-step rectifiers show a similar average efficiency (\(\approx\)60%), but with a broader distribution extending toward the lower end. This variability suggests that while the  
Figure 21: Boxplot showing efficiency distribution of different rectifier designs for energy harvesting. architecture offers flexibility and potential under certain conditions, the risk of low efficiency must be considered, especially in applications with stringent power requirements. Single-step rectifiers also average around 60% but stand out for their notably narrow distribution. This indicates low variability and stable performance, although their efficiency tends to remain at the lower end. Such stability may be desirable in systems where predictable behavior outweighs maximum energy conversion. Full-wave and half-wave rectifiers exhibit comparable mean efficiencies--approximately 50% and 60%, respectively--but both display broad distributions with significant outliers.