## 1 Introduction  
Research on the potential of radio frequency (RF) waves as an alternative energy source has recently increased. RF energy harvesting has many advantages, such as the source being available all the time, low cost, compact size, lightweight, and the feasibility of long-term power transfer [1]. The rectenna is an important part of any electromagnetic wave energy harvesting system. The rectenna captures electromagnetic wave energy and converts the absorbed wave power into direct current [2]. Traditional rectenna's consist of an antenna and a rectifier circuit that effectively harvest energy at a specified angle of incidence and polarization direction [3, 4]. However, environmental electromagnetic waves have variations in the incidence angle, polarization, and operational frequency.  
In recent years, metamaterial-based metasurfaces have become an interesting object to study because they can be utilized in various fields such as optical cloaking [5], po larization conversion [6], antenna applications [7; 8], super lensing [9; 10], sensing [11; 12; 13], absorbers [14; 15], energy harvesting [16; 17; 18], waveguide [19], and imaging [20; 21], etc. Metamaterials are artificial materials consisting of an arrangement of small resonators that electrically create materials with permeability or permittivity that do not exist in nature [22]. A metasurface is two-dimensional form of a metamaterial where the structure is confined to a thin surface or layer. As another candidate for harvesting RF energy, metasurfaces have attracted the interest of many people because it can not only capture RF waves like a perfect absorber but also recycle their energy [23; 24; 25]. This technology can significantly increase the reliability of low-power electronic devices such as sensors and IoT [26]. The development of metasurface technology brings opportunities and challenges in utilizing electromagnetic waves as a source of energy [27].  
One promising direction in metasurface energy harvesting research is the development of simplified structures that employ only a single via and a single resistor per unit cell, while maintaining polarization-insensitive performance. Such designs offer significant advantages in terms of fabrication simplicity, cost-effectiveness, and ease of integration with compact rectifier circuits. Several studies have demonstrated metasurfaces capable of harvesting ambient electromagnetic energy with high efficiency using just one via and one resistor [28; 29; 30]. However, the reported polarization-insensitive characteristics in these works are typically validated over a limited set of polarization angles.  
This limited sampling does not adequately reflect the full polarization behavior of the metasurface, especially for real-world applications where the polarization of incoming waves can vary continuously and unpredictably. Therefore, a more comprehensive analysis across a broader range of polarization angles is essential to accurately assess the actual polarization characteristics of such designs.  
The objective of this paper is to investigate the polarization characteristics of a square patch metasurface using one via and one lumped resistor for harvesting RF energy. This design is proposed for its simplicity, ease of fabrication, and the fact that using only one via and one lumped resistor simplifies the energy absorption process. The absorption characteristics, which are sensitive to polarization and exhibit a voltage dip related to the position of the lumped resistor and the geometric structure of the unit cell, have been verified through simulations and actual measurements. This characteristic is essential for furthering the development of metasurfaces energy harvesting using one via and one lumped resistor. This study also introduces a linear design rule to predict the dip angle based on the resistor's position relative to the center of the patch and proposes an asymmetric structure to reduce polarization sensitivity.