# Integration of Microstrip Slot Array Antenna with Dye-Sensitized Solar Cells
## 2 Integrated Design Array Antenna and Solar Cells  
Due to the influence of climate, environment and other factors, the linear polarization wave easily causes polarization deflection loss. These factors have little effect on the polarization deflection of circularly polarized waves, and, concerning circularly polarized antennas, polarization mismatch does not easily occur. In order to suit practical applications, a circularly polarized microstrip slot antenna is used in this paper. The geometry of a \(2\times 2\) circularly polarized microstrip slot array antenna integrated with dye-sensitized solar cells is illustrated in Figure 1a. The size of the entire array is 140 mm \(\times\) 140 mm, where the size of each solar cell is 35 mm \(\times\) 35 mm. The circularly polarized waves are excited by arranging the four slots crosswise and designing the microstrip feeder network reasonably. The dielectric substrate of the microstrip slot antenna uses a Rogers R4350b plane, a dielectric constant of 3.48, a dielectric loss angle of 0.0037 and a thickness of 0.5 mm. The equal division Wilkinson power divider is used in the feed network to obtain the excitation signal with equal amplitude and phase difference of 90\({}^{\circ}\), as shown in Figure 1b. The isolation resistance is 100 \(\Omega\), and the impedance of the feed port is set to 50 \(\Omega\). Through optimization analysis, the width of microstrip lines is W1 = 1.15 mm (50-\(\Omega\)) and W2 = 0.63 mm (70.71-\(\Omega\)). The slot size is 14.5 mm \(\times\) 1.8 mm, and the eccentric distance of the feed point is 3 mm. The microstrip slot array antenna gain and the available solar cell area on the antenna surface need to be taken into consideration, concerning a slot spacing of 44 mm. Dye-sensitized solar cells are a new type of photovoltaic technology developed by simulating the principle of plants in nature using solar energy for photosynthesis. DSSCs are based on dye sensitizers and nano-TiO\({}_{2}\), which can make the photoelectric conversion efficiency reach a better level. At the same time, dye-sensitized solar cells (DSSCs) are rich in raw materials, non-polluting and low in cost; the manufacturing cost is only one fifth to one tenth that of silicon solar cells [21]. Therefore, dye-sensitized solar cells were chosen for this paper. Dye-sensitized solar cells adopt a stacked structure similar to the microstrip slot antenna, so the metal ground plane of the microstrip slot antenna can be used as the substrate of the solar cell. The integrated design does not change the intrinsic structure of the antenna, and will minimize the impact of the antenna. Due to the conductive material in the dye-sensitized solar cell, it will block the radiation of electromagnetic waves, so it is necessary to retain the slot of the antenna. The dye-sensitized solar cell and the microstrip slot antenna share a metal ground plane, and the cell structure is as described in [22]. The Components of the integration of a circularly polarized microstrip slot antenna  
Figure 1: (**a**) The geometry of a \(2\times 2\) circularly polarized microstrip slot array antenna integrated with dye-sensitized solar cells; (**b**) microstrip feeder network. with a dye-sensitized solar cell are shown in Figure 2. The dielectric constant and conductivity of the dye-sensitized solar cell materials at room temperature are shown in Table 1. The dye-sensitized layer is an electrolyte containing I\({}^{-}\) and I\({}^{-3}\), mixed with sensitizers, potassium chloride, etc.