A 2.4 GHz Coplanar Solar Cell Patch Antenna with a Semi-Analytical Evaluation of Temperature Effects

Abstract

Solar cells integrated with antennas have aroused scientific interest as an attractive energy source alternative in low power devices for IoT and Wireless Sensor Network applications. Since the space for all components in the systems is scarce, different integration ideas have been proposed in this field. However, further analysis of the performance of photovoltaic modules used as structural components of antennas is still lacking. In this context, this work experimentally extracts the necessary parameters to create an equivalent circuit model of a modified solar cell used as a radiator of a 2.4 GHz coplanar patch antenna. The obtained model is then used in the numerical characterization of the Current-Voltage (I-V) curves under temperature variations. Antenna design and performance are described, and the physical modifications of a commercial solar cell used in the prototype are presented. The I-V curves were generated for temperatures ranging from 243 to 325 K. The obtained simulation results within this temperature range showed a 150 mV shift of the optimal operation point, decreasing in approximately 20 mW the supported power with the temperature rise. A predictive methodology is introduced to estimate the possible values for the fill factor, energy conversion efficiency, and current density in a modified solar cell under temperature variations, allowing a fully operational photovoltaic antenna design.