Flexible Antenna Integrated With an Epitaxial Lift-Off Solar Cell Array for Flapping-Wing Robots

We describe the integration of a flexible UHF antenna with an epitaxial lift-off thin-film III-V solar cell array used for power generation and wireless communication in a flapping-wing robotic platform. The antenna is configured to utilize the cells and their interconnections as a part of the radiating element, leading to compact multifunctional antenna/solar cell array surface. The high junction capacitance of individual solar cells allows RF current conduction through the cells without an associated power penalty. Metallic interconnects in the solar cell array carry both the DC power as well as forming part of the UHF antenna. To suppress RF current leakage into the DC circuit used for conducting the solar cell current, a RF choke is inserted between the antenna and the solar cells in the DC path. The performance characteristics of the integrated antenna and solar cell array verify the predicted performance of the antenna for reliable communication. Further, mounting the thin film solar cell array on a 25 μm thick Kapton sheet is shown to be a robust power source when positioned on the flexible wings of flapping robotic platforms. Details about design procedure and performance of the proposed integrated antenna are discussed.