Researchers at the École polytechnique fédérale de Lausanne (EPFL) in Switzerland have combined antennas and solar cells in a breakthrough step towards the development of smaller and more lightweight satellites and autonomous antenna systems.
Traditionally, telecommunication antennas and solar cells have been built separately to avoid interference, the researchers said. This separation impacts the weight and size of satellites because of the adequate surface area required for both antenna systems, which emit and receive data, and solar panels, which supply the electricity. Now, the Julien Perruisseau-Carrier Group, in collaboration with the Transparent Conductive Oxides group (TCOs) which is part of the Photovoltaics and Thin Film Electronics Laboratory (PV-Lab), has developed a mixed surface that allows both the antenna and the photovoltaic cell to perform efficiently together.
“It is not the first time that scientists [have tried] to merge solar cells and antennas. But the advantage of our method is that it allows [us to preserve] good performances for both the antenna and the photovoltaic system, while leaving intact the solar cell’s original structure. You just have to take existing solar cells and add a conductive layer,” Julien Perruisseau-Carrier, who supervised the project, said.
To build the new device, the researchers combined reflectarray (RA) antennas, which are flat, inexpensive and highly efficient with thin-film amorphous-silicon solar cells developed by PV-Lab. A set of conductors was then placed on top of the solar cells. According to the researchers, this layering makes it possible for the solar cells to maintain up to 90 percent of their photovoltaic efficiency.
In addition to reducing the volume, weight and cost of satellites, the new system could also enable the construction of lighter and more mobile autonomous communication systems, which are often used to keep communication lines open after a natural disaster.
“Our device could also support flexible implementation. It could be folded up so that it isn’t deployed until the relief area has been reached,” Perruisseau-Carrier said.
Two versions of the device were developed for use depending on whether priority is to be given to the antenna or to solar-cell efficiency. One version features a copper conductor, which lets no light rays through where the metal is deposited but guarantees very high antenna efficiency, while the other version features transparent conductor (TCOs), which gives priority to solar-cell efficiency.
While the new devices have not been made commercially available yet, “NASA selected a satellite with these antennas and solar panels for a technology demonstration mission planned for 2014,” Perruisseau-Carrie said. “For this mission, NASA is using a platform with solar panels on one side and antennas on the other. Being able to combine these two devices would have saved on surface area, for example. ”
