Miniaturization of Transparent CP Array X-Band CubeSat Antennas Using Meshed Patches

CubeSats are incredibly popular small satellites to explore the space and collect hard-to-find data. The smallest standard size of a CubeSat, according to NASA, is one unit or 1U, measuring 10 by 10 by 10 cubic centimeters. Even with this tiny size, CubeSats accommodate a lot of electronic and science devices, including antennas and sensors, to conduct science experiments and observations. Due to space constraint and new requirements of the structure subsystem of the satellite, the antennas have to be miniaturized. The miniaturization of antenna basically means to reduce the physical dimensions of an antenna without changing the operating frequency. In this paper, the miniaturization of microstrip circularly polarized (CP) antennas, specially designed for the CubeSats, have been demonstrated by meshing the patches. Initially, a standard antenna with linear array was simulated and measured, operating at around 8.03 GHz with more than 13 dBi gain and 65 MHz Axial Ratio Bandwidth (AR BW). Then, with the help of Ansys HFSS simulation software, the solid patches of the antenna were meshed to reduce the operating frequency. Finally, the dimensions of the patches of the miniaturized antenna were reduced as well as the widths of the mesh wires were varied to match the initial operating frequency. In this process, the gain of the meshed antenna was sacrificed a little bit, which is obvious as the size of the antenna becomes smaller. However, the AR BW was very close to the original one. As meshing helps to create optically transparent (OT) antennas, a clear substrate was used to improve the transparency. With the meshed patches and clear substrate, the antenna can be installed on top of the solar panels using the CubeSat body as the ground. This allows more space on the chassis of the small satellite to install other scientific instruments. Moreover, the weight of the antenna gets reduced due to meshing as a significant amount of copper is etched away, and thus the antenna, and ultimately the nanosatellite, becomes lightweight.