Towards Optically Semi-Transparent Planar Endfire Antennas for CubeSats and Other Small Satellites

An endfire high-gain planar antenna design is proposed by including a dense array of air-vias (with varying diameter) within an ungrounded substrate. This makes the structure semi-transparent and supports simple solar cell placement underneath the PCB-based antenna. Moreover, by gradually altering the diameter of the air-vias the effective relative permittivity for the substrate is controlled and this enables a smooth transition and reduced reflections at the edge of the substrate for more efficient radiation into the air region. Initial simulation results demonstrate a directive endfire pattern of more than 20 dBi at 24 GHz. In addition, the 1U antenna size makes the design suitable for placement on CubeSats and other small satellites, and can be conveniently integrated on top of a solar panel. This can support dual-functionality for the space utilized by the antenna, leading to more solar power harvesting. The result is also that more space can be made available on the satellite structure itself for additional communication equipment, sensors, solar cells, etc. and this approach can foster more advanced mission capabilities.