## 5 Industry and Study Cases of Antenna for CubeSats  
CubeSats have become a popular platform for space missions due to their cost-effectiveness and versatility. A critical component of these small satellites is the antenna system, which ensures effective communication with ground stations. Several industry trials and studies have focused on developing and testing antennas tailored for CubeSats. Notable examples include the following:  
X-Band CubeSat Communication System Development: This project focused on designing and testing a complete X-band communication system for CubeSats. It involved simulations, antenna analysis for the X- and S-bands, transceiver design, and optimization of space-to-ground links. The findings contribute to advancing NEN-compatible CubeSat communication systems [111]. A reflectarray antenna was designed and measured for a downlink antenna on the 2-by-3-unit surface of 6U and 12U CubeSats operating in the X-band frequency range (8.025 GHz to 8.4 GHz). A key design requirement is the minimization of the internal volume required to stow the antenna within the CubeSat. The resulting design involves a cavity feed that protrudes less than 4 mm into the CubeSat. This implies that there is still room for an entire unit of payload below the feed. The feed is linearly polarized, and to achieve the required RHCP for the downlink, the reflectarray is designed to generate circular polarization [112]. A novel mechanical beam-steering system was designed for integration with deployable antennas. It uses motors to control rods attached to a parabolic dish, with rod lengths determining the dish's orientation, stored in a codebook. It enables a high-gain deployable antenna for THz-band CubeSat links, achieving an over 40 dB gain across various angles. The design and development of the prototype are in progress [113]. The AcubeSAT mission, developed by SpaceDot at the Aristotle University of Thessaloniki, studies the effects of microgravity and radiation on eukaryotic cells. Its communication system features a 2.4 GHz S-band microstrip antenna and a deployable UHF antenna for telemetry and telecommand. Over three years, the antenna design evolved through multiple iterations with input from ESA experts. Initially, the team considered adapting the UPS at ADM but opted for an in-house design. They share insights into the development process, covering design considerations, ADM architecture, and key lessons learned. Environmental tests on the EQM were conducted, and future improvements are explored [114]. University of San Diego researchers developed and analyzed RF components for a phased array antenna designed for 1U CubeSats. The study assessed the viability of achieving high-speed, low-power, and cost-efficient communications. With a limited power budget of only a few watts and integration of low-power COTS components, a four-element phased array downlink system was deemed feasible. The system is theoretically capable of achieving an 11 Mb/s downlink speed, surpassing any previously deployed CubeSat, while maintaining low power consumption to sustain other onboard subsystems and sensors [115]. In 2022, the Get Away Special (GAS) team at Utah State University launched GASPACS to demonstrate inflatable structures in space. This project was part of NASA's CubeSat Launch Initiative, which funds and launches university and nonprofit satellites for research experiments [116]. SOURCE (Stuttgart Operated University Research CubeSat for Evaluation and Education), as a nanosatellite with dimensions of 10 \(\times\) 10 \(\times\) 36 cm\({}^{3}\), complies with the 3U+ CubeSat standard. It was developed in cooperation between KSat eV and the Institute of Space Systems (IRS) at the University of Stuttgart. As a student CubeSat, it is developed and operated exclusively by students under the supervision of the IRS. As part of the\"CubeSat Technology Internship\" module, many students had the opportunity to gain practical experience over a semester and earn credit points for their participation in the project.