The need for wide, high-speed, and long-range coverage appears ubiquitously in the academic, commercial, and military sectors. Due to their relatively short development times, low cost, and high educational benefit small satellites are growing in popularity and have been standardized almost 20 years after their first launch back in 2003, [1]. Starting from experimental products of single units, they now form swarms of tens to hundreds of units, [1], and they are highly useful for remote sensing. MIMO technology is the only technology that can serve the communication requirements of such systems, but there is a significant lack of studies in air-to-ground and air-to-air environments. Incorporating MIMO technology into airborne systems is of high importance since it increases throughput capability, range, and interference mitigation, all of which are critical aspects needed to support the high demands of 5G and sub-6GHz communication systems. Reliable, high-data rate inter-satellite communications is key to, [2]: a) servicing operations on commercial satellites (i.e., re-fueling, [3]), b) autonomous operations (i.e., network reconfiguration) necessary for deep space CubeSat formations, c) fractionated spacecraft, where one spacecraft is divided into clusters of multiple modules which communicate wirelessly, d) distributed processing, where the data processing load is shared among the small satellites to reduce the otherwise large raw data files into smaller more meaningful files to be transmitted back to Earth.
A critical aspect in the design of MIMO antennas is to provide high isolation between the antenna elements. This attempt is even more difficult when compact MIMO antenna systems are required, since there are known fundamental limits on the number of antennas that can be packed into a given area or volume, [4]. This is exactly what Russo’s primary research goal addresses, namely; “how to design compact MIMO antenna systems that can be packed into a given area”. Part of his research is also focused on the development of physically reconfigurable and deployable MIMO antennas. As shown in Fig. 1, the ultimate goal of his research is the development of a physically and frequency reconfigurable MIMO system for air-to-ground and air-to-air coverage.
The ability of Russo’s designs and the proposed research in general to study, explore, simulate and fabricate MIMO systems that can transform their physical characteristics in a prescribed way can open new avenues in the research community. With a very low system complexity the proposed research aims at the introduction of the concept of the synchronous spatial and time modulation technique, exploiting the physical characteristics of the MIMO structure.
[1] Hugo Sanchez, et al., “Starling1: Swarm Technology Demonstration,” in Proceedings of the AIAA/USU Conference on Small Satellites, Mission Lessons, SSC18-VII-08, 2018.
[2] R. Radhakrishnan, et al., “Survey of Inter-Satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View,” IEEE Communications Surveys and Tutorials, vol. 18, no. 4, pp. 2442-2473, 2016
[3] B. W. Barbee, et al., “Guidance and navigation for rendezvous and proximity operations with a non-cooperative spacecraft at geosynchronous orbit,” J. Astronaut. Sci., vol. 58, no. 3, pp. 389-408, 2011
[4] L. J. Chu, “Physical Limitations of Omni-Directional Antennas,” Journal of Applied Physics, vol. 19, no. 12, pp. 1163–1175, Dec. 1948
