Axelspace Corporation has successfully developed a Ka-band radio for Earth Observation (EO) smallsats — the radio operates with less than half the power consumption of conventional radio.
The collaborative research was jointly developed with Tokyo Institute of Technology (Tokyo Tech) with key collaborators Atsushi Shirane of the Laboratory for Future Interdisciplinary Research of Science and Professor Kenichi Okada and Assistant Professor Takashi Tomura of Department of Electrical and Electronic Engineering.
EO data from smallsats is attracting attention for a multitude of applications such as smart agriculture, environmental monitoring, disaster prevention, and disaster response. Demand for this data will increase in the future and additional, efficient mechanisms for transmitting data from space to Earth are needed.
The radio equipment typically used on microsatellites for EO have limitations. This is especially true with compatibility between capturing and communicating data. This issue arises due to the direction of image capture and antenna communication as they do not match (attitude control).
Large EO satellites in the several-ton class mount multiple types of antennas and they can use different antennas, depending on the distance from the ground stations, or use mechanical gimbals combined with controllable directivity phased array radios that allow the large satellite to avoid conflicts in attitude control. However, smallsats have far less storage space and power and that presents a unique and difficult challenge for adoption of the above methods for microsatellites.
Advances in sensor technology and data services require today’s EO missions to have faster communications. The downlink must achieve the communication of a large amount of data transmission in shorter time periods. To solve these two issues of space and power constrained smallsats, Axelspace and Tokyo Tech have developed a downlink system that combines a broadband Ka-band transmitter and an active phased array antennas.
The Ka-band phased array radio developed in this research consists of a two-port antenna, amplifier, phase shifter, and active hybrid coupler. This enables electrical directivity control with low power consumption. The newly devised dynamic, hybrid coupler, circuit technology significantly reduces the power consumption of the phased array radio, thereby enabling faster and more real-time data communication than was previously possible.
The manufacturing of the radio IC is a CMOS process, which enables mass production at a low cost. Axelspace plans to install the successfully developed low-power phased array radio on the firm’s EO microsatellite. An on-orbit demo will be conducted within a few years with the company’s aim to shorten the time lag between ground capturing and data downloading as much as possible and to accelerate satellite data use.
The research results were supported by the JST Research Results Deployment Program A-STEP Industry-University Collaboration are available at this direct link…