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StatusCompleted
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Status date2025-03-31
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Activity Code7B.047
Nanosatellite constellations are becoming an increasingly popular means of deploying IoT services worldwide. Startup Kinéis, based in Toulouse, France, is now giving some of its IoT devices hybrid terrestrial (868 MHz LORA) and satellite radio (in the 400 MHz band) connectivity. This kind of low-frequency telecommunication uses less power for extended device battery life. But the lower the telecommunication frequency, the larger the antenna. This creates serious challenges for smaller devices.
CEA-Leti, which boasts a strong track record designing and integrating miniature antennas, has worked on this project with Kinéis to shrink the antennas size by a factor of 7.5 to reach 5 x 5 x 3 cm dimensions (that is λ/15 x λ/15 x λ/25 where λ is the wavelength at 400 MHz). Distributed RF loading techniques has been used on the antenna low cost structure. Another strong constraint that has not been dealt with so far is that the antenna has omnidirectional type radiation but with circular polarization.
The breadboard miniature antenna has been measured in the large anechoic chamber of CEA Leti and on the field with Kinéis satellites link.
Main technical challenge concerns the ultra miniaturization on the 400 MHz antenna while maintaining circular polarization and bandwidth (Impedance, Axial ratio). The antenna performance sensitivity to its close context has also been evaluated. A second band at 868 MHz (Terrestrial IoT) is also supported by the developed antenna.
Hybridizing Terrestrial/Satellite link allows to benefit from the best of two solutions. With only 3 cm profile, the antenna can be integrated on a large numbers of scenarios.
The MONAMI project has started from the miniature antenna SotA and market review (early 2021) and ends with the field test of Terr./Sat. IoT links with the breadboard antenna (2023).
Preliminaries studies have allowed to identify most promising antenna technologies and to embrace the trade-off between performance and miniaturization effort. The first breadboard miniaturized circular polarized antenna has been characterized in CEA Leti anechoic chamber and expected performance has been achieved. Final breadboarding of a miniature antenna integrated on a metallic context to emulate container scenario, has been characterized in anechoic chamber and validated during a Kinéis Satellites system-level campaign (Fall 2023). The project is now closed.
