These include instantaneous and ubiquitous Telecommunication services (high-quality voice and high-speed data, as well as TV and radio signals broadcasting), global radio-navigation satellite systems like the Galileo (Europe) and GPS (USA) ones, as well as Earth Observation programs (e.g. Copernicus and Living Planet sponsored by the European Commission -EC- and European Space Agency -ESA) focused on security, environmental and climate change issues. Even the newcomers' 5G and 6G mobile terrestrial networks will be reinforced through satellite-based infrastructure. As a result, worldwide citizens (and particularly European and Spanish ones) are strongly benefitted in terms of economic growth, social welfare, scientific breakthroughs, and technological advances.

Presently, the European Space Program is being pushed (by ESA, EC, and the industrial sector) through next-generation satellites serving major spatial projects, such as the Galileo second and METEOSAT third generations, the forthcoming five Sentinel missions and the EarthCARE satellite of the Copernicus and Living Planet programs, and the new Telecom satellite product lines named Spacebus and Eurostar Neo. Moreover, mega-constellations of small satellites (SpaceX and OneWeb projects) providing ubiquitous Internet connectivity to consumers and devices, are also under full deployment. Advanced satellite communication links, based on novel high-frequency equipment (passive components and antennas) using emergent technologies, will be established among spacecrafts and Earth stations/terminals.

Therefore, as it is also suggested by the major Space sector players (i.e. ESA, as well as multi-national and Spanish companies), novel solutions for high-frequency passive devices and radiating elements must be devised and engineered. They will have to address multiple and interdisciplinary challenges, in terms of electrical size (compactness), adaptive frequency and spectral bandwidth resources (reconfigurability), increased transmission power levels (dealing with discharge and inter-modulation effects), and manufacturing feasibility (accuracy and repeatability issues). Additionally, these requirements will have to be properly tackled in a huge set of frequency ranges (covering the RF, microwave, mm- and sub-mm wave bands).

To this end, a coordinated project (of acronym IMPULSE) to be carried out by a team of five academic research groups (with successful previous collaborations) is proposed. Four complementary sub-projects will jointly develop top-notch research on innovative satellite communication equipment, considering traditional and emerging high-frequency technologies: i.e. those based on planar circuits and 3Dwaveguide structures, hybrid solutions (planar waveguides implemented in dielectric and emptied substrates), and the recently proposed set of gap waveguides. Advanced and tuneable materials (such as bioplastics, graphene, and liquid crystal), together with classical (milling, LTCC) and more recent (additive manufacturing, micro-machining) fabrication techniques, will be also researched.

This subproject, acting as coordinator of the project and participant teams, in addition to overview of the joint work on CAE tools (analysis, synthesis, and optimization methods), and on the integrated demonstrator for a Ka-band multiple beams output stage, contributes to advance on the practical use of several waveguide technologies for space communications. In particular, more focus is put into the coaxial Substrate Integrated Waveguide (SIW) technology, folded and ridged topologies of the empty SIW (ESIW) version, and mechanically tuneable components (mainly filters and diplexers) using 3D waveguide cavities. Practical implementation of prototypes using LTCC and 3D printing (with metalized resins) techniques, as well as experimental validation of equipment (high-frequency effects and communication experiments with small satellites), are also tackled.

  Vicente E. Boria Esbert

Microwave Applications Group (GAM)