The FLEXCOM project, funded by the European Union’s Horizon 2020 research and innovation programme, aimed to develop an innovative flexible phased array system for satellite communication (SatCom) applications.
A fundamental achievement of the project is the successful design, manufacturing, and testing of all its core technological components. Intermediate tests and subsystem assessments have validated the functionality of these building blocks.
Key component-level outcomes include:
• K and Ka Band RF Integrated Circuits (RFICs) with Frequency Conversion: The project successfully developed and characterized two multi-core, multi-band RFICs implemented in SiGe BiCMOS technology. These comprise an RFIC for the receive chain (RX) operating from 18 to 21 GHz, performing down-conversion, and an RFIC for the transmit chain (TX) operating from 27 to 31 GHz, performing up-conversion. Each chip includes 4 analog cores to support dual-polarization radiating elements. Critical building blocks were identified, designed, and successfully tested. Measured performance for the RX RFIC demonstrates gain exceeding 36 dB, a noise figure below 3 dB, and an IIP3 better than -34 dBm across the 18-21 GHz band. For the TX RFIC, measurements show gain between 22.8 and 25.7 dB, OP1dB between 5.5 and 8.5 dBm, and OIP3 exceeding 18 dBm in the 27-31 GHz band. These RFICs have been finalized and successfully tested as of December 2023.
• Highly Integrated In-Package Duplexer: Developed as part of the package board, this component was designed for integration within the package with the goal of significantly reducing its size, enabling it to fit underneath the antenna element. A more compact configuration was developed and fabricated, achieving a 40% reduction in core footprint compared to the initial design model. Experimental tests performed on the integrated in-package duplexer yielded good results.
•Broad-Band K-Ka Circularly Polarized Radiating Aperture: The project successfully developed and characterized a dual-polarized radiating element for both the K (18.4-21 GHz) and Ka (27.5-31 GHz) bands. This element is capable of handling circular polarization (LHCP/RHCP). A 15x15 element array prototype was fabricated for testing purposes. Measurements on the embedded element confirmed the possibility of scanning up to 60 degrees and validated the simulated antenna performance. System-level tests combining the TX RFIC, FLEXTILE antenna, and duplexers further confirmed the proper functioning of the basic system elements. The antenna element has a size of 5x5 mm².
• On-Site-Coding Hardware and Associated Digital Processing Unit: The project developed a digital back-end for signal processing. The On-Site-Coding (OSC) hardware and associated digital processing unit includes a digital beamformer and signal spreading and combining capabilities. Specific high-speed analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) were selected and used for experimental tests of the digital back-end. Loopback tests using a hybrid architecture with DAC/ADC converters were successfully finalized, and the logical design was created and tested. The integration of the digital back-end was finalized.
