These products respond to the main needs coming from SAR antenna manufacturers, which must procure Itar free RF components for space applications, to serve the forthcoming EO market, oriented to mini and micro-satellites clusters, which is highly demanding in terms of compactness and hardware miniaturization. Same technical and logistic needs come from AESA Radars manufacturers, for both airborne and ground applications.
The main targeted customers are Earth Observation Satellites, specifically the SAR antennae, and airborne and ground based AESA radar integrators.
The product provides a solution to their need of better performances, higher integration and cost reduction with respect to the actual exploited solutions. The main end-users and potential customers provided their support for the definition of the product main requirements.
The main users/customers are from Europe (Italy, France, Germany), but also from United States.
The SCFEs, at X- and Ku-band, are Itar free, Highly Integrated MMICs on GaN 0.15 µm technology, which replaces three separate chips HPA, LNA and Switch in a TR module for SAR antenna and AESA Radars.
The technical specifications are studied to target the system requirements for next generations of both satellite SAR and AESA radar, as provided by the main targeted customers and users.
For the X-band, the operating frequency range [8.5 – 11] GHz covers, among others, the bandwidth required by both the 3rd generation of Cosmo Sky-Med front-ends and the new concept of AESA radars under development by one of the most important European manufacturers.
The output power level and the efficiency, 15 W and 35% respectively, have been dimensioned on the basis of the new antenna architectures and, so, of the ratio between the number of modules combined on it and the total power required for the targeted resolution. The elimination of the bulky circulator at the antenna allows to get an overall Noise Figure at the level of the GaAs based modules, lower than 3 dB.
The Ku-band, covering the range [13 – 16] GHz, addresses a new concept of SAR antenna for earth observation, which both the Italian and other European Space Agencies are looking at with increasing interest thanks, also, to the forthcoming class of mini and micro-satellites. The power level, of about 7.5 W, is dimensioned to obtain the same SNR of the X-band satellites with an average antenna power of about the 67% lower. The PAE higher than 35% is confirmed as the main priority at system level and the Noise Figure lower than 3.5 dB ensures the required receiver sensitivity.
The proposed solution gives the opportunity to the system integrators and final users to exploit a new architecture concept at both TR modules and antenna level.
These innovative MMICs, based on the state of the art GaN European technology with very high power density and good noise characteristics, integrate in a small chip the Power Amplifier, exploited along the Tx section, and the Low Noise Amplifier, on the receiver path.
Furthermore, its robustness, both electrical and thermal, makes possible the replacement of the two main cumbersome and bulky components, the ferrite circulator and the PIN limiter. Indeed, the SCFE embeds also a Power Switch (SPDT), capable to isolate the transmitting and the receiving paths, respectively, during the Tx or Rx period. This fulfils, together with the more robust LNA, the robustness’ requirements of the receiving chain.
Figure below compares the block diagrams of a classical front-end with the new SCFE concept.
Thanks to this new concept a classical TR module, e.g. those boarded on SAR antenna of COSMO-SkyMed, may reduce its footprint of at least 50%. This leads to a mass reduction of about 20gr per module, with a huge benefit at antenna level, which, in the 2nd generation, embeds 1280 T/R modules for each polarimetric channel. The SAR antenna will reduce its weight of 51 Kg.
In February 2023, the project was successfully concluded with the final review. The main objectives, to develop two Single Chip Front End MMICs, in X- and Ku-band to be exploited as RF front-end in the TR modules boarded either on future generation of SAR antennae for EO satellites or on AESA radars, have been achieved. In detail: The X-band SCFE is characterized, in the frequency band [8.5 – 11.5] GHz, by an output power of about 20 W and a PAE higher than 35%, during the transmit mode, and by a Noise Figure lower than 3 dB and a linear gain of 25 dB, in receiving cycle. The Ku-band one, in the band [13 – 16] GHz, provides a transmitting power of about 10 W with 30% of PAE, while the Rx chain is characterized by a NF lower than 2.8 dB and 24 dB of gain. These results confirmed that these products target the actual needs of the system integrators to develop a new generation of SAR antennae for Earth Observation and highly integrated AESA radar, based on a drastic simplification of the architecture and, so, of mass and costs, as well as an improving of the overall performances.