The project is focused on designing, manufacturing, and testing reduced-complexity Ka-band electronic scanning array antennas. This breakthrough technology brings cost-affordable solutions for high-value user terminals in Satcom-on-the-Move (SOTM) applications.
The investigated solution implements a reduced complexity Ka-band phased array antenna breadboard suitable for the consumer market (e.g. buses, trains, airplanes). These antennas are currently expensive when compared to mechanical or hybrid scan systems. In particular, the number of radiating elements considerably increases when a wide field of view and a wide operating bandwidth are required. In this case, tiled/sub-arrayed structures can be adopted to reduce the number of amplitude and phase control points. With respect to the existing technology, the PISA array is based on an irregular partitioning of the aperture using polyomino tiles, breaking the periodicity of the quantization distribution of the amplitudes and phases on the aperture. This considerably reduces the level of the secondary lobes over wider bandwidths and scan widths than a conventional antenna array.
The main challenges addressed in the project include:
- the identification and optimization of a highly modular array antenna architecture, aiming to simplify the beamforming network;
- the design of polyomino subarray configurations for large arrays with specific constraints, including a targeted reduction in the number of control points, limited scan-loss, and grating lobes avoidance;
- the optimization of dual-polarized radiating elements to meet the requirements for wide scan and wide bandwidth in modern Satcom applications.
The Ka-band phased array comprises dual-polarized radiating elements with switchable circular RHCP/LHCP, boasting a low-profile design relying entirely on microstrip technology, which results in cost-effective fabrication. Operating in simultaneous transmit and receive modes through two dedicated apertures, a notable achievement includes a 30% reduction in the number of amplitude/phase control chips by grouping elements into tiles controlled by a streamlined set of chips. Moreover, the architecture’s multiple levels of modularity simplify the implementation of the beamforming network. To ensure continuous connectivity with low Earth orbit satellite constellations, even during array platform movement, the array is optimized to meet standard regulatory EIRP masks for scan angles up to 60 degrees. This optimization is achieved while ensuring maximum peak directivity and minimum scan-losses.
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