Overlapped subarray is an attractive structure to achieve low-cost multiple receive beams. However, satisfactory weights of overlapped subarray is hard to design, especially considering the transmit beam pattern. In this paper, a method to optimize the receive excitation of overlapped subarrays on the basis of a given transmit pattern is proposed. The relationship between the two-level weights and the two kinds of sidelobes is analyzed at first. Then, a squential convex programming strategy is adapted to optimize the element-level and subarray-level weights jointly to match the pre-defined transmit beam pattern. The required multi-beam coverage region and minimal sidelobe level could be obtained after these steps. Numerical experiments are presented to verify the effectiveness of this method.
This paper proposes a converged-aperture architecture to enable dynamic reconfiguration of spectral access between platform mission functions. Based on phased-array apertures, intra-platform data throughputs required to support the envisioned architecture are discussed, and integrated photonic transceivers are put forward as a critical enabling technology.
The space industry has shifted its focus to the development of low-cost satellites and large satellite constellations. Notably, most nano-satellites in low Earth orbit operate at UHF (P-band) frequencies to leverage the use of low-cost commercial off-the-shelf electronics. Such constellations would benefit from the rapid steering of multiple beams offered by a phased array antenna (PAA) ground station (GS). The cost of such systems, however, is not conducive to the low-cost philosophy of the satellites. While several universities have identified the need for a low-cost UHF PAA GS, no feasible design or prototype has yet been developed that is suitable for low-cost applications involving PAAs with a large number of elements. This paper proposes and demonstrates a subarray-digital architecture with a novel two-stage analog beamforming segment to optimize resource usage within the PAA, by allowing for the dynamic reconfiguration of the number of required digital ports. It further leverages several cost reduction techniques to design a modular and scalable transmit/receive module and ancillary geodesic dome PAA. An operational prototype is constructed and used to validate and characterize the implemented design. This successfully reduces the costs of a PAA GS while retaining the associated performance benefits.
This paper presents the recent activities carried out at ONERA in the field of antenna arrays using PCB technologies. These activities cover principally wideband applications with strong integration constraints, which require very low profile antennas. Two examples of antenna array developed at ONERA are presented in the paper.
This paper examines how cross-polarization can be effectively reduced in two-dimensional array apertures of linearly-polarized Vivaldi antennas. In previous work it was demonstrated how metallic cross walls, positioned orthogonal to the linear Vivaldi antenna elements in a two-dimensional array, reduce cross-polarization significantly - e.g., -15dB levels for 45° diagonal plane scans. This cross-polarization mitigation technique is expanded upon by showing that slices in the metallic cross walls can further reduce cross-polarization, e.g. -25dB levels for 45° diagonal plane scans. For demonstration, an 8×8 single-pol. Vivaldi array comprising 8 rows of 8-element sub-arrays arranged onto a uniform grid with slots between elements is presented. Cross-polarization measurements are compared to infinite array simulations with and without ‘sliced’ metallic cards inserted (orthogonally) into the slots between radiating elements.
