A variable-coverage satellite antenna system

Lensing system and Fourier transformation using epsilon-near-zero metamaterials

“…2 resembles the classical and metamaterial metallic lenses. 10,[21][22][23][24][25] However, it must be noted that the underlying physics is completely different. The waveguides suggested here have a very small volume fraction in a unit cell, and owing to the fact that they are designed to operate near the cutoff frequency, they behave as an ENZ structure and therefore the phase distribution within each waveguide is indeed nearly uniform.…”

Multiple‐Beam Antennas

“…As shown in Figure 10.39, the stack is the same size as the array, and is roughly one free-space wavelength thick; a voltage gradient is applied across the metal strips to scan the beam in the E-plane. Such a lens is shown in Figure 10.40 (Dion and Ricardi, 1971). In the second scheme, a similar stack of metal strips is close to the array face, but the dielectric plates have been replaced by an array of diodes.…”

Phase-only shaped beam synthesis via technique of approximated beam addition

“…The "current" beamforming phases for the competing strategies are so that the techniques have the same set of active worst-case ground stations. Thus, one only needs to consider the functional gradients as in (6). Assume, for simplicity, that there are no additional SL constraints.…”

“…Assume, for simplicity, that there are no additional SL constraints. From (6) and (9), the operating point satisfies the first-order necessary conditions for a local solution if (25) Using (24), the corresponding relation for the approximate beam-addition technique is (26) By inspection, if an operating point is optimal so that (25) is satisfied, then (26) is satisfied. This shows that a true local solution appears as a solution for the approximated beam addition technique.…”