AST SpaceMobile's whole concept is an enormous phased array in orbit talking directly to ordinary phones. Arrays that big create a problem: stray energy in the sidelobes that can splash onto the terrestrial spectrum and networks the system is supposed to coexist with. US11671850B1, granted to AST & Science, LLC on June 6, 2023, claims "adaptive taper selection for beamforming" to manage exactly that.
The CPC maps the problem: H04W 16/28 (network planning / antenna beam coverage), H01Q 1/288 (satellite antennas) and H01Q 3/30 (phase-controlled steering), plus H04B 7/1851 / 7/195 (satellite transmission). It is a satellite-comms-meets-antenna claim with a coverage-and-interference flavor.
The mechanism is amplitude tapering. By weighting how much power each antenna element radiates — the "taper" across the array aperture — you control the shape of the beam: a uniform taper gives a sharp main beam but high sidelobes, while a graded taper lowers sidelobes at the cost of a slightly broader main beam. The claim makes that selection adaptive, choosing the taper to fit conditions. For direct-to-cell, low sidelobes are not a nicety; they are a regulatory and coexistence requirement.
Spectrum plus geometry, again — and here the geometry (taper across a giant aperture) is being tuned specifically to protect the spectrum environment. The inventor list includes AST founder Abel Avellan, marking this as core IP for the company's defining capability.
AST regarded this as foundational enough to extend: US12200508B2 (January 2025) carries the same "adaptive taper selection for beamforming" title forward. The caveat stands — amplitude tapering is classical antenna theory, so the claim covers AST's specific adaptive selection method, not tapering itself. But the filing maps a real, specific piece of the direct-to-cell moat: how a phone-sized signal gets formed by a space-based array without lighting up the neighbors.