Kramers‐Kronig Relation Empowered Kerker‐Like Effect for Macroscopic Objects

Scattering control pervades nearly all areas of photonics and wave physics, playing indispensable roles for both fundamental explorations and practical applications. The Kerker effect and its generalizations, which rely on designed multipolar interferences, have been instrumental in shaping scattering patterns at subwavelength scales. However, these approaches are inherently narrowband and fail for macroscopic objects, where the proliferation of multipolar modes makes synchronous amplitude and phase control infeasible. Here, we go beyond the conventional Kerker framework of prescribed multipolar interferences and introduce a spatial Kramers–Kronig (KK) design route for backward‐half‐space scattering suppression in electrically large structures. This approach enables wide‐angle suppression across the entire backward half‐space, a regime that is difficult to access through conventional low‐order multipolar engineering. We theoretically develop the concept, validate it through full‐wave simulations, and confirm its performance via experimental measurements. These results show that the spatial‐KK relation can be exploited to shape the scattering of electrically large scatterers through a material‐level mechanism that automatically and collectively regulates many multipolar channels. The introduction of the spatial‐KK relation into the field of electromagnetic scattering offers a route for material‐integrated scattering control in diverse wave systems including acoustic, elastic, and matter waves.