  The rapidly growing volume of drone air traffic demands improved radar
surveillance systems and increased detection reliability in challenging
conditions. The scattering cross-section, which characterizes a target's radar
visibility, is a key element in detection schemes and thus becomes a primary
objective in civilian applications. Here, we introduce a concept of genetically
designed metamaterials, specifically engineered to enhance scattering for
end-fire incidence scenarios. Multi-layer stacks of arrays, encompassing
strongly coupled electric and magnetic resonators, demonstrated above 1 m^2
broadband scattering at 10 GHz, despite having an end-fire physical
cross-section smaller than one squared wavelength. Those performances, crucial
for effective civil radar air traffic monitoring, facilitate exploring highly
scattering structures as labels for small airborne targets. This objective has
been demonstrated with a set of outdoor experiments with the DJI Mini 2 drone.
Lightweight, conformal add-ons with significantly high scattering
cross-sections can serve as auxiliary tools to empower passive monitoring
systems, thereby providing an additional layer of security in urban airspace.
