The article is devoted to the actual problem to study of the possibilities of phase cancellation of scattered electromagnetic waves using thin non-absorbing Pancharatnam-Berry (PB) metasurfaces with the generation of vortex waves with orbital angular momentum (OAM) and a spiral phase front. The aim of the work is to design such metasurfaces (MS) based on unit cells of hexagonal shape and traditional square shape and to compare their scattering characteristics and the possibilities of broadband phase cancellation of scattering. Metasurfaces with a dispersionless PB-phase for circular polarized waves (CP-waves) consist of cells in which the rotation angles of meta-particles change according to a given law. A hexagonal unit cell (like a honeycomb) has six axes of symmetry (instead of four in a square unit cell), which should provide a smaller influence of different rotation angles of adjacent meta-particles of an MS on the properties of the reflection coefficients of the cells. In this paper, a meta-particle in the form of a perforated patch in a hexagonal cell is proposed, which effectively reflects co-polarized CP-waves in the range from 8.5 to 19.7 GHz regardless of the rotation angle of the meta-particle. Four models of metasurfaces from such cells with generation of OAM of different orders were designed. Simulation of scattering of CP-waves by the finite element method confirmed that models with hexagonal cells reduce the backscattering field more effectively (over 10 dB) compared to square cells (only by 8 dB) in an ultra-wide frequency range from 8.5 to 20.8 GHz. Backscattering is reduced due to the generation of funnel-shaped vortex waves with OAM modes of minus the first or plus the third order and a phase singularity of the field on the vortex axis. The obtained results can be useful in choosing the shape of unit cells of metasurfaces intended for broadband scattering reduction
