  Recent years have witnessed an extraordinary spurt in attention toward the
wave manipulating strategies revealed by coding metasurfaces as they build up a
bridge between the physical and digital worlds. Newly, it has been shown that
when two different coding patterns responsible for doing separate missions are
added together based on the superposition theorem, the mixed coding pattern
will perform both missions at the same time. In this paper, via a
semi-analytical procedure, we demonstrate that such a theorem is not
necessarily valid for all possible functionalities with considering phase-only
coding distributions and ignoring the element pattern function. By revisiting
the addition theorem, we introduce the concept of asymmetric spatial power
divider (ASPD) with arbitrary power ratio levels in which modulating both
amplitude and phase of the meta-atoms is inevitable to fully control the power
intensity pattern of the metasurface. Numerical simulations illustrate that the
proposed ASPD driven by proper coding sequences can directly generate a desired
number of beams with pre-determined orientations and power budgets. The
phase/amplitude-encoded Pancharatnam-Berry meta-atoms realize the required
coding pattern in each case and good conformity between simulations and
theoretical predictions verifies the presented formalism. This work exposes a
new opportunity to implement spatial power dividers for various applications
such as multiple-target radar systems, beamforming networks, and multiple-input
multiple-output (MIMO) communication.

Applied Physics