  Metasurfaces composed of subwavelength unit cells usually require a large
number of unit cells which leads to complicated design and optimization.
Aggressive discretization in a metasurface can significantly reduce the number
of unit cells within a period, resulting in lower requirement for phase and/or
surface impedance coverage. Additionally, the enlarged unit cells will
encounter negligible mutual couplings when combined together, hence making
straightforward the process of metasurface design. These advantages combine to
allow the design of a novel class of metasurfaces which support the high
efficiency redirection of electromagnetic (EM) waves over a wide bandwidth and
operation angle. Moreover, an aggressively discretized metasurface may realize
functionalities such as diffraction mode circulation, which are unsupported in
its continuous counterparts. In this paper we propose a simple transmissive
metasurface which can realize diffraction mode circulation by refracting plane
waves with incident angles of -45, 0, 45 degrees to plane waves with refraction
angles of 0, 45, -45 degrees respectively. The power efficiency of each
anomalous refraction is more than 80% at the design frequency of 28 GHz, and
the 3-dB power efficiency bandwidth is 11%. We fabricated and measured the
metasurface, the experiment results agree well with simulation results.
