Pure metallic reflectarray antennas have good power efficiency and low
fabrication cost, which were limited to single band operation. A
dual-band reflectarray antenna is developed for two directional beams by
two feeds. The reflecting elements are metal waveguides, and have novel
properties of both resonant and non-resonant modes at the two frequency
bands. The low and high frequency bands can be easily separated by the
cutoff frequency of waveguide modes. The phase changing mechanisms via
ray optics and fundamental waveguide modes, respectively provide simple
formulations for elemental structure design of directional beams.
Radiation characteristics of the linear and circular polarizations are
cross-examined with good performance by full-wave simulations using
HFSS, FEKO and CST at 28 and 60 GHz bands for 5G front-haul network
applications.