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<p>We present novel multi-bit unit-cell topologies for
reconfigurable reflective surfaces –RRSs– (e.g., reflectarray
antennas) with compact designs for millimeter-wave and terahertz
(mmWave/THz) applications. Typically, mmWave/THz RRSs
utilize one or multiple single-pole-single-throw (SPST) switches
leading to single- or dual-bit modulated surfaces. These surfaces
utilize the switches to manipulate the phase of the imping waves,
beamforming the reflected waves to the desired direction. As such,
RRSs are leveraged either for imaging or wireless communication
applications, which typically require the formation of a single
beam (no grating lobes) and high gains. The gain and quantization
lobe levels of an RRS is strictly related to the number of phase bits
utilized in the unit-cell. Explicitly, more phase bits lead to lower
quantization errors and better maximum gain/aperture efficiency.
However, increasing the number of phase bits requires more SPST
switches integrated within the unit-cell, leading to complex designs
with high RF losses. Herein, we present, for the first time, RRSs
with up to 4 phase quantization bits (16 states) that maintain one
switch-per-bit topology thus retaining a low-complexity design.
The proposed RRSs is presented alongside a series of analytical
and full-wave simulated results.
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A Single-Switch-per-Bit Topology for mmWave and THz Reconfigurable Reflective Surfaces
