Fabrication and Characterization of a 900-Element 222.5 GHz Single-bit Reflective Surface with Suppressed Quantization Lobes

We present a topology for suppressing quantization lobes in 1-bit reconfigurable reflective surfaces (RRSs). RRSs are planar surfaces that redirect the imping waves to the desired direction through phase modulation. For single-bit modulation, plane-wave illuminated RRSs exhibit quantization lobes due to the limited number of available phase bits. To eliminate such lobes, we randomize the quantization error by employing a fixed but random phase delay in every unit-cell of the RRS. Specifically, we focus on the fabrication and characterization of a mmWave single-layer, 1-bit, 30×30 randomized RRS designed at 222.5 GHz. The quasi-optical RCS characterization of the fabricated RRS demonstrates the successful suppression of the quantization lobe using the proposed technique.