Pixelated RF: Random Metasurface Based Electromagnetic Filters

Abstract

Recent trends in photonics have shown that optimized pixelated surfaces can outperform classical designs in reducing design area and improving frequency response. Such pixelated surfaces can also be used to realize random RF components (e.g., filters, matching networks, power splitters/combiners, etc.). There are no closed form solutions to describe the design of these surfaces. We present a method for synthesizing a pixelated surface to act as a filter using a direct binary search (DBS) to realize a dual-band RF filter. The method can be used to reliably create designs for generalizeable RF functions. To demonstrate the capability a prototype dual-band filter is fabricated on a printed circuit board (PCB) and occupies an area of $0.45 \times 0.34$ in$^{2}$. The filter achieves a transmission loss of $\lt 2$ dB in the ISM band at 2.4 GHz and the UNII bands from $5.25 - 7.12$ GHz, using a low-cost 2-layer PCB and fabricated on a laboratory milling machine without any complicated cross-sectional elements (e.g., cavity resonators, dielectric resonators, etc.).