2–Bit Programmable Metasurface for Low Radar Cross Section Antenna and Beam Steering Applications

Abstract

In this paper, a 2‐bit water‐based programmable digital metasurface for beam steering and backscatter field reduction applications is presented, a reflective and transmissive type water based programmable metasurface (WPMS) for RCS reduction and the antenna's beam steering is suggested, respectively. It has been demonstrated that a 2‐bit water‐based programmable unit cell can reduce RCS by changing its state (0/1). If the unit cell channel is empty, the state is “0,” if the channel is filled, the state is “1.” So at different resonance frequencies, the four phase and reflection coefficient responses are achieved as "00"01"10"11". This functionality enables beam steering in both the elevation and azimuth axis and also backscattering reduction of the antenna. Furthermore, the impacts of the number of unit cells and reflection phase states on the far‐field pattern are examined. Beam steering of ±45° in the elevation is attained with 10‐dB impedance bandwidth of 4.25–4.40 GHz, radiation gain of more than 7.1 dBi is maintained. With the present antenna, it is possible to achieve volumetric beamsteering performance directly. The patterns of far‐field radiation that are predicted theoretically coincide well with full waves simulations. As such, the proposed prototype can be a good option for applications that require a low RCS platform including beam steering in radars, 5G/6G, etc.

Reprogrammable metasurface design for NIR beam steering and active filtering

“…This allows for realization of NIR reconfigurable phased array metasurfaces for active beam steering [69][70][71][72], a key requirement for chip-based LiDAR systems. It is worth noting that, unlike programmable VO 2 -based metasurfaces operating in the microwave [23,73], terahertz [72,74], and mid-IR [59] ranges, two critical issues must be addressed when designing a NIR programmable device. These challenges arise due to limitations imposed by the size of the meta-atoms.…”