Continuous beam steering with a varactor-based reconfigurable intelligent surface in the Ka-band at 31 GHz

Abstract

Varactor diodes have been proposed as active tuning elements of reconfigurable metasurfaces in the Ka-band. However, their experimental realization in this frequency range has not been demonstrated yet. We report the implementation of such a reconfigurable intelligent surface (RIS) made of 20×20 unit cells. By active tuning of the bias voltage of the varactors, the phase of the backward diffracted wave can be continuously tuned between 0° and 180°. Thus, the phase tuning can be independently controlled for each unit cell. The frequency working range of the RIS is 1.1 GHz (from 30.6 to 31.7 GHz). As an illustration of the practical use, we demonstrate continuous beam steering of microwave radiation at 31 GHz in a defined propagation plane.

Design and Measurement of a Two-Dimensional Beam-Steerable Metasurface for Ka-Band Communication Systems

“…The phenomena mentioned above cause an attenuation as a function of the beam steering angle θ that does not decay monotonically proportional to cos(θ) as was expected [32]. Similar decaying attenuation patterns have been observed in related studies [33][34][35]. It's worth noting that the primary factors influencing these mechanisms and behaviors are the lossy nature of the varactor and the resonance characteristics of the unit cell.…”

“…In this configuration, the MS steers the beam from the feed and changes its direction, accordingly, improving the directivity, which becomes an issue in 5G point-to-point MMW communication [36]. Furthermore, the suggested configuration enables real-time control over the beam direction and increased stability, which are needed due to environmental influences, such as wind and temperature differences [34]. In this configuration, the MS steers the beam camming from the feed changing the beam direction, accordingly, improving the directivity, which becomes an issue in 5G point-to-point MMW communication [37].…”

“…In this configuration, the MS steers the beam camming from the feed changing the beam direction, accordingly, improving the directivity, which becomes an issue in 5G point-to-point MMW communication [37]. Furthermore, the suggested configuration enables real-time control over the beam direction and increased stability, which are needed due to environmental influences, such as wind and temperature differences [34].…”