A Reflective Metalens With Tunable Focal Length for Millimeter Waves

A novel architecture of reconfigurable, flat metalens is proposed with an electrically tunable focal length for applications in wireless communication systems working at the frequencies of millimeter waves (i.e., 60 GHz). In this approach, a reflective metalens made of silicon bricks is distributed on a grounded multilayer hosting films of a phase-transition material, namely, vanadium dioxide. The multilayer, acting as a ground plane with a controllable position, provides different phase profiles in the same metalens and, therefore, different focal lengths. Our numerical investigation of thermal and electromagnetic effects shows that the metasurface can reversibly tune the focal length at 27, 31, and 33 mm. In addition, in the operating frequency range between 58 and 62 GHz, the tunability of the metalens remains unaltered. Dynamically controlling the focal point of millimeter waves is highly desirable in wireless communications, especially for 5G and 6G cellular systems applications.

Automated summary

A novel architecture of reconfigurable, flat metalens with electrically tunable focal length is proposed for wireless communication systems operating at millimeter wave frequencies. The metalens is made of reflective silicon bricks distributed on a grounded multilayer with phase-transition material films, allowing for different focal lengths. Numerical investigation shows that the metalens can reversibly tune focal length at specific distances and remains tunable within a certain frequency range. This has significant importance for dynamically controlling the focal point of millimeter waves in wireless communications.