A Wideband Programmable Reflective Metasurface Based on Mode Transforming

The existing wideband methodology of 1-bit programmable metasurface commonly relies on spatial rotation or open/short switching of the integrated transmission line within the receiver/radiator. It implies that the bandwidth is naturally restricted by the basic components, such as the polarization converters or radiators. In this article, a novel mode-transforming scheme is proposed to break the limitation and enable the wideband programmable metasurface realization. By controlling the state of diodes inserted within the resonator, the meta-atom can be transformed between dual resonance and single resonance with specific eigenfrequencies, achieving a wideband reflection phase reversal. Furthermore, a hybrid compensation method is developed to relieve the degeneration caused by the parasitic effect of physical diodes. A unit cell sample and metasurface antenna prototype are manufactured and measured, yielding a satisfactory performance across the 9–16.5-GHz band, equivalent to 58.8% bandwidth. Within the operating band, the metasurface antenna can achieve 2-D beam-scanning coverage up to ±60°. All these validated results demonstrate the excellent performance of the proposed programmable metasurface, highlighting its potential for diverse applications in electromagnetic wave manipulation.