A low profile beam controlling antenna based on digital metasurface

In order to solve the problems of high profile of the transmission metasurface, difficult reconfiguration and large volume of beam controlling antenna, a beam deflection and wide/narrow beam switching antenna based on monolayer digital metasurface is proposed. The digital metasurface is consisted of 5×7 dual ring units, in which a PIN diode is placed to achieve 1 bit of digital encoding. A microstrip back-feed structure with parasitic strips is adopted as the source antenna, and the digital metasurface is placed at a height of 0.096λ₀ above the antenna. The beam can be controlled by controlling the biasing voltage of PIN diodes in each column. The measured results of the antenna show that the beam deflection range is 0°− ±45° at the central operating frequency of 3.6 GHz. The gain of the narrow and wide beam antennas is 8.5 dBi and 6.7 dBi, respectively. The 3 dB beam width of the wide beam antenna is about twice that of the narrow beam antenna. The experimental results are in good agreement with the simulation. The antenna has the characteristics of low profile and multi-function which can be used in many fields such as vehicle-mounted communication and airborne communication.