A Reconfigurable Transmit-Reflect-Array Antenna With Arbitrary Variable Transmit-Reflect Function and Continuous Adjustable Power Ratio

A reconfigurable transmit-reflect-array (TRA) antenna is proposed based on a reconfigurable element (RE) with adjustable transmission-reflection amplitude. The RE mainly comprises amplitude modulation structure (AMS) and phase modulation structure (PMS). The AMS is located in the middle of the element, and the PMS is divided into top and bottom parts (PMSt and PMS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub>) by AMS. By using polarization grids, the AMS and PMS hardly interfere with each other. Loading a varactor diode in AMS allows its resonance characteristics to be flexibly regulated. By changing the capacitance of the diode, the transmission/reflection amplitude of the RE can be adjusted to any ratio. Then, the PMSb independently controls the reflection phase. On this basis, an arbitrary transmission phase can be achieved by adjusting the PMSt. Therefore, the proposed RE can independently control the transmission/reflection amplitude and phase response. For instance, based on the proposed RE, a 15×15 metasurface is designed. The proposed TRA radiates a +1<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">order</sup> OAM beam (transmission) and a deflected high-gain beam (reflection). By controlling the reverse biasing voltage of the diode, the proposed TRA can achieve dynamic energy allocation in the entire space by using only a single DC biasing circuit.