Amplitude-Induced Phase Modulation and Its Application to High-Gain Full-Polarization-Tunable Transmitarray Antenna

In this work, an amplitude-induced phase control method is proposed to achieve phase modulation by performing vector synthesis of two components with a tunable amplitude ratio. With a fixed phase difference between the components, continuous phase tuning of the synthesized wave is achieved by adjusting their amplitude ratio. A dual-output element based on a guided-wave structure is designed, enabling both outputs to provide a full 360° phase shift. In this element, tuning the amplitude ratio also controls the phase difference between the two outputs, enabling polarization manipulation of the transmitted wave. A high-gain full-polarization-tunable transmitarray antenna is subsequently designed, fabricated, and measured. Simulated and measured results validate the effectiveness of the proposed phase control method. The transmitarray antenna demonstrates significant advantages in aperture efficiency and polarization tunability. Furthermore, the proposed method requires no active components, avoiding static power consumption and thus making it suitable for power-constrained scenarios such as satellite communications, UAVs, and and Internet of Things (IoT) applications.