Design and optimization of all-dielectric focusing metasurface antennas

Conventional microwave antennas are constrained by the diffraction limit, making it challenging to breakthrough the constraint of wavelength-scale, which hinders their application in high-resolution microwave sensing and detection. To overcome this limitation, this study designs an all-dielectric integrated meta-antenna with super diffraction-limited performance. First, the antenna surface is functionalized using an asymmetric scattering meta-grating array based on the generalized Snell's law, enabling efficient subwavelength beam focusing through precise electromagnetic wavefront manipulation. Then, the geometrical structural of the metagrating is optimized to achieve high-efficiency wavefront control. Finally, the electric field intensity distribution and size of the generated focal spot are analyzed. The simulation results demonstrate that the highest manipulation and diffraction efficiencies reach 98.50% and 72.56%. The achieved focal spot exhibits a subwavelength dimension below 0.73λ with a focal depth of approximately 15.11λ. The designed meta-antenna simultaneously achieves long focal depth and high-efficiency, with its subwavelength focusing capability remarkably enhancing spatial resolution. It provides a novel solution for high-precision sensing and detection in fields such as microwave imaging, non-destructive testing, and biomedical diagnosis, demonstrating substantial potential for practical applications.