A Sandwich-Like Dual-Band Shared-Aperture Dielectric Lens Antenna With Large Frequency Ratio and Wide Scanning Range

Abstract

A sandwich-like, dual-band shared-aperture (DBSA) dielectric lens antenna (DLA) configuration is proposed to realize a wide scanning range in the microwave (MW) and millimeter-wave (MMW) bands with a large frequency ratio. The configuration comprises three vertically stacked lens layers separated by air gaps. This layered structure spatially decouples the propagation regions: electromagnetic (EM) waves of the MW band propagate throughout the entire lens, whereas those of the MMW band are confined to the middle layer by the air gaps and frequency-selective metamaterials (MTMs) in the top and bottom layers. This decoupling fundamentally avoids severe modal interference. Moreover, this configuration allows the adoption of a heterogeneous MTM design with distinct periods across layers, reducing structural complexity and enhancing fabrication tolerance. Two prototypes were designed, fabricated, and measured for verification. The cylindrical DLA covers the 5.8 GHz ISM band and the n258 band (24.25–27.5 GHz), achieving a frequency ratio of 4.48:1 and a wide azimuthal scanning angle of ±77° in both bands. The spherical DLA is used to illustrate the configuration’s scalability in expanding the frequency ratio and scanning dimensions. Covering the 2.4 GHz ISM and n258 bands with an ultra-large frequency ratio of 10.61:1, it achieves an azimuthal scanning angle of ±55° in both bands and an elevational scanning angle of ±55° in the MW band.