Search

In this letter, we demonstrate a double-resonant Huygens’ metasurface. The double Huygens’ resonances serve as the bridges connecting several nonresonant passbands, achieving good transmission performance over an ultrawideband range and available transmission phase coverage far beyond 360°. Then, a dual-band dual-polarized 3-bit phase scheme is proposed to independently obtain sufficient phase coverages at 28/38 GHz. When used for planar lens antenna design, good dual-band radiation performance is achieved. In the 28 GHz band, the measured peak gain is 29.14 dBi at 28.5 GHz with an aperture efficiency of 44.87% and a 3 dB gain bandwidth of 18.2%. In the 38 GHz band, the measured peak gain is 32.03 dBi at 38 GHz with an aperture efficiency of 47.25% and a 3 dB gain bandwidth of 8.7%.

Recently, there has been growing interest in the use of metamaterial (MTM)-based lenses, also known as metalenses, as innovative antenna technology. Increasingly widespread applications of metalenses in modern microwave communication and sensing systems have been found, following the development of the first microwave artificial lens in the 1940s based on the concept of an artificial dielectric, which was later broadly termed an “MTM. ” This article examines the evolution of metalens antennas over the past 80 years and introduces the principles and technologies underlying their design. It then focuses on the latest progress in the research on and applications of MTMs and metasurface (MTS)-based metalens antennas. The principles and basic structures of transmissive focusing metalens antennas in the microwave band are elaborated. Selected metalens antennas are introduced chronologically, starting with metallic waveguide lens antennas, followed by metallic or metal–dielectric Fresnel zone plate lens antennas, transmitarray lens antennas, MTS lens antennas, and flat transformation-optics-based MTM Luneburg lens antennas. The technical merits, challenges, applications, trends, and future research of each type of metalens antenna are also addressed. The information presented in this article will benefit the research, development, and application of metalens antennas in fifth- and beyond-generation communications, Wi-Fi 6 short-range connections, and next-generation microwave sensing and imaging systems.

An ultrathin, dual-band, orthogonally linearly polarized Huygens’ metasurface has been proposed which can be used for 28/38 GHz dual-band lens antenna. It is composed of two types of linearly polarized Huygens' elements spatially interleaved along the orthogonal direction. They work in different frequency bands and have almost no interaction, achieving independent full-phase manipulation capabilities in their respective frequency bands. Then, a double-layer dual-band meta-lens antenna is designed, manufactured and measured. At 28/38 GHz, high gains of 30.61 and 31.99 dBi are achieved, respectively, which corresponds to antenna efficiencies of 54.2% and 40.7%. The 3-dB gain bandwidths are 7.5% and 8.6% in two band, respectively. The simulated and measured results consistently show good dual-band radiated performance of meta-lens. The proposed Huygens’ meta-lens antenna has important applications in the field of antenna engineering.

An ultrathin and low-profile metalens antenna based on chain Huygens’ metasurface is proposed for 28 GHz band applications. The metasurface consists of an array series of modified dipoles etched onto a piece of the dielectric substrate, and there is a half-unit dislocation along the $y$ -axis between these dipoles on top and bottom surfaces. Due to this geometry, the EM response between the pair of adjacent dislocated dipoles as a bridge links them into a whole structure, and thus, the metasurface is regarded as a chain structure. The chain metasurface has the characteristics of full transmission phase coverage, stable angular performance, and the subwavelength-scale EM manipulation ability (half the period of the unit along the $y$ -axis, $\sim 0.215\lambda _{0}$ at 28 GHz, where $\lambda _{0}$ is the wavelength in free space). By utilizing these properties of chain Huygens’ metasurface, an ultrathin and low-profile metalens antenna operating at 28 GHz is designed with an aperture of about $15\lambda _{0} \times 15\lambda _{0}$ and a smaller F/D ratio of 0.32 compared with the usual metalens antenna. The measurement shows that the proposed ultrathin metalens antenna achieves excellent radiated performances, including the peak gain of 30.6 dBi at 28 GHz, the antenna efficiency of 40.3%, and the 3 dB gain bandwidth of 10.7%.

Cisplatin is the first-line drug for treatment of various solid tumors including breast cancer due to the broad anti-tumor spectrum and strong anti-tumor effect. However, serious side effects and long-term medication of reduced sensitivity by high GSH in tumor cells have severely restricted its further clinical application. Herein, a GSH-depleted Pt(IV) prodrug (Platin B) based on cisplatin and 4-carboxylphenylboronic acid pinacol ester was prepared to solve the problems. As an excellent GSH scavenger, 4-carboxylphenylboronic acid pinacol ester could be activated by intracellular redox reactions to release quinone methide, thereby amplifying oxidative stress and leading to breast cancer ferroptosis therapy. Interestingly, the consumption of GSH can also reduce cisplatin inactivation, enhance the sensitivity of tumor cells to cisplatin and efficiently induce apoptosis/ferroptosis. This work highlights the use of GSH scavenger for triggering ferroptotic cell death in breast cancer.

One-dimensional (1D) photonic crystal coupled microcavity structure containing indefinite metamaterials was investigated. The Wannier-Stark ladder (WSL) can be obtained in both the Bragg ordinary and the well-known omnidirectional band gaps by modulating widths of the cavities. The time-resolved transmission of a short pulse showed the existence of two types of optical Bloch oscillation in such structures. The transmission and the period of the oscillation are found to decrease with the increasing gradient δ.

An ultra-compact, broadband Huygens' metasurface based on induced magnetism has been proposed. The induced magnetism in the Huygens' meta-atom originates from the circulating electric currents constituted by the antisymmetric flowing of surface currents on the both conducting elements. The Huygens' metasurface based on induced magnetism is rather compact and easy to fabricate, and has the abilities of manipulating the transmitted wavefront in a broadband transparency window. As an example of application, the Huygens' meta-lens exhibits excellent antenna performance. The Huygens' metasurface based on induced magnetism offer extra opportunities for broadband wave manipulation in transmissive metasurface.