This work experimentally demonstrates a wide-angle beam steering based on an active conformal metasurface lens. Integrated with microwave varactors, the transmission phase of this cylindrical metasurface lens can be tuned in a range up to 195° by direct-current (DC) bias voltages. By compensating the phase difference between different incidences, the proposed cylindrical lens can collimate the incident spherical wave front into a plane wave front with predefined deflection angle. By increasing the number of feeding sources, the beam steering range of conformal lens can be expanded to ± 60°. Having advantages of low cost and simple structure, the proposed conformal lens can be extended to millimeter-wave band and enable a wide range of applications.

Besides the prohibitive cost, complexity, and baseband scale, the development of millimeter-wave (mmWave) digital-beamforming fifth-generation (5G) frontends is facing a physical-layer challenge of thermal dissipation. This is caused by the massively integrated power amplifiers (PAs) and the extremely compact volume due to millimeter-scale wavelengths. In this work, we theoretically analyze and experimentally demonstrate a reconfigurable planar Fresnel lens, based on which a new-concept mmWave beamforming frontend can be implemented with significantly reduced number of PAs. It overcomes the inherent shortcomings of analog beamforming solutions relying on massive use of power dividers and phase shifters and can replace the convex lens used in the recently proposed hybrid beamforming solution. The implemented Ka-band lens is simple-structured, cost-effective, and easy to control, providing multiple modes for beamspace massive-multiple-input multiple-output (MIMO) communications. Experimental results verified its potential in different mmWave 5G systems such as base stations and point-to-point links.

In this communication, a wideband reconfigurable reflectarray based on reflector-backed active second-order bandpass frequency selective surface (FSS) is presented. The reflector is composed of periodic short-circuited parallel plate waveguide (PPW) and the FSS is composed of stacked non-resonant metallic elements separated by thin dielectric substrates. By integrating microwave varactors in the capacitive layers of FSS, more than 270° continuous phase tunability is achieved within a fractional bandwidth of 14%. A one-dimensional reflectarray prototype operating at C band is fabricated and measured. The experimental results show that it can achieve ±55° beam scanning coverage. Symmetric beam steering is observed due to the center-fed configuration. With advantages of low cost and simple structure, the proposed reflectarray can be potentially used in wideband wireless communication and radar systems.

Inspired by animals’ long-distance migration behaviors, we proposed a novel and reliable long-distance true navigation method based on the measurement of geomagnetic fields. By establishing a two-dimensional (2D) gradient approaching coordinate plane with geomagnetic intensity and inclination, long-distance true navigation can be achieved from any starting spots in this area. Without other calibration and auxiliary information, this navigation method is highly independent, which can be used in electromagnetic shielding circumstances, such as deep ocean. The geomagnetic intensity and inclination gradients are estimated with real-time measurement of the geomagnetic field along the navigation trajectory. With estimated local gradients, 2D gradient approaching algorithm can be applied to predict the heading direction, and the agent can press on towards the destination step by step. Theoretical analysis and Monte Carlo simulations verified the feasibility and practicality of this method, proving its robustness in the presence of interference and different measurements errors. It can be a promising candidate in the design of navigation systems used in autonomous underwater vehicles or platform.

Multi-beam system is a core part for wireless concurrent communication and massive MIMO applications. Traditional concurrent communication techniques, like phased-array or digital beam-forming (DBF) system, suffer from massive RF frontends or power-hungry high speed ADCs, which makes them complex and expensive in fabrication. Inheriting the advantages of reflectarray and passive multi-beam system, we reported in this letter a novel and cost-effective concept of steerable simultaneous multi-beam antenna (SMBA). New features and the practicality of it are fully verified with theoretical analysis and experimental implementation of a prototype working at 7GHz with 300MHz bandwidth. With multiple beams steered simultaneously, the SMBA can eliminate the crossover regions between adjacent beams of passive multi-beam antenna. Experimental results indicate its potential in the design of diverse concurrent communication systems such as base stations and point-to-point links.