Evolution of mobile broadband is ensured by adopting a unified and more capable radio interface (RI). For ubiquitous connectivity among a wide variety of wireless applications, the RI enables the adoption of an adaptive bandwidth with high spectrum flexibility. To this end, the modern-day communication system needs to cater to extremely high bandwidth, starting from below 1 GHz to 100 GHz, based on different deployments. This instigates the creation of a platform called the Internet of Everything (IoE), which is based on the concept of all-round connectivity involving humans to different objects or things via sensors. In simple words, IoE is the intelligent connection of people, processes, data, and things. To enable seamless connectivity, IoE resorts to low-cost, compact, and flexible broadband antennas, RFID-based sensors, wearable electromagnetic (EM) structures, circuits, wireless body area networks (WBAN), and the integration of these complex elements and systems. IoE needs to ensure broader information dissemination via simultaneous transmission of data to multiple users through separate beams and to that end, it takes advantage of metamaterials. The precise geometry and arrangement of metamaterials enable smart properties capable of manipulating EM waves and essentially enable the metamaterial devices to be controlled independently to achieve desirable EM characteristics, such as the direction of propagation and reflection. This review paper presents a comprehensive study on next-generation EM devices and techniques, such as antennas and circuits for wearable and sub 6 GHz 5G applications, WBAN, wireless power transfer (WPT), the direction of arrival (DoA) of propagating waves, RFID based sensors for biomedical and healthcare applications, new techniques of metamaterials as well as transformation optics (TO) and its applications in designing complex media and arbitrary geometry conformal antennas and optical devices that will enable future IoE applications.

In this paper, a new technique is introduced for finding direction of arrival (DoA) of an incident signal based on the nullforming and steering theory. On the contrary to the operation of beamforming, the proposed method creates a deep and precise null that is then steered toward all the possible directions to estimate the minimum power that indicates the direction of the incident signal. Additionally, this new method can outperform conventional beamforming as the resulted null is much narrower than conventional beams. The proposed null-forming and steering theory has been proven successfully by both analytical and simulation validation using MATLAB Simulink model and an integrated software defined radio USRP N200.

Computational microwave imaging can reduce reliance on dense antenna arrays and mechanical scanning by encoding scenes using spatially diverse electromagnetic masks. Metasurface apertures are attractive for producing such masks; however, many implementations rely on active tuning, cavity‐backed apertures, folded propagation paths, mechanical reconfiguration, or multiple feeds. This work presents a passive single‐layer randomized leaky‐wave metasurface aperture for broadband near‐field computational microwave imaging. The aperture uses a single feeding port and an integrated 16‐way microstrip power divider to launch guided waves along nonperiodic rows composed of six dispersive H‐shaped unit‐cell types. Eigenmode‐based analysis guides the selection of these unit‐cell types and clarifies how their nonperiodic loading produces frequency‐dependent near‐field masks through leaky‐wave radiation. The fabricated prototype integrates the aperture and feed network on a PCB, demonstrating broadband operation over 18–28 GHz, corresponding to 43.5% fractional bandwidth. Measured near‐field masks confirm broadband low‐redundancy spatial encoding. Imaging experiments demonstrate recovery of test targets and 5 mm two‐target separability in both transverse directions. These results show that static nonperiodic unit‐cell loading and broadband dispersion provide a compact, hardware‐efficient passive route to near‐field computational microwave imaging.