The concept of smart city evolved with the integration of information and communication technology (ICT) in various sub-systems and processes in urban environment. The development of the smart cities is the best possible solution to major urban issues. It contributes towards economic and social development of the residents. It aims to provide the cordial environment in the domains of healthcare, education, transportation, power generation and dissipation, security, living, industry, etc., to the inhabitants to make their lives comfortable. Sustainability of these services is another major objective in a smart city framework. Along with the true realization of the idea of a smart city, advanced computational and communication technologies are contributing hugely towards its sustainable development. Communication technologies act as backbone to ensure connectivity at the various levels in a smart city framework. Novel smart city solutions for different application domains are designed and deployed by the industry using advanced computational technologies like IoT, Artificial Intelligence, Blockchain, Big Data and Cloud Computing. In this work, authors discuss the concept of smart city, its architecture and sustainability. Different operational domains in a smart city ecosystem are elaborated. The cyber physical aspect of the smart cities is discussed in brief. The role of various computational and communication technologies in the sustainable development of smart cities is presented. Limiting factors in the deployment of various advanced technologies in different smart city domains are highlighted. Security issues associated with the technological sustainable development of different smart city services along with existing solutions are discussed. The article is concluded by highlighting the future research directions.

Narrowband antennas fail to radiate short pulses of nano- or picosecond length over the broader band of frequencies. Therefore, Ultrawideband (UWB) technology has gained momentum over the past couple of years as it utilizes a wide range of frequencies, typically between 3.1–10.6 GHz. UWB antennas have been utilized for various applications such as ground-penetrating radars, disaster management through detection of unexploded mines, medical diagnostics, and commercial applications ranging from USB dongles to detection of cracks in highways and bridges. In the first section of the manuscript, UWB technology is detailed with its importance for future wireless communications systems. In the next section various types of UWB antennas and their design methodology are reviewed, and their important characteristics are highlighted. In section four the concept of a UWB notch antenna is presented. Here various methods to obtain the notch, such as slots, parasitic resonators, metamaterials, and filters are discussed in detail. In addition, various types of important notch antenna design with their technical specifications, advantages, and disadvantages are presented. Finally, the need of reconfigurable UWB notch antennas is discussed in the next section. Here various insight to the design of frequency reconfigurable notch antennas is discussed and presented. Overall, this article aims to showcase the beginnings of UWB technology, the reason for the emergence of notching in specific frequency bands, and ultimately the need for reconfiguring UWB antennas along with their usage.

In the current era of technology, the internet of things (IoT) plays a vital role in smart drug delivery systems. It is an emerging field that offers promising solutions for improving the efficacy, safety, and patient compliance of drug therapies. IoT-based drug delivery systems leverage advanced devices, sophisticated sensors, and smart tools to monitor and analyse the health matrices of the patient in real-time, allowing for personalised and targeted drug delivery. This technology is implemented through various types of devices, including wearable and implantable devices such as infusion pumps, smart pens, inhalers, and auto-injectors. However, the development and implementation of IoT-based drug delivery systems pose several challenges, such as ensuring data security and privacy, regulatory compliance, compatibility, and reliability. In this paper, the latest research on smart wearable devices and its analysis are addressed. It also focuses on the challenges of ensuring the safe and efficient use of this technology in healthcare applications.

In recent years, there has been a surge of interest in the field of wireless communication for designing a monitoring system to observe the activity of the human body remotely. With the use of wireless body area networks (WBAN), chronic health and physical activity may be tracked without interfering with routine lifestyle. This crucial real-time data transmission requires low power, high speed, and broader bandwidth communication. Ultrawideband (UWB) technology has been explored for short-range and high-speed applications to cater to these demands over the last decades. The antenna is a crucial component of the WBAN system, which lowers the overall system’s performance. The human body’s morphology necessitates a flexible antenna. In this article, we comprehensively survey the relevant flexible materials and their qualities utilized to develop the flexible antenna. Further, we retrospectively investigate the design issues and the strategies employed in designing the flexible UWB antenna, such as incorporating the modified ground layer, including the parasitic elements, coplanar waveguide, metamaterial loading, etc. To improve isolation and channel capacity in WBAN applications, the most recent decoupling structures proven in UWB MIMO technology are presented.

This article presents the design and analysis of a V-shaped ultrawideband (UWB) antenna and dual-band UWB notch antenna. A rectangular slot is cut into a semicircular partial ground plane of the antenna to achieve ultrawide bandwidth. A U-shape slot is etched on a V-shaped patch that radiates, and an inverted U-shape parasitic resonator is placed beside the feedline to generate dual-band notch characteristics. The overall dimension of the proposed antenna is $28\times 23{ \mathrm{mm}}^2$. The proposed UWB antenna has a gain of 9.8 dB, S₁₁ < −10 dB, impedance bandwidth in the range of 3.4 to 12.3 GHz, response with a linear phase, group delay <1 ns, and stable radiation pattern. The UWB notch antenna shows strong rejection in the WLAN band from 5.15 to 5.8 GHz with a notch at 5.6 GHz and X band from 9.1 to 10.5 GHz with a sharp notch at 9.6 GHz, having a S₁₁ < −10 dB impedance bandwidth ranging from 3.2 to 11.7 GHz. This antenna also exhibits a stable radiation pattern, group delay <1 ns, and linear phase response throughout the bandwidth except at the rejection frequencies.

The research community has been more interested in Nature-inspired antenna solutions in recent years. Well-known organizations all around the world have set up labs to investigate the structures, operations, and traits of creatures that exist. One valuable method is investigating geometrical depictions of biological shapes, including fractal shapes and polarized geometry. This paper focuses on the design of a Leaf shaped antenna, its 4×1 corporate-fed array, and spatial diversity and pattern diversity MIMO antenna which operates in the sub-6 GHz range and specifically covers the 5G bands: N77 (3.3-4.2 GHz), N78 (3.3-3.8 GHz), and N79 (4.7 GHz) (4.4 GHz-5GHz). The radiating element of the array is modeled like a natural plant leaf and defected ground plane is used to reduce size and increase bandwidth. To obtain dual band characteristics and circular polarization, a diagonal slot in the parasitic metallic elliptical disc in the ground plane is used. A corporate feed network is used in 4×1 array for excitation to radiating elements and to generate a high gain performance by ensuring little reflection loss and good impedance matching. Electromagnetically coupled hexagonal array is used in T shape between the inter elements to reduce mutual coupling and increasing the gain of 4×1 array. The proposed multiband antenna array reflects less than 10% of the power between 3.4-4 GHz and 4.51-5.2 GHz and achieves a maximum gain of 6.55 dB with variations of less than 3 dB across the full operating band. MIMO configurations are required to increase the network capacity. Spatial diversity and pattern diversity MIMO antennas are designed which provides good diversity performance and sufficient isolation bandwidth. All the proposed antennas are fabricated on a commercially available FR4 substrate with a dielectric constant of 4.3 and a height of 1.6 mm, making it inexpensive for mass production. Performance of fabricated antennas are compared with simulated antennas. Compact size, planar design, broad bandwidth, and stable gain make proposed antennas suitable for sub-6GHz 5G application.