The Internet of Things (IoT)-centric concepts like augmented reality, high-resolution video streaming, self-driven cars, smart environment, e-health care, etc have a ubiquitous presence now. These applications require higher data-rates, large bandwidth, increased capacity, low latency and high throughput. In light of these emerging concepts, IoT has revolutionized the world by providing seamless connectivity between heterogeneous networks (HetNets). The eventual aim of IoT is to introduce the plug and play technology providing the end-user, ease of operation, remotely access control and configurability. This paper presents the IoT technology from a bird’s eye view covering its statistical/architectural trends, use cases, challenges and future prospects. The paper also presents a detailed and extensive overview of the emerging 5G-IoT scenario. Fifth Generation (5G) cellular networks provide key enabling technologies for ubiquitous deployment of the IoT technology. These include carrier aggregation, multiple-input multiple-output (MIMO), massive-MIMO (M-MIMO), coordinated multipoint processing (CoMP), device-to-device (D2D) communications, centralized radio access network (CRAN), software-defined wireless sensor networking (SD-WSN), network function virtualization (NFV) and cognitive radios (CRs). This paper presents an exhaustive review for these key enabling technologies and also discusses the new emerging use cases of 5G-IoT driven by the advances in artificial intelligence, machine and deep learning, ongoing 5G initiatives, quality of service (QoS) requirements in 5G and its standardization issues. Finally, the paper discusses challenges in the implementation of 5G-IoT due to high data-rates requiring both cloud-based platforms and IoT devices based edge computing.

Smart agriculture techniques have recently seen widespread interest by farmers. This is driven by several factors, which include the widespread availability of economically-priced, low-powered Internet of Things (IoT) based wireless sensors to remotely monitor and report conditions of the field, climate, and crops. This enables efficient management of resources like minimizing water requirements for irrigation and minimizing the use of toxic pesticides. Furthermore, the recent boom in Artificial Intelligence can enable farmers to deploy autonomous farming machinery and make better predictions of the future based on present and past conditions to minimize crop diseases and pest infestation. Together these two enabling technologies have revolutionized conventional agriculture practices. This survey paper provides: (a) A detailed tutorial on the available advancements in the field of smart agriculture systems through IoT technologies and AI techniques; (b) A critical review of these two available technologies and challenges in their widespread deployment; and (c) An in-depth discussion about the future trends including both technological and social, when smart agriculture systems will be widely adopted by the farmers globally.

A novel coplanar waveguide (CPW) fed rectenna with high efficiency is proposed and implemented in this article for 2.45 GHz Bluetooth/WLAN applications. The antenna has compact dimensions of 18 mm x 30 mm that is simulated and manufactured using a low-cost FR4 substrate with a thickness of 1.6 mm. A tuning stub technique with rectangular slots is used for better impedance matching and for enhancing the impedance bandwidth of the antenna with a peak gain of 5.6 dB. The proposed novel antenna for RF energy harvesting applications exhibits dipole-like radiation pattern in H-plane and omnidirectional pattern in E-plane with improved radiation efficiency. Single stage Cockcroft-Walton rectifier with L-shaped impedance matching network is designed in ADS and fabricated on FR4 substrate. The DC output of the rectenna is measured as 3.24 V with a load resistance of 5k Ω. A simulated peak conversion efficiency of 75.5% is attained while the measured one is observed to be 68% with an input signal power of 5 dBm at 2.45 GHz.

Due to the rapid development of wireless communication technologies, the number of wireless users are radically increasing. Currently, ~23 billion wireless devices are connected to the internet, and these numbers are expected to increase manifolds in the years to come. The technology growth of the fifth-generation (5G) wireless systems will be needed to meet this high demand of the network. 5G wireless systems offer data-rates of up to 10Gbps, 1-ms latency, and reduced power consumption. It is a known fact that 5G wireless systems will be exploiting beyond the presently used 3 GHz microwave and millimetre-wave (mm-wave) frequency bands. This is the primary driver in the development of the 5G wireless system. Multi-beam Phased array antenna (PAA) systems are typically used in the deployment of 5G systems for high-gain and directionality. In current 5G and future Beyond 5G (B5G) antenna array systems, beamforming networks (BFNs) such as the Butler Matrix (BM) will play a key role in achieving multi-beam characteristics. So, this paper presents an extensive review of the BM based BFNs, and discusses which type of BM will be suitable for the phased array antenna (PAA) systems in the upcoming 5G and next-generation of B5G wireless systems. Moreover, this paper also summarizes the different types of BM designs based on the number of layers. The BMs are classified into the bi-layer, tri-layer, and four-layer structures. It includes different techniques that have been used to solve the problem of crossing, narrow bandwidth, and size reduction of the BM. From the previous studies, it is found that most of the past research work was performed using the bi-layer BM system, whereas the difficult geometries like tri- and four-layer BM are avoided due to their complex fabrication process. It is also found in this paper that the metamaterial (MTM) based bi-layer BM achieves low insertion-loss and phase-error, excellent bandwidth and compact size, and good S-parameter performance, which makes them an ideal BFN candidate for the upcoming 5G and next-generation B5G systems.

A low-profile, compact, four-element, eight-port multiple-input--multiple-output and diversity antenna for 5G Internet of Things and cellular handheld applications is presented in this letter. This antenna structure contains four antenna elements, which are same in its configuration. The antenna ground dimensions are taken similar to a modern mobile handset, i.e., 60 mm × 120 mm. The four antenna elements are situated at four corners of antenna ground structure. Each antenna element has two feeding ports, thus making a total of eight-port antenna. A single antenna element has two feeding plates, which are placed perpendicular to one another so that they become cross polarized, thus exploiting polarization diversity, whereas spatial diversity also exists between different antenna elements. For reducing mutual coupling between different antenna ports, slots are cut in ground plane, including a small strip etched along the entire length of ground plane and rectangular slots cut in ground plane under every antenna element. The minimum bandwidth attained by all eight ports for S ₁₁ < –10 dB is more than 1.4 GHz from 2.4 GHz to more than 3.8 GHz, which testify that it covers majority of frequency bands allocated for 5G sub-6 GHz spectrum. The isolation obtained between different ports has a minimum value of –13 dB, and the maximum value goes below –30 dB. For the covered frequency bands by this antenna structure, the correlation coefficient is found to be below 0.03, whereas the measured peak gain is in the range of 3.2--5 dB.

This paper proposes a novel compact 4x4 butler matrix (BM) with improved bandwidth based on open-circuit coupled-lines and interdigital capacitor unit-cell to develop composite right/left handed (CRLH) transmission-line (TL) metamaterial structure. The BM is implemented by the combination of compact 3dB quadrature hybrid couplers, 0dB crossover and 45° phase shifter on a single FR4 substrate (εr = 4.3 and h = 1.66 mm). The simulated and measured result shows that the return loss and isolation loss are better than 14 dB at all the ports, good insertion loss of -7 ± 2dB, which cover the frequency range of 3.2 GHz to 3.75 GHz. The phase difference of -45°,135°, -135° and +45° are achieved with a maximum average phase tolerance of 5°. The overall dimension of the BM is 70mm x 73.7mm, which shows the compactness of the proposed design that is 75% size reduction and 8.2 times improvement in the bandwidth (550MHz) as compared to conventional BM. The CST microwave studio is used to design and perform the simulations. Additionally, the simulated and measured scattering parameters and phase differences show that they are in good agreement. This compact and improved bandwidth of the proposed BM is suitable for 5G beamforming network.