One of the many things COVID-19 has taught humanity is that the internet is not just a commodity but a vital service integral to the modern world. As we become ever more connected, there is a growing need to secure data and communication streams. If data is valued, then it should be protected. Unfortunately, some of the least secure devices in modern electronic systems are the Internet of Things (IoT) devices-partly due to their low processing power and always-on functionality. Polymorphism is the notion of changing one's form. In biological organisms, polymorphic (mutating or changing) viruses trick the natural security mechanisms by changing their unique signatures (e.g. DNA or proteins). In computing, antivirus software systems are adapted to detect and remove constantly changing software viruses. However, polymorphism at the firmware level and over the wireless medium is neither well understood nor explored for IoT devices. This paper proposes a novel and bio-inspired framework for securing distributed IoT devices often assumed to be working at the intersection of engineering, computing, and cybersecurity domains. The proposed framework attempts to exploit the notion of polymorphism in resource-constrained (e.g. memory, power, bandwidth) IoT devices. The framework's core aim is to detect, reject, and block foreign agents individually or collaboratively and in real-time within a client and server model by changing the access credentials and encryption keys as soon as an unauthorised client is detected. The framework proposed for the bio-inspired framework for security in IoT devices is designed to remain operationally compartmentalised, functionally integrated, and objectively unified.
The results presented in this paper show that by employing a combination of metasurface and substrate integrated waveguide (SIW) technologies, we can realize a compact and low-profile antenna that overcomes the drawbacks of narrow-bandwidth and low-radiation properties encountered by terahertz antennas on-chip (AoC). In addition, an effective RF cross-shaped feed structure is used to excite the antenna from its underside by coupling, electromagnetically, RF energy through the multi-layered antenna structure. The feed mechanism facilitates integration with the integrated circuits. The proposed antenna is constructed from five stacked layers, comprising metal–silicon–metal–silicon–metal. The dimensions of the AoC are 1 × 1 × 0.265 mm3. The AoC is shown to have an impedance match, radiation gain and efficiency of ≤ −15 dB, 8.5 dBi and 67.5%, respectively, over a frequency range of 0.20–0.22 THz. The results show that the proposed AoC design is viable for terahertz front-end applications.
An innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance bandwidth is enhanced by a factor of two and its gain on average by about 4 dB. Unlike conventional antennas, where the energy is dissipated in a resistive load, the technique proposed here significantly reduces losses. The antenna is excited from underneath the antenna by coupling RF energy from an open-circuited feedline through a slot in the ground-plane of the middle substrate layer. The feedline is shielded with another substrate layer which has a ground-plane on its opposite surface to mitigate the influence of the structure on which the antenna is mounted. The antenna has the dimensions 12.3 × 4.5 × 0.905 mm3 and operates across the 0.137–0.158 THz band corresponding to a fractional bandwidth of 14.23%. Over this frequency range the average measured gain and efficiency are 8.6 dBi and 77%, respectively. These characteristics makes the proposed antenna suitable for integration in sub-terahertz near-field electronic systems such as radio frequency identification (RFID) devices with high spatial resolution.
With climate change and global warming in mind, vertical farms, hydroponics and urban greenhouses can now be found in many cities worldwide as we transform the ways we produce food. Additionally, recent implications of the COVID-19 pandemic prove that as a society we can harness the benefit of remote monitoring and automation for controlled-environment agriculture and horticulture.The subject matter of this paper is implementation of a solarpowered, Internet of Things (IoT) based Real-time Autonomous Horticulture Monitoring System (RAHMS). The RAHMS integrates a mobile application for viewing the greenhouse crop data and camera feed of plants, and interacts with cloud databases such as Firebase and MATLAB ThingSpeak for the scalability. In particular, a simple and distinctive design of a solar-powered, low energy consuming, and inexpensive greenhouse monitoring system is presented. The paper outlines RAHMS design methodology and showcases a proof-of-concept prototype with its core hardware and software components. The proposed system has a potential to further advance the practical aspects of the remote solutions for the cultivation and monitoring of horticulture and controlled-environment agriculture.
Design of a novel triband bandpass filter is presented for wireless communications systems. The filter is based on inter-coupled stepped impedance resonators and inter-digitally coupled to the input/output ports. The configuration of the filter circuit consists of open-loop resonators that are electromagnetically coupled to each other using inverted T-shaped open stubs. The intrinsic characteristics of filter structure generates five transmission zeros that results in triband bandpass response exhibiting sharp selectivity, high inter-band isolation and a wide out of band rejection. Unlike other triband filters reported recently in literature the proposed single layer filter does not require any short-circuited plated through hole which can introduce fabrication complexity and therefore production costs. Moreover, the triband structure can be configured to provide passbands with identical 3-dB fractional bandwidth and whose center frequency can be equally spaced. In the proposed prototype design presented here the passband frequencies are set to 3.6, 4.6, and 5.6 GHz that corresponds to WiMAX, 5G, and WLAN applications. The consequence of employing opencircuited transmission lines in the design results in a relatively large structure, which can be overcome by employing higher dielectric constant substrate. The proposed triband filter was designed to achieve identical 3-dB fractional bandwidth of 11.9%. Measured results confirm inter-band isolation better than 30-dB. The theoretical model is consistent with the measured results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.