Open Access
High gain/bandwidth off-chip antenna loaded with metamaterial unit-cell impedance matching circuit for sub-terahertz near-field electronic systems
(Springer, 2022) Alibakhshikenari, Mohammad; Virdee, Bal S.; Mariyanayagam, Dion; Vadalà, Valeria; Naser Moghadasi, Mohammad; See, Chan H.; Dayoub, Iyad; Aïssa, Sonia; Livreri, Patrizia; Burokur, Shah Nawaz; Pietrenko-Dabrowska, Anna; Falcone Lanas, Francisco; Koziel, Slawomir; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
An innovative of-chip antenna (OCA) is presented that exhibits high gain and efciency 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 signifcantly 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 infuence 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 0.137–0.158THz band corresponding to a fractional bandwidth of 14.23%. Over this frequency range the average measured gain and efciency are 8.6 dBi and 77%, respectively. These characteristics makes the proposed antenna suitable for integration in sub-terahertz near-feld electronic systems such as radio frequency identifcation (RFID) devices with high spatial resolution.
Open Access
Design and empirical validation of a LoRaWAN IoT Smart Irrigation System
(MDPI, 2020) Fraga Lamas, Paula; Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; López Iturri, Peio; Falcone Lanas, Francisco; Fernández Caramés, Tiago M.; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In some parts of the world, climate change has led to periods of drought that require managing efficiently the scarce water and energy resources. This paper proposes an IoT smart irrigation system specifically designed for urban areas where remote IoT devices have no direct access to the Internet or to the electrical grid, and where wireless communications are difficult due to the existence of long distances and multiple obstacles. To tackle such issues, this paper proposes a LoRaWAN-based architecture that provides long distance and communications with reduced power consumption. Specifically, the proposed system consists of IoT nodes that collect sensor data and send them to local fog computing nodes or to a remote cloud, which determine an irrigation schedule that considers factors such as the weather forecast or the moist detected by nearby nodes. It is essential to deploy the IoT nodes in locations within the provided coverage range and that guarantee good speed rates and reduced energy consumption. Due to this reason, this paper describes the use of an in-house 3D-ray launching radio-planning tool to determine the best locations for IoT nodes on a real medium-scale scenario (a university campus) that was modeled with precision, including obstacles such as buildings, vegetation, or vehicles. The obtained simulation results were compared with empirical measurements to assess the operating conditions and the radio planning tool accuracy. Thus, it is possible to optimize the wireless network topology and the overall performance of the network in terms of coverage, cost, and energy consumption.
Open Access
Challenges in wireless system integration as enablers for indoor context aware environments
(MDPI, 2017) López Iturri, Peio; Aguirre Gallego, Erik; Azpilicueta Fernández de las Heras, Leyre; Astrain Escola, José Javier; Villadangos Alonso, Jesús; Falcone Lanas, Francisco; Ingeniaritza Elektrikoa eta Elektronikoa; Matematika eta Informatika Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniería Matemática e Informática
The advent of fully interactive environments within Smart Cities and Smart Regions requires the use of multiple wireless systems. In the case of user-device interaction, which finds multiple applications such as Ambient Assisted Living, Intelligent Transportation Systems or Smart Grids, among others, large amount of transceivers are employed in order to achieve anytime, anyplace and any device connectivity. The resulting combination of heterogeneous wireless network exhibits fundamental limitations derived from Coverage/Capacity relations, as a function of required Quality of Service parameters, required bit rate, energy restrictions and adaptive modulation and coding schemes. In this context, inherent transceiver density poses challenges in overall system operation, given by multiple node operation which increases overall interference levels. In this work, a deterministic based analysis applied to variable density wireless sensor network operation within complex indoor scenarios is presented, as a function of topological node distribution. The extensive analysis derives interference characterizations, both for conventional transceivers as well as wearables, which provide relevant information in terms of individual node configuration as well as complete network layout.
Open Access
Implementation of wireless sensor network architecture for interactive shopping carts to enable context-aware commercial areas
(IEEE, 2016) López Iturri, Peio; Azpilicueta Fernández de las Heras, Leyre; Astrain Escola, José Javier; Aguirre Gallego, Erik; Salinero, Eduardo; Villadangos Alonso, Jesús; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Matemática e Informática; Matematika eta Informatika Ingeniaritza; Institute of Smart Cities - ISC
An interactive shopping cart to enable context aware environments within large commercial areas is presented. A wireless sensor network was designed, with specific nodes embedded within the shopping carts and infrastructure nodes in the shopping area. Due to the complexity of wireless propagation, given the large amount of obstacles and the inclusion of users, an in house deterministic method based on 3D Ray Launching was employed, providing results in terms of adequate transceiver deployment to minimize interference, energy consumption and maximize data throughput. The proposed system was tested in a real commercial scenario, with the implementation of an ad-hoc monitor shopping application, exhibiting successful detection rates in order of 99%. The proposed systems provides an interactive shopping experience for users as well as for commercial managers.
Open Access
Antenna on chip (AoC) design using metasurface and SIW technologies for THz wireless applications
(MDPI, 2021) Althuwayb, Ayman Abdulhadi; Alibakhshikenari, Mohammad; Virdee, Bal S.; Benetatos, Harry; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper presents the design of a high-performance 0.45-0.50 THz antenna on chip (AoC) for fabrication on a 100-micron GaAs substrate. The antenna is based on metasurface and substrate-integrated waveguide (SIW) technologies. It is constituted from seven stacked layers consisting of copper patch-silicon oxide-feedline-silicon oxide-aluminium-GaAs-copper ground. The top layer consists of a 2 x 4 array of rectangular metallic patches with a row of subwavelength circular slots to transform the array into a metasurface. This essentially enlarges the effective aperture area of the antenna. The antenna is excited using a coplanar waveguide feedline that is sandwiched between the two silicon oxide layers below the patch layer. The proposed antenna structure reduces substrate loss and surface waves. The AoC has dimensions of 0.8 x 0.8 x 0.13 mm(3). The results show that the proposed structure greatly enhances the antenna's gain and radiation efficiency, and this is achieved without compromising its physical size. The antenna exhibits an average gain and efficiency of 6.5 dBi and 65%, respectively, which makes it a promising candidate for emerging terahertz applications.
Open Access
Validation of 3D simulation tool for radio channel modeling at 60 GHz: a meeting point for empirical and simulation-based models
(Elsevier, 2020) Celaya Echarri, Mikel; Azpilicueta Fernández de las Heras, Leyre; López Iturri, Peio; Falcone Lanas, Francisco; García Sánchez, Manuel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
The radio channel modelling of the millimeter wave bands for the fifth generation of wireless mobile communications, appears as a challenge for both empirical and simulation approaches. In this paper we discuss the use of experimental datasets for validation of a simulation tool based on deterministic 3D ray-launching technique. The goal it twofold: validating the simulation tool and achieving more consistent results considering the restrictions and performance limits of hardware elements. A microcell canyon street scenario has been chosen for interleaving ray launching prediction and empirical analysis. Simulation results such as received power or angular distribution of path loss, as well as channel dispersion parameters such as root-mean-square delay spread have been presented. In addition, the line-of-sight to non-line-of-sight transition has been modeled as a result of the empirical-simulation interaction. Comparison of simulation and measurement results for the proposed microcellular urban scenario exhibit good agreement, validating the proposed methodology. (C) 2020 Elsevier Ltd. All rights reserved.
Embargo
A new waveguide slot array antenna with high isolation and high antenna bandwidth operation on Ku- and K- Bands for radar and MIMO systems
(IEEE, 2018) Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Abd-Alhameed, Raed; Limiti, Ernesto; Falcone Lanas, Francisco; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper a novel technique is proposed to reduce the mutual coupling between the radiating elements of a waveguide slot array antenna. This is achieved by inserting slots between the waveguide oval shaped slots. The reference waveguide array antenna used in the study was implemented with an arrangement of 3×5 oval shaped slots. By incorporating linear slots between the radiating oval shaped slots in both horizontal and vertical directions significant reduction in mutual coupling is achieved of 24 dB, 20 dB, and 32 dB in the frequency bands of 12.95-13.75 GHz (Ku-band), 15.45-16.85 GHz (Ku-band), and 18.85-23.0 GHz (K-band), respectively. Edge-to-edge distance between the slot radiators is 0.2λ, which is at least twofold smaller than conventional array antennas. With the slot isolators the antenna's minimum and maximum gains improve by 53.5% and 25.5%, respectively. In addition, the radiation patterns are unaffected. The proposed method is simple to implement, low cost solution mass production. © 2018 European Microwave Association.
Open Access
Design and implementation of a feasible model for the IoT based ubiquitous healthcare monitoring system for rural and urban areas
(IEEE, 2022) Bhuiyan, Mohammad Nuruzzaman; Billah, Md Masum; Bhuiyan, Farzana; Bhuiyan, Ashikur Rahman; Hasan, Nazmul; Rahman, Maryland Mahbubur; Miah, Md Sipon; Alibakhshikenari, Mohammad; Arpanaei, Farhad; Falcone Lanas, Francisco; Niu, Mingbo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The Internet of Things (IoT) based real-time health monitoring system has contributed towards a brilliant human welfare both in urban and rural areas. Many of such solutions are not well applicable in developing countries like Bangladesh due to lack of uninterrupted communication system. In this paper, we present an IoT-based real-time health monitoring system that can measure, monitor and report people's health condition online and offline from anywhere. Our proposed IoT based solution is capable to transmit the sensitive health information to medical centres and caregivers in real time. The proposed system has been designed with Arduino UNO, Nodemcu, and Global System for Mobile Communication (GSM) modules to measure body temperature, pulse rate, Oxygen saturation, room temperature, and air quality in a smart home setting. The system can also provide the patient's historical health records. Our implementation was tested on some test cases which works excellent with accuracy. The proposed system has high potentiality for the rural and urban areas in developing countries.
Open Access
Study on isolation improvement between closely-packed patch antenna arrays based on fractal metamaterial electromagnetic bandgap structures
(Institution of Engineering and Technology, 2018) Alibakhshikenari, Mohammad; Virdee, Bal S.; See, Chan H.; Abd-Alhameed, Raed; Ali, Abdul; Hussein Ali, Ammar; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A decoupling metamaterial (MTM) configuration based on fractal electromagnetic-bandgap (EMBG) structure is shown to significantly enhance isolation between transmitting and receiving antenna elements in a closely-packed patch antenna array. The MTM-EMBG structure is cross-shaped assembly with fractal-shaped slots etched in each arm of the cross. The fractals are composed of four interconnected-'Y-shaped' slots that are separated with an inverted-'T-shaped' slot. The MTM-EMBG structure is placed between the individual patch antennas in a 2 × 2 antenna array. Measured results show the average inter-element isolation improvement in the frequency band of interest is 17, 37 and 17 dB between radiation elements #1 & #2, #1 & #3, and #1 & #4, respectively. With the proposed method there is no need for using metallic-via-holes. The proposed array covers the frequency range of 8-9.25 GHz for X-band applications, which corresponds to a fractional-bandwidth of 14.5%. With the proposed method the edge-to-edge gap between adjacent antenna elements can be reduced to 0.5λ0 with no degradation in the antenna array's radiation gain pattern. Across the array's operating band, the measured gain varies between 4 and 7 dBi, and the radiation efficiency varies from 74.22 and 88.71%. The proposed method is applicable in the implementation of closely-packed patch antenna arrays used in SAR and MIMO systems. © 2018, The Institution of Engineering and Technology.
Open Access
Analysis of the combinatory effect of uniaxial electrical and magnetic anisotropy on the input impedance and mutual coupling of a printed dipole antenna
(IEEE, 2021) Bouknia, Mohamed Lamine; Zebiri, Chemseddine; Sayad, Djamel; Elfergani, Issa; Alibakhshikenari, Mohammad; Rodriguez, Jonathan; Abd-Alhameed, Raed; Falcone Lanas, Francisco; Limiti, Ernesto; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The main objective of this work is to investigate the combinatory effects of both uniaxial magnetic and electrical anisotropies on the input impedance, resonant length and the mutual coupling between two dipoles printed on an anisotropic grounded substrate. Three different configurations: broadside, collinear and echelon are considered for the coupling investigation. The study is based on the numerical solution of the integral equation using the method of moments through the mathematical derivation of the appropriate Green's functions in the spectral domain. In order to validate the computing method and evaluated Matlab calculation code, numerical results are compared with available literature treating particular cases of uniaxial electrical anisotropy; good agreements are observed. New results of dipole structures printed on uniaxial magnetic anisotropic substrates are presented and discussed, with the investigation of the combined electrical and magnetic anisotropies effect on the input impedance and mutual coupling for different geometrical configurations. The combined uniaxial (electric and magnetic) anisotropies provide additional degrees of freedom for the input impedance control and coupling reduction.