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Projeto de investigação
Wireless Sensor Network for Environmental Monitoring
Financiador
Autores
Publicações
Metamaterial-inspired Flat-Antenna Design for 5G Small-cell Base-Stations Operating at 3.6 GHz
Publication . Reis, João R.; Fernandes, Telmo R.; Patrício Carreira Vala, Mário António; Caldeirinha, Rafael F. S.
In this paper, a flat-beamsteering antenna for 5G applications is being presented. The antenna, designed to operate at 3.6 GHz (5G new radio (NR) frequency range 1 (FR1) band n78), presents a unique flat form factor which allows easy deployment and low visual impact in 5G dense scenarios. The antenna presents a multi-layer structure where a metamaterial inspired transmitarray enables the two-dimensional (2D) beamsteering, and an array of microstrip patch antennas is utilised as RF source. The use of metamaterials for beamsteering control allows for the reduction of costly and complex phase-shifter networks by using discrete capacitor diodes to control the transmission phase-shifting and subsequently, the direction of the steering. According to simulations, the proposed antenna presents 13.9 dBi of gain, 100 MHz of bandwidth with a maximum steering range of ±20 degrees, achievable in both elevation and azimuth planes, independently.
High Performance Antennas for Early Fire Detection Wireless Sensor Networks at 2.4 GHz
Publication . Oliveira, Tiago E. S.; Reis, João R.; Vala, Mário; Caldeirinha, Rafael F. S.
In this paper, high performance antennas are pro-posed for massive deployment of wireless sensor networks (WSN) for early fire dectection in forested areas. A differential slotted microstrip patch antenna and a Quasi-Yagi microstrip antenna are proposed to be implemented in a WSN at 2.4 GHz (ISM band). Firstly, a microstrip Quasi-Yagi antenna has been studied and optimised to operate at 2.4 GHz, which is sough to be deployed as part of a sectorized base-station. The antenna is comprised of one reflector and six directors around a microstrip patch to create an end-fire radiation pattern. According to simulations, the optimised antenna reaches a gain of 9.41 dBi and a half-power beamwidth of 70° at 2.44 GHz, with a operating frequency band from 2.27 to 2.83 GHz. For the sensor node, a very small differential slotted microstrip patch antenna is proposed, which has been redesigned and optimised to operate at 2.4 GHz. The proposed design takes advantage of slotted resonant elements in order to reduce the overall size of the antenna. Simulation results ensure a realised gain of 4.15 dBi at 2.44 GHz and an operating frequency band from 2.37 to 2.5 GHz. The results present in this paper were performed by using the simulation software CST-MWS.
High-Gain Wideband Parasitic Microstrip Antenna for 5G and IoT at 26 GHz
Publication . Oliveira, Tiago E. S.; Gonçalves, João F.; Reis, João R.; Vala, Mário; Caldeirinha, Rafael F. S.
In this paper, a high-gain wideband parasitic microstrip antenna, for 5G and IoT applications at 26 GHz, is presented. Firstly, a single antenna, composed of a miniaturised parasitic patch antenna, has been studied, characterised and optimised to operate at 26 GHz, aiming at the 5G new radio (NR) frequency range 2 (FR2) band n258. The proposed antenna uses eight microstrip patches as parasitics, in a squared layout, surrounding a central probe-fed patch. The patches operating as parasite elements are coupled by the magnetic and electric field created by the central active patch. According to simulations, a single optimised array antenna has a total dimension of 24×24 mm2, corresponding to 2.1 × 2.1 λ of the operating frequency, exhibiting an effective gain of 14.4 dBi and total bandwidth 4.15 GHz (16.29%), after optimisation in CST MWS.
On the Practical Limitations of Scalable Electronic 2D Beamsteering Using Metamaterials at Micro and Millimetre-wave Frequencies
Publication . Vala, Mário; Reis, Joao R.; Caldeirinha, Rafael F. S.
In this paper, the practical limitations of scalable electronic two-dimensional (2D) beamsteering using metamaterials at Micro- and Millimetre-wave frequencies, are addressed. In particular, the practical effects of using varactor diodes on a metamaterial-based beamsteering transmitarray, are studied and characterised, at four different frequencies of interest: 5, 14, 28 and 60 GHz. The parasitic effects intrinsic to such components, namely the internal resistance and internal inductance, are being studied. A thorough parametric analysis in CST Microwave Studio is conducted, in order to ascertain how the varactor's parasitics affect the frequency response, insertion loss, bandwidth and maximum achieved phase shift and consequent beamsteering resolution, at the proposed frequencies. The parametric study targets the parasitic resistance and inductance values of varactor diodes commercially available, making this study useful for any RF transmitarray implementation.
Unidades organizacionais
Descrição
Palavras-chave
Wireless sensor network,RF CMOS sensor node,Ultra low power,Environment monitoring, Engineering and technology
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia, I.P.
Programa de financiamento
Concurso para Financiamento de Projetos de Investigação Científica e Desenvolvimento Tecnológico em Todos os Domínios Científicos - 2017
Número da atribuição
PTDC/EEI-EEE/30539/2017