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Author

Noor Asniza Murad

Other affiliations: University of Birmingham
Bio: Noor Asniza Murad is an academic researcher from Universiti Teknologi Malaysia. The author has contributed to research in topics: Antenna (radio) & Microstrip antenna. The author has an hindex of 14, co-authored 121 publications receiving 738 citations. Previous affiliations of Noor Asniza Murad include University of Birmingham.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a frequency reconfigurable microstrip patch switchable to slot antenna is proposed, which is capable of frequency switching at nine different frequency bands between 1.98 and 3.59 GHz.
Abstract: A frequency-reconfigurable microstrip patch switchable to slot antenna is proposed. The antenna is capable of frequency switching at nine different frequency bands between 1.98 and 3.59 GHz. The patch is resonating at 3.59 GHz, while the slot produces eight different operating frequencies between 1.98 and 3.41 GHz. Five RF p-i-n diode switches are positioned in the slot to achieve frequency reconfigurability. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses, together with the radiation patterns, are presented.

159 citations

Journal ArticleDOI
TL;DR: In this paper, a multiband Fractal Koch dipole textile antenna is proposed for wearable applications, which is designed to operate at 0.9GHz, 2.45GHz and 5.8GHz.
Abstract: A multiband Fractal Koch dipole textile antenna is proposed for wearable applications. The antenna is designed to operate at 0.9GHz, 2.45GHz and 5.8GHz. Denim materials as the substrate are selected aiming to obtain robustness, ∞exibility and a lightweight textile antenna. The antenna model is designed, simulated, optimized and analyzed using Microwave Studio CST software. Two types of multiband antenna prototypes are fabricated and evaluated with difierent conducting elements (Shield It fabric and copper foil tape). Antenna performance is observed in terms of return loss, bandwidth, radiation pattern and realized gain. Three difierent comprehensive analyses are taken into consideration: measurement antenna with difierent bending sizes, on-body measurement and under wet conditions. The antenna performances are evaluated based on resonant frequency (fo) and bandwidth (BW). The antennas performance with bending on the human body (arm & forearm) is compared and investigated. A suitable placement on the body has been discovered between the chest and backside. The antennas have also been tested under wet conditions to ensure a stable characteristic under the in∞uence of water.

49 citations

Journal ArticleDOI
TL;DR: In this article, the authors present an extensive review of the Butler Matrix (BM) based beamforming networks, and discuss 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.
Abstract: Due to the rapid development of wireless communication technologies, the number of wireless users are radically increasing. Currently, $\sim 23$ 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.

43 citations

Journal ArticleDOI
TL;DR: The technical perspective discusses the theoretical aspects, simulation design procedures, and the measurement setup used to characterize the AMC unit cell, and various recent works of antenna design that involve the incorporation of AMC are discussed thoroughly.
Abstract: Artificial Magnetic Conductor (AMC) is a type of implemented metamaterial in several antennae and microwave design applications. By utilizing the unique characteristics of metamaterials which do not exist naturally, the performance of various microwave devices can be enhanced. This article elaborates on the technical perspective and recent works on AMC for antenna applications. The technical perspective discusses the theoretical aspects, simulation design procedures, and the measurement setup used to characterize the AMC unit cell. Subsequently, various recent works of antenna design that involve the incorporation of AMC are discussed thoroughly. Each of the recent works is highlighted with specific performance enhancements that can be achieved with the introduction of AMC. The conventionally narrow band property of AMC, which is the bandwidth at which the radiation characteristics and directivity of the antenna can be manipulated, is discussed. The property limits the applications of AMC in wideband antenna applications. One of the techniques to improve the narrow band AMC as the ground plane is discussed in detail. The employment of AMC has solved many issues whilst overcoming the typical limitations in conventional antenna designs.

38 citations

Journal ArticleDOI
TL;DR: In this article, a small electrical metamaterial (MTM) antenna, based on a modified electrical coupled resonator for bandwidth enhancement, is presented, and the bandwidth enhancement is achieved using a modified electric coupled (MELC) resonator as the antenna's main radiating element.
Abstract: A small electrical metamaterial (MTM) antenna, based on a modified electrical coupled resonator for bandwidth enhancement, is presented. The bandwidth enhancement is achieved using a modified electric coupled (MELC) resonator as the antenna's main radiating element. This modification is achieved using two strip lines placed below a conventional electric coupled (CELC) resonator. The measured impedance bandwidth at -10 dB is 20.7% at a resonance frequency of 2.62 GHz. The design is validated by experimental results, and the proposed antenna is suitable for worldwide interoperability for microwave access (WiMax) applications (2.5-2.69 GHz).

29 citations


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Journal ArticleDOI

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TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

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Journal ArticleDOI
14 Feb 2020-Sensors
TL;DR: A survey aimed at summarizing the current state of the art regarding smart irrigation systems, which determines the parameters that are monitored in irrigation systems regarding water quantity and quality, soil characteristics and weather conditions.
Abstract: Water management is paramount in countries with water scarcity. This also affects agriculture, as a large amount of water is dedicated to that use. The possible consequences of global warming lead to the consideration of creating water adaptation measures to ensure the availability of water for food production and consumption. Thus, studies aimed at saving water usage in the irrigation process have increased over the years. Typical commercial sensors for agriculture irrigation systems are very expensive, making it impossible for smaller farmers to implement this type of system. However, manufacturers are currently offering low-cost sensors that can be connected to nodes to implement affordable systems for irrigation management and agriculture monitoring. Due to the recent advances in IoT and WSN technologies that can be applied in the development of these systems, we present a survey aimed at summarizing the current state of the art regarding smart irrigation systems. We determine the parameters that are monitored in irrigation systems regarding water quantity and quality, soil characteristics and weather conditions. We provide an overview of the most utilized nodes and wireless technologies. Lastly, we will discuss the challenges and the best practices for the implementation of sensor-based irrigation systems.

264 citations