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1 – 10 of 49Mohammad Pourbagher, Changiz Ghobadi, Javad Nourinia and Rahim Naderali
To achieve right-hand circular polarization (RHCP), a 3-dB Wilkinson power divider with a λ/4 phase shifter is used. The crossed-dipoles are placed at almost λ/4 elevation on the…
Abstract
Purpose
To achieve right-hand circular polarization (RHCP), a 3-dB Wilkinson power divider with a λ/4 phase shifter is used. The crossed-dipoles are placed at almost λ/4 elevation on the ground plane and connected to two coaxial cables. Experiments show that the impedance bandwidth of 49.40% (913.7–1,513.1 MHz) and axial ratio bandwidth (ARBW) of 22.88% (1,145.8–1,441.8 MHz) are achieved.
Design/methodology/approach
In this study, a wideband crossed-dipole antenna with circularly polarized (CP) radiation for L-band satellite and radar applications is presented. The proposed CP antenna comprises two orthogonally placed printed dipoles, a quadrature coupler and a box-shaped ground plane.
Findings
Furthermore, by fixing the box-shaped ground plane under the radiators, 5.13 dBic RHCP peak gain at 1,300 MHz and maximum half-power beamwidth (HPBW) of 84.5° at 1,170 MHz are realized for the antenna.
Originality/value
Eight metallic walls are connected to four corners of the substrate to stabilize the radiation properties in this study. Results show that the ARBW and front-to-back ratio are improved and the maximum HPBW around 127° across the operating frequency band is achieved. The proposed CP antenna is a good candidate for Global Positioning System (GPS) L2 (1.227 GHz), GPS L5 (1.176 GHz) and air route surveillance radar system at 1,215–1,390 MHz frequency band.
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Henridass Arun and Gulam Nabi Alsath M.
This paper aims to present the design and implementation of a circularly polarized co-planar waveguide (CPW) fed wideband pie-shaped monopole antenna for multi-antenna techniques…
Abstract
Purpose
This paper aims to present the design and implementation of a circularly polarized co-planar waveguide (CPW) fed wideband pie-shaped monopole antenna for multi-antenna techniques. Multi-antenna techniques are promising solutions for higher data rate and enhanced reliability of wireless applications. They find numerous applications in 4G/5G networks and in most wireless standards such as wireless local area networks (WLAN), wireless fidelity and worldwide interoperability for microwave access systems to enhance the channel capacity without additional spectrum by means of multi-path propagation techniques.
Design/methodology/approach
The antenna is designed to operate at three WLAN frequency bands of 4.8, 5.2 and 5.8 GHz. The measured 10 dB impedance bandwidth of the proposed antenna element is 1.2 GHz (24.23 per cent). The proposed CPW fed, pie-shaped monopole antenna has a gain of 5.4 dB and an efficiency of 72.8 per cent at 4.8 GHz.
Findings
To use the proposed antenna in a multi-antenna environment, the antennas have to be placed in a close proximity to each other. The close proximity introduces strong mutual coupling between the antennas, which in turn degrades the performance of multi-antenna systems. A multi-antenna system with two antenna elements has been constructed with an edge to edge spacing of 0.24 λ0 (15 mm), and the mutual coupling level is −17 dB. To enhance the isolation between the antenna elements, a shorting pin-based interconnected semicircles enclosed decoupling structure is proposed, which improves the isolation by a factor of 12.67 dB at 4.8 GHz.
Originality/value
To validate the performance of the proposed multi-antenna in working environment, the performance metrics such as envelope correlation coefficient (ECC), diversity gain (DG) and total active reflection coefficient (TARC) are computed for the proposed multiple-input multiple-output (MIMO) antenna. The ECC value is 0.000366 at center frequency and below 0.09 for the entire operating bandwidth, which is well below the acceptable level of 0.5 as per 3GPP standard. The DG value lies above 9.5 dB for the entire operating bandwidths and it is well above the minimum value of 3 dB. The TARC values are calculated based on S parameters, and it proves that the proposed antenna a good candidate for the multi-antenna systems.
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Payam Beigi, Yashar Zehforoosh, Mirhamed Rezvani and Javad Nourinia
This paper aims to present a new triangular crinkle-shaped multiband antenna for multiband operation.
Abstract
Purpose
This paper aims to present a new triangular crinkle-shaped multiband antenna for multiband operation.
Design/methodology/approach
This paper refers to increasing the number of resonance frequency by appending triangular crinkle. Experimental frequency results of the presented antenna are 1.60/2.80/4.00/5.80/7.12/8.32/10.06 GHz.
Findings
The triangular shaped antenna is manufactured on a low-priced FR-4 substrate with small size and tested. The reported antenna with full size 14 × 14 mm2 with a half elliptical ground sheet on the bottom plane of the substrate and a triangular crinkle strip patch in the front of the substrate. The reported antenna has dual polarized, by rectangular slits on the ground sheet can produce the CP radiation on ITU band. The radiation characteristics indicate the mentioned antenna plays good task for multiband structures. Simulation and measured consequences are in desirable agreement and refer to agreeable operation for the introduced antenna.
Originality/value
Also, an evaluation is done based on multiple attribute decision-making method for comparison the proposed monopole antenna with some previously presented multiband monopole antennas.
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Sasireka Perumalsamy, Kavya G. and Rajkumar S.
This paper aims to propose a two-element dual fed ultra-wideband (UWB) multiple input multiple output (MIMO) antenna system with no additional decoupling structures. The antenna…
Abstract
Purpose
This paper aims to propose a two-element dual fed ultra-wideband (UWB) multiple input multiple output (MIMO) antenna system with no additional decoupling structures. The antenna operates from 3.1 to 10.6 GHz. The antenna finds its usage in on-body wearable device applications.
Design/methodology/approach
The antenna system measures 63.80 × 29.80 × 0.7 mm. The antenna radiating element is designed by using a modified dumbbell-shaped structure. Jean cloth material is used as substrate. The isolation improvement is achieved through spacing between two elements.
Findings
The proposed antenna has a very low mutual coupling of S21 < −20 dB and impedance matching of S11 < −10 dB. The radiation characteristics are stable in the antenna operating region. It provides as ECC < 0.01, diversity gain >9.9 dB. The antenna offers low average specific absorption rate (SAR) of 0.169 W/kg. The simulated and measured results are found to be in reasonable match.
Originality/value
The MIMO antenna is proposed for on-body communication, hence, a very thin jean cloth material is used as substrate. This negates the necessity of additional material usage in antenna design and the result range indicates good diversity performance and with a low SAR of 0.169 W/kg for on-body performance. This makes it a suitable candidate for textile antenna application.
Ramakrishna Guttula and Venkateswara Rao Nandanavanam
Microstrip patch antenna is generally used for several communication purposes particularly in the military and civilian applications. Even though several techniques have been made…
Abstract
Purpose
Microstrip patch antenna is generally used for several communication purposes particularly in the military and civilian applications. Even though several techniques have been made numerous achievements in several fields, some systems require additional improvements to meet few challenges. Yet, they require application-specific improvement for optimally designing microstrip patch antenna. The paper aims to discuss these issues.
Design/methodology/approach
This paper intends to adopt an advanced meta-heuristic search algorithm called as grey wolf optimization (GWO), which is said to be inspired by the hunting behaviour of grey wolves, for the design of patch antenna parameters. The searching for the optimal design of the antenna is paced up using the opposition-based solution search. Moreover, the proposed model derives a nonlinear objective model to aid the design of the solution space of antenna parameters. After executing the simulation model, this paper compares the performance of the proposed GWO-based microstrip patch antenna with several conventional models.
Findings
The gain of the proposed model is 27.05 per cent better than WOAD, 2.07 per cent better than AAD, 15.80 per cent better than GAD, 17.49 per cent better than PSAD and 3.77 per cent better than GWAD model. Thus, it has proved that the proposed antenna model has attained high gain, leads to cause superior performance.
Originality/value
This paper presents a technique for designing the microstrip patch antenna, using the proposed GWO algorithm. This is the first work utilizes GWO-based optimization for microstrip patch antenna.
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Sari Merilampi, Toni Björninen, Leena Ukkonen, Pekka Ruuskanen and Lauri Sydänheimo
The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high‐frequency radio frequency identification…
Abstract
Purpose
The purpose of this paper is to develop a wireless strain sensor for measuring large strains. The sensor is based on passive ultra high‐frequency radio frequency identification (RFID) technology and it can be embedded into a variety of structures.
Design/methodology/approach
Silver ink conductors and RFID tags were printed by the screen printing method on stretchable polyvinyl chloride and fabric substrates. The development of the strain‐sensitive RFID tag was based on the behavior of the selected antenna and substrate materials. Performance of the tags and the effect of mechanical strain on tag functioning were examined.
Findings
The results showed that large displacements can be successfully measured wirelessly using a stretchable RFID tag as a strain‐sensitive structure. The behavior of the tag can be modified by selection of the material.
Research limitations/implications
New tag designs, which are more sensitive to small levels of strain and which have a linear response will be the subject for future work. Tag performance under cyclic loading and in a real environment will also be investigated. Future work relating the investigation of practical applications and the system designing for the strain sensor will also be required.
Practical implications
Printing is fast and simple manufacturing process which does not produce much waste or material loss. The sensor is a new application of printed electronics. It also provides new opportunities for system designers.
Originality/value
The paper provides a new kind of wireless strain sensor which can be integrated into many structures (i.e. clothes). The sensor is a new application of printed electronics and it is made from novel materials.
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Dhanalakshmi K.M., Kavya G. and Rajkumar S.
This paper aims to propose a single element, dual feed, polarisation diversity antenna. The proposed antenna operates from 2.9 to 10.6 GHz for covering the entire ultra-wideband…
Abstract
Purpose
This paper aims to propose a single element, dual feed, polarisation diversity antenna. The proposed antenna operates from 2.9 to 10.6 GHz for covering the entire ultra-wideband (UWB) frequency range. The antenna is designed for usage in massive multiple input multiple output (MIMO) and closed packaging applications.
Design/methodology/approach
The size of the antenna is 24 × 24 × 1.6 mm3. The radiating element of the antenna is derived from the Sierpinski–Knopp (SK) fractal geometry for miniaturization of the antenna size. The antenna has a single reflecting stub placed between the two orthogonal feeds, to improve isolation.
Findings
The proposed antenna system exhibits S11 < −10 dB, S21 < −15 dB and stable radiation characteristics in the entire operating region. It also offers an envelope correlation coefficient < 0.01, a diversity gain > 9.9 dB and a capacity loss < 0.4 bps/Hz. The simulated and measured outputs were compared and results were found to be in similarity.
Originality/value
The proposed UWB-MIMO antenna has significant size reduction through usage of SK fractal geometry for radiating element. The antenna uses a single radiating element with dual feed. The stub is between the antenna elements which provide a compact and miniaturized MIMO solution for high density packaging applications. The UWB-MIMO antenna provides an isolation better than −20 dB in the entire UWB operating band.
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Kasturi Sudam Patil and Elizabeth Rufus
The paper aims to focus on implantable antenna sensors used for biomedical applications. Communication in implantable medical devices (IMDs) is beneficial for continuous…
Abstract
Purpose
The paper aims to focus on implantable antenna sensors used for biomedical applications. Communication in implantable medical devices (IMDs) is beneficial for continuous monitoring of health. The ability to communicate with exterior equipment is an important aspect of IMD. Thus, the design of an implantable antenna for integration into IMD is important.
Design/methodology/approach
In this review, recent developments in IMDs, three types of antenna sensors, which are recommended by researchers for biomedical implants are considered. In this review, design requirements, different types of their antenna, parameters and characteristics in medical implants communication system (MICS) and industrial, scientific and medical (ISM) bands are summarized here. Also, overall current progress in development of implantable antenna sensor, its challenges and the importance of human body characteristics are described.
Findings
This article give information about the requirements of implantable antenna sensor designs, types of antennas useful to design implantable devices and their characteristics in MICS and ISM bands. Recent advancement in implantable devices has led to an improvement in human health.
Originality/value
The paper provides useful information on implantable antennas design for biomedical application. The designing of such antennas needs to meet requirements such as compact size, patients’ safety, communication ability and biocompatibility.
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Bokang Patrick Motjolopane and Robert van Zyl
Distributed wireless sensor networks (DWSNs) are applied in a variety of applications that can enhance the quality of human life. Batteries are the predominant source of energy in…
Abstract
Purpose
Distributed wireless sensor networks (DWSNs) are applied in a variety of applications that can enhance the quality of human life. Batteries are the predominant source of energy in DWSNs. One of the key obstacles in the adoption of DWSNs technology is the limited lifetime of batteries in microsensors. Recharging or replacing depleted batteries can significantly increase costs in DWSNs. The purpose of this paper is to address, through a thorough review, this power challenge in DWSNs and to evaluate a 16‐element equiangular spiral rectenna to harvest ambient microwave energy in real‐life scenarios to supply indoor DWSNs.
Design/methodology/approach
The paper focuses on the practical implementation of a rectenna that can be used in electromagnetic energy harvesting. The design and measurement of the rectenna follows a broad overview of rectenna designs reported in the literature.
Findings
The paper concludes that the 16‐element equiangular spiral rectenna has the potential to generate power that enables long periods of operation of the DWSNs without human intervention in the power management process, thus reducing maintenance and administration costs.
Originality/value
Research into electromagnetic power harvesting is very limited in the South African context. The paper presents a concise overview of existing power harvesting techniques that will benefit novice researchers in the field of electromagnetic energy harvesting. It concludes with the performance characterisation of a spiral array rectenna.
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The purpose of this manuscript is to present a novel, compact and ultra-thin “3”-shaped monopole antenna for wireless operations in the laptop computer. The thickness of the…
Abstract
Purpose
The purpose of this manuscript is to present a novel, compact and ultra-thin “3”-shaped monopole antenna for wireless operations in the laptop computer. The thickness of the antenna is only 0.2 mm and is designed using only a pure copper strip of size 17.5 × 6 mm2.
Design/methodology/approach
The simple structure of the proposed antenna consists of two monopole radiating strips, namely, AC and CD and an open-ended rectangular tuning stub BE of length 9mm.
Findings
This structure inspires two resonating modes at 3.45 and 5.5 GHz and achieves the measured impedance band width as 20% (3.21-3.91) GHz in lower band (F_l) and 15% (5.05-5.85) GHz in the upper band (F_u) for voltage standing wave ratio < 2. These two bands cover 5GHz wireless local area network (WLAN) and 3.3-3.6GHz (sub 6GHz) 5G bands. The measured radiation performance including, nearly omnidirectional radiation patterns, a stable gain of around 5 dBi and excellent efficiency around 90% in both operating bands have been achieved. Furthermore, a simplified equivalent circuit model has been derived and its simulation is performed. The simulated and measured results are in good agreement, which demonstrates the applicability of the antenna structure for WiMAX/WLAN operations in the prominent ultra-thin laptop computers.
Originality/value
The proposed antenna is designed without using any reactive elements, vias or matching circuits for excitation of WLAN and 5G bands in the laptop computers. The design also does not require any additional ground for mounting the antenna. The proposed antenna has a very low profile, is ultra-thin, cost-effective, easy to manufacture and can be easily embedded inside next generation laptop computers.
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