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A new antenna of a triple-broadband operation is proposed for digital TV reception and sub-7 GHz 5G applications. The structure made up of an L-shaped printed antenna, it comprises of two asymmetrical sections, which are separated by an inner C-shaped slot of width 1.0 mm. Both sections are connected together through a shorting strip. This new configuration employs a direct coaxial feed to excite both, a C-shaped inner-slot and the two asymmetrical sections. Several resonant modes' frequencies are excited, in which adjacent modes are merged to achieved three broadband operations: 470-1700 MHz, 3100-4800 MHz, and 5100-7000 MHz. A prototype is fabricated and tested. Experimental results of the reflection coefficient, total radiation efficiency, and radiation patterns are all presented, discussed, and compared to other designs in the current-state-of-the-art. Thus, this work represents a promising compact antenna candidate for all current wireless applications ranges from 470 MHz to 7000 MHz. [ABSTRACT FROM AUTHOR]

Power amplifier is one of the main components in the RF transmitters. It must provide various stringent features that can lead to complicating the design. In this paper, a new optimizing method based on the inclined planes system optimization algorithm is presented for the design of a discrete power amplifier. It is evaluated in a 2.4-3 GHz power amplifier, which is designed based on "Cree's CGH40010F GaN HEMT". The optimization goals are input and output return losses, Power Added Efficiency, and Gain. Large signal simulation of the optimized power amplifier shows a good performance across the bandwidth. In this frequency range, the input and output return losses are about lower than - 10 dB, the Power Added Efficiency is greater than 51%, while the Gain is higher than 13.5 dB. A two-tone test with a frequency space of 1 MHz is applied for the linearity evaluation of the designed power amplifier. The obtained result shows that the power amplifier has good linearity with a low memory effect. [ABSTRACT FROM AUTHOR]

In mobile and portable wireless application where wireless devices regularly change their position and angle it is almost unmanageable to continuously match the spatial orientation of the devices. Circularly polarized antennas could be harmonized in wide-ranging range of angles. The Microstrip antenna is some of the best commonly used antennas in applications that need circular polarization. This work offers the proposal of a circularly polarized Microstrip antenna that will work for 2.4 GHz. This range is normally used by WLAN, WPAN devices such as the 802.11 WIFI and the 802.15.4 Zigbee. We achieved polarization through the introduction of a perturbation to a basic circular Microstrip patch. Results indicate that designed Microstrip fed antenna can produce 8.11 dB directive gains. [ABSTRACT FROM AUTHOR]

This paper is concerned with dual-band electronically beam-scanning for millimeterwave (mm-wave). A design encompassing slotted square patch antenna with an Active Frequency Selective Surface (AFSS) screen is presented. Each unit cell of AFSS is constructed of spiral arms endorsed with four varactors to enhance a wide tuning range over dual modes. Among many other features, the design supports dual operation bands at 48.5 and 68.5 GHz which is considered without any 90° phase shifter and is excited by a single-feed microstrip line. The overall size of the proposed antenna is only 3.93.90.1 mm3, which is smaller than some mm-wave antenna modules released recently. The whole structure is an ideal option for wireless applications due to its ability to scan its primary beam in dual-band throughout the whole azimuth plane with a resolution of 60°. The proposed structure can sweep beams throughout the whole 360° angular range and is capable of both dual-band and single-band beam sweeping with high gain, making it an excellent choice for 5G mm-wave applications. [ABSTRACT FROM AUTHOR]

A novel compact Ultra-Wide-Band Planar Inverted- L antenna is presented and investigated in this paper. The proposed antenna consists of a square planar radiating element with a U-shaped slot. The radiating element is supported by a shorting wall, and fed by a single 50 Ohms characteristic impedance microstripe line, printed on the top of the FR-4 substrate. The ground plane of the antenna is printed on the other side of the substrate. The entire antenna occupies only a small volume of 20mm x 35mm x 4mm, and is capable of operating from 4.2GHz to 8.6GHz (68.75%) and offers a maximum gain of 5.24dB. Therefore, it is suitable for UWB systems and other wireless and mobile technologies and, thus, can be integrated into smartwatch, mobile phones, tablets and laptops. The design of this antenna was carried out using 3D software such as CST studio and Ansoft HFSS to compare and validate the results. [ABSTRACT FROM AUTHOR]

Quality of Service (QoS) requirements are possible with actual transmission of updates for wireless applications typically included in mission critical applications such as military use or disaster recovery. This research paper proposes an efficient Secure Quality Oriented Distributed (S-QOD) Secure Enhanced Adaptive 3 Acknowledgment (S-EA3ACK) and implements a new on-demand wireless intrusion detection system. S-QOD can improve a best performance of output quality (QoS) to reduce transmission delay, transmission time and also increase network communication throughput for S-EA3ACK using Enhanced Adaptive Acknowledgement (EAACK) DSA (Digital Signature Algorithm) with MAJE4 symmetric cryptography specially designed for MANET through Network Simulator-2.34 (NS2) to implement it. [ABSTRACT FROM AUTHOR]

In this paper, a novel engineered tetra band microstrip antenna is designed for wireless applications. The proposed antenna is printed on flame-retardant fiberglass epoxy (FR-4) substrate with the dimensions of 40mmx40mmx1.6mm and ground plane etched with rectangular split ring defected ground structure (RSRDGS). The RSRDGS unit cell is used to miniaturize the designed antenna as well as for multiband resonance. The proposed antenna resonates at tetra band frequency points i.e., 3.1GHz, 4.1GHz, 5.1GHz, and 9.8GHz with satisfactory bandwidth of 209MHz, 313MHz, 168MHz, and 195MHz respectively. The total peak gain at tetra band frequency points are 8.54dB, 7.65dB, 1.79dB, and 4.65dB as well as 48% of virtual size miniaturization is achieved. The proposed antenna results make it suitable to use for S-band to X-band wireless applications. [ABSTRACT FROM AUTHOR]

In this paper, super-wideband antenna with reconfigurable characteristics for multiple wireless applications is investigated. Proposed antenna consists of guitar shape radiating patch and chamfered rectangular ground plane with rectangular slot. In order to mitigate the interference caused by existing wireless system (WiMAX, WLAN and downlink satellite system), reconfigurable band stop filters corresponding to interfering bands are generated on the radiating patch by using RF PIN diodes. Antenna covers super-wideband of 3.36–39.61 GHz (ratio bandwidth of 11.78:1) with overall of the dimension 27 × 32 × 0.787 mm3 and occupies comparably less space. Antenna is also investigated in frequency, time and spatial domain with nearly stable radiation patterns with suppression of gain and efficiency at interfering bands. [ABSTRACT FROM AUTHOR]

Abstract A CPW-fed circular polarization reconfigurable antenna is proposed in this paper. The antenna consists of two symmetrically placed inverted L-shaped slots. By using a T-type bias device to change the bias states of two PIN diodes which connect the two slots with the feed port respectively, right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) can be realized accordingly. For both states, the measured −10 dB impedance bandwidth is 5.78–5.96 GHz, while the measured 3 dB axial ratio bandwidth is 5.64–5.91 GHz (4.7%), both the bandwidths can cover the 5.8 GHz ISM band. By using floating ground and reflector board to enhance the front to back ratio of the antenna, 6.84 dBi measured gain can be realized at 5.8 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a compact ultra-wideband (UWB) multiple-input multiple-output (MIMO) spatial diversity antenna with dual band-notches designed on an FR4 substrate is proposed and experimentally investigated. The antenna consists of two radiating elements fed by two tapered microstrip lines. Two inverted L-shaped slits are used to introduce notches at WLAN (5.15-5.85 GHz) and IEEE INSAT/Super-Extended C-band (6.7-7.1GHz). An isolation of more than 15 dB is achieved through the whole working band (2.9-10.8 GHz) by introducing a T-shaped decoupling structure on the ground plane. Furthermore, the envelope correlation coefficient (ECC), diversity gain (DG), multiplexing efficiency, TARC, peak gain and radiation patterns of theMIMO antenna are also discussed. The simulated and measured results show that the proposed UWB MIMO antenna is a good candidate for UWB diversity applications. [ABSTRACT FROM AUTHOR]

A hybrid Minkowskized fractal-like antenna structure for wireless application is presented in this paper. The Minkowskized radiating structure and feed line have been designed at the top layer of the FR-4 substrate (tan(δ) = 0.02, εr = 4.3, h = 1.6). A modified ground plane with a parasitic patch is etched at the bottom side of the dielectric substrate. The fabricated antenna exhibits the resonance at frequencies 0.83, 1.05, 1.6, 2.12, 3.25, 3.75 and 5.2 GHz. It covers six bands of frequencies band-1 (0.825-0.835 GHz), band-2 (0.913-1.22 GHz), band-3 (1.33-1.79 GHz) band-4 (2.04-2.18 GHz) band-5 (2.9-3.91 GHz) and band-6 (4.9-5.64 GHz) for |S11| ≤ -10 dB which are suitable for several wireless communication bands (i.e., GSM 900 MHz, 1800 MHz, Wi-MAX, Wi-Fi 802.11y and WLAN 802.11b/g/a). The surface current distribution and radiation pattern have been studied at resonating frequencies. [ABSTRACT FROM AUTHOR]

Consider a scenario where Alice wishes to send a message m to Bob in a time-slotted wireless network. However, there exists an adversary, Carol, who aims to prevent the transmission of m by jamming the communication channel. There is a per-slot cost of 1 to send, receive or jam m on the channel, and we are interested in how much Alice and Bob need to spend relative to Carol in order to guarantee communication. Our approach is to design an algorithm in the framework of resource-competitive analysis where the cost incurred by correct network devices (i.e., Alice and Bob) is parameterized by the cost incurred by faulty devices (i.e., Carol). We present an algorithm that guarantees the successful transmission of m and has the following property: if Carol incurs a cost of T to jam, then both Alice and Bob have a cost of O(Tφ-1+1)=O(T.62+1) in expectation, where φ=(1+5)/2 is the golden ratio. In other words, it possible for Alice and Bob to communicate while incurring asymptotically less cost than Carol. We generalize to the case where Alice wishes to send m to n receivers, and we achieve a similar result. Our findings hold even if (1) T is unknown to either party; (2) Carol knows the algorithms of both parties, but not their random bits; (3) Carol can jam using knowledge of past actions of both parties; and (4) Carol can jam reactively, so long as there is sufficient network traffic in addition to m. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid design of Sierpinski Carpet and Minkowski antenna for wireless applications. The hybrid antenna is designed, simulated and fabricated on an FR4 substrate with thickness 1.6mm and dielectric constant 4.4. The dimensions of antenna are 45 × 38.92 × 1.6mm3 which operates at various frequencies 3.43GHz, 4.78GHz, 6.32GHz, 8.34GHz and 9.64GHz, and can be used for Wi-Max, C-band applications, Point-to-point Hi speed wireless communication and X-band (satellite Communication) applications. The measured results are also compared with the simulated ones which are in agreement with each other. Ansoft High Frequency Structure Simulator (HFSS) is used to design and simulate the antenna. [ABSTRACT FROM AUTHOR]

Wireless mesh networks with directional antennas are expected to be a new promising technology and an economic approach for providing wireless broadband services in rural areas. In these networks, the effective use of multiple non-overlapping channels can significantly enhance the network capacity by allowing more concurrent transmissions. However, the performances of wireless mesh networks are severely degraded by interference between links with overlapping channels in nearby areas. In this paper, we address the issue of joint utilization and balance in channel assignment for rural wireless mesh networks. We design a new channel assignment framework with the goal of optimizing the channel resource utilization across the entire network while taking balanced allocation into account. This balanced channel assignment allows for the costeffective reuse of channels without a consequent loss of quality in the rural wireless mesh networks. We also evaluate the proposed framework on some Cartesian product graphs that are popular interconnection network topologies. The framework guarantees that these topologies require a small number of channels for balanced allocation. [ABSTRACT FROM AUTHOR]

Neighbor discovery (ND) is a critical primitive for 60-GHz wireless networks with highly directional radios. Prior work has attempted to improve the ND efficiency but overlooks the unique properties of 60-GHz phased-array antennas and spatial channel profile. In this paper, we first conduct a systematic study of the ND problem using a reconfigurable 60-GHz radio. Combined with an analytical model, we find that environmental characteristics and client mobility substantially affect 60-GHz ND latency, and due to inherent spatial channel sparsity of 60-GHz channels, even short-distance links can experience intolerable latency. To solve these new challenges, we propose a mechanism called FastND that accelerates ND by actively learning the spatial channel profile. FastND leverages steerability of 60-GHz phased-array antennas and accumulates channel information by overhearing beacon preambles along different beam directions. Using a compressive sensing framework, together with a strategical beam selection mechanism, FastND can infer the strongest spatial angle to listen to, thereby increasing the likelihood to quickly decode beacons and achieve ND. Our testbed experiments and ray-tracing tests demonstrate that FastND can reduce 802.11ad ND latency to 1/10–1/2, with different levels of mobility, human blockage, environmental sparsity, and non-line-of-sight links. [ABSTRACT FROM AUTHOR]

Drilling engineering is technology-intensive and involves many subjects and large amounts of data. To improve the quality of production and management, decisions need to be made based on the latest data to direct the work on-site. Therefore, it is necessary to establish a safe, reliable, and efficient drilling management system that can meet daily production requirements. In this study, we describe a real-time monitoring system of field data. The system comprises real-time collection of borehole drilling parameters, ground drilling parameters, on-site video and borehole position data, and wireless data transmission to site and rear managers. The system is based on real-time monitoring of field data, the recognition and prediction of the conditions inside the borehole, the wireless transmission of data, and rear-base data analysis and feedback modules. The rear managers can view the real-time and historical drilling data at any time and compare and analyze drilling data by using the rear software of the management system to optimize the drilling program and feedback to the site. The application of the management system in production suggests that it can significantly improve drilling efficiency, reduce drilling costs and accidents in wells, and improve the automation of drilling operations. Moreover, at the same time, it can also predict complex conditions and drilling accidents in time and provide reliable real-time data to drilling technicians for on-site decision making. [ABSTRACT FROM AUTHOR]

The wireless technology plays a vital role in various fields such as aerospace, home appliances and global positioning system etc. This is important, especially in a biomedical wireless communication, which communicates wirelessly with patient control device for monitoring and external communication. It reduces the invasiveness range of test and discomfort of some invasive procedure such as endoscopy etc. Wireless communication has taken for supporting mobility while monitoring vital body function in hospitals, clinical diagnosis, remote repository system and gastrointestinal tract exploration etc. The Brushless DC motor (BLDC) is ideal for these applications of wireless communication due to their easiness of control, low maintenance, high efficiency and reliability. The BLDC motor placed in these devices, which allow variable speed and motion to acquiring the required data. In this paper, a novel control strategy for controlling the speed of BLDC motor, which fill the need of medical analyzer, is presented. The results are compared with other recently published work in terms of various performance specifications. [ABSTRACT FROM AUTHOR]

A multiband rectangular microstrip patch antenna integrated with angled split- ring artificial magnetic conducting (AMC) structure is proposed. In order to achieve high gain, directivity and radiation efficiency, an 3×2 array of proposed angled split-ring patches which has multiple in-phase reflection phase characteristics at S-band (2-4 GHz) is presented as a reflector. A rectangular microstrip patch antenna integrated with the proposed angled split-ring AMC is fabricated, tested and its parameters are compared with the microstrip patch antenna backed with a flat metal sheet, and microstrip patch antenna integrated with conventional split-ring AMC structure. The presence of high scattered field amplitude between the angled arms lead to improved radiation characteristics and make the antenna more suitable for real-time wireless applications. The antenna attains 2.138 dBi increment in gain and 1.87 dBi increment in directivity when it is backed with the proposed angled split-ring artificial magnetic conducting structure instead of a flat metal sheet. A good pact is obtained between the simulated and the measured results. [ABSTRACT FROM AUTHOR]

Abstract: A novel four‐port multiple‐input‐multiple‐output (MIMO) antenna with high isolation is proposed in this article. This antenna is fabricated on a FR4 substrate with a compact size of 84 mm × 26 mm × 1.6 mm (0.98λ × 0.3λ × 0.019λ, λ is the wavelength at 3.5 GHz). The design adopts curved slot‐lines on both sides of the substrate to enhance the isolation level and radiation in the working bands. The measured results show that the fabricated prototype can cover the working bands of advanced TD‐LTE, WiLAN/WiFi, and cognitive radio applications with good radiation pattern characteristics. Furthermore, the isolation among multiple ports exceeds 15, 28, and 16 dB in the three working bands respectively, and high channel capacities could be achieved by this four‐port design. [ABSTRACT FROM AUTHOR]

Low frequency communication, taking advantage of the features of low frequency electromagnetic signals in near field, is widely used in through-the-earth (TTE) wireless applications. However, the low frequency non-Gaussian noise severely limits the communication performance. In this paper, an adaptive noise cancellation algorithm based on time delay estimation (ANC-TDE) and maximum correntropy criterion (MCC) is proposed. The explicit time delay estimation algorithm based on MCC (MCC-ETDE) is used to estimate the time-varying delay and the noise correlationship between the primary input and reference inputs. With a reference noise selected and time delay compensated, the non-Gaussian noise is canceled by adaptive filter based on MCC. The proposed algorithm is implemented on field programmable gate array (FPGA) and the performance is evaluated by simulation and experiment. As shown in the results, the ANC-TDE algorithm can reduce the complexity of ANC filter and adaptively compensate the varied time delay between the primary input and reference input. With the time delay compensated, the ANC-TDE algorithm has better performance in non-Gaussian noise environment and is more suitable for real-time systems. [ABSTRACT FROM AUTHOR]

A highly miniaturized significant gain triple band patch antenna loaded with a new modified double circular slot ring resonator (MDCsRR) metamaterial unit cell is presented in this paper. New MDCsRR is a compact low frequency slot ring resonator. The principle of the proposed patch antenna element is based on adding series capacitance to decrease the half wavelength resonance frequency, thus reducing the electrical size of the proposed patch antenna. The transmission line model is used to analyze passband and stopband characteristics of the radiating bands. Circulating current distribution around MDCsRR slot with increased interdigital capacitor finger length causes multiple modes to propagate. The MDCsRR metamaterial unit cell consists of a new modified circular slot ring resonator (MCsRR) with metallic strip finger. The proposed structure is compact in size with radiating element dimensions of 0.20λ×0.20λ×0.008λ at first resonating frequency. The proposed antenna offers triple band operation with significant calculated antenna gain of 3.28 dBi at first center frequency of 3.2 GHz, 2.76 dBi at second center frequency of 5.4 GHz and 3.1 dBi at third center frequency of 5.8GHz. The electrical size of the proposed antenna is miniaturized by about 68.83% as compared to the conventional patch antenna operating at first resonating frequency. [ABSTRACT FROM AUTHOR]

Human beings reflect nomadic behaviour as they keep on travelling place to place whole day for personal or organizational purposes. The inception of modern networking technologies and the advent of wide range of applications in terms of services and resources have facilitated the users in many ways. The advancements in numerous areas such as embedded systems, WN (Wireless Networks), mobile and context-aware computing, anticipated pervasive computing dominated the human communication at large. Pervasive computing refers to the environment where information is accessible anywhere and anytime while existing system is invisible to the user. On the other hand, the invisibility of pervasive computing is also a problem in its adoption as users are unaware when and what devices collect their personal data and how it is being used. It has caused new security chaos as the more information about user is collected the more privacy and security concerns it raises, thus, the pervasive computing applications became key concern for user. This paper is aimed at analyzing the security and protection issues that arise while traveling from place to place connected with wireless mobile networks. The paper reviews many existing systems that offer possible security to pervasive users. An easy, precise and relative analysis and evaluation of surveyed pervasive systems are presented and some future directions are highlighted. [ABSTRACT FROM AUTHOR]

In this paper, a novel multiband microstrip patch antenna with small frequency ratio is designed and analysed. One can design a multiband antenna at any desired frequencies through these proposed methods. The proposed antenna shows six operating frequencies with very small frequency ratio between two consecutive resonant frequencies 1.1248, 1.1123, 1.0792, 1.1469 and 1.3254 and can be used for various wireless applications, i.e., 2.5 GHz for UMTS and Wi-Fi, 2.812 GHz for CCTV with wireless video links, 3.128 GHz and 3.376 GHz for WiMAX, 3.872 GHz for C-band applications and 5.132 GHz for Lower WLAN. Design procedure and formation of all six bands are presented and discussed. Analysis is done by Ansoft HFSS v. 15 which is based on Finite Element Method (FEM), and simulated results are verified with experimental results of fabricated prototypes which are found in close agreement. [ABSTRACT FROM AUTHOR]

Abstract: This article presents a novel compact size (20 mm × 16 mm × 0.8 mm) Tai‐chi‐shaped antenna for wireless applications. Dual frequency operation (3.14–4.58 GHz and 4.97–6.53 GHz) is achieved by optimizing the antenna during designing steps. The antenna gives circulary polarization from 3.26 to 4.42 GHz and from 5.45 to 6.63 GHz frequency ranges. The 4.2 dBic stable gain is another evident advantage of proposed work. [ABSTRACT FROM AUTHOR]

In this paper, a wide stop-band microstrip coupler is presented. The proposed structure consists of coupled lines and step impedance cells, which are integrated to operate at 2.82 GHz for wireless applications. This coupler is formed by a symmetric structure so that the locations of the output ports relative to input are quite similar. Accordingly, the magnitudes (also phases) of S21 and S31 overlap each other so that input signal can be selected through the output ports equally. There are little differences between the magnitudes and phases of S21 and S31 so that 0.97° phase shift is obtained. In comparison with previous works, the performance of the introduced coupler is improved. To get a better isolation, return loss and harmonic attenuation the frequency response is optimized without significant increase in circuit size. Moreover, the first, second and third harmonics of S21 and S31 are well attenuated as well as a wide stop-band is obtained up to 15.1 GHz. The realized coupler is fabricated and measured. There is a good agreement between simulated and measured results, which confirms the design process. [ABSTRACT FROM AUTHOR]

A miniaturized UWB antenna with multiple notch bands is proposed for modern wireless applications. The proposed microstrip-line-fed antenna consists a Y-shaped strip supported by defected ground structure. Procedure of bandwidth enhancement with multiple notch bands is presented. 163.6% of impedance bandwidth ranging from 1.5 to 15 GHz with three notch bands at 3-3.6, 6-6.8 and 9.2-9.8 GHz is achieved with gain of 2-6 dBi within the band. Accurate equivalent circuit model is presented for proposed antenna structure. Proposed antenna shows good radiation characteristics with very large bandwidth including three notch bands and suppressed cross-polarization level up to − 35 dB. The designed antenna is tested experimentally and measured results are verified with the simulated and theoretical results. [ABSTRACT FROM AUTHOR]

This paper presents design of Compact Hybrid Multiband Antenna (CHMA) for various wireless applications. The projected antenna geometry is designed by integrating moore and gosper curves and their characteristics are investigated. The antenna reveals multiband behavior along with satisfactory values of all performance parameters in spite of less complexity and compact size. The small cost simulated antenna is designed on FR4 substrate, which shows gain of 16.65 dB along with return loss of −18.39 dB and VSWR of 1.27 at 2.4 GHz frequency. Simulated results exhibits six operational bands that cover various significant frequency bands like Air traffic control RADAR (0.96-1.215 GHz), GSM (1.85-1.99 GHz), Wi-Fi (2.4 GHz for 802.11b, 802.11n and 802.11g), WLAN 802.11a/b (5.15-5.35 GHz), WLAN 802.11ac (5.5 GHz) and military satellite applications (7.9-8.4 GHz). The simulation results of antenna in terms of antenna parameters like Return Loss (RL), radiation pattern, Voltage Standing Wave Ratio (VSWR) and Gain (G) are evaluated using HFSS (High Frequency Structural Simulator); v13 software. The hybrid antenna is designed with line feed having compact size of 55 mm (L) × 60 mm (W) × 1.6 mm (H) on FR4_epoxy substrate with ε 4.4. Both simulated and measured results are analyzed, compared and presented in the paper. Proposed antenna operates from 0.98 to 8.1 GHz and covers L, S, C and X band applications. [ABSTRACT FROM AUTHOR]

In this article, an Ultra Wide Band (UWB) monopole antenna based on Metamaterial (MTM) unit cell with reconfigurable feature has been developed. The proposed antenna covers 3.1–10.6 GHz for UWB applications and it has a reconfigurable narrow-band for L-band (1.27 GHz) and wireless applications. The gaps in Split Rings Resonator (SRR) element are made for the Left-hand capacitance and Ω-shape strip layer by four via junctions are used for Left-hand inductance. The antenna is printed on FR-4 low cost substrate with relative permittivity of 4.4 and thickness of 1.6 mm. The total size of the antenna is 40 mm × 40 mm. The simulation is carried out using HFSS commercial full-wave software. In addition, the experimental results are presented and compared with simulated results. The antenna gives a maximum peak gain of 6 dBi with Omni-Directional radiation pattern and high efficiency of more than 70%. By embedding four switches in Ω-shape strip layer, a reconfigurable antenna has been successfully designed for wireless applications with sufficient qualification. The monopole part covers the UWB spectrum and the CRLH is responsible for the controllable narrowband resonance. The simulation and experimental results are confirmed by the numerical results. [ABSTRACT FROM AUTHOR]

To ameliorate high collision, a nefarious side effect of route discovery stage of reactive routing protocols in wireless networks, jitter mechanisms are proposed which enforce wireless nodes to postpone their transmission for a random amount of time so as to reduce probability of simultaneous transmission. Although it has been shown that jitter mechanisms can dramatically improve reactive routing protocols, it was not until recently that jitter mechanisms have been subjected to study. In this paper, different random distributions are proposed for jittering mechanisms and also shaping function, with the aim of which a simple routing protocol like AODV becomes sensitive to any arbitrary metric, is defined. Comprehensive simulation of routing metrics and jitter mechanisms have revealed that simple modification of a jitter mechanism, which can be even implemented independent of a routing protocol, greatly improves routes discovered by any routing protocol. [ABSTRACT FROM AUTHOR]

This paper proposes a tripple-band microstrip antenna. The proposed antenna is designed to operate at Bluetooth (2.4-2.485 GHz), WiMAX (3.3-3.7 GHz) and WLAN (5.15-5.35 GHz, 5.725-5.825 GHz) bands. The antenna consists of a straight microstrip feed line and an inverted assymetric T shaped slot at ground plane. The microstrip feed line acting as quarter wave monopole is responsible for obtaining WiMAX band and the slot of ground plane is responsible for obtaining Bluetooth and WLAN band. The simulated and measured results have good agreement. [ABSTRACT FROM AUTHOR]

Dual-polarised triple-band multi-beam multiple input multiple output (MIMO) antennas are evaluated for wireless local area network/worldwide interoperability for microwave access (WLAN/WiMAX) access points. The dual-polarised antenna consists of two identical crossed triple-band dipoles each of which is printed on each side of a square substrate, forming a compact planar configuration. The triple-band dual-polarised antenna is placed above a metal reflector to achieve high gain and directional radiation patterns. Measured results show that the dual-polarised triple-band antenna covers the WLAN 2.4-GHz band, WiMAX 3.5-GHz band, and WLAN 5-GHz bands with return loss >10 dB and isolation >20 dB. An eight-port MIMO antenna, a four-beam MIMO antenna and a 32-port four-beam MIMO antenna are investigated for high-capacity and widecoverage wireless applications in high-density environment. [ABSTRACT FROM AUTHOR]

This paper presents very close and high isolation composite right left handed transmission line MIMO antennas. The MIMO antennas consist of two elements each operates at 5.8 GHz for wireless applications. The two antenna elements are designed using one composite right left handed unit cell separated by only 0.034 λ. The reduction of mutual coupling between the two antenna elements depends on current reversal between two antenna elements. The proposed MIMO antennas have the advantage of compactness (its size is only 3 × 2.6 cm). In order to evaluate the performance of MIMO antennas, analysis of mutual coupling, correlation coefficient, diversity gain and total active reflection coefficient are presented. The proposed antennas can achieve isolation = 45 dB and envelope correlation = 0.0002 at 5.8 GHz. The simulated results are confirmed by the measurement results. [ABSTRACT FROM AUTHOR]

This study proposes a novel square-circle structure fractal multibroadband planar antenna, similar to an ancient Chinese coin-like structure, for second generation (2G), third generation (3G), fourth generation (4G), WLAN, and navigation wireless applications. The device is based on the principles and structural features of conventional monopole antenna elements, combined with the advantages of microstrip antennas and fractal geometry. A fractal method was presented for circular nested square slotted structures, similar to an ancient Chinese copper coin. The proposed antenna adapted five iterations on a fractal structure radiator, which covers more than ten mobile applications in three broad frequency bands with a bandwidth of 70% (1.43–2.97 GHz) for DCS1800, TD-SCDMA, WCDMA, CDMA2000, LTE33-41, Bluetooth, GPS (Global Positioning System), BDS (BeiDou Navigation Satellite System), GLONSS (Global Navigation Satellite System), GALILEO (Galileo Satellite Navigation System), and WLAN frequency bands, 16.32% (3.32–3.91 GHz) for LTE42, LTE43, and WiMAX frequency bands, and 10.92% (4.85–5.41 GHz) for WLAN frequency band. The proposed antenna was fabricated on a 1.6 mm thick G10/FR4 substrate with a dielectric constant of 4.4 and a size of 88.5 × 60 mm2. The measurement results reveal that the omnidirectional radiation patterns achieve a gain of 1.16–3.75 dBi and an efficiency of 40–72%. The good agreement between the measurement results and simulation validates the proposed design approach and satisfies the requirements for various wireless applications. [ABSTRACT FROM AUTHOR]

ABSTRACT In the present work, a metamaterial-based insulator is proposed as a mean to achieve both highly compact and loosely coupled array of antennas. Its main working principle is summarized through a general qualitative analysis. The theoretical results are supported by experimental evidences. The chosen operating frequency is 2.4 GHz considering that it is a usual frequency for many indoor wireless applications. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1420-1423, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT A non-orthogonal frequency shift keying (NOFSK) modulation technique, which increases the bandwidth efficiency of an optical wireless link based on a yellow phosphor coated-light emitting diode (ypc-LED), is proposed in this article. A 4-NOFSK signal is transmitted using an optical wireless link based on the ypc-LED. One more bit per symbol are transmitted successfully showing the only 3% increase of 2-MHz physical bandwidth at the bit error rate (BER) below 10−5. It is implied that the bandwidth efficiency is increased twice as much as ypc-LED modulated by off keying (OOK) signal. Furthermore, there was no ICI effect at the frequency spacing of 2 kHz (0.1% of 2-MHz physical bandwidth), which corresponds to 0.1% of the symbol rate of 2 Msymbols/s. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1371-1375, 2017 [ABSTRACT FROM AUTHOR]

Trustworthy, efficient and low-latency communications are arguably the most crucial factors in mobile Peer-to-Peer (P2P) network. In this paper, we present trustworthy multi-point relays data dissemination model for mobile objects in wireless ad-hoc environments. The proposed data delivery model is designed to work in conjunction with our SeCuRE trustworthy scheme and mobile scheduling techniques, forming a novel integrated framework to disseminate messages amongst mobile peers. We evaluate the proposed framework on a number of key metrics for mobile environment, including; transmission cost, computational cost, latency and message deliverability performance. The results of our experiments are used to make comparisons with current state-of-the-art techniques, namely; pure flooding and Trustworthiness-based Broadcast ( TBB ) scheme, from which the effectiveness of our proposed approach is identified. [ABSTRACT FROM AUTHOR]

Mobile Ad hoc Networks (MANETs) are becoming indispensable and ubiquitous in future due to proliferation of laptops and mobile phones. These short lived networks are an effective solution in emergency conditions. These networks can be created anytime, everywhere by portable wireless devices such as smart phones and laptops without any installation and infrastructure cost. Distant mobile nodes communicate with each other with cooperation of other nodes which relays communication packets by acting as routers. Due to freely movement of mobile nodes independently in any direction, routing is a challenging issue in ad-hoc network. Different routing protocols have been introduced for discovering and maintaining a route in ad hoc network. These routing protocols are of three categories viz. table driven, reactive and hybrid protocols. In our paper, we have used AODV and DSR routing protocol to find efficient and shortest route in MANET. Our simulation results demonstrate that AODV routing protocol outperforms DSR routing protocol in terms of packet delivery ratio and throughput. [ABSTRACT FROM AUTHOR]