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This research constructs a 26 GHz waveguide slot antenna with decent gain. The application of millimeter-wave requires high bandwidth and gain to increase the traffic and users for millimeter-wave and 5G technology. The application of millimeter waves requires a high gain and bandwidth to achieve the requirements of traffic and users increasing for 5G technology and existing millimeter-wave. High-gain and power handling are provided by waveguide slot antennas. Three waveguide structures which are two waveguide antennae and a waveguide horn have been simulated by using CST and fabricated by a 3D printer. The tilt technique has been used with a waveguide to increase the bandwidth and gain of an antenna. A waveguide with broad wall tilt slots has one diction beam while a waveguide with broad and narrow wall tilt slots has two direction beams, each length of the wall enough to distribute six symmetric tilt slots. The gain of 14.3 dB and 1.9 GHz bandwidth are recorded for an antenna with broad wall tilt slots with one beam. While the waveguide with broad and narrow wall tilt slots achieved a gain of 13.9dB and a bandwidth of 1.9 GHz. The proposed antenna is a decent candidate for use with millimeter waves. [ABSTRACT FROM AUTHOR]

This paper focuses on the design of a multibeams antenna using waveguide slots technology at Xband. The multi-beams radiation is proposed to expand the coverage of the single antenna, thus more capacity is enabled. Waveguide slots antenna is a well-known antenna for high power and gain transmission capabilities. Therefore, it is preferred. In this work, four variations of waveguide slots antennas are studied. The slot distribution covers one to four broad and narrow walls of the waveguide. This technique enables multibeams patterns. The performance of the proposed antennas is simulated using CST microwave software. The simulated responses of the antennas show that a good matched with return loss greater than 10 dB at the desired frequency. The four proposed antennas achieved a good gain between 6.3 and 7.4 dB with directional beamwidth of 15 degree. The proposed antennas are suitable for implementing in radar applications. [ABSTRACT FROM AUTHOR]

This paper describes the development of a Fractal printed Yagi-Uda antenna for wireless local area network (WLAN) applications operating at 2.4 GHz frequency. In miniaturizing the dimensions of an antenna, fractal method is applied where the first iteration and second iteration is implemented. The Computer Simulation Technology (CST) software is used as the platform to design and simulate the antenna. The substrate material used is the FR-4 board which has a dielectric constant of 5.4, the thickness of 1.6 mm and tangent loss of 0.019. The antenna performance interm of the reflection coefficient, radiation pattern and gain are compared and analyzed. For the first iteration, 22.81% of reduction size has been achieved and 30.81% reduction of the antenna size for second iteration has been achieved. [ABSTRACT FROM AUTHOR]

A single layered metamaterial structure with capabilities of switching from a wideband metamaterial absorber to an AMC reflector and vice versa is presented in this paper. A flame retardant 4 substrate with physical thickness of 1.60mm was used. The absorption rate, reflection rate, reflection phase and surface current distribution were studied and discussed. The operational incidental wave angles were varied from 0° to 65°. A peak reflection of about 90% was achieved at 11.20 GHz with a usable bandwidth (-90 to +90) of 3.01 GHz by the AMC reflector. The metamaterial absorber demonstrated a wideband performance (from 8.10 GHz to 14.30 GHz). It achieved 100% absorption at 11.20 GHz and not less than 65% absorption across the entire X-band frequencies except for incidental wave angles above 55°. [ABSTRACT FROM AUTHOR]

This paper proposes the correction of faulty sensors using a synthesis of the greedy sparse constrained optimization GSCO) technique. The failure of sensors can damage the radiation power pattern in terms of sidelobes and nulls. The synthesis problem can recover the wanted power pattern with reduced number of sensors into the background of greedy algorithm and solved with orthogonal matching pursuit (OMP) technique. Numerical simulation examples of linear arrays are offered to demonstrate the effectiveness of getting the wanted power pattern with a reduced number of antenna sensors which is compared with the available techniques in terms of sidelobes level and number of nulls. [ABSTRACT FROM AUTHOR]

In this paper, a mutual coupling study is conducted between two-element array antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on dual substrate are constructed with one of them is incorporated with three EBG unit cell on the bottom substrate. The radiating patch is on the top substrate, while the EBG unit cell is on the bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements are closely separated by a distance of 22 mm with a significant reduced mutual coupling of - 26.61 dB. This corresponds to a distance reduction of 34.68%. The proposed structure implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG with the antenna is also presented. [ABSTRACT FROM AUTHOR]

In this paper, a simple method is proposed to diagnose the position of the damaged sensors. The position of the damaged sensors is diagnosed on the basis of the null depth level and the number of nulls for the degraded radiation pattern. The method is initiated with tabulation of the array radiation pattern with a single damaged sensor. The corresponding pattern is set as the reference to the radiation pattern of the failed sensors. The tabulated damaged array sensors are compared to a configuration of the assumed damaged sensor. The radiation pattern with deeper null depth level will be the location of the damaged sensor. Moreover, the symmetrical sensor damaged (SSD) technique diagnose the position of damaged sensor, in which on the basis of nulls one can detect the location of damaged sensors. The proposed method diagnoses the location of damaged sensors on the basis of pattern without complex computation as compared to available methods. [ABSTRACT FROM AUTHOR]

ABSTRACT A dual band Artificial Magnetic Conductor (AMC) with capacitive tuning of reflection phase at lower band frequency is proposed. The AMC operates at upper band of fixed frequency at 5.8 GHz while the lower band reconfigurable frequency is from 2.5 GHz up to 3.1 GHz. The simulated reconfigurable frequencies are 2.5, 2.62, and 3.10 GHz. The corresponding resonance structure for each band is circular patch and circular slotted ring with single capacitor per AMC unit cell. Subsequently, the AMC is incorporated with conventional UWB antenna. The effects of AMC capacitive tuning to UWB antenna performance are studied in terms of frequency reconfigurability, gain, and radiation patterns. Measurement is also carried out for the reflection coefficient and radiation patterns. Parametrical studies of the antenna such as the misalignment between the top and bottom substrate layers, air gap between the substrate layers, and capacitance tolerance of the capacitor to the reflection coefficients are also discussed. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2422-2429, 2016 [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a technique to enhance the bandwidth of a rectangular dielectric resonator antenna using a circular slot. The structures are designed and simulated using CST Microwave Studio software, and it is found that the circular slot exhibits a bandwidth of 36.44% (0.92-1.33 GHz). The circular slot is compared with the rectangular slot. It is shown that the rectangular slot produces a bandwidth of 6.39% (1.06-1.13 GHz). Both structures exhibit similar radiation patterns with slightly different gains at 3.10 and 3.25 dBi. The bandwidth is enhanced more than five times using the circular slot, compared to the rectangular slot. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:506-509, 2016 [ABSTRACT FROM AUTHOR]

ABSTRACT A composite right-/left-handed transmission line metamaterial antenna with enhanced bandwidth and efficiency is proposed. The antenna combines zeroth-order resonant (ZOR) and positive-order resonant (POR) modes for the bandwidth enhancement. An asymmetrical coplanar waveguide technique is used to feed the antenna and also to achieve certain degree of compactness. The overall size of the antenna is 0.32λ0 × 0.38λ0 × 0.012λ0 (40 × 48 × 1.52 mm) at 2.4 GHz. Simulation results show that a bandwidth enhancement of 41% is obtained with the radiation efficiencies of 95 and 97% for the ZOR and POR modes, respectively. The measured impedance bandwidth shows that the antenna has potential applications for WLAN (2.39-2.45 GHz) and WiMAX (2.5-2.69 GHz) operations. The simulated and measured antenna performances in terms of return loss and the radiation patterns are presented and compared. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:252-256, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a duals-band metamaterial antenna with a new composite right/left-handed (CRLH) unit cell configuration is proposed. The antenna is a coplanar waveguide (CPW) base which uses quarter wave resonators without via. Both sides of the CPW ground plane are short circuited to the CRLH-transmission line. The dimension is 31 mm × 22 mm × 1.52 mm, with electrical size of 0.23 λo × 0.17 λo × 0.011 λo at 2.26 GHz, and which is compact in size. Resonance frequency of the negative mode can be altered by controlling the loop currents. Peak gains of 1.74 and 2.69 dBi are obtained at 2.26 and 2.89 GHz. Radiation efficiencies of 64% and 92% are obtained at 2.26 and 2.89 GHz, respectively. The simulated and measured return losses, as well as the radiation patterns, are presented and compared. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1575-1579, 2014 [ABSTRACT FROM AUTHOR]

This article presents the design, simulation, and fabrication of a new planar left-handed metamaterial (LHM), which consist of a combination of a modified square rectangular split ring resonator and strip wire. Both structures are on the same plane. The structure is simulated and measured with the microstrip antenna operating at frequency 5.8 GHz. The LHM has been analyzed using Nicolson-Ross-Weir approach to obtain the negative permeability and permittivity at 5.8 GHz. The fabrication of the LHM is on FR-4 board substrate. From the simulation and measurement results, the gain of the microstrip antenna with LHM has increased by 4.0 dB. The return loss of the antenna with LHM is improved to 15.7 dB compare without LHM structure. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2828-2832, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27186 [ABSTRACT FROM AUTHOR]

A novel frequency and pattern reconfigurable Yagi antenna is proposed. The antenna is formed by a driver, a reflector and two directors. The introduction of switches using a PIN diode at the arms of the driver element produces three switchable frequencies at 1.25 GHz, 1.85 GHz and 2.45 GHz. By controlling the switches at the directors and reflector, the radiation pattern can be configured to near omni-directional pattern or directional pattern at those three frequencies. Simulated and measured results are used to demonstrate the performance of the antenna. The simulated and measured return losses and the radiation patterns, are presented and compared. It was found that the gain of the antenna increases from 3.3 dB to 5 dB in a directional pattern, when compared to the near omni-directional pattern. [ABSTRACT FROM AUTHOR]

A novel hybrid dielectric resonator antenna (DRA) excited by a printed monopole antenna is proposed and implemented. This new microstrip-fed fork-like stepped monopole antenna is designed to obtain a wide impedance bandwidth from 2 to 6 GHz. A quad-band characteristic is achieved by incorporating two modified cylindrical dielectric resonators with a high dielectric constant of 80, on top of the monopole exciter. Measured results demonstrated that the proposed DRA can be used in multiband wireless operations, covering GSM, PCS, UMTS, WLAN, and WiMax systems, from 1.75 to 5.85 GHz. Experimental and simulation results show a good agreement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2887-2890, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26407 [ABSTRACT FROM AUTHOR]

In this article, the design of log periodic fractal Koch antenna using the second iteration has been developed for ultra high frequency band applications. The ability to reduce the size as maintaining the performances of the antenna such as input return loss and radiation patterns brings fractal Koch and becomes enticing among researchers. The design of the log periodic fractal Koch antenna has been elaborated in this article. The computer simulation technology software has been used to analyze the performances of the designed antenna. This has been compared between simulation and measurement. The results show that this antenna has been reduced by up to 27% in size from the normal log periodic planar dipole antenna. The performance of the antenna has been compared in terms of return losses, bandwidths, and radiation patterns. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26111 [ABSTRACT FROM AUTHOR]

An innovative technique involving the usage of a mushroom Electromagnetic Band Gap (mEBG) structure with an ultra wideband (UWB) antenna is reported in this work. A single unit of mEBG lattice is incorporated within a novel UWB antenna to perform the band rejection operation. The antenna can be fixed to reject or reduce the transmit power for any band within the UWB spectrums of frequencies through a careful design of this mEBG structure, thus solving the problems concerning interference and reducing the requirements for complex filtering electronics within the UWB devices. [ABSTRACT FROM AUTHOR]

A textile artificial magnetic conductor (AMC) waveguide sheet with a textile diamond dipole is proposed to improve wireless on-body transmission. The sheet-like waveguide provides an independent transmission path which can reduce the performance degradation caused by the human body. The proposed AMC sheet is made entirely of textiles for both the substrate and the conducting parts, thus making it suitable for wearable communications. Transmission characteristics between antennas are studied rigorously in free space and on-body environments. Significant transmission enhancement is observed for all the tested orientations and positions for both free space and onbody placements. With the presence of the AMC, the S21 has peaks of up to a maximum of -9.9 dB. This textile AMC sheet constitutes a new approach for efficient wearable wireless body-centric communications. [ABSTRACT FROM AUTHOR]

This work presents a 28 GHz Dual Element Multiple Input Multiple Output (MIMO) Planar Inverted-F Antenna for millimeter wave 5G mobile terminal. The antenna design employs PIFA design concept as it is a common antenna type use for mobile phone as it provides wide bandwidth and good performance. The antenna design begins with a characterization of the single element PIFA design and then extended to Dual Element MIMO PIFA design. The single element PIFA design is enhanced to MIMO design by extending the ground plane and locate the second PIFA at the other end. Isolation between the antenna elements of the MIMO PIFA is analyzed by varying the gap distance between the antenna elements. The result for Envelope Correlation Coefficient, Diversity Gain and Multiplexing Efficiency is also presented. The simulation computed using Computer Simulation Technology (CST) Microwave Studio software. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application. [ABSTRACT FROM AUTHOR]

TGFBI-related corneal dystrophy (CD) is characterized by the accumulation of insoluble protein deposits in the corneal tissues, eventually leading to progressive corneal opacity. Here we show that ATP-independent amyloid-β chaperone L-PGDS can effectively disaggregate corneal amyloids in surgically excised human cornea of TGFBI-CD patients and release trapped amyloid hallmark proteins. Since the mechanism of amyloid disassembly by ATP-independent chaperones is unknown, we reconstructed atomic models of the amyloids self-assembled from TGFBIp-derived peptides and their complex with L-PGDS using cryo-EM and NMR. We show that L-PGDS specifically recognizes structurally frustrated regions in the amyloids and releases those frustrations. The released free energy increases the chaperone’s binding affinity to amyloids, resulting in local restructuring and breakage of amyloids to protofibrils. Our mechanistic model provides insights into the alternative source of energy utilized by ATP-independent disaggregases and highlights the possibility of using these chaperones as treatment strategies for different types of amyloid-related diseases.ATP-independent amyloid-β chaperone L-PGDS disaggregates corneal amyloids in surgically excised human cornea of TGFBI-related corneal dystrophy patients by recognizing and releasing structurally frustrated regions. [ABSTRACT FROM AUTHOR]

The demand for health technology is increasing especially in the telemetry applications. These applications generally use implanted antennas to be utilized for data transfer from patients to other reader devices. This procedure can make the health care more efficient since it provides fast diagnosis and treatment to the patient. Therefore, in order to effectively implement an implanted antenna inside the human body, thorough numerical analysis and simulations are required prior to the fabrication of antenna. In this work, an implanted antenna has been proposed to be designed at 402.5MHz within the biomedical frequency band of 402-405MHz. By introducing a compact loop antenna for telemetry applications in a Pacemaker, a number of advantages can be achieved for health care such as efficient data information and quick diagnosis. Moreover, in this work an investigation of compact loop antenna with casing in Pacemaker has been carried out by placing the antenna inside the phantom of human body model. [ABSTRACT FROM AUTHOR]

Wideband-multiband reconfigurable elliptical monopole antenna is investigated in this paper. By having conventional elliptical monopole antenna, wideband operating frequency is obtained. With the combination of dual pairs of slotted arms and a band-pass filter on the ground plane of the elliptical monopole, multiband is achieved. Dual-band operating frequencies at 1.6 GHz and 2.6 GHz while wideband operates from 3.35 GHz to 9 GHz. Therefore, wide range of wireless communication systems is obtained from the proposed antenna to support the multiband mode (i.e. GPS and LTE) and UWB systems. Frequency reconfigurable is achieved by controlling the switches integrated on the antenna structure. Simulated results of reflection coefficient, radiation patterns and gain performance are presented. The proposed antenna design is suitable candidate for different wireless communication applications. [ABSTRACT FROM AUTHOR]

ABSTRACT A wideband antenna fed by a coplanar waveguide (CPW) with reconfigurable function is presented. The wideband function is achieved from 1.39 GHz to 8.11 GHz using an elliptical radiator with a CPW feed line. Meanwhile, three pairs of slot dipoles which are fed by CPW are used to achieve triple-band function at 2.4 GHz, 3.5 GHz and 5.2 GHz. Four ideal switches are placed on the proposed antenna. The proposed antenna is designed, simulated, fabricated and tested. All simulated and measured results of return loss, radiation pattern and gain are presented. Good results of return loss and radiation pattern are obtained thus verifying that the proposed antenna is suitable for future multimode radio systems. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2079-2082, 2016 [ABSTRACT FROM AUTHOR]

ABSTRACT A new reconfigurable multiband antenna is presented. The antenna operates in triple band and can be switched to operate either in single or dual band. The multifrequency band is achieved by using slots dipole antenna fed by a coplanar waveguide (CPW). Six switches are used and positioned at specific locations in the slots to achieve frequency reconfigurability. The antenna reconfiguration is realized when the dipole arms are coupled or decoupled from the slot edges. Three different sub-band frequencies (2.40, 3.50, and/or 5.20 GHz) are obtained. Measured and simulated results are presented. The proposed antenna may be suitable for future multimode applications such as cognitive radio systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:735-740, 2014 [ABSTRACT FROM AUTHOR]

A slot dipole antenna with a reconfigurable operating frequency is presented. The antenna comprises two pairs of slot arms. Each arm incorporates a number of varactor diodes. The antenna is capable of operating in single-band or dual-band mode. In each case, the location of these bands can be altered by varying the voltage applied to the varactor diodes. The antenna can be tuned over a wide frequency range, namely 1.5-4.5 GHz (i.e. a ratio of 3:1). The antenna is potentially useful for cognitive radio application, particularly in a small base station or access point terminal. [ABSTRACT FROM AUTHOR]