Workers using an implantable cardioverter defibrillator (ICD) are classified by European Directive 2013/35/EU as being at particular risk because of the potential interference between implanted medical devices and electromagnetic fields. The aim of the study was to investigate ICD function using a human-shaped phantom in high magnetic fields of a shunt reactor at a 400 kV substation. We used the phantom in the following experiment periods: isolated from the ground, grounded by a foot, or grounded by a hand. We performed five ICD tests using five different ICD devices. In experiment place A, the magnetic field was over 1000 μT, and in experiment place B, the exposure was over 600 μT. We did not find any disturbances in the ICDs. However, we conducted only 5 ICD experiments in real exposure situations at 400 kV substations. Although it is not possible to draw a strong conclusion regarding risk level, the risk of such ICD disturbances from magnetic field exposure at 400 kV substations does not appear to be high.

A novel dual-band unidirectional circularly polarized (CP) antenna fed by coplanar waveguide (CPW) for wireless applications is proposed. The antenna configuration consists of a ring-shaped ground, an F-shaped central strip, and a spherical cap reflector. The longer and shorter branches of the F-shaped central strip help to produce radiant waves at lower and higher frequencies. The CP characteristics are achieved through adding two solid arcs and a grounded tuning stub. Both simulated and measured results are given and analyzed. Measurement results show a 10 dB return loss with a bandwidth of 56% (2.15 GHz-3.83 GHz) at 2.45 GHz (ISM), and a bandwidth of 42.6% (4.67 GHz-7.2 GHz) at 5.8 GHz (HiperLAN), a 3 dB axial ratio bandwidth of 15.1% (2.25 GHz-2.62 GHz), 4.1% (5.67 GHz-5.91 GHz). The maximum gain within the two CP bands are 8.7 dBic and 10.2 dBic, respectively.

An omnidirectional low-profile multiband antenna is designed and fabricated for vehicular telecommunication applications. The fabricated antenna with a radiator patch size of 0.26λ_L×0.3λ_L has a low-profile of 0.022λ_L and shows multiple resonant frequencies at 1.14, 1.91, and 2.45 GHz. Omnidirectional radiation patterns in the azimuth plane and vertical polarization at all operating frequency bands were obtained. Antenna gains greater than 1.7 dBi were obtained at the three operating frequencies, and the antenna height is 6 mm. Therefore, the proposed antenna is applicable to the vehicular telecommunication system.

Many government-led wind farms are being constructed in Korea as sources of clean and renewable energy. However, construction of these wind farms is continuously opposed by nearby military bases that operate X-band tracking radar because the amplitude and phase of the electromagnetic waves reflected from the wind turbines may interfere with tracking radars installed along the coastline of the Korean peninsula. This paper proposes a method to analyze the effect of a wind farm on tracking radar, and presents the results of using the radar cross section of the blade of a real turbine predicted by the method of physical optics. Simulation results using various flight scenarios demonstrate that the tracking accuracy may be considerably degraded; thus appropriate action is required to eliminate this effect.

Fundamental properties of carbon nanotube antenna are firstly investigated to predict the antenna bundle response. The carbon nanotube effects are mathematically introduced via a quantum mechanical conductivity. This paper presents a new formulation based on integral equations system to study the coupled carbon nanotube antennas. The proposed integral equations system is numerically solved by the moments method. Each dipole antenna is excited at its center by a gap voltage source. The aim of the developed method is to investigate the antennas interaction effects for any coupling distance. The obtained input impedances, the current distributions and the antenna radiation patterns are in agreement with those obtained by the effective conductivity method or by the array factor method, according to the coupling distances.

Transponders (also known as polarimetric active radar calibrators or PARCs) are commonly used for radiometric calibration of synthetic aperture radars (SARs). Currently three methods for the determination of a transponder's frequency-dependent radar cross section (RCS) are used in practice. These require either to measure disassembled transponder components, or a separate radiometric measurement standard (like a flat, metallic plate or a corner reflector), leading to additional uncertainty contributions for the calibration result. In this paper, a novel method is introduced which neither requires disassembly nor an additional radiometric reference. Instead, the measurement results can be directly traced back to a realization of the meter, lowering total measurement uncertainties. The method is similar in approach to the well known three-antenna method, but is based on the radar equation instead of Friis transmission formula. The suitability of the method is demonstrated by a measurement campaign for DLR's three new Kalibri C-band transponders, completed by an uncertainty analysis. The method is not universally applicable for all transponder calibrations because (a) three devices are necessary (instead of only one for the known methods), and (b) the transponders must provide certain additional features. Nevertheless, these features have become standard in modern SAR calibration transponder designs. The novel, potentially more accurate three transponder method is thus a viable alternative for transponder RCS calibration, ultimately contributing to synthetic aperture radars with a reduced radiometric measurement uncertainty.

We report, for the first time, a study on the biocompatibility of the poly(ethylene glycol)-thiol (PEG)-coated Au/Ag alloyed nanobox (PC-ANB) particles in zebrafish. We measured the mortality rate and the hatch rate of the zebrafish embryos injected with the PC-ANB particles and observed the distribution of the PC-ANB particles in the zebrafish embryos at different stages of growth development. The results show that the PC-ANB particles have negligible toxicity to the zebrafish embryos even at extra-high concentration (1.2 mg ml^-1), while uncoated Ag nanoparticles, used in the form of nanospheres or nanoplates, were found to cause embryo deformation or even death. Additionally, we have investigated the distribution of the PC-ANB particles within the zebrafish in the interest of studying their behavior in the zebrafish using imaging. For this, we used the three-photon luminescence imaging technique and it has been found that the PC-ANB particles mainly assemble in the backside muscle tissues of the zebrafish, suggesting that the PC-ANB particles are mostly metabolized out after about 96 hours of growth development.

In a previous paper, we have introduced an innovative approach called the self-adaptive correlation method (SACM). It consists in treating the reflectogram in order to amplify the signatures of soft defects and make them more easily detectable. This method allows to highlight the soft defect while attenuating the noise present on the reflectogram and has the advantage of reducing the computational complexity compared to the state of the art. We drew attention to the sensitivity of the performance of this method to noise. In this paper, we propose a solution for the pre-denoising of reflectogram before applying the SACM. This solution consists of an adapted version of the empirical mode decomposition algorithm, we called MEMD for Modified Empirical Mode Decomposition which bypasses some limitations of the conventional EMD.

A novel surface plasmon based square-shaped ring resonator with bending metaldielectric-metal input/output (I/O) waveguide at optical spectral range is investigated. The influence of various geometric parameters is studied in detail, with parallel finite difference time domain method. The results validate that vertical coupling disturbance can be efficiently suppressed by employing the modified I/O structure. The transmittance performance has all the resonant frequencies workable with better extinction ratios, higher finesse and higher Q-factors compared to the original plasmonic micro-ring resonator. From these analyses, it is found that the proposed waveguide is outstanding in aspects of the total field extinction and frequency selectivity characteristic.

In performing the experiments, the interference source has the form of a hollow PVC tube wrapped with a current-carrying coil, while the detector has the form of a PIN (Positive-Intrinsic-Negative) photodiode. The experimental results show that the electromagnetic disturbance (EMD) signal effect is dependent on the number of turns, the direction of the electromagnetic field, and the frequency and amplitude of the interference voltage. Specifically, it is shown that when the electromagnetic field acts in the opposite direction to that of the laser beam, the intensity and optical power of the detected signal decrease with an increasing interference frequency or amplitude. By contrast, when the electromagnetic field acts in the same direction as that of the laser beam, the intensity and optical power increase with an increasing interference frequency or amplitude. In addition, it is shown that the effect of EMD on the intensity of the laser beam increases with an increasing laser beam dispersion (i.e., an increasing distance from the laser source).

This paper proposes an imaging method of multi-direction swath and digital beamforming (DBF) in elevation for spaceborne Hybrid Phased-MIMO SAR that combines traditional phased-array radar with a new technique for multiple-input multiple-output (MIMO) radar to achieve multifunctional synthetic aperture radar (SAR). At first, we build a signal model and derive a virtual control matrix of the Hybrid Phased-MIMO SAR. Furthermore, considering the image overlap and range ambiguity caused by multiple direction imaging, we present adaptive Digital Beamforming based on Linearly Constrained Minimum Variance (LCMV). In this approach, the first constraint is dedicated to make the overall beamformer response equal the quiescent response in the desired signal region so that the signal is not cancelled when it is present, and additional constraints are included to assure proper reception of the desired signal and form nulls in the direction of interference at the same time. The diagonal loading method is combined with this method to reduce small eigenvalue interference for its eigenvector, which improves the convergence speed in sidelobe. The substantial improvements offered by the proposed adaptive Digital Beamforming technique as compared to previous techniques are demonstrated analytically and by simulations through analysis of the corresponding range compression results and achievable output performance of interference suppression. Simulation results validate the effectiveness of the adaptive DBF.

In the hyperthermia therapy, multiple microwave sources can be arranged with appropriate spacing around the tissue containing tumor by using left-handed material (LHM) lenses. We employ some low loss LHM lenses schemes for an effective non-invasive microwave hyperthermia treatment of large tumors up to several centimeters of depth inside the biological tissues. Different configurations of LHM lenses are proposed and compared in order to assess the efficiency of hyperthermia treatment. High-resolution focusing of microwave radiation can be achieved by joint heating of several microwave antennas behind a conformal flat LHM lens. We show that a microwave radiation can be effectively focused in a 1.2 cm diameter tumor located within a lossy breast tissue. The results show that hyperthermia (temperature over 42°) is reached and then maintained for one hour without involving the surrounding healthy tissues. Lastly, the heating area is adjusted in both lateral and longitudinal directions changing the position of the microwave sources or selecting LHM lenses with different thickness. This approach confirms that the conformal four-lens system is more efficient to achieve microwave tumor hyperthermia than single- and double-lens schemes.

In this paper, properties of three types of Circular Polarization Selective Surface (CPSS) cells including Pierrot, Morin, and Tilston, for using in dual circular polarization reflectarray antenna design are investigated. First they are designed for a center frequency about 10 GHz, and circular polarization properties including Reflection Loss, Transmission Loss, Reflected Axial Ratio, and Transmitted Axial Ratio are calculated and presented. Finally, reflection phase curves are presented, and the comparison between simulated properties is accomplished. Simulations show that Tilston cell is more optimum in dual circular polarization reflectarray antennasr

A compact balanced UWB bandpass filter (BPF) is proposed in this paper, which is based on the half-mode substrate integrated waveguide (HMSIW) and the differential defected ground structure (D-DGS). Using the HMSIW, the filter can achieve compact size, wide passband and good compatibility. Two D-DGS cells are employed to provide good suppression for the common-mode (CM) noise, while they have small effect on the performance of differential-mode (DM) signals. To validate the design theory, a microstrip balanced UWB BPF is designed, fabricated and measured to meet compact size, low insertion loss, good return loss as well as proper bandwidth. The predicted results are compared with measured data and show reasonable agreement.

An analytical expression of an Airy-Gauss beam passing through a fractional Fourier transform (FRFT) system is derived. The normalized intensity distribution, phase distribution, centre of gravity, effective beam size, linear momentum, and kurtosis parameter of the Airy-Gauss beam are demonstrated in FRFT plane, respectively. The influence of the fractional order p on the normalized intensity distribution, phase distribution, centre of gravity, effective beam size, linear momentum, and kurtosis parameter of the Airy-Gauss beam are examined in FRFT plane. The fractional order p controls the normalized intensity distribution, phase distribution, centre of gravity, effective beam size, linear momentum, and kurtosis parameter. The period of the normalized intensity, phase, and centre of gravity versus the fractional order p is 4. The period of effective beam size, linear momentum, and kurtosis parameter versus the fractional order p is 2. The periodic behaviors of the normalized intensity distribution, phase distribution, centre of gravity, effective beam size, linear momentum, and kurtosis parameter can bring novel applications such as optical switch, optical micromanipulation, and optical image processing.

In this paper, we propose novel omnidirectional UWB printed monopole antenna for in-body microwave imaging applications. The proposed antenna consists of a square radiating patch, a microstrip feed line and a ground plane with pair of rotated T-shaped slots and another T-shaped slot that placed in between of two slots. The designed antenna provides a wide usable fractional bandwidth of more than 136.5% (2.96-15.8 GHz). This antenna has the advantages of wide bandwidth, compact size, low cost, good omnidirectional radiation patterns, and acceptable time domain behavior for using in In-Body microwave applications. The maximum measured gain for the fabricated antenna is around 6.1 dBi with an average efficiency above 89% throughout the bandwidth.

A center-feed dual-band dual-polarized circular microstrip antenna employing the curved slots on the ground is proposed. The proposed antenna radiates φ-polarization by introducing 10 units of curved slots symmetrically on the ground and θ-polarization by the coaxial probe at the center. The measured results show that the proposed antenna provides two resonant bands, TM₀₁ and TM₀₂ modes, covering the frequency bands of the WLAN (2.4-2.484 GHz) with an omnidirectional right-handed circular polarized (RHCP) radiation pattern and the WiMAX (3.3-3.6 GHz) with an omnidirectional horizontal polarized radiation pattern, respectively. In addition, the effects of the unit number of the curved slots and the width of the slots on the frequency ratio of these two resonant frequencies are studied. Furthermore, for the low profile of 0.056 λ₀ and good omnidirectional characteristic, the antenna is suitable for the modern multi-band wireless communication systems.

The focusing properties of radially polarized hypergeometric Gaussian beam are studied using the Richards-Wolf vectorial diffraction model. Such a polarized beam is decomposed into radial and longitudinal polarization. With a proper combination of the beam order, beam size and imaginary parameter variables, the adjustably confined flat-topped focus and focal hole can be obtained in the focal region. Moreover, we got originality characteristic for the axial intensity distribution of two shaped symmetric light spots. The tight focusing of a hypergeometric Gaussian beam may find applications in data storage, laser drilling, optical trapping, etc.

Variety of designs for artificial magnetic materials have been proposed in the literature. in most designs such as split-ring resonators, the inductive and capacitive responses of metallic inclusions are dependent since the area and perimeter of the resonators' geometry cannot be tuned independently. In this work, three generic resonators for the design of artificial magnetic materials are proposed. The resonators are called rose curve resonator, corrugated rectangular resonator, and sine oval resonator. The proposed resonators' patterns are characterized so that their areas and perimeters vary independently. Thus, the geometries are capable of satisfying any realizable combination of area and perimeter designed for an artificial magnetic material with desired properties. Numerical studies are considered showing the effectiveness of the new geometries to fulfil design specifications.

A number of transverse stratified configurations of metal and dielectric layers are studied for modulating Terahertz radiation in amplitude and phase. Pass band flat-top response and high wide-band transmission is achieved by means of a metallic grating filled with Liquid Crystal (LC) in different configurations and with the use of either grazing angles of incidence or cuts pierced within the grating. The transverse configuration with thin LC films allows for high speed tunability with low applied voltage. A dielectric grating with non-continuous electrodes is studied showing wide pass band response suitable for phase modulation applications.