An impedance-permeability (Z-μ_r) resonance phenomenon is firstly founded and numerically demonstrated when electromagnetic metamaterials with negative permeability are firstly introduced into inductance coil. Numerical results reveal that the impedance-permeability relationship exhibits an extraordinary self-resonant phenomenon at a certain negative value of relative permeability, which is related to the dimensions of the core but nearly independent to the coil size. Such a mechanism is proposed to increase the sensitivity of eddy current (EC) sensors up to about 270 times, offering a new method to greatly improve the sensitivity of EC sensors and the spatial resolution with micrometer scale.

Low loss circular birefringence is found in three-dimensional artificial triple helices. High values of chirality index are generated. Within the transmission bandwidth, there is a significant difference in the refractive index value of the right- and left- polarized waves. The outgoing waves from a wedge structure designed from these triple helices are proved to split with a wide angle. The wave polarizations agree with earlier simulation results.

This paper presents a design of perforated nanoantenna reflectarray. The use of metallic nanostructures made of Silver and/or Gold at appropriate wavelength cause fascinating unusual electromagnetic effects. Reflectarray consists of an array of unit cell made from Silver is investigated. The effect of the number of perforated holes in the unit cell configurations is investigated for proper reflection coefficient phase compensation. A linearly polarized pyramidal nano-horn is used to feed the perforated nanoantenna reflectarray. The radiation characteristics of 9 × 9 perforated nanoantenna reflectarray are illustrated. A high gain of 20.5 dB is obtained at the designed frequency of 735 THz. A comparison between solid Silver sheet with no perforation holes and the proposed perforated reflectarray is explained.

In this paper an in-depth parametric analysis of shielding effectiveness obtained when using ferromagnetic or conductive screens to mitigate the field generated by duct banks is presented. Due to the need of a case-by-case approach, all the simulations, performed by a finite element software (GetDp), are applied to a case study composed by 9 (3x3) ducts, with six of them including high voltage single-core cables and the three left empty for eventual future expansion. Two shielding geometries are tested: horizontal and U-reverse, changing in each one the main parameters: width, thickness, clearance to conductors, etc. Moreover, the conductors are grouped in two balanced in-phase three-phase circuits arranged in three configurations: vertical, horizontal and triangular. The mutual phase ordering of both circuits is the one that minimizes the field, so no further field reduction can be obtained by simple methods. The power losses and cost of different shielding solutions are also presented, including the effect of adding a third circuit if required.

In this paper, the applications of chiral layers and metamaterials as radar absorbing materials are investigated. A perfect electric conductor plate covered by a chiral metamaterial is considered and after the formulation of the problem, reflection of the structure under an oblique plane wave incidence of arbitrary polarization is investigated. Then several examples of the applications of chiral layers in nondispersive, dispersive, and chiral nihility conditions are provided to design of zero reflection coatings. Finally, application of chiral metamaterial structures as microwave absorbers is discussed. In some of the provided examples, the method of genetic algorithm is used to optimize chiral coatings for the minimization of co- and cross reflected power.

In this paper, we present an efficient Artificial Neural Network (ANN)-based model to estimate both azimuth and elevation arrival angles of a signal source. To achieve this goal, the ANN model is constructed using measurement data obtained by a rectangular antenna array in the space-frequency domain. Unlike classical super-resolution algorithms such as 2D MUSIC, the proposed model is capable to account for imperfections of measurement equipment as well as mutual couplings between array elements. The neural model has been verified for several angular positions and frequencies. It is shown that use of ANN model to estimate angular positions of a signal source yields more accurate results when compared to 2D MUSIC. Moreover, the neural model significantly outperforms 2D MUSIC in terms of speed of computation.

It is potentially useful to perform target identification using micro-Doppler features because they contain information on the geometrical structure of the target. In this paper, the m-D effect of the rotationally symmetric ballistic target (BT) is analyzed which reveals that the m-D is not a form of sinusoidal modulation due to the sliding-type scattering. Inspired by the extended Hough transform (EHT), a method to extract all the six parameters of the BT is proposed. The m-D effect and the performance of feature extraction algorithm are demonstrated by the measured data in a microwave anechoic chamber.

The theory and design of a new family of multifrequency monopole antennas by smartly loading a set of complementary metamaterial transmission line (CMTL) unit cells are investigated. The distributed CMTL elements, epsilon negative (ENG) or double negative (DNG) through incorporating additional capacitive gaps, contain a Koch-shaped extended complementary single split ring resonator pair (K-ECSSRRP) etched on the signal strip. The K-ECSSRRP features dual-shunt branches in the equivalent circuit model, rendering a distinguished resonator with dual zeroth-order resonant (ZOR) modes. By smartly controlling the element layout and loading different numbers of unit cells, ten antennas covering different communication standards (GSM1800, UMTS, Bluetooth, DMB and WIMAX) are designed and four of them are fabricated and measured. At most of operating frequencies, the antennas exhibit impedance matching better than -10 dB and normal monopolar radiation patterns. Numerical and experimental results both confirm that the single-cell or dual-cell ENG and DNG CMTL-loaded monopoles exhibit almost identical dual ZOR modes. Moreover, the loaded elements also contribute to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. These antennas are compact and the multiple operating bands can be arbitrarily engineered, enabling an alternative and easy avenue toward monopoles with multifunction and high integration.

The need to find ways to effectively utilize the large quantities of agricultural waste that are produced is indicative of the huge potential associated with producing an alternative pyramidal microwave absorber for anechoic chamber-testing applications. We propose the development of a pyramidal microwave absorber that can use sugar cane bagasse (SCB), a byproduct from the production and processing of sugar cane, as the absorbent. In this paper, we report the results of our use of dielectric probe measurement to determine the dielectric constant and loss tangent of SCB. These values were used to model and simulate an SCB pyramidal microwave absorber in Computer Simulation Technology's (CST's) Microwave Studio. This absorber was operated in the microwave frequency range between 0.1 GHz and 20.0 GHz.

In this paper, the network expression is proposed for finite-length multiple transmission lines in arbitrary directions. Crosstalk between two bent transmission lines is analyzed using the proposed approach as an example of application. The resultant network function is obtained in the form of an ABCD matrix for two bent transmission lines is obtained. The validity of the proposed approach was confirmed by comparing experimental results with computed results and those simulated by a commercial electromagnetic solver for some bent-line models.

This paper presents a novel dielectric resonator antenna (DRA) for multiband mobile terminal communication applications. A variation of circular sector dielectric resonator antenna partially coated with metal on its surface is used as the main radiating element. The DRA is fed by a monopole slot-coupled 50-Ω microstrip feed line, which can also provide another radiation mode. By thorough design, the antenna achieves the desired 470-960 MHz band for DVB-H/GSM850/900 operation and 1710-1990 MHz band for DCS/PCS operation. The dimensions of the antenna presented are λ₀/17 x λ₀/9 x λ₀/35 at 470 MHz with appropriate dielectric permittivity ^{ε_r = 16}.

This paper deals with the dielectric loaded Exponentially Tapered Slot (ETS) antenna needed for ultra-high-speed, high-capacity wireless communication systems which work at 60 GHz and illustrates its specifications and requirements. The antenna in such system requires high gain, high-efficient and high performance design specifications. The ETS antenna and the loaded dielectric are integrated using the same single substrate resulting in easy fabrication and low cost. The ETS antenna with rectangular and elliptical shaped loaded dielectrics were designed and fabricated. These antennas have high gain and wider beamwidth in both E-plane and H-plane. The proposed antenna design is simulated using 3D electromagnetic software CST Microwave Studio and the comparison is made with Ansys HFSS to validate the design procedure. The results obtained from the simulations and the measurements are in good agreement.

An APF (All-Pass Filter) delay module in which eight single-ring resonators are serially cascaded is designed and fabricated. The polymer waveguide used for the realization of the APF delay module is a buried structure whose core width and height are 1.5μm. The core and cladding index are 1.51 and 1.378, respectively, which corresponds to the relative index difference of 8%. In order to use a thermo-optic effect of polymer materials, electrodes are evaporated above the ring resonator to provide heating currents. The time delay is measured to be about 50 ps when 2 rings are in resonance, and about 105 ps and 150 ps, respectively, when 4 and 6 rings of APF are in resonance, respectively. When all of 8 rings are in resonance, the delay is measured to be about 200 ps.

A broadband zeroth-order resonant (ZOR) antenna based on asymmetric coplanar waveguide (ACPW) is presented. By adopting the epsilon negative transmission line (ENG-TL), a zeroth-order resonance mode can be achieved. We propose an asymmetric coplanar waveguide structure which offers the design freedom to realize the broadband ZOR antenna, where the antenna's bandwidth is characterized by an equivalent circuit parameters. The antenna has the compact unit cell dimensions of 5×13.8 mm². The measured results show that the operating bandwidth is about 1050 MHz (1.90-2.95 GHz), and the peak gain and radiation efficiency are 2.46 dBi and 91% at 2.3 GHz. Owing to the characteristics of broad bandwidth, high efficiency, omnidirectional radiation, and easy manufacturing, the proposed ACPW ZOR antenna is very suitable for modern wireless communication systems (UMTS, WLAN, WIMAX, LTE).

Present work deals with the microwave absorption characteristics of BaFe₁₂O₁₉ of interest as radar absorbing material (RAM). There are very few reported works available where particle size has been critically analyzed for absorbing characteristics at microwave frequencies, therefore, in this paper microwave absorption properties of the BaFe₁₂O₁₉ with different particle sizes were investigated. The results showed that the particle size had significant influence on the dielectric and absorption properties of the composites in the 8.2-12.4 GHz frequency range. BaFe₁₂O₁₉ powder of different particle sizes were synthesized by varying the annealing time and it was observed that the real part of permittivity of the composite increases from 5.18 (average value) to 7.50 (average value) and imaginary part increases from an average value of 0.20 to an average value of 2.33, whereas the real part of permeability increases from 0.95 (average value) to 1.11 (average value) and imaginary part of permeability was measured in the range of 0.02 to 0.07. These changes in permittivity and permeability affects microwave absorption application. It is observed that the maximum bandwidth for average particle size of 240 nm is 3.02 GHz and with the increase in average particle size, microwave absorption properties increased.

In the applications of synthetic aperture radar (SAR) data, a crucial problem is to develop precise models for the statistics of the pixel amplitudes or intensities. In this paper, a new statistical model, called simply here GΓΓ, is proposed based on the product model by assuming the radar cross section (RCS) components (texture components) of the return obey a recently empirical generalized Gamma distribution. Meanwhile, we demonstrate theoretically that the proposed GΓΓ model has the well-known K and g⁰ distributions as special cases. We also derived analytically the estimators of the presented GΓΓ model by applying the "method-of-log-cumulants" (MoLC). Finally, the performance of the proposed model is tested by using some measured SAR images.

In this paper, we present a broadband out-of-phase power divider with high power-handling capability. The proposed device consists of several sections of double-sided parallel-strip lines (DSPSLs), a mid-inserted conductor plane, and two external isolation resistors, which are directly grounded for heat sinking. A through ground via (TGV), connecting the top and bottom sides of DSPSLs, is employed. The special metal via is realized to short the isolation resistors at full-frequency band when the odd-mode is excited. Meanwhile, it can be ignored as the excitation is even-mode. This property is efficiently utilized to improve the bandwidth. To examine the proposed power divider in detail, a set of closed-form equations are derived. Meanwhile, the power operation analysis illustrates that the proposed power divider is a good candidate for high power applications. The design charts show that the proposed device can support a wide frequency ratio range (1-1.7). Furthermore, broadband responses can be obtained when proper frequency ratios are adopted. For verification, an experimental power divider operating at 1.25/1.75 GHz is implemented. The measured results exhibit a bandwidth of 44.3% with better than 15 dB return loss and 18 dB port isolation is achieved.

This paper develops a more precise analytical model for calculating salient pole synchronous machine (SPSM) inductances in case of general eccentricity including static, dynamic and mixed eccentricities. The developed method is based on the modified winding function approach (MWFA) which accurately considers variable air gap function and leads to pure analytical expressions of inductances. Available analytical techniques, based on MWFA, approximate the air gap function and simplify the geometrical model of SPSM, whereas, in this study, the influence of the openings between the rotor salient poles has been taken into account by using an effective form of rotor pole shoes. Using this technique, flux fringing effect is considered. By taking into account machine geometry, type of windings connection and flux fringing effect, this method is able to model most of the important features of an eccentric SPSM. The developed analytical expressions can calculate time varying inductances of SPSMs with any eccentricity type and degree in the frame of a single program. Simulation results for static eccentricity are compared with experimental tests on a laboratory generator to verify accuracy of the proposed model.

A unit cell based numerical approach to model the metal powders and metal-dielectric composites at microwave frequencies is proposed. The unit cell based numerical modeling helps to compute the equivalent reflection and transmission coefficients of these materials, which are commonly used measured parameters at RF and microwave frequencies. The computation of the reflection and transmission coefficients of these artificial dielectric samples also facilitates the determination of their effective constitutive properties, defined in terms of the effective permittivity and permeability, using the reflection transmission approach. The applicability of the proposed unit cell method is first verified for some mixed dielectrics using the classical mixing formulas, and the standard waveguide approach. Once the validity of the proposed approach is ascertained, the effective constitutive properties of copper powder is determined. A detailed parametric analysis is also carried out in order to study the effect of various parameters such as the packing fraction, the grain size and the gap between adjacent spherical shaped metal particles, on the effective constitutive properties of the copper powder compact. This detailed analysis is quite helpful in order to optimize various parameters of the microwave sintering of metal powders and metal-dielectric composites before the actual start of the sintering process using microwaves.

In the above paper [1], there are two classes of several errors. The first one is related to mistakes/misprints in equations and irrelevant references. The second one is assertions about innovations, which were claimed as ``for the first time" in the literature. In addition to them, the commentators want to attract attentions of the readers with an additional part of comments in order to make more useful and better understanding of the work in [1]. All details about these issues are discussed at following parts: