A complementary tunable method is proposed based on the Hybrid coupler. The odd-even mode analysis shows that the method can achieve continuously tunable power division ratio by changing two 50/2Ω transmission lines in the circuit, and it can achieve larger tunable range by improving the complementary tunable method based on the cascaded Hybrid coupler. Using the improved method, a novel π-type reconfigurable

This paper proposes a fast inverse synthetic aperture radar (ISAR) motion compensation (MOCOM) method. The various motion compensation methods using minimum entropy algorithm such as stage-by-stage approaching (SSA) algorithm were reported recently. However, the computational efficiency and the clearance of the ISAR image were hard to achieve simultaneously. In particular, as the number of the local

In this work, a broadband polarization converter in transmission mode based on tri-layered metamaterial structure is proposed to realize asymmetric transmission and linear polarization conversion simultaneously. The proposed design model consists of a hexapolar split ring structure and two orthogonal sub-wavelength gratings embedded in two dielectric substrates. The appropriate parameters of the unit

In this paper, we designed a dual band metamaterial perfect absorber (MPA) for Ku band applications. The overall ultrathin layer of proposed absorber consists of square patch with 450 diagonal slot structure within a copper square patch which loaded on both sides of dielectric thickness 1.6 mm FR-4 substrate. The results show that designed MPA gives two absorption bands at 12.45 and 14.18 GHz and absorption

ABSTRACT The goal of this work is to extend the Edge Meshless Method (EMM) presenting a new way to build the vector shape functions based on the H(curl) space. These vector shape functions allow the use of four, five and six edges in the support domain. For this, the basis functions polynomial order is increased. The new EMM vector shape functions are applied to eigenvalues problems with different

Numerical analysis of the scattering of a plane monochromatic electromagnetic wave from a discrete parabolic reflector made of parallel cylinders (wires) with perfect electric conductivity is carried out in the exact and approximate formulations, the latter neglecting all interactions between the wires. Both the TE and the TM polarizations of the incident field are considered. It is shown that the

This study presents the micro-Doppler signature (MDS) of small drones based on resonance phenomena. The MDS analysis of a drone is conducted for various detection conditions. The Doppler frequencies due to the rotation of rotor blades, characterized by different materials and dimensions, are extracted at specific angular frequencies. It is confirmed that the resonance phenomenon caused by the copper-coated

In this paper, a high Q-factor-based defective ground structure (DGS) etched microwave resonator is demonstrated to identify the unknown thickness of non-destructive monolayer dielectric material. The proposed structure consists of coupled sharp-edged split-square resonator (CS-SSR), a high-impedance microstrip line, and symmetrically coded DGS optimized by adaptive genetic algorithm (AGA), which is

The H-polarized plane wave scattering by the infinite double-layer strip grating with several strips removed in every layer is considered. The scattered field is represented as a sum of the field of currents on the ideally periodic double-layer grating and field of correction currents excited due to the absence of strips. The Fourier amplitudes of these fields are obtained from the singular integral

This paper proposes a DTV/LTE antenna design without physical structure for laptop computers. By changing the laptop’s right revolving axis to a non-conductor material and exciting several dipoles and loop paths formed by the display, keyboard ground plane and metal revolving axis using a feed matching circuit at an appropriate position of the slot on the hinge to cover the frequency bands for DTV

ABSTRACT This paper describes a new design strategy which is used to obtain a fivefold increase in the 3 dB axial ratio bandwidth of linear to circular polarization convertors based on anisotropic frequency selective surfaces composed of single screens of cross slots. The performance improvement is obtained by employing stratified dielectric media to carefully tailor the shape of the TE and TM spectral

The shielding of radio wave by steel-containing structures is desirable for electronics protection but undesirable for telecommunication signal reception. This work investigates the shielding behavior of steel structures consisting of members in various configurations, with the practical aim of determining how the configuration can be exploited to control the shielding. Differently oriented continuous

We consider a plane E-polarized wave scattering from an infinite flat grating of slots cut in a perfect electrically conducting plane, backed with a dielectric slab. At first, we reduce this problem to a dual series equation for the complex amplitudes of the Floquet spatial harmonics. Then we perform its analytical regularization, based on the inversion of the main part with the aid of the Riemann-Hilbert

In this paper, the arc array for squint-less near-field focusing is used, theoretically analyzed, and verified. The arc array is designed to overcome the squint phenomenon in the near-field and transfers the maximum power at a focused distance. The implemented transmitter is composed of 16×1 vivaldi antennas with a 0.7λ spacing and operates at a frequency of 5.8 GHz. In addition, the design method

A compact wideband dual-/quad-element multiple input multiple output (MIMO) antenna, using jeans textile material for WiMAX (IEEE 802.16d) and 5G application band, is proposed. The wideband nature of basic single element antenna with a frequency span of 2.74 to 4.41 GHz (47%) is analyzed in detail by using circuit model representation. Thereafter, in order to resolve different practical issues, such

This paper presents a 4-port compact UWB MIMO antenna. It has 45 0 tilted offset feed for better impedance matching and connected to cornered cut-out quad-radiators. Radially symmetric resonators are provided for impedance matching and isolation improvements. A miniaturized magnetic LC (MMLC) Minkowiski fractal loop acts as a magnetic shield between electric walls of feed and resonator for Wi-max band rejection

Recently, Barde C, Choubey A, Sinha R. [A set square design metamaterial absorber for X-band applications. J Electromagn Waves Appl. 2020;34:1430–1443.] have demonstrated the metamaterial absorber for X-band applications. In the present communication, we numerically investigated that a cross-polarizer is mistakenly reported as a wideband metamaterial absorber. Authors ignored the cross-polarized reflection

In this paper, a novel design of a diplexer for mobile communication base station is proposed, theoretically investigated and successfully tested. The proposed design of the diplexer is implemented on the base of interdigital filters. Successfully fabricated and tested diplexer operates within frequency bands 2.3–2.4/2.49–2.69 GHz and shows high performances: reflection loss within pass bands is less

This article presents a dual notched Frequency Selective Surface (FSS) using a compact structure. Four sub-cell square split ring resonators (SSRRs) are imprinted over 8×8 mm2 FR-4 substrate in a 90° clockwise rotational symmetric manner. Dual resonant bands are obtained at 3.08 GHz ranging from 2.5 to 3.6 GHz and 10.2 GHz ranging from 7.95 GHz to 12.3 GHz. The proposed FSS covers the WiMAX band ranging

On the basis of the characteristics of the heterotypic metallic enclosure with a built-in dielectric plate, this paper proposes an analytical method to evaluate the shielding performance of an apertured enclosure with convex or stepped structure under the plane wave illumination. First, the heterotypic enclosure is modeled based on the electromagnetic topology (EMT) theory, where the scattering parameter

In this paper, the mode matching (MM) method is applied to analyze the dispersion of the newly proposed transmission line (TL), centrosymmetric double-slotted line (CSDSL). For simplicity, the lateral metallic vias are replaced with the electric walls (EWs). Furthermore, four magnetic walls (MWs) are added to guarantee the boundary condition (BC) of MM. The proposed method is compared with the 3D electromagnetic

System-level electrostatic discharge (ESD) noise due to electromagnetic fields radiating from an ESD generator were measured and analyzed in a solid-state drive (SSD) storage system. The field sources of an ESD generator were efficiently modeled from the measured tangential magnetic fields in front of a ESD generator. The extracted field sources were incorporated into a full-wave solver, and the fields

A new modified Equivalent Circuit Model (M-ECM) enabled Whale Optimization (WO) assisted electromagnetic (EM) approach is presented for an efficient design of a double square loop frequency selective surface (DSL-FSS) based conformal shielding structure. A simple single-layer DSL-FSS is designed, fabricated, and measured to suppress both wireless local area network (WLAN) bands without affecting the

ABSTRACT The paper presents an NFC antenna based on a rectangular spiral examining the effect of the geometry and the addition of a ferrite sheet. Several prototypes are fabricated and tested where the influence of a human wrist and a conducting body close to the antenna are studied.

ABSTRACT The paper presents an NFC antenna based on a rectangular spiral examining the effect of the geometry and the addition of a ferrite sheet. Several prototypes are fabricated and tested where the influence of a human wrist and a conducting body close to the antenna are studied.

ABSTRACT We propose a semi-analytical scheme for investigating the electromagnetic beam scattering by a uniaxially anisotropic chiral object. The scattered and internal fields are expanded in terms of appropriate spherical vector wave functions, and the method of moments procedure is employed for determining the unknown expansion coefficients. Normalized differential scattering cross sections are evaluated

ABSTRACT Poly-spirals are composed of contiguously interconnected spiral elements and are ubiquitous in the monuments of various cultures since prehistoric times. In adopting poly-spiral geometries for antenna applications, we may in general choose these contiguously connected spirals to be identical or dissimilar, such as by selecting them to be of circular, eccentric, or polygonal shape. We focus

ABSTRACT Proceeding from the scattered field expansion in cylindrical harmonics, we define partial invisibility or partial cloaking as suppression of finitely many lowest-order field harmonics. We show that for benchmark structures (a dielectric rod and a perfectly conducting cylinder of circular cross section covered by a concentric dielectric layer), such multiple suppression can be achieved. For

ABSTRACT Federal Communications Commission (FCC) has released the regulation for medical body area network (MBAN) in 2012 as a BAN specialized for medical applications. MBAN is a narrowband BAN allocated on the 2360-2400 MHz frequency band. It is very promising, as it has the advantages of BAN modules like low power and high accuracy, which are essential parameters for medical applications. This paper

In a recently published paper, Chetan Barde et al. [Barde C, Choubey A, Sinha R. A set square design metamaterial absorber for X-band applications. J Electromagn Waves Appl. 2019:1–14.] have proposed a wideband metamaterial absorber and have attempted to elaborate reflection theory for the absorptivity. They have claimed a wideband absorption rate due to ignorance of cross-polarization component of

ABSTRACT In this study, a spatially separated eight-port box shaped multiple-input-multiple-output (MIMO) cylindrical dielectric resonator antenna (cDRA) is presented which supports quad-directional pattern diversity characteristics. Initially, a cDRA is radiated with the assistance of two different excitation mechanisms to generate decoupled orthogonal modes. This dual-port primary structure is combined

Cognitive radio (CR) exploits the spectrum efficiently and minimizes the interference between different devices. Meanwhile, multiband frequency-reconfigurable antennas (FRA) are desirable for CR where it is beneficial to dynamically reconfigure a single antenna to be transmitted and/or received on multiple frequency bands. As stated by the literature review, there is a dearth of work into multiband

In this paper, we have developed a system of Time Domain Electric Field Integral Equation (TD-EFIE) for the resolution of a scattering electromagnetic problem by various shapes illuminated by an incident transient wave. The solvability of the TD-EFIE system is based on the Time Domain Method of Moments (TD-MoM) using Galerkin's method in space and time domains. In time domain, a linear combination

In this paper, a novel ultrawideband (UWB) four ports multiple-input multiple-output (MIMO) antenna was developed. The MIMO antenna is based on four wideband circular monopoles with inscribed Fibonacci circles in order to reduce the size and stabilize the impedance over a wider bandwidth. The array shows a frequency bandwidth from 3.6 GHz to 13.8 GHz, obtaining inter-port coupling below −15 dB over

A small structure for chipless RFID tag is proposed; it is inspired by a C-shaped structure and based on HCSRR. This structure has curved strips, which are obtained by fine cutting the substrate from the symmetry of the C-shaped structure as base structure, and then missing part of the path is compensated by creating the PMC boundary condition in the cut-off point according to the image theory. Hence

ABSTRACT In this paper, a dual annular ring patch antenna with high isolation for Multiple Input Multiple Output (MIMO) Satellite application at 4 GHz is presented. The mutual coupling reduction and circular polarization are achieved by some perturbations in annular ring patch and microstrip stubs between antennas. These perturbations will excite two modes which is orthogonal ie. equal amplitude and

Based on the scattering cancellation technique, an approach is proposed to improve the mantle cloak’s performance for electrically large cylinders. The procedure is based on the observation that the number of dominant scattering coefficients and corresponding magnitudes for a cylinder decreases when oriented obliquely to the incident wave. Thus, it is quite advantageous to design a mantle cloak under

In this simulation study, we describe a microstrip transmission line (MTL) array coil, designed to provide a uniform |B1| field along the spinal cord in 7 T MRI. The coil structure was designed by segmenting the spinal cord into four sections according to its shape. The geometry and properties of the MTL coils were optimized individually to obtain a uniform |B1| field distributed according to the shape

A novel printed monopole antenna with simple, low-profile and convenient design is presented in this paper. The antenna composes of a printed monopole antenna and a folded-line stepped impedance resonator (SIR) loaded on the bottom of the substrate. The resonant frequency is decreased by the coupling between the folded-line SIR as the near-field resonant parasitic (NFRP) element and radiation patch

In this paper, a microstrip low-pass filter (LPF) using folded-flag-shaped resonators is designed and presented. Its base resonator length is 12.4 mm, and the proposed low-pass filter has a sharpness of 0.08 GHz. The filter cut-off frequency is 1.44 GHz, and the return loss is reduced to a level of −17 dB, indicating a flat pass-band. Also, the suppressing cell is used to weaken the disturbing harmonics

A novel low-profile tri-band bandpass frequency-selective surface (FSS) is proposed in this paper. The structure is designed by the two-dimensional repetition of a unit cell consisting of four apertures. Each aperture is a combination of T-shaped, U-shaped and a rectangular-shaped aperture aligned horizontally or vertically. The performance of the designed FSS structure is independent of the angle

Based on the MGT positioning method, the performance of combined magnetic beacon is studied. The unit size of beacon is designed as D = 2 cm and L = 8 cm, the performance of different structure magnetic beacons combined have been studied and compared in detail, results show that the magnetic field intensity of cross structure is about 30000nT higher than the orthogonal structure which have generated

ABSTRACT This paper presents a time modulated far-field radiation pattern synthesis of a compact circular antenna array (CAA) by employing a stochastic optimization technique known as grey wolf optimization (GWO). The compactness of the antenna array is achieved by reducing the inter-element distances between the elements of the array which leads to the miniaturization of the antenna array size. On

In this endeavor, a cascade system of an attenuator in series with a Low Noise Amplifier (LNA) will be studied. A discussion on past related works followed by a study of different Attenuator-LNA arrangements not analyzed collectively in those previous works will be presented. This is important for addressing the lowering of system noise figure (NF), which is critical for applications such as GPSs and

A compact coplanar waveguide (CPW)-fed band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) flexible antenna on liquid crystal polymer (LCP) substrate is designed. It is composed of two orthogonal elements, tampered feeder and asymmetric ground plate. To improve the port isolation (S 21), an inverted F-shaped branch is added. The measurement results demonstrate that the antenna has

This paper conceptualizes the development of a frequency selective surface (FSS) with 3-D unit cells. The FSS unit cells individually present a three-dimensional structure, whereas collectively these are more like planar FSS. The unit cell substrate has been printed using 3-D printing technique and metallized using copper paint. The 3-D printing offers a degree of freedom to fabricate substrate material

An improved ultra-wideband metamaterial absorber (MA) with high absorptivity in the infrared region is proposed. It features a mixture of copper and GaAs at the top layer, which can greatly raise the bandwidth and absorption rate due to the coupling effect between copper and GaAs. The spectrum with absorption rate of 90% in the infrared region from 98 to 152 THz can be obtained. The input-impedance

In this paper, a compact substrate integrated waveguide (SIW) based dual-band filter which utilizes the dual resonance provided by asymmetric double-ring D-shaped resonators that are incorporated on the upper metallic layer of SIW is communicated. The two passbands are generated well below the cut-off frequency of the SIW due to evanescent mode propagation. Such propagation is responsible for the substantial

We propose a new broadband flexible waterproof antenna suitable for Internet of Things applications. The antenna is comprised of three components: radiating elements fed by a 50-Ω coplanar waveguide transmission line and two layers from an elastomer composite (used as a substrate and top encapsulation) which completely covers the antenna's radiating elements to provide water and dust resistance. An

An efficient time-domain method based on the waveform relaxation with transverse partitioning (WR-TP) techniques and the delay extraction passive compact circuit (DEPACT) macromodel is presented for evaluating the electromagnetic (EM) transient response of multiconductor transmission lines (MTLs) excited by an external EM field. Firstly, the equivalent distributed sources due to the tangential components

Cloaking structure designs have been widely performed in a form of metamaterial development. However, physics-based design approach makes it difficult to define complex material profiles. This study proposes an alternative design method for multi-directional cloak design via topology optimization method using a dielectric material. The phase field design method, which uses the reaction-diffusion equations

Magnetic absorbing material (MAM) embedded with electric ring resonator (ERR) is demonstrated to broaden the absorbing bandwidth in low-frequency range. We obtained the relation between input impedance and absorption bandwidth under specific reflection threshold to verify the influence of the embedded ERRs on impedance matching characteristic. Numerical simulations were carried out and the results

A planar sensor designed using the fourth Hilbert fractal curve iteration for solid material characterization at multiple frequencies is reported in this paper. The fractal curve is self-similar with space-filling properties. The Hilbert fractal geometry is used to form a compact resonator, with a multiband frequency response where miniaturization is achieved since a large transmission line length

A wide band, dual radiator Multiple input multiple output (MIMO) antenna resonating at 2.4 GHz Industrial Scientific and Medical (ISM) band is designed and analysed for the body-centric wireless communication. Defected ground structure (DGS) is used to reduce the antenna size and to achieve wide bandwidth. Moreover, a decoupling slot is also etched in the ground plane to improve the port isolation

ABSTRACT In this paper, the design of an interaction structure for a 10-kW, W-band gyrotron is presented. The beam voltage and beam current are chosen as 30 kV and 1 A, respectively. The mode of interaction was chosen as TE6,2. A parametric design code and a gyro large-signal analysis (LSA) code were developed. The computational steps are discussed in brief. The LSA was done using the in-house developed

ABSTRACT In this letter, a microstrip-line type Bruce array antenna with a wide fan beam and high gain is proposed. The unit composed of the radiating edge and non-radiating edge is repeatedly arranged symmetry to the feeding part. The repeated radiating edge operates as an array of magnetic current sources, which radiates the wide beam pattern in the E-plane and achieves high gain in the H-plane.

Bandstop filters with single and dual stop-bands were implemented using coupled mode microstrip slot resonators (MSRs) for the first time. With compact and ease of fabrication, the MSRs provide excellent filter response as desired. It is found that the MSRs can offer narrow bandwidth of less than 20% fractional bandwidth and large isolation of more than 40 dB. The designs of MSRs and filters are systematically

Traveling wave tubes are rapidly evolving to provide unprecedented power level in comparison to solid state devices in the millimeter waves region of the spectrum (80–300 GHz) thus enabling a wide range of applications. Wireless communications, imaging, plasma diagnostics, healthcare and many others will gain substantial features if high power at millimeter waves would be available from compact sources

In this paper, we present the compact bandpass cavity filters for UHF range. We investigate the properties of coaxial resonators with various numbers of tubular posts from one to four. We show that the resonant frequency can be four times smaller for the four-post resonator in comparison with the single post resonator with the same cavity dimensions. We synthesized and manufactured fifth-order bandpass

An effective method combined with finite element method (FEM) and boundary integral method (BIM) is presented in this paper to study the composite electromagnetic scattering from a 2-D coated object partially buried in a 1-D dielectric rough surface. The field within the coated object is modelled by FEM, while the coupling field between the object and rough surface is considered by BIM. The fields