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The paper deals with modelling of radiation from arbitrarily shaped thin wires above a multilayer and related engineering applications. The formulation is based on the set of corresponding Pocklington integro-differential equations (IDEs) for curved wires. The influence of lower layered half-space is taken into account by means of simplified reflection coefficient stemming from modified image theory (MIT). The set of coupled IDEs is handled via Galerkin Bubnov variant of indirect boundary element method (GB-IBEM) for curvilinear elements. The related field radiated from a wire configuration is obtained from corresponding integral expressions including integration of the currents along a given wire configuration. Some illustrative computational examples for certain wire configurations pertaining to dipole antennas, power communication systems (PLC) and instrumental landing systems (ILS) are given in the paper.

This paper presents an efficient time-domain analysis of RF/microwave nonlinear circuits in the presence of the incident uniform plane wave. In this paper, a set of differential equations, includin...

As a power system turns out to be all the more heavily loaded and more unpredictable, maintaining stability becomes a difficult issue. In this paper, we propose an optimal control procedure for power system adjustment utilizing a proportional-integral-derivative (PID) controller in a coordinated power system. In modern applications, the most generally utilized controller is the PID controller, which necessitates productive techniques to control the distinctive parameters of the plant. The proposed strategy uses the particle swarm optimization algorithm-based way to deal with producing the optimal tuning parameters. This paper investigates the execution of the power system and dynamic execution of the controller is compared with the conventional controller with approval of the adequacy of the proposed mixture controller. Experimental results demonstrate that the proposed system has upgraded the system stability of the power system all the more adequately existing systems.

In part I of the present paper, we analysed helical slow-wave structures of travelling-wave tubes (TWTs) taking into account the space harmonic effects arising from the axial periodicity of helix turns as well as azimuthal periodicity of the dielectric helix-supports and metal vanes of the envelope of the structure. Here, in part II of the paper, we extended the analysis to the fast-wave regime to study a disc-loaded circular waveguide interaction structure of a gyro-TWT taking into account the space harmonic effects arising from the axial periodicity of the annular discs. Four variants of the structure were studied. Two of these variants use thin and thick metal discs, respectively. The third variant has inherently two interwoven metal disc-loaded structures, and the fourth variant has dielectric discs interposed between consecutive metal discs. We studied the effect of tapering the disc parameters and predicted the optimized parameters for the wideband and high-gain gyro-TWT performance. The ana...

This paper employs the finite-difference time-domain method (FDTD) to model and study the propagation characteristics and distribution features for extremely low frequency (ELF) in Earth-ionosphere (EI) system. For electromagnetic pulse source whose bandwidth is 10 Hz, the ELF electromagnetic wave forms standing wave. When the bandwidth is 100 Hz, there exists 180° phase reversals. Due to EI system, the electromagnetic field generated by horizontal dipole antenna is mainly vertical electric field and horizontal magnetic field when the receiver is away from the source antenna and locates on the surface of the earth. The distribution is mainly determined by the polarization direction of the source antenna other than the topographic feature and the conductivity. The ELF electromagnetic field can be used as incident field to detect conductivity anomaly underground. Thus, this paper may provide valuable information for long distance and large-scale underground detection, showing potential applications ...

This paper proposes a new hybrid method called MS-GEC/PO. This method is based on the coupling between the multi-scale combined to generalized equivalent circuit method (MS-GEC) and the hybrid approach MoM-GEC/PO (MoM-GEC method coupled to Physical Optic method). The MS-GEC method, in its new formulation based on local modal operators, can reduce considerably the requirements (CPU time and memory resources) especially when the number of scales increases. However, the MoM-GEC/PO can reduce these requirements because it is based on a single test function permitting an important reduction of the manipulated matrices size. Consequently, applying the new hybridization MS-GEC/PO, we can take the advantageous of both of these methods assuring a multiple gain in requirements. In this paper, we present the new considered hybridization and we validate it on an example of application. The obtained results are in agreement with the MoM-GEC method.

In this paper, the beam steerable isotropic Linear Antenna Array is designed for reducing the side lobe level using evolutionary optimization technique. The optimization techniques particle swarm optimization (PSO) and Novel PSO are used to reduce the side lobe level (SLL) as well as to steer the main beam in specific direction. In this design of steerable Linear arrays, the amplitude excitations are optimized. Obtained results show that the maximum peak of SLL of the resultant patterns is as per requirement. This paper presents a good performance in the array factor response and suppressed SLL for different numbers of elements and different values of the steering angle of direction of the main beam with evolutionary optimization.

In this paper, the physical model is extended for vias embedded in layered media between two parallel-plate pairs. The effect of this inhomogeneity on signal integrity analysis is crucial, but is rarely studied especially by using the equivalent circuit model. The model presented in this paper is constituted by upper and lower via-to-plane capacitances which are different from each other due to the inhomogeneous dielectrics and equivalent impedance matrix of the parallel-plate cavity with equivalent wave number. The via-to-plate capacitance with layered media is calculated by using cascaded Green’s function with image theory and integral equation method based on partial capacitance, which is the main contribution in this paper. The parallel-plate impedance is calculated by using the cavity resonator method. Transverse resonance method as well as an equivalent approximation method is used for wave number evaluation. For the first time, the circuit model presented in this paper is used for the issue of laye...

In this paper, a new approach for electromagnetic modeling of the diffraction of finite multi-dielectric thickness in metallic wave-guides is presented. The proposed model, based on the method of moments combined to the generalized equivalent circuit, can concern several applications such as the investigation of vegetation leaves properties. Hence, in this work, we are interested in studying a corn leaf which is assumed as a superposition of rectangular dielectric slabs. We develop an electromagnetic analysis of a rectangular wave-guide loaded with a dielectric model that is composed of a leaf plant with a finite thickness. Interest has been focused on the influence of the wave diffraction according to the geometrical intern of the corn leaves. In this paper, we are particularly interested in studying these parameters against the dielectrics widths and the distances separating them. To validate this work, the obtained results are compared with those previously measured and published. A good agreement with...

International audience; Metal additive manufacturing processes, such as laser beam melting (LBM), can play a key role in developing antenna-feed chains because monolithic and multifunctional parts can be manufactured with high geometric freedom in the design phase. Using LBM technology, lighter and more compact antennas can be produced and manufac-turing costs can be reduced. However, the surface roughness of internal surfaces in waveguides produced by LBM is much higher (about 10 μm Ra) than that produced by conventional manufacturing tech-nologies. Consequently, such high surface roughness of the internal surface can affect electrical current propagation through the waveguide and corresponding transmitted power. In this paper, abrasive flow machining (AFM) was used to reduce the surface roughness of the internal surfaces of four different waveguides used at both K and Q bands. A significant reduction in the transmission loss at both K and Q bands was observed as their internal surface rough-ness decreased from about 10 μmto1μm Ra. This was assumed to be due to an increase of the internal surface electrical conductivity with the decrease of roughness in waveguides channels.

This paper presents the design and simulation of a novel TE10 to TE30 mode converter operating at 3.7 GHz and is subjected to high RF power of 500 kW in Continuous Wave (CW) regime. The design inco...

A wideband antenna pair used for 5G mobile phones is proposed in this paper. Both elements of the antenna pair consisting of an open slot and a coupled feeding line can cover the band of 3.3–6 GHz,...

This paper develops an original theory of bandpass (BP) negative group delay (NGD) function from three-port symmetric circuit. The BP NGD analysis is applied first time to three-port topology. The ...

In this paper, a novel method to decrease the sidelobe level (SLL) of conformal leaky-wave antennas (CLWAs) which are synthesized based on the holographic techniques is proposed. For this purpose, ...

Various decoupling methods were proposed and investigated for multiple-input multiple-output (MIMO) Base Station (BS) systems. These methods can effectively decouple the dual-polarized co-polar signal but fail to decouple the cross-polarized signal, similarly limiting the BS's overall decoupling performance. In this paper, different antenna arrays are designed to illustrate the coupling mechanism of cross-polarized BS antennas, and a comprehensive study of the relationship between antenna configurations and mutual couplings is conducted. It is shown that compact size antenna elements enlarge the edge-to-edge separation, and the loop-shaped dipole elements reduce the cross-polarization couplings. Finally, the array-antenna decoupling surface (ADS) method is applied in a 2×2 array composed of the designed antennas. Thanks to the improved antenna unit, the decoupling task is eased, and a better decoupling performance is achieved compared with the original ADS work.

In this paper, a dual-band power amplifier based on tri-band impedance matching circuit is proposed. This amplifier uses reverse thinking to combine the tri-band impedance matching network with the...

This paper presents the unique structure of a hybrid antenna with a blend of Peano–Gosper, Koch and Minkowski curves using a modified partial ground plane for multi-standard wireless applications. ...

In this paper, first the basic principles of monostatic RCS enhancement (RCS ENH) for a structure are established. Then it is shown that for a periodic structure with periodicity larger than half w...

To improve the detection capability of laser fuze, this paper researches the laser echo signal detection method and echo power calculation method on laser fuze. From the multi-attitude intersection...

The paper contributes by developing computational and reviewing theoretical methods to propagate electromagnetic fields in free space, while taking account of the fact that the sources are typicall...

In this paper, a low-profile quad-band frequency selective surface (FSS), designed as a sub-reflector for satellite communication is presented. This single layered FSS employs non-concentric open l...

In this paper, the design of an interaction cavity for a very high-power W-band gyrotron is proposed for the generation of megawatt range of power. The proposed gyrotron is designed to generate 1.5...

Wireless underground sensor network (WUSN) is widely used in agriculture, frontier defense, and other fields with great research value. This paper takes the propagation characteristics of the elect...

This paper presents a ‘reconfigurable narrow open-slot LTE MIMO antennas for metal-rimmed smartphone applications,’ which consist of two structurally identical L-shaped slot antennas combined with ...

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...

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. ...

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 ...

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 transmission responses. We demonstrate that a bandwidth of 24.5% can be achieved at a center operating frequency of 10.6 GHz using an array of unequal length cross-slots embedded centrally between two 2.25 mm thick dielectric slabs (εr = 9.0). Moreover it is shown that the inherent self-filtering behavior of the structure provides greater rejection of unwanted signals than designs embedded in lower permittivity material. Computed and experimental axial ratio results are compared to verify the new design methodology

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 tra...

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...

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 late...

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 aper...

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 infl...

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 propos...

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 Fibon...

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 in...

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 re...

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 circula...

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 sharpne...

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...

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 the...

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 o...

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 is effectively confined in a limited area. The sensor provides five resonances in the frequency range from 0 to 5 GHz. The resonant frequencies are 0.56, 1.68, 2.72, 3.69 and 4.72 GHz, all used to measure the real permittivity of known samples with a sensitivity of 7, 20, 27, 43 and 50 MHz/permittivity, respectively. The sensor is used to measure dielectric samples with 20 x 20 mm2 areas with several thicknesses. Simulations and measurements demonstrate that the Hilbert fractal geometry can be used to design a multiband planar sensor for solid dielectric material characterization.

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...

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 objec...

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...

This paper presents a design investigation of the Electron Optical Gun (EOG) for a 42 GHz, 200 kW second harmonic gyrotron operating in the TE0, 3 mode. The initial design of MIG is done using esta...

Sparse arrays play an important role in the widely used acoustic and electromagnetic applications such as sonar, radar, and satellite. In this paper, a recently proposed swarm intelligence algorith...

This paper presents a robust optimization method to design patch antennas that consider uncertainties from the substrate electromagnetic properties and the manufacturing equipment. The robust optim...

In the paper, the design and simulation of the TEM-TE10 wideband and high-power mode converter (MC) are investigated. The working frequency of the MC is in the frequency range of 4.3–8.8 GHz (68.7%...