This paper presents a novel high gain rectangular microstrip patch antenna (RMSA) with vertically placed Yagi elements. The antenna is fed by a coaxial probe to excite TM01 fundamental waves at 2.4GHz, which is suitable for wireless local area network (WLAN) applications. In order to increase the antenna gain, Yagi elements are placed in groups of 5, on each side of the substrate in order to serveas

A novel and simple scheme to generate Ultra-wideband (UWB) doublet signal with tunable notch band based on a tunable delay-line filter is presented. The first-order differentiation is realized by a dual-drive Mach–Zehnder modulator (DD-MZM), which differentiates the Gaussian pulses to the monocycle pulses. Subsequently, the UWB monocycle pulses are transmitted to an optical delay-line filter implemented

This paper presents the electrical design of a high power ring-bar TWT amplifier at Ku-band. The design parameters of Slow-wave structure (SWS) were synthesized theoretically. Further, the design was optimized using a computer simulation technology (CST). The dispersion and interaction impedance characteristics were simulated using the eigenmode simulation (EMS) technique at a beam voltage of 14.5 kV

This paper is to reconstruct the periodic inhomogeneous dielectric distribution of the scatterer buried in the rough surface. In order to explore the dielectric coefficient distribution of the unknown dielectric object under the rough surface, we emit electromagnetic wave to the object and measure the scattered electromagnetic wave above the rough surface. Base on Green's identity and the induced current

This article deals with a new hybrid approach combining a Moment Method (MOM), with the Geometrical Theory of Diffraction (GTD), this approach evaluates the currents surface on the microstrip antenna placed in the rectangular Electric Magnetic Electric Magnetic(EMEM) Waveguides. The incident field is taken as a TEM polarized plane wave in the principal plane. The new hybrid current function based on

Using the perturbation theory (PT), reflected field both in specular and non specular directions from a slab made of topological insulator (TI) material with rough interface is studied. The specular reflections are described by zeroth order terms of the perturbation series while non specular reflections are associated with higher order terms. To describe the surface states on the TI, γ-model characterized

We report a broadband ultra-high frequency (UHF) radio frequency identification (RFID) tag antenna of compact size mounted on a metallic object in a near field communication (NFC) RFID system. One half of the square radiation patch has a semi-annular strip feedline embedded inside a semicircle-shaped slot to improve the antenna bandwidth and gain, and the other half of the radiation patch has an L-shaped

The aim of this paper is to correct errors of a published study [Afzaal M, Syed A, Imran A, et al. Scattering of electromagnetic plane wave by a PEC strip in homogeneous isotropic chiral medium. Journal of Electromagnetic Waves and Applications. 2014;28(8):999–1010]. The investigation is a prominent and attractive subject in the field of electromagnetic scattering that has studied the electromagnetic

This paper presents a novel two-element multiple input multiple output (MIMO) reconfigurable antenna that can be switched among 600 MHz, 1.8, 2.4, 3.5, and 5.5 GHz bands. The proposed antenna consists of two semi-circular ring-shaped strip-lines and a rectangular slot on the top conducting layer of the substrate and a U-shaped slot, etched on the bottom side of the substrate. Frequency reconfigurable

In this paper, a compact wideband circularly polarized slot antenna consisting of two L-shaped resonators is proposed. The slot antenna is loaded with a band-stop frequency selective surface (FSS) reflector to improve the gain of the antenna and to reduce the profile of the antenna. The radiation and scattering characteristics of FSS loaded slot antenna are compared with the metallic reflector loaded

This paper presents a novel compact high-isolation cavity-backed inverted U-shaped slot antenna using substrate-integrated waveguide (SIW) for C-band applications. The SIW cavity is loaded by an inverted U-shaped slot that produces two fictitious aperture for radiation at two distinct frequency bands and to exhibit self-diplexing antenna (SDA) characteristics. Two orthogonal microstrip feed lines are

In this paper, an X-band perfect cross-polarization convertor (CPC) that consists of Γ-shaped metal patch imprinted on a metal-backed FR-4 dielectric substrate is designed, analyzed, and characterized. The unit cell dimensions of the developed structure are optimized to achieve more than 99.9% polarization conversion ratio (PCR) for a frequency range of 8–12 GHz (X-band) at normal incidence angle.

In this work, a wideband microwave resonating-type absorber is investigated in terms of metal backed metamaterial absorber (MMA). Expanded graphite-silicone (EG-Si) composite is encapsulated in the flexible silicone rubber matrix to build periodic unit cell of the MMA. Microwave material characterization of the EG-Si composites with different weight percentages (1, 3, 5, 7, 9 and 11 wt. %) is carried

The use of strong magnetic fields for brain imaging has shown that increased SNR and resolution can be obtained. Such MRI systems are prone to field non-uniformities that are more likely to appear in deep brain structures making high-quality imaging of deep brain regions a challenge. We investigate the combination of a dipole antenna and Birdcage coil to generate a uniform magnetic field with high

A slot array substrate integrated waveguide antenna is proposed by utilizing novel center inclined slots with non-uniform spaces for imparting feeding advantages of standing and traveling waves. This 1 × 8 array antenna introduces a 13.2 dB gain at center frequency of 59.9 GHz with −10 dB return loss from 58.9 GHz to 60.9 GHz (roughly 2 GHz) and cross-polarization levels more than 45 and 20 dB in E

An analytical solution for the diffraction of plane waves by a right angle impedance wedge which is lying between double negative and positive materials is investigated. In order to satisfy the boundary conditions and shifted shadow boundary, the diffracted fields are divided to subfields. As a result, an anomalous shift of shadow boundary is observed towards to lower surface of the wedge. In addition

In this article, the plane wave diffraction by two strips is studied. Fractional boundary condition is required on strips when the fractional order for each strip is different. The goal of the paper is to investigate the resonant properties of such structures. The mathematical apparatus for the solution of the problem is given. The frequency dependency on the total radar cross-section is constructed

A high transmission tunable metamaterial structure is proposed and manufactured experimentally in the THz range. A transmission peak is achieved at resonance frequency 5.97THz based on the bright-bright modes coupling effect. The transmission peak can be controlled by changing the periodicity P of the unit cell or the diameter D increasing. Moreover, the transmission peak can also be controlled by

The design and development of multiband antenna for useful operating bands are the current state-of-the-art research in the field of antenna research. A simple and single-layer printed multiband radiation structure eliminates the packaging complexity of modern communication devices. The present investigation proposes such simple and single-layer multiband antenna for ISM 2.5 GHz/WiMax 3.5 GHz/WLAN

This paper demonstrates symmetric backward wave quasi-0 dB coupled line coupler (CLC) based on the globe shaped composite right/left-handed transmission line (GS-CRLH-TL). The proposed CLC shows quasi-0 dB backward wave coupling with measured maximum backward coupling level of −0.72 dB at 3.07 GHz. −3 dB bandwidth of the backward coupling region is from 2.75 GHz to 3.34 GHz, corresponding to fractional

A low-profile multi-input-multi-output (MIMO)/diversity antenna suitable for wireless local area network (WLAN) applications is presented. In the proposed antenna, two identical elements (each of size 20 × 47 mm2) are designed to operate at 2.4 GHz and other two identical elements (each of size 20.5 × 20 mm2) at 5.8 GHz. All elements of the proposed diversity antenna are printed on 1.6 mm thick FR-4

In this paper, we design a compact MIMO antenna with high isolation. The antenna covers 2.5/5.8 GHz frequency bands, which are allocated for Wi-MAX / WLAN applications. The suggested MIMO antenna consists of two identical F-shaped monopole antenna elements, which are symmetrically positioned on the top side of an FR-4 substrate. To increase the isolation between the two radiating elements, a T-shaped

The design method of an unequally spaced array was based on the density tapering in the textbook “Antenna theory” in 1969. The effects on grating lobe reductions were shown by radiation pattern calculations. However, no proof for the achievement of density tapering was shown. In this paper, through direct comparisons of the objective amplitude distribution with electric field distributions by electromagnetic

An efficient approach for in-band radar cross section (RCS) reduction of microstrip patch array antenna without employing extra-low RCS artificial materials is proposed and analysed. The element of the array has a simple structure, consisting of a corner-cut square patch and two tiny perturbation elements. By controlling two independently biased PIN diodes, it can produce linear polarization (LP),

The present work aims to propose a new formulation by combining the moment method and generalized equivalent circuit's method (MOM-GEC) to study the performance of a frequency reconfigurable antenna commanded by a PIN diode(s) as switching component(s). This method makes it possible to reduce the 3D problems to an alleviate calculation in the discontinuity plane using the admittance operators. The

Magnetized ferrites are anisotropic materials used in passive non-reciprocal components. One of the main applications of ferrites at microwave frequencies is the isolation effect. In this work, the non-reciprocal propagation in a ferrite coplanar coupler is studied from simulation results. The proposed structure exhibits a low insertion loss less than 1 dB, and return loss better than 20 dB, with significant

This article presents a novel non-destructive microwave technique for predicting fluoride contamination in pure water. The proposed microwave-based sensing technique uses an open-ended coaxial probe (OECP) microwave sensor for monitoring fluoride concentration in water. The sensor output is the input of Artificial Neural Network (ANN) for predicting the complex dielectric constant of contaminated water

A novel three-in-one waveguide resonator is proposed in the paper. The resonator is composed of three rectangular partial-height posts inserted along a rectangular waveguide cross-section. A pair of posts is mounted symmetrically whereas the third antipodal post is centered. The resonator provides a bandstop response if all the posts are of equal height. Both singlet-type and pseudoelliptic characteristics

We propose a new approach to solve the problem of optimal power synthesis of array antennas, so that maximum possible bandwidth can be granted to fixed sidelobe-level performances. The proposed approach can be applied to any kind of fixed-geometry array that radiates pencil beams and to linear equispaced arrays that generate shaped patterns. The designing problem is cast as a sequence of Convex Programming

In this paper, a novel frequency reconfigurable filtering antenna is proposed for modern wireless communication systems. The feed network is composed of a stepped impedance resonator filter and a 50-Ω microstrip line. PIN diodes are used to switch the antenna to operate at either an ultra-wideband state or a dual-band state. For the dual-band state, the antenna operates at both 3.35 and 5.2 GHz. The

A novel method for the calculation of eigenfrequencies of non-uniformly filled spherical cavity resonators is developed. The spectrum is determined through the introduction of effective “dynamic” potentials which encode the infill inhomogeneity. For angularly symmetric cavity, regardless of its radial non-uniformity, the set of modes is shown to be a superposition of TE and TM oscillations which can

In this paper, a water based All Dielectric Frequency Selective Surface (ADFSS) is presented made of renewable materials. This surface is based on a modified dielectric resonator incorporating air holes inside the water to increase its Q factor. The ADFSS shows a low pass response with a cutoff frequency of 3.7 GHz. The surface is simulated and measured giving reasonable results.

In this paper, the electromagnetic fields of a horizontal infinitely long wire source buried in a three-layered medium are studied. The source and the observation points are located in the middle region. The expressions of the electromagnetic waves are more complex because of the multiple reflections from the up and down boundaries. The electromagnetic field components between the two boundaries are

In this paper, a high power millimeter wave gyrotron cavity was modelled and studied for its beam-wave interaction, beam-misalignment, and thermal issues. The sub-assemblies including the magnetron injection gun (MIG), RF output window, and electron beam collector were investigated. The MIG has produced an annular electron beam with transverse velocity spread less than ∼4%. The Particle–In–Cell simulation

The present work focuses on the radiation field excited by a horizontal electric dipole (HED) in a four-layered region composed of a perfect conductor covered with two dielectrics and the air above. Analytical expressions for the radiation field are derived for the case of both the source and the observation point being on or near the air-dielectric boundary. The propagation characteristics of the

This paper presents a comprehensive review of the state of art techniques and geometries which have been explored in the areas of Dielectric Resonator Antennas (DRA). With the evolution of first rectangular geometry to the current investigations, the basic aims of research in this field of electrical size miniaturization, retrofitting bandwidth as per commercial needs and radiation pattern stability

Transmission through a slot in a an infinite metallic shield of finite thickness, inhomogeneously loaded with dielectric material, is modeled using an analytical approximation based on the slot being small compared to a free space wavelength. Resonances of relatively broad bandwidth (Fabry-Perot) as well as of very narrow bandwidth (Fano) are found. We show that by introducing a gap of different dielectric

Rectennas are key contributors in wireless power transmission. Such prominent technology requires intensive works to gain a better performance thus a reliable energy source. In this paper, we present an electromagnetic model of rectenna using nonlinear resolution approach. This was achieved by a hybrid MoM-GEC (the Moments method combined to the generalized equivalent circuit) and the Harmonic balance

In this work, a design method for artificial magnetic conductor metasurfaces based on generalized boundary conditions is proposed as an alternative to analytic expressions and to conventional optimization approaches. First, the required surface susceptibility is analytically obtained by using generalized boundary conditions and the equivalent circuit model. Then, the geometry of the PEC scatterers

As a first of its kind in India, indigenous development of dual-polarization C-Band Doppler weather radar (DWR) is discussed in the manuscript. Radar Development Area (RDA) of ISRO Telemetry Tracking and Command Network (ISTRAC) have developed the system and the DWR is installed at Thumba Equatorial Rocket Launch Station (TERLS) of Vikram Sarabhai Space Centre (VSSC) which is a centre of Indian Space

A compact planar inverted-F antenna (PIFA) placed on one of the two hinges of a laptop computer is proposed for wireless local-area network (WLAN) operation. The aim of this design is to integrate the PIFA’s metal surroundings as part of the radiating structure. When the PIFA is fed, resonant modes in the hinge slot bounded by the two hinges, display ground plane, and keyboard ground plane can in turn

In this paper, high port isolation in dual feed orthogonally polarized square patch antenna array is achieved by the use of Defected Ground Structure (DGS). A simple rectangular-headed cross DGS is implanted in the ground plane underneath the square patch in order to achieve high port isolation between two orthogonal ports at 2.95 GHz. The proposed design offers 58.55 dB port isolation between ports

In this paper, an ultra-wideband circular polarization (CP) maintaining reflector is proposed based on an anisotropic metasurface, which is an orthogonal anisotropic structure with a pair of symmetrical axes u and v perpendicular to each other. The simulated results show that the reflector can realized CP-maintaining reflection under both right-handed and left-handed CP (RHCP and LHCP) incidences in

In this paper, the concept of the circularly polarized agile, multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) structure for fifth generation (5G) new radio application in mobile terminal is presented. Two prototypes have been fabricated, namely one with cylindrical DRA (CDRA) referred as A1 and a second one with ring DRA (RDRA) named as A2. These practical realizations of dual-port

An approach for improving the invisibility performance of mantle cloak is proposed. It is based on an interesting observation that the cloaking performance of mantle cloak can be significantly enhanced if the cloak is operated under tilted conditions with respect to the incident radiation (such that the wave is incident obliquely onto the cloak). The mantle cloak is thus designed by judiciously choosing

In the present endeavor, a CPW-fed dome-shaped monopole radiating elements with 2 × 2 MIMO configuration is presented. The dual-band response of the antenna is obtained by embedding a pair of comb-shaped slots in the ground plane. The measured dual frequency bands of 2.11–4.19 GHz (lower) and 4.98–6.81 GHz (upper) effectively cover LTE, Wi-Fi/WLAN, Bluetooth, and Wi-MAX applications. A T-shaped stub

Most electromagnetic phenomena pertaining to metamaterials are observed at the resonance positions. In this review, we have collated and analyze the most prevalent forms of resonance-based phenomena observed in metamaterials to serve as a ready reference for future researchers. Our focus will be on metamaterials operating at the terahertz frequency domain. Starting with the origin and evolution of

In this paper, a proposal of a four-port antenna for MIMO applications is presented with high interport isolation. The isolation among elements is implemented by limiting the surface current distribution of each radiator by placing them on different substrate layers, leading to a size optimization. The array is implemented by four drop-shaped slot radiators. The antenna performs from 1.7 to 7.2 GHz

In this paper, a kind of bi-layer extrinsic chiral metamaterial is proposed to realize asymmetric transmission (AT) of circularly polarized waves in the microwave region. We have studied numerically and experimentally the transmission properties of the proposed structure. The results show that under oblique incident wave the asymmetric transmission effect occurs with a 1.5 GHz operation band. The maximum

A one-dimensional nonreciprocal structure comprising two asymmetric multilayers filled with magneto-optical dispersive media and a defect layer is designed. The nonreciprocal optical Tamm states (OTSs) are excited at the interface of the two asymmetric multilayer structure with an opposing external magnetic field. With the excitation of the nonreciprocal OTSs, the numerical results show that the waves

This paper proposes a 3.5-GHz four-element multi-input multi-output (MIMO) antenna system for fifth-generation (5G) laptops. The four antennas are configured into two dual-antenna units, measuring 26 × 3 × 2 mm3 each and separated by a distance of 6 mm, the latter of which accounts for the isolation between the two units. The two antennas in each unit are located on the two sides of the same substrate

This paper presents a 4 × 4 multiple-input–multiple-output (MIMO) antenna array for ultra-wide band (UWB) applications with 5.5 GHz wireless local area network (WLAN) band rejection characteristics. The single UWB antenna element consists of modified patch antenna with partial ground plane. WLAN band has been rejected by etching a U-shaped slot in the antenna element. The antenna elements have been

In this work, we present the analysis and design of a perfect metamaterial absorber (MA) based on the circular cavity with one side open in the terahertz region. This structure consists of a metal plate where one circular cavity with one side open is vertically placed on. Based on the circular-cavity-theory, a formula can be used to calculate the resonant frequency. In terms of normal incidence, the

This paper reviews recent progress in perfect absorbers of electromagnetic waves that utilize metamaterials (MMs). Various numerical techniques that are inevitable for the research on MMs, along with their pros and cons, are commented on and discussed. Abandoning the conventional periodic-boundary conditions is crucial for understanding the discrepancy between simulation and experiments for certain

This paper presents a new design of a compact dual-band Multiple Input Multiple Output (MIMO) antenna with high isolation for WLAN and X-band satellite applications. The proposed antenna is realized using three slots: the first slot is used on the upper layer to create the second resonance frequency at 5.3 GHz and two symmetrical slots are etched on the bottom layer to enhance the impedance bandwidth

An alternative approach for the design of feeding networks designated for two-beam antenna arrays that ensure similar radiation patterns in a very broad frequency range has been proposed. The presented concept is based on directional filters that are utilized for smooth change of excitation signals of two broadband radiating elements and a broadband directional coupler used for ensuring quadrature

In this paper, we studied the impact of material characteristics on the optical response of a perforated surface plasmon system as a general trend by employing dielectric function of metallic film. To this end, different artificial materials were modeled based on a single interband transition peak in the form of a Lorentzian function in the imaginary part of dielectric function ε2 as well as a Drude

This paper presents a set square design which serves as a wideband Metamaterial Absorber (MA) for X-band applications. The simulation results show that the absorber has −8 dB absorption bandwidth of 2.51 GHz (8.36–10.87 GHz) and the Full Width Half Maximum (FWHM) bandwidth of 3.55 GHz (7.47–11.02 GHz). MA proposed in this paper uses FR4 as a substrate having thickness of 1.6 mm and overall dimensions

This paper presents the design of fidget spinner-shaped antenna (FSSA) loaded with parasitic EC-SRR (edge coupled-split ring resonator) for multi-standard wireless applications. Parasitic EC-SRR element-loaded antenna helps to improve the impedance matching and bandwidth of antenna in comparison to the unloaded FSSA. The 50 Ω microstrip line fed has been applied to the structure of proposed antenna