A multiband reflective linear-polarization (LP) converter based on an anisotropic metasurface is proposed. The unit cell of the metasurface is composed of a hollow oval sheet and a rectangle patch. Simulation results show that the converter can convert LP wave to its orthogonal state and the polarization conversion ratio (PCR) is above 90% in four frequency bands (4.60–12.27 GHz, 13.79–13.90 GHz, 14

The performance of a multi-layered parallel plate waveguide, supported by graphene plates, is evaluated here. The graphene layers were biased with both magnetic and electric fields. The graphene plates weremodelled as an anisotropic surface derived from the Kubo formula. Maxwell's equations were solved for these waveguides; and it is shown when both magnetic and electric biases were applied to the

In this article, a compact uni-planar printed slot antenna with SAS geometry is proposed, facilitating UWB multi-bands, band-rejectionality, LP and CP using reconfigurable technique, with 2 x SMD diodes. For SMD1-ON, SMD2-ON, states antenna operates in SAS mode from 2.4–10.6 GHz and for SMD1-OFF, SMD2-OFF states antenna operates in slot mode, resulted in band-rejection from 2.7–4.3 GHz. For aforementioned

This paper presents a series of novel designs for dual-band bandpass filters (BPFs) with excellent in-band and out-band filtering performances. By imbedding the spiral-line resonator into the coupling open-loop structures and adjusting the symmetrical structure, the second-order quad-mode BPFs are designed and then the fourth-order oct-mode dual-band BPFs. The final two designs possess eight resonant

Aiming at the problems of low-frequency coverage, angle and polarization instability of ultra-wideband (UWB) frequency selective surface (FSS) in practical application, this paper introduces the additional circular parasitic patches and two-stage rectangular bent grids to enhance coupling, miniaturize geometry size, broaden bandwidth and suppress the drift of resonance frequencies based on the construction

A high-efficiency compact split-ring resonator (SRR)–complimentary split-ring resonator (CSRR)–substrate integrated waveguide (SIW) rectangular resonator antenna based on a composite right/left-handed transmission line is presented in this paper. A four-element rectangular CSRR structure is etched on the front of the antenna, and a four-element rectangular SRR structure is loaded on the back of the

In this paper, a reconfigurable dual-band bandpass filter, using memristive switches, is proposed. The applied memristor is non-volatile and has low-power consumption, which could be potentially used as an RF switch. The dual-band bandpass filter is based on the dual-mode resonator with a memristor. The odd-mode and even-mode method is utilized to analyse the proposed reconfigurable filter. By loading

A novel cascade trisection (CT) coupling structure, based on half-wavelength resonators, is proposed for designing constant absolute bandwidth (CABW) tunable bandpass filters. The tunable resonators have both electric and magnetic dominant coupling regions with predefined coupling coefficients. The third-order and fifth-order tunable bandpass filters (BPFs), which can realize CABW and a high side cross-coupling

In this paper, we have presented the influence of surface traps/states on RF and microwave performance of fully recessed Schottky anode AlGaN/GaN lateral Schottky barrier diode (L-SBD) using numerical modeling and simulation. During the etching/treatment of AlGaN or GaN surface, the surface traps are induced, whose physical modeling is proposed here. Through this study, the physical insights on the

A leaky-wave antenna made of cavity-backed-slot radiating elements with open-stopband suppression is presented. The cavity-backed slots are seriesly fed by a strip. The bandwidth of the unit cell of the array is enhanced by a recently-proposed technique that uses a matching stub. The open-stopband effect is mitigated by misaligning the stub with respect to the slot. An array is designed and fabricated

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 manufacturing costs can be reduced. However, the surface roughness of internal surfaces

At terahertz frequencies, the detailed fine structures on target’s surface can be compared with the wavelength, and the dispersive dielectric property of metals becomes obvious. Then, it is naturally thought that scattering characteristics of metallic spheres will exhibit a special phenomenon when compared with the situation in microwave band or infrared. Thus, a novel method of scattering modeling

An automated microwave technique for the monitoring of hidden objects for strategic applications has been presented. The proposed approach is quite novel as it implements and integrates the time-domain method in free-space with the indigenously developed automated scanning setup to obtain the dielectric profile of hidden objects in standard sand or behind the concrete structure. The existing imaging

Mutual coupling effects among the array elements can degrade the performance of the beamformer seriously. In this paper, we propose a novel robust adaptive beamforming method, which is robust against unknown mutual coupling. The main idea is to reconstruct the interference-plus-noise covariance matrix (IPNCM) with the estimated eigenvector and eigenvalue corresponding to the interference. The eigenvector

ABSTRACT In this paper, the RF behavior of a 35 GHz, TE04 mode cylindrical cavity gyrotron is investigated using the nonlinear multimode theory and PIC code “CST Particle Studio”. A code is developed to realize the beam-wave interaction mechanism using time-dependent multimode theory. The cold cavity behavior is observed for the cavity operation in the designed TE04 mode and 35 GHz frequency. The magnetic

This paper introduces, for the first time, an extended modal integral technique for reliable characterization of multilayered symmetrical/asymmetrical planar structures built on arbitrary number of uniaxial electric/magnetic anisotropic layers. Based on a simple but efficient recursive algorithm devoted to composite substrates, the proposed hybrid mode analysis involves the Galerkin’s procedure combined

A sparse array synthesis method based on improved wind-driven optimization algorithm (IWDO) and fast Fourier transform (FFT) for the purpose of sidelobe suppression was introduced. First, the uniform linear array was sparse by the FFT algorithm. Then the amplitude excitation weighting of array elements was optimized by IWDO algorithm based on probability factor chaotic map. During the optimization

The covariance matrix reconstruction based robust adaptive beamforming (RAB) methods overcome the performance degradation due to the imprecise knowledge of the steering vector and the covariance matrix. However, high complexity limits the application of them. In this paper, we proposed a new RAB method based on interference plus noise covariance (INC) matrix reconstruction and desired signal steering

The design of a W-band gyrotron traveling wave tube amplifier is presented. The device with a lossy ceramic interaction circuit operates in the fundamental harmonic TE01 circular electric mode. The 70-kV, 6-A electron beam is produced by a double anode magnetron injection gun with an average perpendicular-to-parallel velocity ratio of 1.2 and a parallel velocity spread of less than 3%. The beam-wave

ABSTRACT The integration of extra wireless services in the limited size of mobile devices is a very challenging task. In this context, the antenna array presents the best choice to meet these requirements. This research demonstrates a reconfigurable antenna array system proposed for future 5G applications. The characteristics of the proposed structure are examined while using electromagnetic modeling

Telegrapher’s equations that account for the speed and acceleration of a current and voltage were derived using a modified Ohm’s law formula that includes relaxation components. Examining the exact analytical solutions to these equations allowed us to conclude that abrupt changes in the target functions observed in solutions to classic telegrapher’s equations were eliminated, which indicates the elimination

In this paper, pixelated Frequency Selective Surface (FSS) layer embedded in two carbonyl iron-filled silicon rubber (CISR) sheets are used for design of broadband microwave absorber in frequency range of 3.95 to 8.2 GHz. Top and bottom layers of CISR sheets are prepared with 24% and 33% of Carbonyl Iron (CI) powder by volume, respectively. Reflectivity of microwave absorber, complex permittivity and

This paper presents the results of theoretical and experimental studies of electromagnetic waves backscattering by partially non-reciprocal media. It is proposed to implement a controlled reflector that allows to simulate the polarization properties of an arbitrary partially non-reciprocal medium.

This paper presents an efficient implementation of the inversion algorithm based on the conjugate-gradient method (CGM) for solving inverse scattering problems. The original CGM provides good image reconstruction and robustness to noise-corrupted data. This method requires the solution of the forward scattering problem and the Fréchet derivative operator of the cost function at each iteration step

In this study, a 2-D mathematical model of a high-directive microwave antenna with a miniaturized volume profile is developed analytically. The antenna is a rectangular patch antenna on a metaferrite substrate. The substrate is a parallelepiped-shaped dielectric matrix with periodically embedded thin cylindrical ferromagnetic inclusions of a circular cross section. It is assumed that the inclusions

Under radar observation, every moving target contains a unique micro-Doppler (m-D) signature due to its structural component movement, which has been considered as one of the target class characteristics in their identification. It becomes challenging to identify the type of target and its motion parameter analysis for the simultaneous presence of multiple moving targets in the radar observation channel

The novel ridge-gap waveguide (RGW) technology which has recently been introduced has many advantages in micro/mm-wave frequencies such as low loss, broad bandwidth, low sensitivity to manufacturing errors and easy integration with active components, etc. In this paper, a Ku-band 8-way Wilkinson power divider (WPD) is proposed and simulated based on the RGW technology for the first time, to the best

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 incorporates a stepped impedance transformer as opposed to the conventional capacitive button to improve the return loss and power handling capacity of the converter. A rigorous RF, breakdown and multiphysics

Identifying the core of the convective cloud is paramount important to the identification of the Mesoscale Convective System (MCS) and its evolution is of great significance in the weather and climate system. To study the initiation and development of convective core systems, an automatic tracking algorithm named “Convective cell Identification and TRAcking (CITRA)” has been developed to identify and

The present paper deals with an approach to investigate the rectangular waveguide (RWG) using the conformal mapping technique, where the rectangular shape is converted to a sectoral one for the theoretical investigation. The wave equation is solved in the transformed domain to obtain the eigenfunction and the eigenvalue. The cut-off frequency and the internal field patterns for different TE and TM

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

Due to their subwavelength thickness, light weight and easy fabrication, metasurfaces show obvious advantages over 3D metamaterials. Among this, a new concept so-called digital coding metasurfaces which are described in a direct manner by quantized reflection or refraction phases was proposed. This paper proposes a scheme to achieve simultaneous and independent control of phase and amplitude responses

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 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 power amplifier to mismatch the intermediate frequency as the isolation band. And the intermediate frequency is 3.0 GHz. Besides, the design process of dual-band power amplifier is given, and an example

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

An artificial neural network (ANN) based frequency controlled automated RF sensor system for the characterization of dispersive liquids is presented. The frequency of the designed structure is electronically controlled by varying the applied reverse-biased voltage to the complementary split ring resonator (CSRR) attached varactor diode. A hybrid modelling approach has mainly been devised to account

A dual-band high-gain linearly polarized antenna for wideband operation using a defective frequency selective surface (DFSS) is proposed and demonstrated experimentally. The designed antenna consists of radiating patch, truncated ground with a half-inverted L-shaped rectangular ring and frequency selective surface (FSS) with a defective ground plane. The dimensions are optimized to achieve dual band

ABSTRACT An ultra-thin and ultra-wideband anisotropic metasurface, acting as a linear polarization converter through reflection is designed and simulated in this research. The operation frequency range covers almost completely the Ku-band and the entire K- and Ka-band. The unit cell of the proposed metasurface is composed of a arrangement of concentric square metallic loops on a grounded dielectric

The existing literatures, concentrating on the statistical analysis of transient response of antennas, radiated by high-altitude electromagnetic pulse, always choose an area-based method to calculate the statistics from the perspective of explosion. However, it may be more suitable to analyze from the view of the affected facility position. In this paper, we demonstrate a statistical analysis comparison

This work proposes a Machine Learning (ML) approach for the analysis and classification of Ground Penetrating Radar (GPR) given a limited number of B-scan images. Specifically, we consider both a custom Convolutional Neural Network (CNN) and a wellestablished Deep Learning (DL) architecture, DenseNet, that is opportunely scaled down to take into account the small dataset. Those networks are then employed

This paper proposes a low-profile, low-cost, and wideband quad-layer element for designing transmitarray antenna (TA). Changing the dimensions of the element shifts its passband. Sometimes, this shift is so large that the passband of the element exits the desired operating band of the TA. In other words, areas of the passband with low transmission magnitudes match the desired operating band. In this

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 a metal rim with a 1 mm wide opening. The slots are 3 mm wide and 90 mm long, and are placed diagonally on the upper left and lower right corners of the mobile phone in a mirror-symmetrical manner to achieve

A metamaterial lens was designed based on a two-dimensional host transmission line network loaded with inductors and capacitors. The planar negative refractive index (NRI) periodic structure, consisting of a unit cell array with a concave side, works as a curved lens matched to free space operating at S-Band. An equivalent unit cell dispersion relation was developed to determine the transmission characteristics

A high-resolution near-field focusing metasurface lens (MSL) was proposed to meet the high-resolution and miniaturization requirements of focusing devices in the Ka-band passive millimeter wave (PMMW) imaging system. Based on coaxial ring structure with polarization insensitivity, the design of a single refraction surface phase gradient MSL capable of focusing on plane waves is completed. Furthermore

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, and the isolation is larger than 10 dB. The ground clearance and the total size are 1.5 mm and 30 mm × 1.5 mm × 7 mm, respectively. Using the antenna pair, four- and eight-element multiple-input–multiple-output

The research addresses the problem of analytical description of energy detection procedure being one of the most favourable mechanism of white-space detection for cognitive radio and Internet-of-Things as well as unknown signal detection in radars and Unmanned Ground/Aerial Vehicle applications. A novel closed-form analytic solutions for average quality metrics (average receiver operating characteristic

A compact T-complementary split-ring resonator (CSRR) antenna was developed. Different from traditional designs, the proposed CSRR functioned not only as a loading structure but also as a radiator. The operation of the T-CSRR antenna was similar to that of a slot antenna with a gain of 3.1 dBi. Because of the loading effect of the CSRR, the size of the radiator of the proposed antenna was only 0.14λ0 × 0

An array antenna of two high-coupled patches with an edge-to-edge distance of only 0.02λ0 at 3.45 GHz merged with a Jerusalem-like parasitic structure (JPS) is reported. This JPS is compactly sandwiched between two patches and consists of two strips, horizontal (HS) and vertical (VS). HS perturbs the current distributions and so presents two mechanisms for improving the impedance matching and exciting

In this paper, electronic textile (E-textile) antenna design, with spurious mode suppression and low specific absorption rate (SAR), at a nearest distance of 1 mm from on-body phantom is investigated. The textile antenna is designed using a denim substrate material with conductive patch as a radiating element. The slots are introduced on the patch for spurious mode suppression so that external radio

In this report, a miniaturized low profile circularly polarized (CP) monopole antenna with broad 3 dB axial ratio (AR) bandwidth is investigated. The proposed antenna comprises an equilateral triangular monopole radiator, an inverted L-shaped element (ILSE) protruded from the finite ground plane to perturb the current distribution on the finite ground plane and an inverted L-shaped strip (ILSS). The

This paper presents design of a multi-slotted quadband 2-element MIMO antenna suitable for 4G and 5G applications. The design is realized on an 18.5 × 56 mm2 (0.154 λo × 0.467 λo, where λo is the wavelength of the lowest resonant frequency of 2.5 GHz) FR4 epoxy substrate having a thickness of 1.6 mm and a relative permittivity of 4.4. The simulated and measured results agree well with each other. A

High-speed switching capabilities of modern ICs cause generating more heat, and it must be ejected via metallic heat-sinks behaving as an antenna at certain frequencies. Having different radiation patterns(RP) at different frequencies may cause a malfunction on nearby electronics placed on the other part of PCB. In this study, 50W equivalent heat-sink is investigated at 2-8 GHz in terms of feeding

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 present study develops originally a BP NGD investigation of three-port circuit constituted by R, L and C lumped components. The equivalent S-matrix modelling is elaborated with the uncommon circuit theory

A miniaturized four-port polarization diversity ultra-wide band multiple input multiple output (MIMO) antenna is presented in this article. Different structures are combined and excited with the tapered transmission line to obtain a reduced symmetric layout with the orthogonal arrangement in compact size. An inverted-c-shape partial ground plane is used to decouple the antenna elements placed in close

In this article, a 2×2 broadband circularly polarized antenna array using the sequential rotation (SR) technique in the feed network is presented. This antenna covers the 5G-band of 3.5–3.6 GHz and 4.8–4.9 GHz. So, it can be used for 5G-band communication [1]. The performance of the antenna is obtained by simulation and experiment, as follows: the bandwidth of S11 parameter below -10 dB is 3.7 GHz

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, the holographic relation is modified by using the modulation index as a function of the spatial component corresponding to the propagation direction of the reference wave. In order to create a fascinating

The integrated THz pattern over any MMIC appears to be a good opportunity to enclose calibration kit suitable for accurate measurements. An original technology based on polymer has been developed. Sub-millimeter single-mode conductor-backed coplanar waveguides using benzocyclobutene polymer and interconnecting via between ground planes are processed and measured up to 760 GHz. The experimental performances

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

Designing a simple and planar antenna for high speed short distance ultra-wideband (UWB) communication has become a buzzword over the last few years. There are two very different categories of UWB technologies of vital relevance, i.e. (i) carrier-free direct sequence UWB (DS-UWB), and (ii) the Multi-Band orthogonal frequency division multiplexing UWB (OFDM UWB) technology. In, Multi-Band OFDM UWB technology

High-Resolution Range Profile (HRRP) is effective in various Radar Automatic Target Recognition problems. Multi-scale techniques have been verified in aircraft target HRRP feature enrichment to achieve aircraft recognition performance optimization. The involvement of multiple training-classification procedures in existing multi-scale methods results in tremendous resource consumption which challenges