Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

The gain enhancement using superstrate has been widely investigated. Different from the existing research work, this letter focuses on the study of dielectric slab superstrate (DSS) antenna element with electrically small size. For the electrically small DSS antenna, the gain enhancement mechanism based on the multireflections between interfaces with infinite sizes is no longer available. By using

An irregular antenna synthesis technique with jointly optimized array subset layouts has been proposed for efficient beam setup and reliable communication in 5G. The proposed approach addresses both the electromagnetic and thermal challenges in 5G arrays by integrating zooming and wide-angle scanning functionality into interleaved-shared layout aperiodic arrays with low side lobes. The effectiveness

An antenna array is developed to radiate angularly distributed multibeams. The proposed antenna utilizes a 2-D Luneburg lens as a beamforming network (LL-BFN) to produce rotationally symmetric excitations. The concept is to replace an equivalent circular aperture of Luneburg lens by a circular array of excitation output ports. Thus, in addition to the beam selection ports, antenna excitation ports

In this letter, an algorithm for synthetic aperture radar imaging of electrically small targets embedded in multilayered cylindrical geometries (e.g., pipes) using nonuniform measurement points is presented. In contrast to previous approaches, this algorithm is able to efficiently handle nonuniform points without exhibiting relevant side lobes in the image. For these purposes, the approach exploits

Three attenuation statistics combination methods are evaluated and compared in this contribution for the first time using a consistent set of propagation data used as input and as a reference to test the methods’ performance. The three approaches, which rely upon different statistical assumptions, aim at estimating the total tropospheric attenuation statistics by combining the complementary cumulative

A planar array antenna consisting of 6 units of rectangular dielectric resonators fed by means of novel microstrip lines through aperture coupling is presented. The structure is designed in such a way that two different modes are excited in the array elements that yield a high bandwidth and gain. Based on the experimental results, the antenna is seen to have an impedance bandwidth of 6.98% centered

A single-layer, dual-mode microstrip patch antenna with self-nulling patterns is proposed. The antenna consists of a circular microstrip patch antenna, surrounded by a shorted concentric ring patch, exciting the TM 11 and TM 21 modes, respectively. Adaptive radiation patterns with self-scanning and nulling capabilities are realized by concomitantly exciting these two modes. To attain the mode purity

An intelligent radome that can realize asymmetric propagation of electromagnetic (EM) wave and energy isolation is presented and investigated in this letter. The radome is constructed with multilayer composites. The whole structure mainly consists of a broadband polarization-sensitive polarization converter (PC) and a frequency selective rasorber (FSR) with p-i-n diodes embedded. Among them, the function

In this letter, we present a novel time-domain analytic formula for the elementary radiator antenna pattern of a metal plane surface with infinite conductivity. The formula is presented as a function of time and the integration angle. The formula refers to a flat metal aperture without regard to its shape. We also describe a novel equation for the primitive impulse response function (PIRF) of a circular

By incorporating the complex envelope (CE) method and the higher order concept, unconditionally stable perfectly matched layer (PML) is proposed based on the Crank–Nicolson approximate-factorization-splitting (CNAFS) algorithm to simulate the bandpass problems in finite-difference time-domain lattice. The proposed algorithm has the advantages of the CNAFS algorithm, higher order PML concept, and CE

A reliable and efficient way is proposed for investigating the electromagnetic (EM) scattering from a large marine environment containing multiple vessels. To enhance the computational efficiency, an improved method is proposed based on the facet-based simplified small slope approximation to calculate the scattering field from the sea surface. In addition, the overall sea surface is decomposed into

Using a single patch antenna to generate a vortex electromagnetic wave greatly simplifies the application systems of orbital angular momentum (OAM) modes. OAM modes can be synthesized from degenerate modes, and thus, characteristic mode theory is a helpful tool to guide the construction of OAM antennas. Based on this idea, a single-fed circular patch with an arc segment as a symmetrical perturbation

Electromagnetic inverse scattering problems (ISPs) aim to retrieve permittivities of dielectric scatterers from the scattering measurement. It is often highly nonlinear, causing the problem to be very difficult to solve. To alleviate the issue, this letter exploits a linear-model-based network (LMN) learning strategy, which benefits from both model complexity and data learning. By introducing a linear

A broadband measurement technique for the normal-incidence absorptivity based on parallel-plate waveguide (PPW) is proposed. The method is well suited for frequency-selective surface (FSS)-based absorbers. By employing the PPW structure, only a small sample size, i.e., 1-D array of FSS, is required for the measurement. The thru-reflect-line (TRL) calibration is implemented to remove the time-gating

In this letter, a dual-band 8 × 8 multiple-input–multiple-output (MIMO) antenna that operates in the sub-6 GHz spectrum for future 5G MIMO smartphone applications is presented. The design consists of a fully grounded plane with closely spaced orthogonal pairs of antennas placed symmetrically along the long edges and on the corners of the smartphone. The orthogonal pairs are connected by a 7.8 mm short

Electromagnetic–thermal cosimulation of large antenna arrays is performed by using a supercomputing-based parallel domain decomposition method. In this letter, frequency-domain electromagnetic and thermal fields are solved self-consistently and then coupled via Joule heat and temperature-dependent material properties. The developed cosimulation solver is first validated with the commercial software

A novel uniplanar chipless RFID solvent vapors/gas sensor is proposed in this letter. The sensor etched on an extremely thin capton substrate is composed of the folded dipole resonator loaded by the interdigital capacitor located inside the planar rectangular metallic loop that improves the radar cross section (RCS) response. When illuminated by a plane wave, the folded dipole causes a notch in the

Adaptive circular antenna arrays with beam-steering are very important components of space navigation, and radar systems. A problem may occur when the receiver is jammed by an interference signal, and a quick reaction is required in this regard. An immediate solution to this problem is to have an adaptive fast beamforming algorithm that suppresses the interference signal by steering the radiation pattern

The prediction of the 2-D electric field strength distribution from a limited set of measurements and without any prior information on the source is addressed in this letter. Towards this aim, an innovative sparseness-promoting approach is presented based on the profitable integration of a total-variation compressive sensing (TV-CS) recovery technique with the LOLA Voronoi adaptive sampling strategy

In this letter, a self-interference cancellation (SIC) method is presented for short-range full-duplex multiple-input–multiple-output (MIMO) communication. The proposed SIC consists of the following steps. First, each peer has multiple transmitting (Tx) and receiving (Rx) antennas optimally arranged to form a one-rank self-interference (SI) matrix between Tx and Rx. The optimal antenna arrangement

This letter investigates the feasibility of designing a high gain on-chip antenna on silicon technology for subterahertz applications over a wide-frequency range. High gain is achieved by exciting the antenna using an aperture fed mechanism to couple electromagnetics energy from a metal slot line, which is sandwiched between the silicon and polycarbonate substrates, to a 15-element array comprising

Polyimide film is a practicable alternative to the conventional substrates utilized in conformal antennas. Due to its flexibility, the antennas based on the polyimide film can be easily conformed to the platform surface. An eight-element linear-phased array operating at the P -band with a wide scan angle is investigated in this letter, which is constructed by the dipoles printed on the polyimide film

Commercial 1.164 km long microwave link (CML) data with frequencies of 72.75 and 82.75 GHz (E-band) deployed in the Prague urban area were used to estimate the wet antenna attenuation (WAA). By analyzing the time series of WAA, a WAA model of E-band CML is proposed based on the long short-term memory neural network. The results show that the predicted value is consistent with the real value, especially

In this letter, we transplant the epsilon-near-zero response into the design of a flexible antenna with invariant operating frequency using the magnetron sputtering and through-silicon-via crafts. The antenna is based on a section of substrate-integrated waveguide operating at its transverse TM 100 and TM 110 modes, to provide a difference pattern and a sum broadside pattern, respectively. The flexibility

A novel design method of bandpass absorptive frequency-selective structure (AFSS) is presented in this letter. The proposed AFSS is based on double-sided parallel-strip lines (DSPSLs), which is different from those based on the conventional parallel L-C resonator. Its lossy layer of a unit cell consists of the DSPSLs and striplines loaded with four lumped resistors, in which one end of the DSPSL connects

A dual-polarized Eleven antenna fed by two passive baluns is proposed in this letter. As the dual-polarized Eleven antenna generally has four differential ports, the feed structure is carefully designed to reduce the number of input ports, and consequently, simplify the overall structure. The simulated results show that this antenna can operate from 5 to 16 GHz with the voltage standing-wave ratio

In this letter, a wideband differential hollow rectangular dielectric resonator antenna (DRA) designed using higher order mode is investigated. The fundamental TE 111 y and higher order TE 113 y modes of the rectangular DRA were employed for the design. To merge these two DRA modes together, the hollow DRA with its air region displaced from the center is employed. Both the single- and dual-port wideband

Radiation leakage of a global positioning system (GPS) module was investigated for a drone detection system by measuring the attenuation effect and long-range detection on the outside of a building. The GPS module consisting of the radio frequency components is essential to control the flight of a drone. There is an unavoidable leakage in the GPS module during operation, and the leakage signal from

In this letter, a coupler integrated microstrip patch linear phased array is proposed as a new self-calibration system. The proposed coupler placed along the edge of the microstrip patch antenna is weakly coupled to the antenna array. This allows self-calibration without affecting the radiation performance of the antenna array. A 1 × 4 coupler integrated patch linear phased array and a beamformer operating

This letter proposes a novel successive weighted received signal strength (RSS) indoor localization and tracking system that projects previous time instance estimated mobile device (MD) position to provide projected RSS values. Such RSS projection increases the number of available RSS from Nm to Nm + N AP , where N AP is the total number of access points and Nm is the number of RSS values measured

This letter presents, for the first time, a custom-built high frequency (HF) radio frequency identification (RFID) system that enables the communication with an RFID transponder (tag), which is attached to an object located in an enclosed metal housing. Proof-of-concept measurements of the custom-built HF RFID system show a good system performance and a favorable extension of the read range in the

Air-to-ground (AG) communications have attracted much attention for future advanced wireless communications. Unmanned aerial vehicle, as a critical enabler in AG communications, can be operated in various environments, such as over-water, hilly, and built-up environments. A better understanding of radio channels in various scenarios can immensely facilitate the deployment and design of wireless systems

In this letter, a CPU/field-programmable gate array (FPGA) coprocessing implementation of the matrix assembly phase of the method of moments (MoM) is presented. The approach combines the frequency-domain integral equation-based formulation with piecewise-linear (triangular) basis function and method of images to evaluate the radiation pattern of the localizer antenna system. To benefit from the given

It is well known that radome has adverse effects on the performance of the antenna array while protecting it from outside environments. In some extreme cases, e.g., when an airborne radome is ablated during the flight of a high-speed vehicle, the impaired radome will severely alter the radiation pattern (RP) of the antenna array. To counteract this effect, it is desirable that the RP of the array can

Using plane-wave generator (PWG), an array consisting of a number of radiating sources, to emulate incoming signals from the far-field zone across the aperture of the antenna-under-test (AUT) is an alternative solution for antenna testing, especially for electrically large AUTs. The locations and weights of PWG elements need to be carefully designed to satisfy the required accuracy of the far-field

One of the singularity cancellation schemes proposed in the literature is applied to calculate singular integrals arising in the method of moments (MoM) analysis of 2-D periodic planar structures in multilayered media. Discrete complex image method is utilized for the accurate approximation of Green's function which also makes possible the application of the Ewald transformation for the efficient computation

Integrating particle swarm optimization (PSO) and binary PSO into multiobjective evolutionary algorithm based on decomposition (MOEA/D) by group operator in parallel, an improved mixed optimization algorithm MOEA/D-M is proposed as an automation design scheme for compact high-isolation multiple-input–multiple-output (MIMO) antenna design. When the algorithm runs, each particle has several neighboring

In this letter, the stacked dual-slotted substrate integrated cavities (SICs) are proposed to achieve a filtering antenna. The dual-slotted SIC shows dual-mode behavior (quasi-dual-slot mode and quasi-cavity mode), which can achieve multiorder response with fewer SICs. Furthermore, the antenna exists at two frequencies at which the electric field has opposite horizontal component ( $E_{x}$ ) near each

A compact dual-polarized filtering base-station antenna is presented in this letter. The entire size (include the ground plane) of the element is only 0.53λ × 0.72λ × 0.14λ (λ is the wavelength of the central working frequency). Four vertical slots etched on the coupling cross slot are for improving the high-frequency suppression of the antenna. The C-slots on the Gnd1 reduce the cross-polarization

In this article, we present a dual-ID radio frequency identification (RFID) headgear based on quasi-Yagi antenna where we reuse the reflector element as the second dipole antenna that provides radiation pattern upward from the user's head. Thus, we achieve simultaneously the broadside and endfire patterns without increasing the size of the antenna platform. For avoiding the unpredictable impact of

In this letter, we propose an inverse synthetic aperture radar (ISAR) imaging method using time-domain (TD) scattering echo simulated by time-domain physical optics (TDPO) method. First, the TD pulse plane wave is taken as the incident wave and the transient scattering echo data matrix is obtained by using the TDPO method under different look angles of the target. Then, demodulation, pulse compression

The proposed antenna combines a conventional patch with an artificial magnetic conductor (AMC) ground plane and a frequency selective surface (FSS) superstrate with the height of 0.35 λ 0 (at f = 8.5 GHz) from the feed antenna. In this structure, to create circularly polarized waves, a FSS superstrate composed of an array of quasi-crescent shaped unit cells is used. In addition, to compact the antenna

This letter proposes a novel capacitively coupled microstrip comb-line (CCMCA) array antenna for millimeter-wave band applications. The proposed antenna has the advantages of low profile, low cost, and ease of fabrication for the millimeter-wave band. By adjusting the gaps between the radiating strips and feeding line, an antenna with low sidelobe level can easily be designed. To verify the suitability

In this letter, a novel method is proposed to design a low-profile multibeam transmitarray. Instead of a conventional horn feed, a slot array (SA) feed is used to illuminate uniformly same size transmitarray aperture (TA) in near field with a plane wave excitation, and TA is designed to transform plane wave to high gain multibeam pattern. The separation between SA feed and TA is independent of aperture

A mechanically flexible and optically transparent millimeter-wave broadband absorber was proposed and fabricated. The absorber showed >90% absorption in (73.5–110) GHz, covering the whole W-band. The key frequency selective surface used a concise metal mesh structure fabricated by the electrohydrodynamics (EHD) printing technology, which formed a classic sandwich structure together with a transparent

Orbital angular momentum (OAM), providing an additional degree of freedom, has attracted much attention for spectral efficiency and its potential in communications. The need for more compact OAM-based communication systems has inspired research into quasi-circular arrays (QCAs) producing quasi-OAM beams. In this letter, a QCA-based communication system prototype is designed to transmit and receive

A novel nonuniform metasurface antenna is designed based on the characteristic mode analysis for wearable applications. A metasurface layer consists of a 3 × 3 unit cell array, in which the center and corner cells are rotated counterclockwise, whereas the other four unit cells are rotated in the opposite direction with a same rotation angle. The structure of a nonuniform metasurface is optimized according

A dual-resonance wideband full-metal cavity-backed slot antenna array (CBSA) with high efficiency is proposed. A cavity mode and a resonant-iris mode are used to produce a wide impedance bandwidth. Radiation slots (elements) placed on the top wall are directly fed by electric fields of the modes using a single feeding slot without extra structures. This simplified feeding structure can reduce the antenna

In this letter, theory concerning scattering of electromagnetic (EM) waves with orbital angular momentum (OAM) is presented, in which a metallic sphere illuminated by OAM waves is adopted to simplify the study. Based on the series expansion and the physical optics (PO) methods, expressions of incident and scattered OAM waves are obtained. To get the expansion coefficients of the scattered fields, boundary

A broadband balanced-to-single-ended (BTSE) four- way power divider (PD) with out-of-phase is designed in this letter. The proposed four-way PD composed of three-series T-junction PDs, a balanced U-type microstrip–slotline transition structure, and multiple cross-junction microstrip–slotline transitions. The series T-junction PD achieves equal amplitude and out-of-phase power distribution at the output

We present a recursive version of the previously proposed fast algorithm for computation of the field scattered from arbitrary-shaped multilayer objects. As in the original version, the field at each layer is represented by a series of cylindrical functions with unknown coefficients. In order to determine these coefficients, a linear system of equations is obtained through a procedure based on the

The characteristics of different resonance modes of a dielectric sphere (Alumina ceramic, permittivity around 10) are investigated by Mie's theory and confirmed by field simulations and by measurements. Based on the dominant transverse magnetic resonance mode of the sphere, an on-chip antenna design is proposed. The antenna for operation at 180 GHz is using a spherical dielectric resonator of Alumina

This letter presents two designs of pattern-reconfigurable wearable antennas for body-centric wireless communications (BCWC). The reconfigurabilities of these two designs are realized utilizing two totally different mechanisms. In the first design, two subantennas with different radiation patterns are integrated. With a reconfigurable feeding network, the design can switch between the two subantennas

This letter presents a symmetrically stacked planar antenna (SSPA) featuring switchable quasi-omnidirectional and omnidirectional radiation patterns to accomplish a quasi-isotropic radiation coverage. The proposed antenna consists of two identical planar patch antenna elements. By separately controlling the phase of the two excitation ports, the comprised antenna collectively emulates either an electric

A low-cost millimeter-wave circularly polarized (CP) planar integrated magneto-electric dipole (ME-dipole) element with simple structure is proposed, which is fed by a low-profile feeding structure capable of being directly integrated with Ka -band front-end circuits. Two rotationally symmetrical L-shaped patches are adopted to replace the two straight arms of the original linearly polarized ME-dipole

A compact linearly polarized quarter-mode substrate-integrated waveguide (QMSIW) dual-frequency millimeter-wave antenna is presented in this letter. The antenna has two unequal-sized quarter-mode parts of two square substrate-integrated waveguide (SIW) cavities for two operating bands. Each quarter can be tuned independently. The two quarters are realized within one layer of substrate laminate and

This letter presents coherence bandwidth values at 1945 MHz over 50 MHz using mobile channel data from 107 small areas in an urban environment with transmit ranges up to 4 km. Empirical relationships between coherence bandwidth for correlation levels 0.9 and 0.5 and root mean square (rms) delay spread are derived and compared with those from the literature. In contrast to previous modeling attempts

This letter presents a dual-sense circularly polarized (CP) microstrip patch antenna with a dual-coupled line. The rectangular patch antenna operating in TM 01 mode is utilized as a basic design, and a single-coupled line is introduced to excite the TM 10 mode with a phase difference of 90°, generating CP operation. As different polarizations can be obtained by changing the position of the single-coupled