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.

In this letter, the use of flat-top broad beams is proposed for the improvement of the robustness against direction-of-arrival (DoA) ambiguities in amplitude-monopulse systems, if compared to the conventional use of narrow tilted beams. Oscillations of the monopulse function outside the field-of-view are eliminated, thus suppressing false detections created by signals coming from outside the angular

This letter proposes a compact 435 MHz telemetry, tracking, and command (TT&C) CubeSat antenna, which does not require an in-orbit deployment mechanism for proper operation. It uses characteristic modes on spacecraft's body to increase the radiating aperture, resulting in a λ/4 sized antenna (as calculated along diagonal of the cube). The antenna aims to provide reliable communication, operating independently

Although the 60 GHz band meets the higher data rate demands for various wireless applications, large path losses and small size of 5 mm free-space wavelength makes the design, fabrication, packaging, and measurement of 60 GHz antenna arrays challenging. In this letter, we present a low-cost and high-efficiency patch antenna array fabricated using a printed circuit board (PCB) process. As the mini-connector

This letter presents a high-gain 32 × 32-element full corporate-feed array antenna using a simplified assembly of only two split blocks. This is made possible by a new feeding configuration which eliminates the cavity-backed layer used in conventional designs. E-plane T-junctions, as well as the single-ridge waveguide output structure, are used in the full corporate-feed network to reduce its size

The near-field ultrahigh-frequency (UHF) quadruple-loop antenna (QLA) with uniform field distribution for item-level tagging is proposed. The proposed antenna consists of quadruple fan-shaped small loops and the middle feeding lines of each loop located at the top and bottom of the substrate using vias. The currents flowing through feeding lines are cancelled due to opposite directional currents (ODCs)

This letter presents a broadband 3-D-printed circularly polarized (CP) spherical Luneburg lens (LL) with the linearly polarized feed antenna for the X -band. In order to implement spatially continuous varying effective refractive index (RI), the proposed LL is divided to many unit cells and their effective RI is simulated and calculated by effective medium theory. Since the effective RI of unit cells

A novel wideband circularly polarized microstrip patch antenna (MPA) with multimode resonance is proposed in this letter. The TM 1/2,0 mode, the zeroth-order mode, and the TM 1,0 mode are excited by inserting the shorting pins underneath the driven patch and the parasitic patch. Therefore, a wide impedance bandwidth is achieved under triple-mode resonance. By sequentially rotating the triple-mode elements

Solving the combined field integral equation (CFIE) for the large-scale scattering problem is computationally expensive. In this letter, we investigate the feasibility of applying deep learning to solve the CFIE for 2-D perfect electrically conducting objects. Inspired by the conjugate gradient method, an iterative deep neural network is designed to learn the manner of solving the surface current density

In this letter, a dielectric resonator antenna (DRA) with an engraved groove and a comb-like metal wall for beamwidth enhancement in both E- and H-planes is proposed. First, with an engraved groove, the radiation intensity on the top wall of the rectangular DRA can be enhanced, which significantly broadens the half-power beamwidth (HPBW) in the E-plane. Second, by placing a regular notched metal wall

A reconfigurable antenna with a compact size and quad-polarization reconfigurability is presented. By employing a switchable feed scheme, the antenna can operate at single-fed and dual-fed modes. At single-fed mode, the feed structure allows output ports switching to produce the excitations for either slant +45° or −45° linear polarization (LP). At dual-fed mode, it serves as a switchable phase-shifting

We present an algorithm for designing and manipulating pulsed caustic (accelerating) beams that propagate along a predefined planar curved beam-axis trajectory in free space. These pulsed beams are localized time-dependent wave packets. We evaluate the pulsed aperture field (source) distribution that radiates the beam along the desired trajectory. The aperture field is evaluated by setting its delay

In order to analyze the time-domain characteristics of multilayered lossy medium, a novel theoretical solution for calculating the transient reflected wave from the multilayered lossy medium is presented. We obtain the formulas of the time-domain interfacial reflected coefficient of the interface that separates two lossy media for the transverse electric (TE) and transverse magnetic (TM) modes according

A compact quarter-mode substrate integrated waveguide (QMSIW)-based self-quadruplexing antenna is proposed for compact radio frequency (RF) front ends. The QMSIW-based self-quadruplexing antenna has four unequal resonators resonating at the Industrial, Scientific, and Medical (ISM) band (2.45 GHz), fifth-generation (5G) band (3.5 GHz), wireless local area network (WLAN) band (4.9 GHz), and wireless

In this letter, we present a new approach of using time-modulated phased arrays to synthesize multicarrier directional modulation (DM) symbols for physical-layer security. In particular, the modulated waveform synthesis is achieved with the careful design of the switching time sequences, instead of in digital baseband; thus, reducing the peak-to-average power ratio of signals going through the radio

A new two-port same-polarized rectangular patch antenna based on generating two out-of-phase TM 10 modes for multiple-input–multiple-output (MIMO) access-point antenna application is proposed. Two simple probe feeds located at two opposite positions along the resonant direction of the TM 10 mode modify the excited electric field distribution inside the resonant cavity such that the zero or very weak

A millimeter-wave (mm-wave) dual-strip coupled dual-patch antenna is proposed, which is achieved by high density interconnect antenna-in-package process. The dual patches and dual strips are closely placed on the same layer and produce two resonances with broadside radiation and x -direction polarization. Compared with the state-of-the-art single-layer patch antennas, the proposed antenna can achieve

We previously used back propagation neural network (BPNN) with the meteorological factors of the receiver point to establish a model for predicting propagation delay of Loran-C signal over a short distance. Nevertheless, for a long propagation path, it is not proper to use only the meteorological factors of the receiver point. In this letter, a propagation delay prediction model that considers multiweather

A pattern-reconfigurable Yagi–Uda antenna based on liquid metal is presented. The antenna consists of a balun-fed active dipole and a pair of stretchable passive parasitic dipoles, which are implemented by eutectic gallium-indium (EGaIn) alloy embedded in microfluidic channels. The parasitic dipoles are driven at each end by two low-cost, three-dimensional printed media rods. Afterward, spinning the

This letter presents a method to convert the split dual-beam into a single one in the quasi-E-plane with low cross-polarization level for the pin-loaded fundamental EH 0 -mode microstrip leaky-wave antennas (MLWAs). By exciting a pair of them under differential operation with proper configuration, the ϕ -polarized dual beams can be reshaped to achieve a single-beam radiation, so as to widen its potential

This letter presents the analysis of a channel sounding campaign in the hull of a bulk carrier vessel at sub-6 GHz frequencies 868 MHz and 2.4 and 5.25 GHz as well as millimeter-wave (mmWave) frequency 60.48 GHz. For the sub-6 GHz frequencies, path loss (PL) is measured using omnidirectional antennas. The measured PL is fitted to a one-slope PL model that takes into account attenuation due to engine

A single-layer low-profile circularly polarized (CP) filtering patch antenna is investigated for wireless local area network (WLAN) applications. The CP antenna mainly consists of a feeding loop, four L-shaped radiating patches, and a square ground plane. To integrate the filtering function, four thin microstrip stubs and four shorting pins are introduced to the patches, and two U-shaped slots are

A novel frequency continuously tunable patch-slot antenna with wide-angle discrete scanning performance and one optional backward radiation state is presented. This antenna originates from combining one patch antenna with two endfire radiation slot antennas. By loading varactors on the patch, the working frequency is continuously adjusted, and simultaneously the maximum beam direction could be reconfigured

A broadband folded reflectarray antenna (FRA) is presented employing a novel single-layer cross-polarization conversion (CPC) subwavelength element in this letter. The proposed element has a very simple structure and consists of only a square ring resonator loaded with two splits, thereby realizing easy fabrication with low cost. By varying the length of the ring and mirroring the element, a 360° phase

Dry microwave imaging (MWI) systems are more practical, hygienic, and fast to operate since they do not require immersion liquid. However, the dielectric contrast between air and the part of the body under examination is larger, causing larger refraction effects. Including refraction in the image reconstruction algorithm significantly increases the computational effort, especially when imaging nonuniform

A novel single-feed ultrawideband cavity-backed slot antenna with a reconfigurable polarization capability is demonstrated in substrate-independent air-filled substrate integrated waveguide (AFSIW) technology for Internet-of-Things applications in the [5.15–5.85] GHz frequency band of the unlicensed national information infrastructure. The antenna achieves an ultrawide impedance bandwidth by exploiting

In this letter, we established the feasibility of producing localized ablation zones using microsecond pulsed microwave ablation (MWA) as an alternative to conventional continuous wave (CW) MWA. We verified that a thin floating-sleeve dipole ablation probe can withstand pulsed power delivery with peak powers as high as 25 kW, with pulsewidth on the order of 1 μs. We conducted MWA experiments in egg

Presents corrections to author information in the above named paper.

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.

In this letter, the problem of monopulse angle estimation error under mainlobe interference for dual- polarization array is investigated. The adaptive monopulse angle estimation considering cross polarization with array beam scanning is analyzed. To reduce the angle estimation error, an adaptive polarization-constrained monopulse approach based on combined constrained cross polarization and main polarization

A dual-bowtie antenna loaded with a double-sided dielectric lens is presented for wideband and high gain performance. The dielectric lens is a combination of the elliptical and conical frustum lenses formed on two sides (top and bottom) of a rectangular dielectric block, respectively. The conical frustum lens is mounted at the backside of the bowtie radiator to collect the radiated energy toward the

The wideband radar system is usually exploited to obtain the 3-D image of the target under test. However, the wide bandwidth increases the system complexity and cost. Emerging techniques, such as the reconfigurable reflectarrays, reconstruct a near 3-D image via using single-frequency millimeter-wave (MMW) and near-field focusing of the beam, which greatly simplifies the system design, whereas the

In this letter, a low-profile wideband pattern diversity antenna based on metasurface (MTS) is proposed. Initially, based on the theory of characteristic mode (TCM), the two adjacent intrinsic modes, which correspond to the broadside and conical radiation pattern, respectively, are exploited to realize a wideband pattern diversity characteristic under a low profile. Then, by analyzing the modal current

A grooved metal ground with slits is utilized to achieve scattering cross section (SCS) reduction of a microstrip patch array antenna in this letter. By arranging the grooves and slits on the ground, 180° scattering phase differences between the elements on the ground and in the grooves are attained on the aperture, and obvious SCS reduction is obtained in a broadband. The proposed low-SCS microstrip

Economical sensing and recording of temperature are important in the transportation and management of fragile goods such as medicine, fish/poultry, and other temperature-sensitive items. Existing approaches measure the entire temperature profile using electronic devices running on a continuous power source. This letter presents a simple, intelligent, and battery-free solution for capturing interesting

This letter presents a compact cavity-backed slot antenna using dual mode for Internet of Things (IoT) applications. The proposed antenna has stub structures for generating additional resonant mode, by which two polarization components orthogonal to each other are realized within the impedance bandwidth. By the combination of the two modes, circularly polarized radiation is generated. The impedance

This letter explores geometrical optics-based raytracing in combination with modal analysis to realize an open cavity structure as an advanced variant of the resonant cavity antenna (RCA). Additional ray confinement has been ensured by determining accurate phase-locking conditions as demonstrated for the first time. Its combination with the analysis of the cavity mode has also been introduced to determine

This letter presents a novel wideband printed circuit board (PCB)-stacked Luneburg lens antenna with a flared open edge for multibeam scanning application at 5G millimeter-wave band. The lens consists of two groups of parallel PCBs. Each group includes 12 layers of low-cost FR4 PCB, which are fixed by metal screws. Inside the lens there is no dielectric, resulting in an air-filled structure. With drilling

A novel 2-D composite right/left-handed transmission line (CRLH-TL) metamaterial in polar coordinates is proposed for the first time, and applied to a multistandard antenna. The prototype antenna with triband operation and colocated pattern and polarization diversity is specifically designed to eliminate the need for multiple antennas in the processing center side and to significantly reduce antenna

A dual-polarized (DP) metasurface (MTS) antenna with miniaturized radiating aperture is proposed for polarimetric synthetic aperture radar. The antenna consists of an MTS radiator and a cross aperture antenna. Characteristic mode analysis (CMA) is utilized to analyze the working mechanism of the MTS radiator and to guide the miniaturization of the radiating aperture. Then, the CMA is used for the optimization

This letter presented a nematic liquid crystal (LC) based metal-dielectric-metal structure to fully electronically modulate the reflection phase of electromagnetic waves. The demonstrated structure is composed of a thin LC layer sandwiched between copper comb electrodes and a single slotted reflection array. Based on a proper application of the external electric field, the whole process of nematic

A design method using simple patches with nonresonant mode to achieve broadband phase-gradient metasurfaces of reflective type is proposed and an example to apply it for radar cross section (RCS) reduction is given. The method is based on treating the patch in an element as a pixel and the phase differences are obtained by setting the pixels to be empty or full. As only two states can be guaranteed

This letter presents the design of a single point-fed, geometrically simple circularly polarized (CP) antenna for 28 GHz Ka-band applications. The proposed antenna is based on a straight microstrip line printed on one side and coupled with the nearly square patches through a 45° inclined V-shaped slot aperture on the other side. In order to generate circular polarization, the fundamental radiating

This letter presents a novel concept of beam-steerable transponder based on antenna array and phased modulators. The steerability of the beam is achieved by optimally delaying the modulated reflected signal at each antenna element (i.e., changing the phase in frequency domain) with load modulation technique. In this manner, the reflected backscattered signal power can be maximized at one particular

A dielectric slab waveguide based four-element leaky-wave antenna array configuration, with open-stopband suppression, operating in K $_a$ -band is presented. A one-to-four power divider using Y-junctions is developed for the feed network of the antenna array. Leaky-wave antennas are inherently directive in the plane of the length of the aperture. Owing to the array configuration, the beamwidth of

A millimeter-wave dual-band shared-aperture high-efficiency reflectarray antenna (RA) based on the structure-reuse technique is proposed in this letter, which consists of two sets of elements with full 360° phase compensation ranges. The oblique dipole element excited by the substrate integrated waveguide (SIW) is employed for the lower frequency band. The equivalent metallic waveguide element with

In this letter, a multiple-input–multiple-output (MIMO) antenna with wideband performance for 5G smartphones is presented. First, a planar inverted-F antenna (PIFA) with an inverted-T-shaped open-slot is introduced. The proposed PIFA operates with a wide bandwidth of 78% due to the multimode technology. Then, two such PIFAs are attempted to be merged as a PIFA-pair, constituting a 2 × 2 sub-MIMO antenna

In this letter, a novel and compact 180° circular sector microstrip antenna has been proposed. The patch surface has been designed with a proper design insight to perturb and control the orthogonal surface current paths and orthogonal field components at the truncated edges for suppression of cross-polar (XP) radiations over the whole elevation without hampering its radiation pattern and bandwidth

Sum and difference beams are two kinds of field patterns, which have been commonly used in monopulse radar systems for detecting and tracking targets. This letter proposes to synthesize sum and difference beams based on a binary programmable metasurface (BPM). Moreover, the sum and difference beams can be steered by reprogramming digital coding schemes of the BPM. A prototype of the BPM is designed

This letter presents a compact 2-D Butler matrix (BM) realized by multilayer substrate integrated waveguide (SIW) technology. The 2-D BMs in the open literature suffer from either bulky size or poor integration with the radiation portion. Facing this issue, a new SIW 2-D BM is developed and realized in planar configuration easily integrated with the slot antenna array. The key point of this letter

In this letter, a physical optics (PO)-based scattered field calculation method is introduced. The proposed method divides the object into circular meshes. This technique exploited the analytical solution of scattered fields from circular plates to make it compatible with the PO surface integral framework. Therefore, it has no need for triangular-based surface reconstruction. The proposed method is

In this letter, an electronically beam scanning reflectarray antenna is implemented using nematic liquid crystals (LCs). By loading a tunable phase shifter with a delay line structure in the resonance unit, the phase shift is achieved by tuning the dielectric constant of the LCs with a fixed structure through an external dc bias voltage for each unit. In doing so, dynamically controlling the reflection

In this letter, a high-gain circularly polarized (CP) array antenna with low profile and low grating lobe property is proposed. The array is composed of high-gain and low sidelobe CP patch elements based on odd high-order modes. By adding perturbation structure, a pair of orthogonal modes (TM 30 /TM 03 ) of the patch with 90° phase difference is diagonally excited. Meanwhile, by introducing five circular

A novel wideband substrate integrated waveguide (SIW) cavity-backed antenna element and its array are proposed in this letter. The proposed linearly polarized array element consists of a SIW cavity, stacked patches, and a coaxial probe. The SIW cavity-backed array element is implemented with physically connected stacked patch. The coaxial pin is directly connected to the two patch radiators. Blind

A 3-D printed multibeam spherical lens antenna with 2-D ultrawide-angle coverage is presented in this letter. The two-layer spherical dielectric lens can be fabricated easily by 3-D printing technology based on the effective medium theory. The circularly polarized U-slot patch antenna is introduced as the feed for the spherical lens due to its good radiation performance and compact configuration. The

This letter presents a 4 × 4 single-layer dual-band array antenna operating in the K - and Ka -band using gap waveguide (GW) technology. Radiating elements consist of I-shaped slots located on the top plate of the antenna and backed by a novel coaxial cavity with the dual-frequency operation. The antenna presents two ports, one for each band, and radiates a directive far field pattern with linear polarization

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.