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Unlike popular multiband antenna array radiation based on either electric or magnetic surface currents, the use of mutually interleaved and tightly coupled electric and magnetic currents results in an aperture-reuse space-efficient multiband radiating surface for highly integrated antenna-frontend architecture and spatial power combining design scenarios. In this work, slot and dipole modes corresponding to magnetic and electric currents are effectively interleaved and excited in a surface to develop a space-efficient dual-wideband aperture-shared radiating surface. In this case, due to an effective reuse of the antenna aperture over both frequency bands, a high aperture-reuse efficiency is achieved. First, we devise a planar magneto-electric (ME)-dipole-alike antenna and analyze it in both the frequency and time domain. The antenna is then studied by the characteristic mode theory and the findings are validated using full-wave simulations. The developed planar ME-dipole-alike antenna is used to realize a dual-wideband radiating surface in which electric and magnetic currents are mutually coupled and interlaced, which is excited by properly oriented and distributed sources on the antenna's surface. Eventually, a highly isolated dual-wideband prototype was developed and fabricated using a cost-effective multi-layer Printed Circuit Board (PCB) process that operates in the Ku-band with both impedance and gain bandwidth of approximately 42% and in the Ka-band with respective impedance and gain bandwidth of 29% and 16.32%. [ABSTRACT FROM AUTHOR]

In this paper, a compact leaky-wave planer antenna is proposed. The proposed antenna fabricated by the printed circuit board technology can scan a large part of its upper half-space. The proposed antenna consists of a metallic six-pointed star on a regular hexagon. The back of the hexagon is wholly covered with a conductor. The structure's detailed design and analysis have been done using the dispersion diagram. In the proposed antenna, changing the frequency can steer the main beam in elevation at six-step angles of azimuth. The simulation and measurement results confirm the theory well. The leaky wave structure is an attractive and economical method to scan half-space. [ABSTRACT FROM AUTHOR]

Wideband operation is a crucial topic in patch structure research. Various wideband methods have been developed for patch antennas. However, some of the key benefits of patch antennas, such as semi‐space radiation and easy fabrication, are degraded. In this study, we refer to the planar inverted‐F antenna (PIFA) and propose a co‐plane terminal loading strategy, resulting in an antenna model termed the co‐plane terminal loaded antenna (CTLA). It transforms the dipole‐to‐background metallic via in PIFA to a dipole‐to‐feed gap in CTLA. Because the gap is a coupling connection, the impedance‐match and resonant‐frequency performance improve, resulting in a wider bandwidth. Based on the proposed approach, three CTLAs, including an original CTLA, an improved CTLA, and a multi‐path CTLA, were constructed and simulated, with relative bandwidths of 63.5%, 55%, and 62%, respectively. The radiation pattern is typically patch‐like, radiating in semi‐space, and hybrid polarisation over the working band. Finally, the improved and multi‐path CTLAs are fabricated and measured to validate this method and ensure that the results are consistent with the simulation results accurately. This study proposes a terminal‐loading method for patch structures, which results in wideband radiation. It can be used in wideband phased arrays, communication systems etc. [ABSTRACT FROM AUTHOR]

Summary: In this research work, the design and analysis of a compact microstrip antenna having a monopole structure with 64.86% of wide bandwidth is presented. The main radiator of the structure is a fractal‐based geometry with the shape of a half‐Koch snowflake, and the ground plane is partial (defected ground). The design methodology of the antenna is presented using analytical modeling, and the structure prototype is fabricated to verify the performance. Measurement outcomes confirm the −10 dB bandwidth in range of 4–7.84 GHz, thus covering approximately the C‐band with omnidirectional radiation patterns. The proposed antenna shows a peak realized gain of 3.4 dBi at 7.2 GHz and has an overall dimension of 0.33λ × 0.49λ × 0.03λ, at 5.8 GHz. The structure is found compact compared to some recently reported designs and the read range is found to be 1.98 cm at 5.8 GHz. The read range and validation of the propagation test indicate the suitability of the compact and wideband planar antenna in various short‐range reader applications. [ABSTRACT FROM AUTHOR]

The innovative design presents a new hexagonal ring-shaped microstrip antenna capable of operating at triple-band high-gain for WLAN/WiMAX and 5G applications. The antenna structure comprises concentric circular ring patches with a single feed line via a modified plus-shaped structure, resulting in a triple band that enhances return loss, gain, and radiation pattern. The antenna's geometry has been adjusted to improve impedance matching at the prescribed frequency bands. Test results affirm that the proposed triple-band antenna features a compact structure, favorable return loss, consistent omnidirectional pattern, satisfactory gain, and bandwidth across all distinct bands. The proposed antenna delivers gains of 3.51dBi, 4.91dBi, and 5.23dBi with efficiencies of 92%, 90%, and 95% at 2.4/3.5/5.5 GHz, respectively. Moreover, the bandwidth in the triple band spans 230 MHz, 880 MHz, and 230 MHz at the first, second, and third resonant frequencies, respectively. The proposed triple-band antenna provides sufficient bandwidth to support WiMAX, WLAN, and 5G applications, positioning it as a promising solution for future wireless communication systems. [ABSTRACT FROM AUTHOR]

This paper presents a new optimization algorithm that efficiently can optimize the beamforming of the linear and planar antenna arrays. The new algorithm is called the corrosion diffusion optimization algorithm (CDOA) because its concept is concluded from the behavior of the corrosion distribution on the metal surfaces. The general performance of the new algorithm is compared with some other important algorithms via some standard benchmark functions. This comparison results in about 100% success rate for the proposed algorithm with high execution speed and low complexity compared to the other algorithms. Subsequently, CDOA is applied to solve some of the antenna array beamforming problems by optimizing the amplitude of the antenna weights vector and/or the inter-element spacing between the elements of the array. The algorithm results in a side lobe ratio larger than 22 dB in solving the problem of enhancing the side lobe ratio. Besides, CDOA operates efficiently in generating a flat top and triangular beam shaping with enhanced side lobe ratio. Furthermore, all the jamming signals are perfectly eliminated in the anti-jamming antenna array system when optimizing the weights vector of the array using the proposed algorithm. For each beamforming problem, the outcomes of CDOA are compared with other optimization algorithms to highlight its superiority in solving these kinds of problems. [ABSTRACT FROM AUTHOR]

In modern wireless communication, the enhancement of 5G wireless applications vigorously increases the growth for gaining in MIMO (Multiple Input Multiple Output) technologies. In the conventional method, the MIMO antenna is not efficient by having 5GHz with a resulting 75 % and the interference is difficult to exclude. The proposed MIMO antenna design is modeled by four truncated circular patches of radius 9.35 mm at the top layer with a dual partial ground of 10 mm x 60 mm at the bottom to provide better performance. The FR-4 epoxy substrate is counted with the dimensions of 70 mm x 60 mm x 1.6 mm. An impedance bandwidth ranging from 1.7 GHz to 12.4 GHz with 10 dB return loss and isolation of 15 dB is observed for all four planar antennas. The defective ground sketch in the planar plane is functioned by several slots, metamaterials, etc. achieved by the band-notch. The proposed system is obtained to improvise the performance by HFSS simulated results for operating frequency by MIMO antenna as 1.7 GHz to 12.4 GHz. It provides the directivity as 4.6 with a relative permittivity of 4.4 and isolation as 15 dB. Further, the gain of 5.7 dB with an efficiency of 87.95 % has been achieved by the insertion of the Electromagnetic Band Gap (EBG) structure between the two partial ground planes at the bottom. Hence the proposed EBG is proven better than the conventional method SISO antenna in all performance aspects through the MIMO antenna in 5G applications. [ABSTRACT FROM AUTHOR]

Planar inverted F antenna (PIFA) is one of the emerging technologies suited for various mobile applications. Though it is capable of covering a wide range of applications in wireless services, these antennas are designed for multi-band frequencies. To enhance its applications in the areas of wireless communication, an antenna is integrated with IoT (Internet of Things) devices. The compact size and low profile of the PIFA antenna is a notable feature, enhancing its suitability for integration into small devices. In this research paper, we proposed a Multi-Band Planar Inverted F-Shaped Antenna (PIFA) specifically designed for general close-range Internet of Things (IoT) applications. The proposed designed antenna produces an average gain of 2.62 dBi with a return loss of – 20 dB and its operating bandwidths are 2.40 – 2.45 GHz, 3.9 – 4.3 GHz, and 5 – 5.2 GHz covering Zigbee, Bluetooth, and Wi-Fi frequency band applications. Its multi-band frequency response is obtained by inserting an L-shaped slots of various lengths on a radiating patch of PIFA antenna, allowing for precise tuning of operation frequencies. In the design of an antenna, the resonance frequencies for each band are controlled by manipulating the lengths of the corresponding slots. In addition to the desired frequency and gain, the paper evaluates key parameters including bandwidth, directivity, and radiation patterns with the help CST simulation environment and ensures accuracy in predicting the antenna's performance parameters. [ABSTRACT FROM AUTHOR]

In this study, the distributions of electron temperature and ion density on a vertical section in a weakly magnetized inductively coupled plasma were measured using radially movable floating probes placed at different axial positions. The chamber used in this experiment included two cylindrical parts: a smaller radius top part with a planar antenna on the top quartz window and a larger radius downstream part. A magnet coil around the chamber top part maintained a divergent magnetic field in the discharge region. As the current in the magnet coil increased, the magnetic field also increased. Due to the variations of the radio frequency electric field in the plasma, the increase in electron temperature can be divided into different stages. At the higher magnetic field, the electric field of the electrostatic wave can increase electron temperature at the chamber center axial. Also, since the electron cyclotron resonance (ECR) heating in the chamber downstream part changed with the magnetic field, the maximum ion density was observed when the magnetic field around the bias electrode was slightly larger than the ECR magnetic condition. The reasons for these variations were verified in the plasma numerical simulations. The ion flux distribution measured on the bias electrode can change from a center-high distribution to an M-shape distribution with the increased magnetic field. [ABSTRACT FROM AUTHOR]

Copyright of Informacije MIDEM: Journal of Microelectronics, Electronic Components & Materials is the property of MIDEM Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Developing contemporary antennas is a challenging endeavor that requires considerable engineering insight. The most laborious stage is to devise an antenna architecture that delivers the required functionalities, e.g., multiband operation. Iterative by nature (hands-on topology modifications, parametric studies, trial-and-error geometry selection), it typically takes many weeks and requires considerable engagement from a human expert. Consequently, only a few possible design options concerning the fundamental antenna geometry may be considered. Automated topology rendition and geometry parameter optimization are highly relevant, especially from the industrial perspective. Therein, reducing time-to-market and limiting the involvement of trained experts is critical. This research proposes an innovative procedure for unsupervised development of planar antennas. Our method leverages flexible antenna parameterization based on re-sizable elliptical patches. It permits the realization of a massive number of geometries of diverse shapes and complexities using a small number of decision variables. Computational intelligence methods are employed to conduct antenna evolution exclusively based on specifications and possible constraints (e.g., maximum size). Fine-tuning of the structure geometry is achieved through low-cost local search routines. Our methodology is demonstrated by designing several antennas featuring distinct characteristics (broadband, single-, dual- and triple-band). The obtained results, supported by experimental data, underscore the presented approach's versatility and capability to render unconventional topologies at reasonably low computational expenses. As mentioned earlier, the design process is fully automated without human expert involvement. [ABSTRACT FROM AUTHOR]

This work presents a knowledge-based decision-making robust antenna design (KDRAD) method that employs a heuristic-optimisation technique for antenna design. The method is used to create and scale a single-element antenna to operate at multiple frequencies within the 5 G range. In this study, a low-profile planar four-element microstrip antenna of 14.8 mm × 14.8 mm × 0.508 mm gives simulated and measured impedance bandwidths of about 1.18 GHz (26.43–27.61 GHz) and 1.08 GHz (26.42–27.50 GHz), respectively, with a centre frequency of 27 GHz. The mm-wave planar four-port antenna has a maximum gain of 7.2 dBi; isolation of 33.2 dB; and multiple antenna matrices with minimal ECC (0.000000109), high diversity gain (10 dB) and channel capacity loss of 0.00110 bits/s/Hz. [ABSTRACT FROM AUTHOR]

ABSTRACT A compact eight‐port MIMO structure containing planar inverted‐F antennas (PIFAs) as radiating elements is designed for 5G cellular communication applications within the sub‐6 GHz band. The proposed antenna consists of four radiating elements that are placed at four corners on the same plane of geometry. The overall dimension of the ground plane is considered to be 59 mm × 120 mm to make it convenient for modern smart mobile handsets. Each radiating element has 2‐feeding plates, which are situated perpendicular to each other in orientation to make the arrangement cross‐polarized, which in turn exploits polarization diversity as well as spatial diversity among the combination of different radiating elements. The patches are structured by embedding rectangular slots in a meandered shape, and the ground plane is configured by introducing rectangular slots and narrow metallic strips. The prototype of the prescribed MIMO PIFA model has been fabricated and experimentally tested. It shows multi‐band operations (3.27–3.37, 4.16–4.35, 4.93–5.06, and 5.47–5.68 GHz) within the sub‐6 GHz spectrum. The isolation among various patches is observed within the range of −35 dB to −42 dB. The peak gain reaches around 8.1 dBi. The designed MIMO PIFA exhibits superior diversity performance by producing ECC ≤ 0.0006, DG ≈ 10 dB, CCL < 0.20 bits/Hz/s, and MEG ≤ −3 dB. Furthermore, the specific absorption rate (SAR) is evaluated according to the standard values of fat, skin, and muscle at 3.3 GHz. The prescribed model maintains acceptable SAR values for 1‐g and 10‐g tissues, which makes it suitable for smartphone applications. [ABSTRACT FROM AUTHOR]

As the physical size of a communication system for satellites or unmanned aerial vehicles demands to be reduced, a compact antenna with high directivity is proposed as a core element essential to the wireless device. Instead of using a horn or an array antenna, a unit planar antenna is combined with a surface-modulated lens to convert a low antenna gain to a high antenna gain. The lens is not a metal-patterned PCB but is dielectric, which is neither curved nor very wide. This palm-sized lens comprises pixels with different heights from the backside of PolyPhenylene Sulfide (PPS) as the dielectric base. The antenna gain from the unit antenna of 4.5 cm × 4.5 cm is enhanced by 10 dB with the help of a compact dielectric lens of 7.5 cm × 7.5 cm at 24.5 GHz as the frequency of interest. The antenna design is verified by far-field measurement as well as near-field observation, including sensing a metal object behind a blocking wall by using an RF test bench. Moreover, antenna performance is understood by making a comparison with conventional designs of antennas in terms of directivity and physical sizes. [ABSTRACT FROM AUTHOR]

To optimize sparse rectangular planar array antennas under multiple constraints, including array aperture, number of elements, and minimum element spacing, an improved sparrow search algorithm (ISSA) is proposed. Initially, a position distribution matrix is generated using the Blackman window weighting method. The sparrow search algorithm (SSA) is then enhanced by incorporating Kent mapping for population initialization, which improves the initial population's diversity. Additionally, the strategy for updating the discoverer's position integrates elements from the sine cosine algorithm (SCA), along with a nonlinear sine learning factor, thereby enhancing global search capability. Finally, a crossover strategy is embedded into the SSA to refine the optimization accuracy by improving the search methodology used by the vigilantes. To verify the efficacy of our approach, we carried out simulation experiments. The results demonstrate that this method significantly enhances the performance of the array antenna by reducing the peak sidelobe level and minimizing the zero-trap depth. These findings validate the reliability and effectiveness of the suggested method. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A compact circularly polarized (CP) planar spiral antenna with ultrawide bandwidth and directional radiation pattern is proposed for ultra‐wideband (UWB) positioning applications. The proposed antenna consists of a dual‐arm planar spiral with a tapered microstrip line, two L‐shaped metallic shorting stubs, and a square ground plane with four stepped slots. By connecting two L‐shaped metallic stubs to both the ends of the dual‐arm spiral through metal posts, the traveling wave current path is effectively extended, resulting in a significant improvement of the CP bandwidth. Additionally, both impedance bandwidth and circular polarization performance of the proposed antenna can be enhanced by adopting four stepped slots on the square ground plane. Measured results show that the planar spiral antenna features an impedance bandwidth from 3.23 GHz to 7.0 GHz (more than 73.7%), a 3‐dB axial ratio (AR) bandwidth of 62.1% (3.05 GHz–5.8 GHz), and finally achieves an overlapping bandwidth of 56.9% (3.23 GHz–5.8 GHz). On the overlapping bandwidth, this antenna maintains a gain consistently above 6 dBic while the peak gain reaches about 7.4 dBic. The overall size of the antenna is 0.59λg × 0.59λg × 0.17λg (λg is the free‐space wavelength at the lowest frequency, 3.23 GHz). Thanks to the ultrawide CP bandwidth and compact size, the proposed antenna can be a promising candidate for UWB positioning applications. [ABSTRACT FROM AUTHOR]

In this paper, a planar, bow-tie antenna with an enhanced bandwidth and a bi-directional radiation pattern is proposed. The concept of multi-resonance is applied by implementing the superposition of three different bow-tie components with various radii and flare angles in an overlapped fashion into a single element, resulting in a significant increase in bandwidth. The antenna has an electrical size, kr, of 1.10, calculated at the lowest frequency of operation. The proposed antenna is simulated, and a prototype is fabricated for verification by measurement. The result is a wide −10 dB bandwidth of 80.3% (1.23–2.88 GHz) from the measurements. The antenna also maintains a bi-directional radiation pattern, with a negligible difference between the forward and backward realized gains, within the entire −10 dB bandwidth. The measured realized gain values in the forward and backward directions are between 1.5 dBi and 3.7 dBi over the −10 dB bandwidth. The comparison of the measurement and simulation results shows good agreement. [ABSTRACT FROM AUTHOR]

The homogeneity of the microwave magnetic field is essential in controlling a large volume of ensemble spins, for example, in the case of sensitive magnetometry with nitrogen-vacancy (NV) centers in diamond. This is particularly important for pulsed measurement, where the fidelity of control pulses plays a crucial role in its sensitivity. So far, several magnetic field-forming systems have been proposed, but no detailed comparison has been made. Here, we numerically study the homogeneity of five different systems, including a planar antenna, a dielectric resonator, a cylindrical inductor, a barrel-shaped coil, and a nested barrel-shaped coil. The results of the simulation allowed us to optimize the design parameters of the barrel-shaped field-forming system, which led to significantly improved magnetic field uniformity. To measure this effect, we experimentally compared the homogeneity of a field-forming system having a barrel shape with that of a planar field-forming system by measuring Rabi oscillations of an ensemble of NV centers with them. Significant improvements in inhomogeneity were confirmed in the barrel-shaped coil. [ABSTRACT FROM AUTHOR]

This paper proposes a 10 × 10 MIMO multiband broadband planar antenna for tablets or laptops. The designed antennas cover a large number of the popular sub‐6‐GHz application bands, such as 0.617–0.96, 2.1–2.7, 3.5–4.5, and 6.1–7.2 GHz for public safety communications, radio systems, Bluetooth, Wi‐Fi, and satellite communications. The proposed antenna is designed with grounded branches, which can generate a wide bandwidth and cover most of the sub‐6‐GHz application band by coupling between branches of different lengths and antennas. MIMO antennas have been measured to have an envelope correlation coefficient of less than 0.7 and have met the standards set by international organizations for human radiation absorption simulations. The proposed antenna validates the unique 10 × 10 MIMO antenna structure and feasibility. Multiple operable frequency bands are realized, and the radiation effect of the antenna on the human body is analyzed if it complies with international market standards. The proposed antenna design is well suited for multiband and broadband requirements. [ABSTRACT FROM AUTHOR]

A dual-band, dual-pattern antenna is presented for 1.437 GHz L-band and 2.45 GHz Industrial Scientific and Medical (ISM) band applications. The antenna is based on multilayer circular patches with symmetric slots and two asymmetric cylindrical vias that shorten the multiple layers with the ground plane using Plated Through-Holes (PTHs) to generate the required resonant modes. The first mode is operated at 1.437 GHz, providing an omnidirectional radiation pattern, while the second mode is operated at 2.45 GHz, providing a directional or broadside radiation pattern. The antenna was fabricated to validate the simulation results and excellent agreement was found between the simulation and experimental results. The antenna has a total size of only 6x6x0.443 cm³, which corresponds to an electrical size of 0.5λ0x0.5λ0x0.03λ0 at 2.45 GHz and 0.28λ0x0.28λ0x0.02λ0 at 1.437GHz, thanks to the loading effect of shorting vias. The gain of the antenna is 1.62 dBi at 1.437 GHz and 6.48 dBi at 2.45 GHz, along with quite good radiation efficiencies of 83.4% and 96%, respectively. For body-centric applications, the performance of the antenna was also examined in close proximity to the human body. Nearly stable performance was found in close proximity to the human body, comparable to free space performance in terms of both impedance matching and radiation patterns. The 10g Specific Absorption Rate (SAR) of the antenna was also measured and found to be below the international compliance limits. These characteristics make the antenna a very promising choice for body-centric communications. The antenna also applies to other wireless systems such as MIMO, wireless ad hoc networks, etc. It offers radiation pattern diversity in a single planar package with a highly flexible and adaptable design by providing much more degrees of freedom than classical microstrip antennas. [ABSTRACT FROM AUTHOR]

This paper presents, an Ultra-Wide Band CB-CPW based planar antenna design for biomedical applications. The proposed low-profile antenna boasts a compact size, measuring 66 × 52 × 1.57 mm3. Here, a comparative analysis is performed of designed antenna with and without the CB-CPW technique. The designed antenna operates at resonance frequencies of 1.9 GHz and 5.37 GHz. It exhibits significant bandwidth from 1.6 to 6GHz. The gain of designed antenna is 2.8 dBi and 4.8 dBi at 2.45 GHz and 5.78 GHz respectively. Here, the designed UWB planar antenna is simulated using CST MWS and the results are verified experimentally. The antenna with CB-CPW technique demonstrates efficiency of 88.2% at 2.45 GHz and 78% at 5.8 GHz. The designed antenna is simulated with body phantom and also against the structural deformation (Bending). The antenna simulated and the experimental results demonstrate the efficacious performance of the designed antenna, even when subjected to structural deformation like bending. SAR analysis of the designed antenna has been simulated with HUGO human body model of VOXEL family using CST MWS software. Moreover, designed antenna indicate a significant low specific absorption rate (SAR) value with in the IEEE and FCC guidelines. The proposed antenna has low profile, compact size, low SAR, negligible backward radiation, broad bandwidth and high gain, position it as an excellent choice for BAN biomedical applications. [ABSTRACT FROM AUTHOR]

In WiFi 7 (IEEE 802.11be), Multiple Input Multiple Output (MIMO) technology plays a crucial role in enhancing throughput. This combination enables numerous applications for wearable WiFi devices. For instance, WiFi can be utilized for tracking and fall detection purposes. Additionally, wearable devices used in gaming, vital signal monitoring, and tracking can benefit from the implementation of wearable MIMO antennas. Despite the demand for wearable WiFi antennas, specifically in the new 6 GHz band, a significant gap exists in the investigation of antennas that are completely made of textile, are low profile, and provide vertical polarization and omnidirectional patterns. Addressing this gap, in this paper, a wearable planar antenna is introduced, which is specifically designed to offer an omnidirectional pattern and linear polarization. To ensure its practicality and ease of use, the antenna utilizes lightweight and wearable textile material. The design details and performance of the proposed antenna are presented. The antenna covers all three bands of WiFi, namely, 2.4 GHz, 5 GHz, and 6 GHz bands. The 10-dB return loss bandwidth is 2.4 GHz-2.5 GHz, and 4.6 GHz-7.2 GHz. The maximum Specific Absorption Rate (SAR) for an input power of 500 mW is calculated at 1.053 W/Kg for a 2 mm air gap between the antenna and tissue surface. The size of the antenna is given by a circular area of π x (50 mm)², and a thickness of 6 mm. [ABSTRACT FROM AUTHOR]

A high‐power, high‐isolation, dual‐polarised planar phased array antenna is presented. Based on a multi‐layer microstrip structure, two sets of polarisation ports are fed through orthogonal slot coupling, achieving high isolation and low cross‐polarisation. Double‐layer radiation patches and cavity interlayers are used to expand the bandwidth and increase the gain. Metal vias are added around microstrip feeders and between array units to suppress surface waves, thereby improving the scanning performance of the phased array. A smooth gradient microstrip structure is designed to improve the power capacity while realising broadband impedance matching. The measured results show that in the 8–10 GHz frequency band, the isolation of the dual polarisation ports is greater than 50 dB, and the impedance bandwidth reaches 22.2%, with active VSWR <1.5 when not scanning. Both sets of polarisation can achieve 2‐D beam scanning in the range of E‐plane ±20° and H‐plane ±40° without grating lobes, maintaining the scan loss below 2.4 dB, cross‐polarisation below −20 dB and active VSWR <2. Each unit achieves a high gain of 7.4 dB and large power capacity of 5 kW; so the entire 8 × 8 phased array can achieve a main lobe gain of 25.5 dB and realise high‐power directional radiation with the effective isotropic radiated power of 92.5 dBm. The proposed planar antenna has a low profile of 5.5 mm (0.17λ0). [ABSTRACT FROM AUTHOR]

In this study, we propose the wide field of view (FoV) radar module for autonomous vehicles. The proposed wide FoV radar (WFR) module was constructed using of an RF module comprising wide beamwidth microstrip patch antennas, an AWR1642 radar sensor chip, and a control module. To achieve a wide FoV of 150° using the fabricated radar module, the 3-dB beamwidth characteristic of the applied microstrip patch antenna had to wider than 150°. The patch antenna was designed using a comb-line structure along 10-by-1 array structure, each radiator characterized by a shorted patch structure, such as a planar inverted-F antenna. The designed antenna was then fabricated on the same board surface as the sensor chip. To identify the characteristics of the implemented radar module, a trihedral corner reflector with a radar-cross-section of 180 m2 was used as the reflector target, and the CA-CFAR (cell averaging constant false alarm rate) target detection algorithm was applied. The measurement results, showed good detection performance of the radar in the view angle of 150°, from -75° to +75°, and a broad bandwidth of 4 GHz in the 77-81 GHz millimeter band. Therefore, the proposed WFR is applicable for used in blind spot detection sensors in autonomous vehicles. [ABSTRACT FROM AUTHOR]

This article presents a systematic design and optimization process for a compact 0.27λ0 × 0.31λ0 multiband monopole antenna for Internet of Vehicles (IoV) applications, including navigation, Vehicle to Infrastructure (V2I), Wi-Max, and 5G. The antenna's modified ground plane enables installation within a shark-fin module on a car roof, aligning with its low-profile dimensions and high performance. Structural modifications to the initial antenna element, including the T-shaped structure and integrated stub between quad rings, enable circular polarization in the GPS L1 band. With simulated total radiation efficiency exceeding 60% at four bands, numerical simulations and physical fabrication on an FR-4 substrate are followed by antenna radiation measurement in an anechoic chamber. The measured gain at 1.575 GHz, 2.6 GHz, 4.8 GHz, and 8 GHz is 1 dBi, 2.2 dBi, 3.2 dBi, and 3.8 dBi, respectively. Additionally, ray tracing techniques evaluate the antenna's performance when mounted on a car, considering interactions with other vehicular antennas and infrastructure in urban propagation scenarios. Urban propagation analysis illustrates efficient operation, characterized by minimal delay time, favorable line of sight, and controlled path loss at frequencies 2.6 GHz and 4.8 GHz. These findings demonstrate the antenna's potential for adoption in the automotive industry. [ABSTRACT FROM AUTHOR]

In this article, a semi-circle shaped planar monopole antenna is proposed for 5G applications for improved gain. The gain of the proposed antenna is increased by loading the ground plane with a proposed FSS layer. The hexagonal shaped unit cell is proposed to construct the FSS layer. This article presents the composition of architectural equations for creating the band pass hexagonal reflector employing hexagonal geometry and planar monopole radiator. The proposed antenna dimension was in compact size of 20 × 18 mm². The monopole and FSS substrates both fabricated on FR4-substrate (εr = 4.4) with a height of 1.6 mm. The hexagonal patches are placed with the spacing of 0.6 mm and 14 mm below the main radiator The hexagonal reflector and printed monopole antenna shapes are designed for n77 and n78 NR bands. The ANSYS HFSS software is used to execute the simulations. The prototype is fabricated and the results are validated by measuring the S parameter, Gain and Radiation pattern. The results are validated by taking measurements in Anechoic chamber with the aid of VNA with 0.6 mm spacing between the elements. The measured/simulated fractional bandwidth of the antenna is 19.14 %, with a peak gain of 6 dBi and a maximum directivity of 6.2 dBi. The proposed hexagonal FSS structure provides better gain (nearly 6 dB improvement) and impedance matching from3.9 GHz to 5.04 GHz and well suited for 5G applications. [ABSTRACT FROM AUTHOR]

A packaged transmit array (TA) antenna is designed for automotive radar applications operating at 77 GHz. The compact dimensions of the proposed configuration make it compatible with standard quad flat no-lead package (QFN) technology. The TA placed inside the package cover is used to focus the field radiated by a feed placed in the same package. The unit cell of the array is composed of two pairs of stacked patches separated by a central ground plane. A planar patch antenna surrounded by a mushroom-type EBG (Electromagnetic Band Gap) structure is used as the primary feed. An analytical approach is employed to evaluate the primary parameters of the suggested TA, including its directivity, gain and spillover efficiency. The final design has been refined using comprehensive full-wave simulations. The simulated gain is 14.2 dBi at 77 GHz, with a half-power beamwidth of 22°. This proposed setup is a strong contender for highly integrated mid-gain applications in the automotive sector. [ABSTRACT FROM AUTHOR]

The proposed surface‐mountable self‐isolated MIMO antenna covers n78 and n79 5G frequency bands. The presented design has two semicircular slots with engineered geometry to get the desired frequency spectrum. Antenna presents the bandwidth in the order of 8.77% and 2.81% at frequency resonance of 3.42 GHz and 4.98 GHz, respectively, covering FR1 5G and WLAN applications. The design presents an acceptable gain of 2.95 dBi and 2.42 dBi. The elements of MIMO antennas are kept an adequate distance apart to achieve self‐isolation in order of 19 dB. It aids further in achieving optimal MIMO diversity parameters. The 2D electrical size of the presented self‐isolated planar antenna is 0.97λ × 0.65λ at the lowest resonance. The MIMO antenna parameters were examined for the stated antenna design. The optimal envelope correlation coefficient (ECC) is near to 0.02, channel capacity loss (CCL) is around 0.2 bits/sec/Hz, directivity gain (DG) is around 9.98 dB, and the MEG ratios are near to unity. The computed performance of the resonator is validated through fabrication and experimentally tested using VNA 9912A in an anechoic chamber environment. [ABSTRACT FROM AUTHOR]

Summary: A band‐notched super wideband (SWB) planar monopole antenna with improved notch characteristics is proposed in this article. A hexagonal SWB antenna operating in the frequency range from 3.04 to 36 GHz is initially designed on Arlon substrate. The hexagonal patch is then loaded with optimum sized U‐shaped slot to eliminate WLAN band (5.15–5.85 GHz). The notch band's characteristics are further improved by incorporating a frequency selective surface (FSS) of a square array at a specific distance below the antenna to introduce a phase delay of 180° between the back radiation reflected by the FSS with the front radiation at the notched frequency. Improvement of notch band gain, efficiency, and antenna front‐to‐back ratio (FBR) are studied. The antenna without embedding an FSS exhibits working spectrum from 3.1 to 33.6 GHz with notch frequency gain of −2.6 dBi and efficiency 53%. The inclusion of an FSS layer at 25.2 mm behind the antenna results in notch frequency gain of −7.6 dBi with an efficiency of 23%. FBR improvement of about 16 dB is achieved at 8 GHz, and FBR is reduced by about 5 dB at the notch frequency. 169% fractional bandwidth with bandwidth dimension ratio (BDR) of 1622 is achieved in this proposed FSS integrated antenna. The inclusion of FSS to improve the band elimination performance represents the novelty of this proposal. The data are validated by electromagnetic simulation and physical measurement techniques. [ABSTRACT FROM AUTHOR]

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Two-dimensional leaky-wave antennas (LWAs) are a class of planar, traveling-wave radiators with attractive features of a low profile, ease of feeding, frequency reconfigurability of the radiation pattern, and polarization agility. Their use in conjunction with array feeders has been the subject of various investigations in recent decades, thanks to the additional degrees of freedom provided by the presence of multiple independent sources. Here, we provide a review of some of the most recent and promising array-fed two-dimensional (2-D) LWAs, selecting a couple of the most significant structures in application, namely Fabry–Perot cavity antennas and bull's-eye antennas, and discussing some of their recently proposed advanced features. [ABSTRACT FROM AUTHOR]

A rectenna designed for wireless power transfer at 900 MHz focuses on conjugate impedance matching and image impedance matching for improved efficiency. To do them, a voltage doubler rectifier circuit (VD) and a planar monopole antenna (PMA) were engineered with the same pure resistance value and integrated into the rectenna. The input impedance of the VD with 30 Ω load resistance indicated a pure resistance of approximately 73 Ω. This value closely matches the input impedance of a dipole antenna operating as a pure resistor. Since the prototype rectifier circuit is unbalanced, the authors constructed a PMA, an unbalanced antenna similar to a dipole antenna, on a double‐sided circuit board. In this setup, a microstrip line was created by extending the radiating element, achieving the impedance matchings. Measurements indicated a voltage standing wave ratio of approximately 1.03. A rectenna efficiency of 37.4% was observed for a transmission distance of 50 cm. The rectification efficiency of the VD is nearly 0% when the input power is less than −20 dBm, and the received power of the PMA is less than −20 dBm when the transmission distance is 60 cm or more. It is predicted that the rectenna efficiency will be 0% when the transmission distance is 60 cm or more. However, the rectenna efficiency was 24.6% when the transmission distance was 60 cm. This over 20% improvement is due to the connection between the PMA and the VD using pure resistance. Key Points: This study introduces the development of an integrated rectenna for RF WPT focus on achieving impedance matching to enhance efficiencyPure resistance was employed in both a voltage doubler rectifier circuit and a planar monopole antenna designMeasurements revealed that an efficiency enhancement is achieved by approximately 20% [ABSTRACT FROM AUTHOR]

In a highly integrated analog radio-over-fiber transceiver, seamless integration of the antenna-frontend is crucial as an antenna is generally implemented on a high-κ material, which is set to highly degrade the antenna's performance. This work is concerned with the radiation behavior improvement of a planar leaky-wave antenna with an inductive partially reflecting surface (PRS) on a high-κ substrate for the development of a highly directive antenna. To begin with, we show how a thin and single-mode resonance (SMR) inductive PRS on high-κ materials in a planar leaky-wave antenna is set to provoke two resonance frequencies (i.e., PRS and cavity resonances) to converge, thereby diminishing the antenna's broadside directivity. By applying an equivalent circuit model, we explain how a multi-mode resonance (MMR) PRS can adequately be applied to address the underlying challenges. Subsequently, the leaky-wave radiation behavior of an antenna with a heterogeneous substrate is investigated and analytical equations are derived and verified with a full-wave simulation. The effects of material permittivity and thickness in a heterogeneous-cavity antenna on leaky-wave performance are investigated using these approximate yet accurate-enough equations. To justify the findings, two 9 × 9 planar leaky-wave antennas are prototyped on heterogeneous substrates based on SMR and MMR PRS and the radiation performances are compared. Our investigations reveal that in the proposed scenario, an MMR PRS can significantly enhance the antenna's broadside directivity by over 4 dBi at the resonance frequency (27.5 GHz), which is also set to improve radiation pattern compared to a SMR-based antenna. Finally, a single-fed dual-band aperture-shared antenna with a large frequency ratio (S-band and Ka-band) is developed and fabricated on a high-κ substrate based on the proposed MMR PRS. [ABSTRACT FROM AUTHOR]

This letter proposes a novel planar endfire circularly polarized antenna with widened half‐power beamwidth. Widened azimuth beamwidth mechanism of 2D sectorial electric dipole is theoretically revealed, thus it is able to combine with a rectangular magnetic dipole to yield a half‐power beamwidth widened planar endfire circularly polarized antenna. Finally, a prototype planar endfire circularly polarized antenna with sectorial flared angle of α = 270° is fabricated, simulated, and implemented to validate the design approach. As investigated, the antenna exhibits broadened azimuth half‐power beamwidth of 150° over a frequency range of 2.40–2.45 GHz. [ABSTRACT FROM AUTHOR]

This article proposes a Ka‐band substrate integrated waveguide (SIW) quasi‐Yagi array antenna with the advantages of thinness, compactness, wide bandwidth, and higher gain. Analyzing the microstrip‐to‐SIW transition structure to confirm that the designed structure provides the best performance, the optimum reflectance coefficient bandwidth can be obtained. With the optimized rectangular etched slot structure at the antenna end, the impedance matching can be tuned to improve the bandwidth. The designed array antenna is fabricated and measured for verification. The substrate is based on Al2O3 ceramic and the antenna size is 23.3 mm × $\times $ 13 mm × $\times $ 0.5 mm. The measurement results indicate that the antenna achieves an impedance bandwidth of 13.59% below −10dB, with an average gain of approximately 7 dBi and a peak gain of 7.4 dBi in 28.1–32.2 GHz. Therefore, the 1*2 antenna proposed in this paper has the advantages of compact and planar structure, easy fabrication, and easy integration into RF circuits, which is very suitable for Ka‐Band applications. [ABSTRACT FROM AUTHOR]

This article presents a novel multiprobe planar near-field range (PNFR) measurement system. The said system simplifies the overall mechanical design, making it simpler than the existing scanning probe PNFR measurements, and also significantly reduces testing time. A dielectric-based probe is introduced to reduce the antenna size, thereby improving resolution. The probe under consideration is an antipodal Vivaldi antenna offering broadband support and ensuring wideband characteristics of aerials. Numerical results for representative X-band antenna models, presented in the Matlab environment, demonstrate robust performance of the developed measurement system. [ABSTRACT FROM AUTHOR]

In this paper, we propose a printed circuit board (PCB)-based planar antenna pair, operating at 2.4 GHz and 5.0 GHz frequency bands, respectively, for dual-band routers. The antennas are both rectangular and consist of twisted radiating elements and microstrips etched on an FR4 dielectric substrate. Etching slots on the radiating elements and adjusting the serpentine microstrips influence surface current distribution and therefore effectively reduce antenna size and enhance antenna gain. The proposed antenna features a compact size compared to general router antennas and demonstrates high gain characteristics compared to dipole antennas. In the 2.3–2.5 GHz band, the simulated S11 of the 2.4 GHz antenna was lower than -10 dB, while the gain was 3.9 dBi at 2.4 GHz. In the 5.1–5.9 GHz band, the simulated S11 of the 5.0 GHz antenna was lower than -10 dB, and the gain was greater than 4.8 dBi. The proposed antenna has potential for application to router antennas. [ABSTRACT FROM AUTHOR]

This work presents a new compactly printed ultrawideband antenna for mobile satellites (8.025 GHz), metrological aids (9.5 GHz), and aeronautical radio navigation (9-9.2 GHz) applications. The proposed antenna is made up of four straightforward radiating rectangular-shaped strips, the overall geometry of which resembles two U-shaped in the radiating patch, fed by a 50O microstrip feed line. Two exponential patches, along with a rectangular patch, are implemented in the ground part of the structure, which can be effectively constructed by varying the sizes and geometries of these two U-shaped strips. The proposed antenna is compact overall. The proposed antenna is designed, simulated, fabricated, and tested minutely. The measured values of 10 dB return loss absolute/fractional BW of 10 GHz/142 % at the center frequency, minimum/maximum gain of 2/6.1 dBi, and maximum/minimum radiation efficiency of 92/70 % are achieved from the 2 to 12 GHz frequency range. These bandwidths are also well suited for 2.5/3.5/5.5-GHz WiMAX bands and 2.4/5.2/5.8-GHz WLAN bands. In addition, a comparison table is provided to prove the state-of-the-art design of the antenna. [ABSTRACT FROM AUTHOR]

Integrated quantum photonic circuits require the efficient coupling of photon sources to photonic waveguides. Hybrid plasmonic/photonic platforms are a promising approach, taking advantage of both plasmon modal confinement for efficient coupling to a nearby emitter and photonic circuitry for optical data transfer and processing. In this work, we established directional quantum dot (QD) emission coupling to a planar TiO2 waveguide assisted by a Yagi-Uda antenna. Antenna on waveguide is first designed by scaling radio frequency dimensions to nano-optics, taking into account the hybrid plasmonic/photonic platform. Design is then optimized by full numerical simulations. We fabricate the antenna on a TiO2 planar waveguide and deposit a few QDs close to the Yagi-Uda antenna. The optical characterization shows clear directional coupling originating from antenna effect. We estimate the coupling efficiency and directivity of the light emitted into the waveguide. [ABSTRACT FROM AUTHOR]

• A novel parabolic rigid deployable antenna based on origami was designed; • The optimization framework of parabolic rigid deployable antenna structure was estU:\ES\DTD560\JASR\17318\S5ablished; • Connection nodes and rotating axis were designed to circumvent collision during the process of deploying and folding. This paper introduces a novel approach for optimizing the packing and design of deployable parabolic rigid antenna structures based on origami, tailored to meet specific requirements related to the number of solid-surface blocks and the size of the folded antenna. The study begins by selecting a single-vertex four-crease configuration with one degree of freedom from the origami pattern, guided by mobility analysis, to optimize block arrangement. Subsequently, a planar model is employed to qualitatively examine the impact of geometric parameters on the stowage efficiency of the antenna. Building upon the insights gained from the planar model, an optimization framework for the parabolic rigid deployable antenna structure is established. The objective function of the optimization is the stowage volume, while simultaneously adhering to stiffness, collision, and mobility constraints. The design parameters of the antenna structure are thoroughly analyzed. To mitigate collision risks during folding, design considerations are applied to placement of support nodes, location of rotating axes, and block division, leveraging the optimized parameters. The practicality of the proposed method is successfully demonstrated through the folding of a simulated 3D model and of a physical 3D printed model. These tangible representations show the feasibility of the presented approach, affirming its potential applicability in the optimization and design of deployable parabolic rigid antenna structures. [ABSTRACT FROM AUTHOR]

The letter presents a low‐windage omnidirectional antenna for high‐speed aircraft in the UHF and L bands. It combines a planar biconical antenna with a printed tape parasitic branch monopole antenna. Upgrading the traditional restricted‐length biconical antenna to a double‐layer planar design meets the compact, lightweight, and low windage requirements of airborne use. To enhance bandwidth and meet the lightweight, compact criteria of high‐speed aircraft, the planar‐printed monopole antenna integrates parasitic stubs and loop antenna concepts. Experimental results exhibit excellent isolation between antenna elements, with over 15 dB segregation and operational spectrum return loss of 27% and 18% at 10 dB. The voltage standing wave ratio is below 2, with less than 5 dB variation in the horizontal radiation pattern across frequency bands. The antenna, measuring 20 mm × 190 mm × 270 mm and weighing around 0.5 kg, holds great promise for high‐speed aircraft applications. [ABSTRACT FROM AUTHOR]

Summary: The investigations related to the planar antenna array have attracted much attention due to their vast applications in the areas of advanced wireless communication and electromagnetics. This article presents an effective synthesis method of a sparsely thinned symmetric planar antenna array using three well‐known meta‐heuristics including symbiotic organism search (SOS) algorithm, moth fly optimization (MFO), and multi‐verse optimization (MVO) algorithms. The main aim of this work is to optimize the positions of the switched‐on antenna elements on the array aperture in order to reduce the value of side‐lobe levels in the radiation field pattern in multiple planes for a desired first null beam width and subsequently to obtain the maximum reduced number of array‐elements in the antenna array. Two different cases are performed to optimize the radiation pattern in different azimuth angles with two different examples. The proposed methods can constrain the total number of array elements, inter‐element distance, and aperture area of the array. The radiation pattern characteristic and computation time linked with each example and each algorithm are recorded and compared with each other as well as with a fully populated planar symmetric rectangular array antenna of same aperture size for arriving at the conclusion. The simulation‐based results demonstrate the effectiveness of the proposed design and the efficiency of the performance using the SOS algorithm. [ABSTRACT FROM AUTHOR]

In this manuscript, the design of a compact-size circular patch Ultra-Wideband (UWB) antenna with enhanced fractional bandwidth (BW), peak realized gain (PRG), and proper impedance matching is presented. The modified antenna has three circular slots etched from the circular path (top), fed by a 50O microstrip feed line. These circular slots play a significant role in improving the impedance bandwidth. Additionally, the partial ground plane with a slot integrated with a rectangular stub is used in order to achieve a bandwidth for an operating range of 3.25 GHz - 27 GHz. The proposed antenna is designed, fabricated, and tested in the laboratory in order to validate with simulation data. The designed antenna size is 25 mm? 20 mm × 0.508 mm. The experimental value of 10 dB return loss absolute/fractional BW of 23.75 GHz/157.08% at the center frequency, minimum/maximum gain of 5.90/12.05 dBi, and maximum/minimum radiation efficiency of 85/97 % are achieved from the 3.25 GHz to 27 GHz frequency range. In addition, a comparison table is provided to prove the state-of-the-art of the antenna's design. The proposed antenna is suitable for wireless services, radar, and satellite communication. [ABSTRACT FROM AUTHOR]

To tackle the challenge of keeping 5G mobile devices compact while supporting millimeter-wave bands, we've created an ultra-compact 4-port dual-band MIMO antenna with a defected ground structure (DGS). This design minimizes mutual coupling and covers a broad frequency range. Built on a Rogers TMM4 substrate with dimensions of 17.76×17.76 mm2, the antenna includes four planar patch antennas positioned perpendicularly at the corners. Each antenna operates at 28/38 GHz and features a rectangular patch with four rectangular slots and a full ground plane. The patches are separated by 0.5 λo, with the DGS further reducing mutual coupling. Both simulations and measurements indicate a significant reduction in mutual coupling (−39 to −60 dB), improving ECC, TARC, MEG, and DG. Time-domain and SAR analyses confirm the antenna's efficiency and its suitability for 5G devices. [ABSTRACT FROM AUTHOR]

A novel compact dual-band antenna based on dual-cap metasurface (MS) is proposed. By etching circumferential circular ring slots on one side of the substrate and a large cruciform slot on the other side, the dual-cap MS operates in two frequency bands. In addition, by placing the dual-cap MS at the back of a circular ring planar antenna which serves as a reflector, the impedance characteristic of the antenna in lower band and gain both in two bands are improved. The results show that this dual-cap MS antenna operates in the Wireless Local Area Network (WLAN) bands of 2.43-2.6 GHz and 5.48-6.05 GHz. Moreover, the maximum gains in lower and upper bands can reach 6.9 and 5.8 dBi, respectively. [ABSTRACT FROM AUTHOR]

The presented research aims to analyze in detail the characteristics of broadband matching antennas specifically designed for 5G mobile communications applications, with an emphasis on innovative composite materials. The study focuses on a compact planar loop antenna designed for use on smartphones, covering the LTE/WWAN frequency bands 824 to 960 MHz, 1,710 to 2,690 MHz, and 3,300 to 3,600 MHz for full coverage of modern 5G networks. Experimental and numerical methods are used to broadly analyze the frequency range associated with 5G networks. The features of the use of composite materials in the implementation of antenna devices in 5G technologies are noted. A broadband matching circuit (BMC) with elements with lumped parameters and a reduced sensitivity invariant has been synthesized. A 3D model of the adaptive selective surface controller (SSC) was developed using CST Studio. The study results highlight the benefits of new composite materials in improving the performance of 5G antennas. This research makes a significant contribution to the development of 5G technologies by optimizing antenna design for efficient data transmission in modern mobile networks and can be a valuable resource for engineers and designers working in this field. [ABSTRACT FROM AUTHOR]