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A novel simple cosine-shaped resonator is proposed in this paper, intended to reduce mutual coupling between units. The proposed methodology is based on resisting the propagation of surface waves. Initially, a configuration consisting of 2 × 3 cosine-shaped resonators placed between two patch antennas is designed, resulting in a reduction of over 13.5 dB at the frequency of 5.8 GHz. Subsequently, a fractal microstrip array antenna is employed as a test case to demonstrate the efficacy of the proposed strategy. The radiating element is designed using a Koch snowflake fractal structure. A 4 × 4 microstrip array prototype antenna, fed by an aperture-coupled, corporate feeding structure, was designed, fabricated, and evaluated. Periodic arrangement of the cosine-shaped resonators around the radiation elements results in a 3.28% increase in impedance bandwidth. The measured results indicate an impedance bandwidth of 9.83% (5.54–6.11 GHz), an improvement in peak gain up to 20.46 dBi at the operating frequency, and a 3-dB gain bandwidth of 19.14% (5.21–6.32 GHz). [ABSTRACT FROM AUTHOR]

A wideband filtering antenna design has been proposed in this paper. The proposed filtering antenna design is cavity-backed substrate integrated waveguide (SIW) based on a single layer slot antenna. Two E-shaped slots are engraved onto the ground face of the design to improve filtering selectivity and operational bandwidth. For achieving wideband response, a modified half-TE110 mode and a decreased radiation null are all produced by the E-shaped slots in the right-half cavity. The design is simple and compact, with only one substrate layer and a larger working bandwidth than its counterparts. The filtering antenna has a 13.1 % fractional bandwidth and works at a frequency of 28 GHz. The proposed prototype has been structured, tested, and the simulation and measurement results were analyzed. [ABSTRACT FROM AUTHOR]

Directional sources like the Huygens source enable electromagnetic wavefront forming/shaping with great flexibility and have made impacts in photonics, applied physics, metasurfaces, and antenna engineering. The related Janus source features a strongly directional near‐field and a quasi‐isotropic far‐field, which gives it promising application potentials distinct from, and complementary to, the Huygens source. Nevertheless, most existing Janus sources face strong limitations in efficiency and/or 3D operation, hindering their practical application. This paper introduces a 3D active Janus source that achieves near‐field directionality over a wide bandwidth and a power efficiency much improved over existing passive Janus sources. It is shown that a class of quasi‐isotropic antennas are actually active Janus sources (which is referred to as the Janus antenna). A well‐designed Janus antenna is demonstrated which (a) exhibits near‐field directionality over a broad bandwidth of 28.9%, and (b) in a practical usage environment, achieves a power efficiency ≈60 times higher than a passive Janus source. This work elucidates the connection between the “Janus dipole” concept in physics and the “quasi‐isotropic antenna” concept in antenna design, and paves the way for the design of future directional devices with much improved bandwidth and efficiency. [ABSTRACT FROM AUTHOR]

Summary: This paper presents two different configurations of ±45° dual‐wideband dual‐polarized (DWDP) antennas. The antenna comprises eight end‐loaded broadband dipoles grouped into two sets based on the bands of operation. The high‐frequency dipoles are strategically placed within the low‐frequency ones to form the elementary unit. Further optimization has been performed on the elementary unit in terms of the radiator placement to suppress sidelobe levels for array formation. Both configurations are meticulously fabricated using an all‐metal structure, demonstrating durability and the simplicity of fabrication. The antenna designs achieve ±45° polarization, high gain, satisfactory cross‐polarization discrimination (XPD), and wide impedance bandwidth covering 0.67–1.04 GHz and 1.54–3 GHz bands. Despite the nested configuration, mutual coupling is well within acceptable limits. Formation of the array based on the optimum elementary unit has been investigated by simulation, revealing reasonable gain enhancement and low sidelobe levels across all bands. This comprehensive approach yields a robust, high‐performing antenna configuration suitable for indoor distributed antenna system (IDAS) applications. [ABSTRACT FROM AUTHOR]

A low-profile dual U-shaped monopole antenna designed for WLAN, WiMAX, and C-band applications has been implemented in this paper. The proposed antenna has covering frequency ranges of 2.7-3.1 GHz, 4.0-5.2 GHz, and 5.9-6.4 GHz. The compact antenna's antenna size is 24×30×0.8 mm², and the antenna has achieved bandwidths of 13.79%, 26.67%, and 8.1% across the respective bands. This frequency band is achieved as a result of dual inversion to each other in U shape. The low profile of the proposed antenna enables its easy and fast inculcation in modern communication devices. [ABSTRACT FROM AUTHOR]

This paper presents a miniaturized Vivaldi antenna with a scan volume of ± 30° designed for the 6–18 GHz tactical operational band, commonly employed in phased array systems and modern surveillance applications. The proposed antenna offers enhanced radiation characteristics, low cross polarization, broad beam width, and moderate gain. The design presented in this paper follows a step-by-step approach to achieve enhanced performance in terms of multi-octave bandwidth and compact size. Initially, a traditional Vivaldi antenna was designed and examined, with a modified feed structure. Subsequently, corrugated edges were inserted into the antenna, increasing its electrical length and resulting in good impedance matching, especially in the 6–10 GHz frequency band. A prototype model is fabricated and tested to validate its performance against the simulation results. The measured results demonstrate that the return loss (S11) remains below −10 dB across the operating frequency range, achieving a 50% bandwidth, with a gain of 3–7 dB, and improved co-cross polarization of −23 dB at 6 GHz and −26 dB at 18 GHz. [ABSTRACT FROM AUTHOR]

In this study, a high-gain broadband circularly polarized crossed dipole antenna is designed. This antenna utilizes two pairs of cross dipoles and a pair of phase delay lines to form circularly polarized radiation. Open-circuit stubs are symmetrically loaded on the four arms of these dipole pairs to introduce new circularly polarized resonating frequencies. Additionally, a symmetrically positioned rectangular ring patch is introduced directly beneath the cross dipoles to generate the third circularly polarized resonating frequency, thereby enhancing the axial ratio bandwidth of the antenna symmetrically. Furthermore, metal posts are symmetrically loaded at the four right angles of the rectangular ring patch to augment the antenna gain, maintaining the overall symmetrical balance crucial for optimal circularly polarized radiation performance. This symmetric design ensures that the antenna achieves a 3dB axial ratio bandwidth of 29.2% (1.9–2.55 GHz) and sustains a gain of 7.5 dB within the passband, showcasing excellent circularly polarized radiation attributes. [ABSTRACT FROM AUTHOR]

This research examines the performance of two Z-shaped dielectric resonator antenna designs that employ silicon substrate material and operate at a frequency of 10 terahertz. CST software was used to simulate and create a two-Z shape DRA. Results of enhanced gain are analyzed and compared with earlier research. The suggested Two Z shape DRA has a gain of 7.31 dB and a return loss of -15.9 dB.The two Z-shaped dielectric resonator antennas have an impedance bandwidth of 66.66%.The VSWR of two Z-shaped dielectric resonator antennas is around 2 dB, which is acceptable. This proposed approach may be suitable for a wide range of communication applications, including wireless and terahertz applications. [ABSTRACT FROM AUTHOR]

This paper describes a novel multiband monopole cavity-backed (MCB) microstrip antenna design with a wide axial ratio bandwidth (ARBW). This study explores the challenge of achieving a wide ARBW in MCB antennas for C-band applications. To attain the desired parameters, the proposed MCB antenna prints a circularly polarized monopole radiator onto the substrate. The cavity-array structures, known as resonating elements, strategically positioned vias on both the monopole-radiating patch and the substrate. The proposed MCB, which consists of semi-circular ring slots, improves impedance matching, radiation, and bandwidth (BW). We present two MCB antennas that meet specific frequency ranges and polarization. The first antenna, with a 5 mm patch size, covers the S, C, and X bands, while the second antenna, with a 3 mm patch size, resonates at the X and C bands. Furthermore, the 5 mm and 3 mm MCB antennas have wide ARBWs of 400 MHz (5.00–5.4 GHz) and 610 MHz (4.87–5.48 GHz), respectively. To determine its superiority, we compare the proposed MCB's performance to that of other antenna designs. We also examine how the proposed MCB functions in two other configurations: one with circular cavities and one without, as well as semi-circular rings of varied radius. We validate the proposed antenna designs by comparing their simulated and measured results. We compare the suggested antenna to other antennas in terms of ARBW, gain, size, efficiency, BW, and applications. [ABSTRACT FROM AUTHOR]

The incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element at unequal spacing. Dual hybrid HOMs are analyzed inside a substrate integrated waveguide-based cavity to design a wide band, enhanced gain dual-polarized antenna. The radiating element of the antenna is designed with multiple slots positioned at unequal spacing but symmetrical along the origin. This methodology provides three-fold advantages: a reduction of side lobes, an adjustment of phase center, and a significant reduction of radiation nulls. The antenna has been fabricated, and experimentally validated. The antenna exhibits a reduction in radiation null to − 0.5 dB, a phase adjustment of the main lobe to 0°, and a reduction in side lobe level from − 14.4 dB (N = 2, equal spacing) and − 15.5 dB (N = 4, equal spacing) a maximum of − 19.7 dB (N = 4, unequal spacing) at 12.35 GHz in the phi-0 plane. Excellent agreement between measured and simulated results corroborates the efficacy of the proposed approach. The significant improvement in the radiation performance of the single-element antenna design sets the antenna design apart from the state-of-the-art solutions. [ABSTRACT FROM AUTHOR]

A miniaturized high‐performance metasurface (MTS) antenna with cross‐shaped strips is designed, which can be applied to wireless communication systems. The resonant frequency of the main mode of the proposed MTS is reduced by embedding a 2 × 2 cross‐shaped strip array in the gaps of the 3 × 3 circular MTS array, resulting in a lower operating frequency and miniaturization. The main mode of the MTS and the probe mode are excited simultaneously by the L‐probe structure, resulting in a dual‐mode resonance for a broadband performance. The entire design mechanism of the antenna is explained analytically through characteristic mode analysis (CMA) method. Additionally, the cross‐polarization levels in H‐plane are effectively suppressed by a metal via positioned at the MTS center. Measured results show a wide impedance bandwidth of 32.6% (reflection coefficient ≤ −10 dB) with an MTS size of 0.44λ0 × 0.39λ0 (where λ0 is the free‐space wavelength of 6.6 GHz). The achieved peak gain is 7.1 dBi, with a 2 dB gain bandwidth of 36% (5.25‐7.55 GHz) and a low cross‐polarization level below ‐20 dB. [ABSTRACT FROM AUTHOR]

In this paper, the Fibonacci slot is configured for Ku- and S/C -band antenna applications. In the Ku-band antenna, the slot is placed on the patch and the desired band is achieved by a rectangular omega-shaped slot etched out from the lower ground plane. While in the S/C band antenna, the Fibonacci slot is etched out from the ground plane. With the size of 55 × 40 mm2, the Ku-band antenna operates from 13.04∼17.68 GHz. The S/C band antenna of size 30 × 30 mm2 has a band from 3.55 to 6.07 GHz. A peak gain of 6 and 3.8 dBi is noted from the Ku- and S/C band antenna, respectively. Parametric analysis is done to analyze the effect of slots. The antennae are validated experimentally through impedance bandwidth plot, radiation pattern, and gain. Simulated and experimental results are compared for both antennae and a good match is observed between them. [ABSTRACT FROM AUTHOR]

A compact dual-element microstrip antenna, employing a parasitic artificial magnetic conductor (AMC), is proposed for facilitating 4G and 5G wireless communications. The antenna design entails microstrip dipoles fed by a T-shaped feedline. Notably, the antenna achieves a measured bandwidth of 5.35-6.7 GHz (with S11 = -10 dB). To enhance performance, a proposed parasitic AMC reflector is integrated into the antenna structure. Incorporating a 3 × 3 AMC array, the antenna extends its -10 dB measured bandwidth from 4.57 to 6.80 GHz, catering to both 4G and 5G communication standards. Comparative analysis with an antenna lacking AMC reveals a reduced size of 34%, alongside a notable gain of 8 dBi and unidirectional radiation patterns. Additionally, a low-profile wideband two-element array, coupled with a 3 × 4 AMC reflector, demonstrates a broad bandwidth spanning from 4.55 to 6.8 GHz within the C-band. This configuration results in increased gains for the two antenna elements and ensures acceptable isolation exceeding 30 dB, crucial for multiple-input multiple-output (MIMO) systems. The efficiency and gain of all elements are obtained, almost 90% and 8 dBi, respectively. Moreover, an AMC unit cell, well founded on a parasitic patch, resonates at 6.12 GHz with a bandwidth extending from 5.25 to 7.15 GHz. Furthermore, the offered equivalent transmission line model of the antenna with the AMC is demonstrated, yielding desirable results. This model accurately predicts the input impedance of the 1 × 2 array with AMC across a broad frequency band ranging from 4.63 to 6.73 GHz. This comprehensive coverage demonstrates the effectiveness and versatility of the offered model in characterizing the electrical behavior of the antenna system across a wide frequency band, thus facilitating its design and optimization for various applications. [ABSTRACT FROM AUTHOR]

This study uses annular circular rings to create multi-band applications using crescent-shaped patch antennas. It is designed to be made up of five circular, annular rings nested inside of each other. Three annular rings are positioned and merged on top of the larger rings, with two annular rings set along the bottom of the feed line. The factors that set them apart, such as bandwidths, radiation patterns, gain, impedance, and return loss (RL), are analysed. The outcomes show how compact the multi-band annular ring antenna is. The proposed circular annular ring antenna has return losses of −33 dB and operates at two frequencies: 3.1 GHz and 9.3 GHz. This design is modelled and simulated using ANSYS HFSS. The outcomes of the simulation and the tests agree quite well. The X band and WLAN resonant bands have bandwidth capacities of 500 and 4300 MHz, respectively. Additionally, the circular annular ring antenna design is advantageous for most services at these operating bands. [ABSTRACT FROM AUTHOR]

This paper presents the design of broadband miniaturized C-band stacked antenna and its analysis using TLM. The proposed antenna operates at C-band and acquires 45% bandwidth with a peak gain of 8 dBi. The generalized transmission-line model, developed earlier for the analysis of multilayered stacked antennas (without slots), has been implemented and modified for the analysis of the proposed antenna (having a slot in the driven patch). The slot coupling effect is incorporated in the modified TLM model for the circuit-level simulation and analysis of the designed antenna. Circuit simulation results agree with EM simulation and measured results. The proposed antenna occupies an overall volume of 52 × 50 × 4.5 mm3, while volume of the radiating elements is 13 × 19.89 × 4.5 mm3, which makes the design quite compact. The proposed stable antenna has unidirectional radiation patterns throughout the band of operation and is thus suitable for applications such as remote sensing, target detection, and imaging. [ABSTRACT FROM AUTHOR]

We propose a method for increasing the bandwidth of a substrate‐integrated‐waveguide (SIW) cavity‐backed antenna with taper‐based microstrip SIW transition feeding. For radio transmission, a circular slot is etched on top of the SIW cavity. For optimal antenna design, the slot is etched slightly away from the cavity center to generate circularly polarized waves. Simulations show a wide axial ratio bandwidth of 7.860% between 11.02 GHz and 11.806 GHz. Experimental results confirm a similar wide axial ratio bandwidth of 4.9% between 10.8 GHz and 11.35 GHz. An SIW feed from an inductive window excites the radiating circular slot, resulting in a simulated wide impedance range of 1.548 GHz (10.338 GHz–11.886 GHz) and bandwidth of 13.93%. Experimental results show a wide impedance of 2.08 GHz (10.2 GHz–12.08 GHz) and bandwidth of 18.84%. The SIW cavity‐backed antenna creates a unidirectional pattern, leading to gains of 6.61 dBi and 7.594 dBi in simulations and experiments, respectively. The proposed antenna was fabricated on a Rogers RT/Duroid 5880 substrate, and the reflection coefficient, radiation patterns, and gains were tested and compared using a computer simulator. The developed broadband antenna seems suitable for X‐band applications. [ABSTRACT FROM AUTHOR]

In this manuscript, we propose a circularly polarized (CP) antenna design that can achieve broadband axial ratio (AR) bandwidth in the X-band. A sequentially rotated serial feeding network is applied to achieve the broadband requirement. The proposed antenna consists of two substrates, one is for feeding elements and the other is for radiating elements. The 16 radiating elements located on an upper substrate are fed through cross-shaped slots located in a ground plane between two substrates. The feed network is based on a 1:4 power divider design and consists of a serial connection of the power dividers resulting in the proper power splitting to the 16 radiating elements. The proposed antenna is designed to exhibit an optimal radiation characteristic of around 8.2 GHz with a CP antenna gain greater than 16 dB and similarly wide impedance and AR bandwidths. Experiments with the fabricated CP antenna were performed to support the proposed CP antenna design theory and are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Ring shape microstrip antenna designs supported via an altered ground plane profile are proposed for multi-band response with wider bandwidth in each band. The impedance bandwidth of a single ring patch supported via a slot cut ground plane on a substrate having a thickness of * 0.1λg, is 45.8% and the broadside gain is 5.6 dBi. By employing additional stack patches, dual and triple-band configurations are obtained. In the respective operative frequency bands, maximum 15% of bandwidth is achieved in the suggested antenna, with a maximum broadside gain of more than 5.5 dBi. Through the acquired antenna features, the proposed configuration fulfills the criteria of E-GSM900/Secondary Surveillance Radar/Aeronautical Radio Navigation Applications. [ABSTRACT FROM AUTHOR]

A new multi‐band frequency response controlling method using groove loading technique on the narrow wall of an open‐ended waveguide is proposed by the authors. The feature of this scheme is a larger stopband spacing that is independent of the position of the loading structure. A tri‐band antenna is designed as an example to verify the effectiveness of the idea. Two notches are introduced, and the bandwidths, as well as stopband spacings, can be adjusted by independent parameters. The tri‐band prototype can be fabricated using 3D printing technology or machining technology. Reasonable agreement between the measured and simulated results of impedance and radiation characteristics have been achieved. [ABSTRACT FROM AUTHOR]

The study of arbitrary patch antenna design represents a critical endeavor in the advancement of wireless communications technologies. This study delves into the construction of a random patch antenna using 3D electromagnetic software, namely the HFSS simulation program. By altering the antenna's physical structure, particularly its ground plane and patch section, we hope to enhance the antenna's performance. Antenna efficiency as measured by gain, S11 parameter, and bandwidth is compared between two different materials, FR4 and Rogers, with varying relative permittivity. Advancements in communications systems and technologies have been made possible by optimizing efficiency, reducing antenna size, and improving performance through modifications to the patch antenna's material composition and design. [ABSTRACT FROM AUTHOR]

In this article, a low profile multiband and multistrip with microstripfed triple L shaped monopole antenna has proposed. The antenna is designed to operate at 1.8GHz, 3GHz and 5.8GHz bands for GSM, WLAN and WiMAX applications. Including insert three L strip to generating multiband operation and the impedance bandwidth are coving frequency range 1.7GHz -1.88GHz/1.8GHz, 2.8 GHz -3.4GHz/3GHz and 5.4GHz-6.8GHz/5.8 GHz. The proposed antenna total occupied area is 27x40xmm³ and impedance bandwidth are achieved are 22%, 20% and 24%. The antenna is design on ANSYS HFSS software. Radiation pattern of proposed antenna is crating of omni-directional. The proposed antenna has very miniaturized than the references antenna are discussed in this article. [ABSTRACT FROM AUTHOR]

This paper presents a compact and wideband square microstrip patch antenna using low cost and easy available FR‐4 substrate of ground size 30 mm × 30 mm (0.51 × 0.51λ02 at lowest resonant frequency 5.07 GHz). The radiating patch of antenna is designed by embedding three T‐shape notches of same dimension formed by two rectangular notches of size 6 mm × 5 mm and 3 mm × 2 mm. The radiating patch is optimized by parametric variation of notches and feed line. The wideband fractional bandwidth (S11 < −10 dB) of 47.2% (2810 MHz) is achieved from 4.55 to 7.36 GHz with good return loss of −47.27 dB at 5.07 GHz for an optimized dimension of notches and feed line. However, the measured fractional bandwidth of 43.9% (2340 MHz) is achieved from 4.16 to 6.50 GHz with return loss of −37.34 dB at 5.14 GHz. A stable simulated gain of 4.69 to 5.93 dBi and measured gain of 4.4 to 5.9 dBi is observed in complete resonating band. The antenna is excited by line feed of 50 Ω and simulated by IE3D simulation tool. The entire resonating band 4.55–7.36 GHz is suitable for different applications in C‐band (4–8 GHz). [ABSTRACT FROM AUTHOR]

A novel broadband circularly polarized compact antenna is designed with broad axial ratio bandwidth (ARBW) for Sub-6 GHz fifth-generation applications. The antenna is printed on a Duroid substrate (ϵr= 2.2, thickness of 0.8 mm). The proposed configuration consists of two diagonally opposite symmetric parasitic strips energized by the matched transmission line and supported by a defected ground plane on the other side. By utilizing two parasitic strips and DGS concepts, wideband bandwidth of 3.4 GHz (2–5.4 GHz) Simulated and 3-dB ARBW of 2.5 GHz (2.9–5.4 GHz) is achieved. The CP behavior of the proposed antenna is investigated and discussed in detail with the help of the surface current distribution plot and magnitude/phase vs frequency plot. Simulated findings are justified by the measured results. The suggested antenna's simple design and high AR bandwidth make it a promising option for a wide range of wireless networks. [ABSTRACT FROM AUTHOR]

This paper introduces a feeding structure that employs a series capacitor and a parallel capacitor to control input impedance. Accordingly, a wide impedance bandwidth was achieved in a simulation. A comparative analysis of the characteristics of the reference antenna and the proposed antenna was conducted to demonstrate the proposed antenna's improved bandwidth and enhanced efficiency. According to the simulation and measurement data, the bandwidth of the proposed antenna was approximately 400 MHz (range, 680-1,080 MHz) under a 3:1 voltage standing wave ratio. Moreover, the efficiency improved from 43% to 59% (range, 690-960 MHz), and the radiation pattern showed satisfactory performance. The proposed technology thus offers promising development prospects for the antenna designs of lowfrequency systems for mobile communication. [ABSTRACT FROM AUTHOR]

Optimization of antenna parameters is important for achieving the best design that has higher results for gain and bandwidth while also having a smaller size. One such antenna design is numerically investigated and presented in this research. The antenna is optimized to an O-shape fractal design from a square patch design. The antenna is created by etching a slot of a square patch and making an O-shape fractal metamaterial patch antenna that operates on the THz band. The THz patch antenna is also investigated for its metamaterial properties. The optimization of the THz patch antenna is carried out for substrate height, slot length, and slot width. The optimized design has a size of 65 × 65 µm2. The highest bandwidth of 31.4 THz (138%) and the highest gain of 11.1 dBi is achieved. The optimized design is then investigated for multiple elements. The two-element MIMO antenna design using an O-shape patch is investigated to observe its performance and compare it with an O-shape single-element design. The two-element MIMO antenna design gives two bands with a bandwidth of 18 THz (113%) and 21 THz (56%). The gain of this design is 5.18 dBi and the size is 130 × 65 µm2. A comparison between the O-shape single-element fractal design, two-element fractal MIMO design, and other published designs is carried out. The compact, broadband, and high gain design presented can be used for 6G high-speed mobile communication devices. [ABSTRACT FROM AUTHOR]

The proposed hexagonal shaped antenna is designed to possess circularly polarized triple resonating band operation using a novel technique of paired open-ended slot embedded around antenna axis. The open-ended slots cut at and along either side of horizontal axis of the hexagonal radiating patch create meandered electrical path which allows the current circulation at the center of patch to degenerate the two orthogonal modes for circular polarization (CP) radiation. Hexagonal antenna fed with CPW feed give rise wide impedance bandwidth and wide axial ratio bandwidth. Circular polarization purity is achieved by optimizing the length of paired open-ended slots. A rectangular tunable notch embedded in the ground plane controls the impedance bandwidth by limiting its upper edge frequency. The proposed antenna possesses a wide impedance bandwidth of 68.4%, axial ratio bandwidth (ARBW) of 57.14% and peak gain of 4 dB. The proposed circularly polarized antenna holds triple circularly polarized bands resonating at 1.52 GHz, 1.73 GHz and 3.78 GHz with axial ratio bandwidth (ARBW) of 15 MHz, 15 MHz and 2720 MHz respectively, which is about 0.98%, 0.98% and 57.14% with respect to center resonating frequency. Antenna reports peak gain of 4 dB. The magnitude of axial ratio near to 0dB for all bands indicates purity in CP. [ABSTRACT FROM AUTHOR]

The primary goal of this study is to design a simple antenna that has a wide bandwidth and low return loss for biomedical applications. The paper shows the recommended antenna's three-stage modeling, with the goal of assessing every important parameter while a Teflon or polytetrafluoroethylene (PTFE) polymer substrate is used. In order to better comprehend, a comparison with prior studies employing teflon and similar substrate materials is conducted for the proposed patch antenna. The analysis includes the phantom model, evaluating performance criteria such as specific absorption rate (SAR), return loss, bandwidth, and gain values relevant to biomedical applications. The antenna works at two different frequencies: 9.73 and 9.39 GHz, one in free space and another in a skin-cotton layer. The bandwidth of the antenna is 4.067 GHz in free space at the resonance frequency of 9.73 GHz, where the return loss is -62.18 dB. The performance of the proposed antenna in the field of biomedical applications, its underlying reasons, and its impacts are discussed in detail in this study. [ABSTRACT FROM AUTHOR]

In this work, a super-wideband (SWB) Sierpinski triangular fractal antenna has been proposed. Keeping electrical dimension (ED) small and bandwidth dimension ratio (BDR) high is a big challenge in SWB antenna design. Sierpinski triangular fractal, slotted and tapered grounds have been used to meet these challenges with a wide operating frequency bandwidth. Operating range of the antenna is from 1.6 to 45 GHz, with a gain more than 1 dBi, bandwidth ratio of 28.1:1, VSWR less than or equal to 2, and with a reflection coefficient (S11) less than − 10 dB. ED of the proposed SWB antenna is 0.12λk × 0.14λk, here λk is the wavelength as per the lowest operating frequency. FR4 material is used as substrate to design and fabricate antenna. Results are measured till 20 GHz which are found quite promising in terms of − 10 dB impedance bandwidth. BDR of the designed antenna is 11,087.3 and ED are small which proves the design effectiveness. Proposed SWB antenna is useful for multiple bands such as WiMax, WiFi, Fixed Satellite Services, Radio Navigation, L, S, C, X, Ku,and Ka bands. [ABSTRACT FROM AUTHOR]

The paper studies the design of ultra-wideband printed loop antenna based on the characteristic mode manipulated in a large frequency band. The structure of this antenna is very simple. The wide impedance bandwidth of 60% with |S11| < –10 dB (2.76–5.16 GHz) is obtained due to a simultaneous excitation of the significant antenna modes. A stable radiation pattern is also achieved within the frequency bandwidth. The antenna is designed on FR4 substrate and fed with 50 Ω coupled tapered transmission line. [ABSTRACT FROM AUTHOR]

A sinuous antenna is a frequency-independent antenna known for its wide bandwidth and consistent gain, which makes it valuable in broadband applications such as ultrawideband (UWB) radar and ground-penetrating radar (GPR). However, sinuous antennas tend to be rather large. Consequently, numerous studies have explored miniaturization methods, with the gap-loading method emerging as a prominent approach. Unfortunately, it is still difficult to achieve broad bandwidths for conventional miniaturized sinuous antennas. In this paper, we use a novel approach incorporating a meander shape into the sinuous curve and employing gap loading with meandering. This innovative technique results in the development of a fractal-structured two-arm sinuous antenna characterized by an ultra-compact size and significantly expanded bandwidth. Adding a meander line in the outermost part maximizes the capacitance, thereby enhancing the gap-loading effect and minimizing the overall size of the sinuous antenna. In addition, the introduction of an inner meander line increases the inductance, contributing to a further expansion of the antenna's bandwidth. For example, the electrical length of the antenna without the meander line is 0.552 × 0.552 × 0.052 λ g 3 , while the electrical length of the antenna with the meander line is only 0.445 × 0.445 × 0.036   λ g 3 , i.e., 19.4% smaller. The antenna lacking the outermost meander line exhibits a 10 dB impedance bandwidth, spanning from 0.74 to 10.53 GHz. In contrast, the antenna featuring the outermost meander line has a 10 dB impedance bandwidth, extending from 0.51 to 10.72 GHz, which results in a remarkable enhancement in the fractional bandwidth (by 8.1%). Hence, the proposed antenna design is a good candidate for broadband applications that require miniaturization. [ABSTRACT FROM AUTHOR]

A penta-band circular polarized ultra-wideband (PBCP-UWB) antenna design is proposed for UWB applications. The PBCP-UWB structure comprises a circular radiator with L-shaped slits which is fed by a microstrip feed line. The proposed antenna is fabricated on an FR4 substrate. Further, the performance of the PBCP-UWB antenna is analyzed based on different parameters including impedance-matching bandwidth, fractional axial ratio, and radiation efficiency. The proposed antenna provides a fractional axial ratio bandwidth of 17.75% (3.81–4.53 GHz), 0.2% (6.91–7.05 GHz), 3.9% (9.29–9.66 GHz), 0.744% (10.71–10.79 GHz), and 1.671% (18.40–18.71 GHz), while its fractional impedance-matching bandwidth is 170%. The major advantage of the proposed PBCP-UWB antenna is its simplicity of design which results in good radiation efficiency. The measurement results for the fabricated antenna are found to be similar to those of the simulations. [ABSTRACT FROM AUTHOR]

This paper focuses on enhancing the bandwidth and gain of a coaxially fed microstrip patch antenna using Near Zero Refractive Index (NZRI) Metasurface. A metasurface comprising closely spaced 4 × 4 concentric circular rings is proposed to generate a wideband NZRI surface. The proposed metasurface provides µeff = 0.0018 and ϵeff = 4.4, making its refractive index near zero (i.e. – ηeff = 0.09) at 2.4 GHz. It is a wideband structure with an effective refractive index of less than 0.14 in 1–3 GHz. The metasurface is arranged over a coaxially fed microstrip square patch antenna to enhance its gain and bandwidth. The antenna and metasurface are printed on FR4 substrate of thickness 1.6 mm and dielectric constant 4.4 to verify its performance. A patch antenna is designed to operate near 2.4 GHz. A prototype of size (0.72λ × 0.72λ × 0.048λ) is fabricated and tested. The metasurface can improve the gain of the developed patch antenna by 4.3 dB and bandwidth by 11.5% (i.e. 45 to 320 MHz) at 2.4 GHz. 1 dB gain bandwidth is the same as that of impedance bandwidth. [ABSTRACT FROM AUTHOR]

A novel flexible printed monopole antenna with a windmill-shaped fractal design, which is fed by co-planar waveguide (CPW) is presented in this manuscript for ultra-wideband (UWB) applications. By integrating a modified windmill-shape fractal into the conventional irregular hexagonalpatch, the antenna achieves a significantly wider impedance bandwidth extending up to 156.6% across the frequency band of 1.37-11.25 GHz. Additionally, increasing the number of the windmill-shaped fractals leads to the emergence of further resonances. The overall dimensions of the designed antenna are 50×70×0.2 mm³, and it boasts an impressive bandwidth-dimension ratio (BDR) of 4457, showcasing exceptional efficiency in utilizing its compact size. The maximum gain reaches 4.8 dBi, while the radiation efficiency attains an impressive 98%. The modified windmill-shape fractal antenna design leverages the multifractal concept, providing monopole antennas with enhanced flexibility in controlling resonances and bandwidth. This manuscript offers a comprehensive presentation and discussion of the process used to improve the impedance bandwidth, shedding light on the antenna's exceptional performance and capabilities. [ABSTRACT FROM AUTHOR]

The proposed antenna introduces a wideband double-resonance substrate-integrated waveguide (SIW) cavity-backed slot antenna with shorting vias. The antenna is compact and has a wide frequency range. By loading the SIW cavity slot with shorting pin/vias, the authors describe the mechanism of operation and electric field distributions of the double resonance antenna. By etching the HBT-CRS at the center of the cavity, which creates the dual modes. One is an upward shift in the lowest mode (TE 120 mode or TE 210 mode) and a downward shift in the highest mode (TE 320 modes/TE 230 modes), and these two are paired together. As a result, the fabricated antenna has a very large bandwidth and a strong sense of double resonance. The antenna is designed, and then prototypes are built and tested. The key benefits are compactness, low fabrication cost, performance, and ease of integration with planar circuitry. SIW antennas are impactful in present wireless communication systems. A simulated double resonance design antenna with a low profile of 0.05 λ 0 (free-space wavelength) has a bandwidth of 1.854 GHz (frequency range varies from 12.58 - 14.38 GHz and fractional bandwidth of 13.93%) and a peak gain of 6.56 dBi across the whole bandwidth while measured bandwidth is 2 GHz (frequency range from 12.5 - 14.5 GHz and fractional bandwidth of 14.81%) and the gain over the entire bandwidth is 6.46 dBi. In addition, the antenna has outstanding unidirectional radiation characteristics for Ku band applications. [ABSTRACT FROM AUTHOR]

A Coplanar Waveguide (CPW) fed antenna with a T-type slot and Partially Reecting Surface (PRS) for gain, bandwidth, and efficiency improvement is presented. The antenna is miniaturized to get size reduction of 46.50%. The miniaturized antenna covers frequencies in C band. The presented antenna structure is easy to design and has size of 0:682λg × 0:99λg × 0:053λg. The PRS with parasitic patches is placed on top of the antenna at a distance of 0.25λg. The presented antenna design has a bandwidth of 4.42 GHz (Antenna 1) and 3.87 GHz (Antenna 2) with a percentage bandwidth of 75.81% and 59.58% respectively having average radiation efficiency above 90%. The gains obtained are 7.03 dBi and 6.12 dBi for Antenna 1 and Antenna 2. The gain has < 3 dB variation over the complete band. The obtained results support the design and make the antenna suitable for C band applications. [ABSTRACT FROM AUTHOR]

The bistatic global navigation satellite system's (GNSS) signal reflection technology has become an effective means of space-based sea surface wind field retrieval and height retrieval. By adopting a wider signal bandwidth, a higher pulse-limited footprint resolution can be achieved. However, for the GNSS-Reflectometry (GNSS-R) system, its signal bandwidth is affected by the signal bandwidth of the GNSS satellite, which limits the further improvement of the pulse-limited footprint resolution. This article proposes a method based on the novel signal bandwidth joint principle to improve the resolution of GNSS-R pulse-limited footprints. Firstly, currently in-orbit GNSS-R satellites use the traditional single frequency band (TSFB) method, which is limited by the GNSS satellite's signals and has a theoretical upper limit on its signal bandwidth. In response to this issue, this article proposes the novel joint bandwidth (NJBW) method (Galileo E5a and E5b signals) based on the auto-correlation function (ACF) signal ambiguity theory. The NJBW method reduces the main lobe width of the ACF of the GNSS-R signal by jointly processing the signals of E5a and E5b frequency bands, thus improving the pulse-limit footprint resolution of GNSS-R. Secondly, in order to verify the improvement effect of the novel joint bandwidth method on the pulse-limited footprint resolution of GNSS-R, this paper designs and fabricates an NJBW antenna verification prototype for the joint Galileo E5a and E5b frequency band and tests it in a microwave anechoic chamber. The test results indicate that the radio frequency (RF) bandwidth of the NJBW antenna validation prototype can cover both the frequency bands of E5a and E5b, making it suitable for use as the NJBW method for the GNSS-R receiving antenna. The bandwidth test values of the NJBW antenna validation prototype are consistent with the design values, which verifies the correctness of the NJBW antenna design model and further proves the feasibility of the NJBW method. Thirdly, based on the joint Galileo E5a and E5b frequency band signals, the NJBW method was applied to analyze the improvement effect of the pulse-limited footprint resolution. Compared to the TSFB method, the application of the NJBW method can increase the resolution of the GNSS-R pulse-limiting footprint by 1.73 times, which effectively improves the performance of the GNSS-R system. The NJBW method proposed in this article provides the theoretical method foundation and key technical support for sea surface wind field retrieval and height retrieval and the antenna design for the future high-precision and high pulse-limited footprint resolution GNSS-R sea surface wind field retrieval and height retrieval verification satellite. [ABSTRACT FROM AUTHOR]

The proposed antenna presents a dual-band monopole antenna with a wide axial ratio bandwidth, by using the modified ground plane. The tilted inverted L-shaped strip with an angle of α is printed on the FR4-epoxy substrate and is excited by the microstrip feedline. The overall dimension of the proposed antenna is 0.408λ0 × 0.326λ0 × 0.013λ0. The ground plane has been modified by introducing a Y-shaped strip, cutting a slot and connecting a stub for improving the characteristics of antenna performance. The design and simulation have been carried out by the EM simulator HFSS v.15 software. Once the antenna design is completed, the proposed antenna is fabricated and various characteristics are measured. The proposed antenna exhibits two distinct bands along with the percentage impedance bandwidths and axial ratio bandwidths of 75.32% (resonant at 2.35 GHz), 14.26% (resonant at 6.1 GHz) and 55.88% (center at 2.845 GHz), 15.96% (center at 6.075 GHz), respectively. The measured results are experimentally verified with simulated results and a good agreement is found between them. The measured impedance bandwidth, axial ratio and gain are good enough for commercial bands of wireless communication systems such as Bluetooth, Wi-Fi, WLAN, and WiMAX. [ABSTRACT FROM AUTHOR]

In this research work, a low-profile microstrip patch antenna has been designed with broad circularly polarized resonant bandwidth. The designed antenna consists of an equilateral triangularshaped radiating patch with two triangular coplanar parasitic elements along with a square-shaped ground plane. The unique feature of this antenna design is a generation of circularly polarized radiation by only optimum corner truncation of the two parasitic elements along with a small portion of the driver patch. The designed antenna can be used for (5.725-5.850 GHz) WLAN and (5.85-5.925 GHz) dedicated short-range communication applications with circularly polarized radiation property. The overall resonant bandwidth for (S11 ≤ -10 dB) is 1.52 GHz 24.75% with a frequency range (5.38-6.90 GHz), and the circularly polarized resonant bandwidth for (Axial ratio ≤ 3 dB) is 240MHz 4.13% with a frequency range (5.69-5.93 GHz). The gain of the antenna is 4 dB at 5.81 GHz and almost remains the same for the entire resonant bandwidth. The complete design of the antenna has been done using theoretical calculation and HFSS ver13 simulation software. After that, it has been fabricated, and different parameters have been measured using Vector Network Analyser. It has been found that the measured results are very much similar to the simulated results. [ABSTRACT FROM AUTHOR]

This paper presents a low-profile wideband, dual-polarized patch antenna using differential-paired, multi-mode arms. By employing the arrow-shaped, differential-paired arms, three modes of them are excited simultaneously, leading to a broad bandwidth. The shorting pins are uniquely inserted at the wings of the arms to obtain stable radiation patterns. Then, two pairs of arms are structured like the dipoles and a dual-polarized antenna is designed. In addition, by employing coplanar coupling feeding structures, a good wideband impedance matching is also achieved without increasing the height. For demonstration, a wideband dual-polarized patch antenna is designed and measured. Benefitting from the advantages of the multi-mode patch and symmetrical structure as a dipole antenna, the proposed dual-polarized antenna operates between 2.10–3.95 GHz, possessing a 10-dB impedance bandwidth of 61%, a profile of 0.1λ0, an average gain of 7.31 dBi, and stable radiation patterns. [ABSTRACT FROM AUTHOR]

A universal ultrahigh‐frequency (UHF) near‐field radio‐frequency identification (RFID) reader antenna with wide bandwidth and adjustable reading area is proposed in this letter. The antenna consists of an inverting power splitter base on double‐sided parallel stripline and adjustable traveling‐wave near‐field radiation units, which consists of two symmetrical meander microstrips and a complementary open resonant ring loaded on the ground plane. A design example with three radiation units is simulated, fabricated, and tested for verification. The result indicates that the proposed antenna has the 10‐dB impedance bandwidth of 128%, which completely covers the universal UHF RFID band from 840 to 960 MHz. The 100% read–write rate is achieved within the read–write distance of 10 mm according to the reading test. The reading area of 731 × 120 mm2 can be obtained for increasing the number of radiation units to 10. Moreover, the antenna features low far‐field gain, low‐cost, strong and uniform magnetic field distribution. Therefore, the proposed antenna and design method have good application prospects in the Internet of Things. [ABSTRACT FROM AUTHOR]

In this paper, a simple and compact monopole antenna with a high bandwidth ratio (BDR) of around is investigated for super wideband (SWB) applications. Using an F4B substrate with a dielectric constant of 2.65, loss tangent of 0.002, and connecting it to a triangular tapered 50‐Ohm line, the suggested antenna achieves its performance objectives. The proposed antenna has an electrical dimension of 0.14λ × 0.22λ and spans the SWB frequency range of 2.89–60 GHz with a 181.5% fractional bandwidth and reflection coefficient S11 < −10 dB. It has been revealed that the results of both experiments and simulations are remarkably similar to one another in terms of their conclusions. In comparison to other SWB antennas, the suggested antenna has a greater BDR, a larger bandwidth, and a more compact size. Apart from that, the antenna has good gain and good radiation characteristics over the whole operational frequency range. [ABSTRACT FROM AUTHOR]

A compact, wideband, low cost, high radiation efficiency and planar half mode substrate integrated waveguide (HMSIW) horn antenna is proposed in this work. For the first time, HMSIW is used to design a horn antenna. By using HMSIW waveguide structure instead of Substrate Integrated Waveguide (SIW), the impedance bandwidth of antenna is increased significantly. The use of this waveguide structure in the design of the horn and its feeding system has increased the impedance bandwidth of the antenna. In fact, leaking the electromagnetic waves gradually along the horn increases the bandwidth of antenna. By applying the design equations of the H-plane horn antenna and half mode substrate integrated waveguide, the initial dimensions of the antenna have been obtained, then the best possible solution has been extracted by parametric study and optimization. Simulation results exhibit an impedance bandwidth of 50% from 24GHz to 40GHz. Also, the proposed design shows a gain between 7dB and 10 dB together with radiation efficiency higher than 95% over the frequency band of 25 to 35GHz. The innovation of this work is in providing a new horn structure based on HMSIW with wide impedance bandwidth. In the previously presented works, which are mainly based on SIW, the antenna suffers from a narrow impedance bandwidth. [ABSTRACT FROM AUTHOR]

In this paper, a microstrip V-shaped long wire antenna is proposed and designed using HFSS simulation software. The antenna design includes a V-shaped radiator positioned on the top of the substrate, along with bottom side tuning stubs. The fabrication of the antenna is made on a Fr-4 epoxy substrate, resulting in overall dimensions of 16 x 16 x 0.32 mm³ and 18 x 16 x 0.8 mm³. After conducting simulations and measurements, the resonant and non-resonant antenna parameters have been compared. The resonant antenna operates at a frequency of 5.8 GHz, while the non-resonant antenna operates at 5.2 GHz. The resonant antenna exhibits a bandwidth of 17.2%, whereas the non-resonant antenna demonstrates a bandwidth of 15%. [ABSTRACT FROM AUTHOR]