Maximum Gain Research Articles

System design of a microstrip antenna by dimension and substrates optimization

The microstrip antennas matured and improved over the last 25 years. Throughout these years, the limitations, and specifications of the said antennas have been overcome and significantly improved. Known to be lowprofile, suitable for mobile, and lightweight, these microstrip antennas are the focus of this research. In this paper, the researchers designed a microstrip antenna with varying lengths and substrates. They tested the changes and the effects in microstrip antennas of different lengths, along with altering substrates. To verify the differences, the researchers compared the performance parameters maximum gain (dBi), minimum gain (dBi), and S11 graph on each tested length and changed substrate. The rough set theory was used to determine the optimal design via MATLAB. From there, the researchers analyzed the results gathered and drew their respective conclusions. Additionally, they saw and compared each data result to know what antenna has the best performance parameters. From the results, a change in the dimension will result in a decrease in the said performance parameters. Furthermore, the change in substrate thickness also diminishes these changes.

Design of higher gain linearly polarized 2×2 microstrip patch array antenna for wireless communication

The fifth-generation technology is popular and best as far as data rates are concerned for wireless applications. To meet the increased demand of the modern world for faithful communication, this research work is carried out. In this approach, a single patch, 1×2 array, and 2×2 array are designed using a low-cost FR4 dielectric substrate ( =4.4) covering the 3.3–3.8 GHz frequency band. Due to the lack of gain from arrays in the present research, an attempt is made to achieve excellent gain from arrays with a minimum number of patches. First, the gain of a single inset-fed antenna is compared with another normal single patch of the same thickness but with an additional air dielectric medium. Next, the second single patch is extended to obtain a rectangular 1×2 array and a 2×2 array antenna. A second single patch measuring 50×32.5×0.8 mm is designed assuming an infinite ground plane. It has 3mm air gap between the patch strip and the ground. Air acts as a second dielectric layer that reduces power loss. This allows a maximum gain of 15.2 dB with a return loss of -22 dB. Also, antenna efficiency and bandwidth are 91% and 267.69 MHz, respectively.

Tri-band antenna with metasurface-based ground plane for Sub-6 GHz 5G and 6G WPT applications

In this paper, a spiral-shaped metamaterial-loaded rhombic slotted microstrip patch antenna is investigated for Sub-6 GHz 5G and 6 GHz tri-band applications. A 1.524 mm thick Rogers RO4003 substrate (ϵr = 3.55, LosTanδ = 0.0027) opts for the antenna design. A partially grounded mechanism is implemented to control the operating frequencies of the antenna. A 5×5 triangular unit cell metasurface is deposited beside the partial ground plane to enhance the impedance bandwidth as well as to improve the impedance matching. A G-shaped metallic structure enclosed within the rhombic slotted antenna helps in creating circular polarization (CP) properties. The presented antenna resonates at 3.28 GHz (Mid-range Sub 6 GHz 5G band), 4.94 GHz (Upper range Sub 6 GHz 5G band), and 6.92 GHz (Sub 6 GHz 6G Band) frequencies. The maximum gain offered by the antenna is 8.81 dBi. Also, the developed antenna offers CP characteristics in all three operating bands with wide axial ratio (AR) bandwidth characteristics above 400 MHz in both the first and third operating bands. The radial characteristics of the proposed antenna show its capability of receiving EM signals from all directions as desired for a WPT system. For validation purposes, a prototype is fabricated and characterized as well.

Development and comprehensive evaluation of a dual-port textile UWB MIMO antenna for biomedical use

In this paper, a textile two-port multi-input multi-output (MIMO) half-circle antenna with corrugated borders is designed and fully analyzed for nearfield ultra-wideband biomedical diagnostic applications. The orthogonal polarization technique is introduced for mutual coupling reduction, signal quality, and imaging accuracy improvement. A low pass filter with significant out-of-band rejection is inserted between the two MIMO structural elements to improve the isolation from element to element. For simple system integration, A 50 ohms feed coplanar waveguide is suggested for each element. The entire antenna is constructed using textile materials, with the radiating element composed of conductor fabric. The substrate, on the other hand, is crafted from cotton material which possesses a relative permittivity of and a tan δ value of 0.025. The size of each antenna element has low-profile dimensions of 40 × 40 × 0.3 mm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${mm}^{3}$$\\end{document}. The measured results obtained demonstrate an extremely broad bandwidth extends from 2.5 GHz to 12 GHz. Omnidirectional radiation pattern is obtained, with 6 dBi maximum gain and 96% efficiency. In order to ensure flexibility, a range of bending conditions were analyzed, and the durability was assessed through wash ability testing. Safety was confirmed by measuring the specific absorption rate. Furthermore, time domain and MIMO performance assessments were performed to ensure its suitability for imaging systems.

Investigation of Residual Stress Distribution and Fatigue of 7050-T7451 Alloy Hole Components with Laser Shock and Ultrasonic Extrusion

Small-hole structures, such as the millions of fastener holes found on aircraft, are typical stress-concentration structures prone to fatigue failure. To further improve the strengthening process of this small-hole structure, we make up for the limitations of laser shock processing (LSP) of small holes by combining it with the ultrasonic extrusion strengthening (UES) process to form a new strengthening method—laser shock and ultrasonic extrusion strengthening (LUE). The influence of the LUE process sequence and process parameters on residual stress distribution was studied through FEM, and the gain of fatigue life of specimens after LUE strengthening was also explored through tests. The results show that when using LUE technology, the friction force decreases with the increase in amplitude and decreases by 3.2% when the amplitude is maximum. The LUE process eliminates the thickness effect generated by LSP, which can achieve good stress distribution of small-hole components under smaller laser shock peak pressure, and reduces equipment power. LUE can significantly improve the fatigue life of small-hole components, and the maximum fatigue life gain can be up to 310.66%.

Miniaturized Vivaldi antenna with multiband and high-gain for millimeter-wave applications

ABSTRACT A novel miniaturised quad-band printed Vivaldi antenna is proposed for millimetre-wave applications. It can be seen as a two-arm antenna where the antenna arms bound the tapered Vivaldi slot. The antenna arms are printed on the opposite sides of a flexible millimetre-wave substrate. Three periodic structures are added to the antenna geometry and printed in the area surrounding the radiating slot structure to improve the impedance matching over the antenna’s four operational frequency bands and enhance the gain. These periodic structures are parasitic ring array loaded to the antenna arms, ring-array reflector inserted between the antenna arms and the ground plane, and metamaterial director printed in front of the antenna arms. A prototype of the proposed antenna is fabricated for experimental assessment of the antenna performance. The experimental measurements show good agreement with the simulation results. The proposed antenna impedance is matched over the four frequency bands centred at 25 , 35 , 45 , and 55 GHz . The bandwidth of each operational band is about 5 GHz with percent bandwidths of 20 % , 15 % , 11 % , and 9 % , respectively. The corresponding values of the maximum gain are 7.5 , 10.5 , 12 , and 13 dBi , respectively. The radiation efficiency is maintained above 93 % over the entire frequency band (20–60 GHz).

AC Characteristics of van der Waals Bipolar Junction Transistors Using an MoS2/WSe2/MoS2 Heterostructure.

Two-dimensional layered materials, characterized by their atomically thin thicknesses and surfaces that are free of dangling bonds, hold great promise for fabricating ultrathin, lightweight, and flexible bipolar junction transistors (BJTs). In this paper, a van der Waals (vdW) BJT was fabricated by vertically stacking MoS2, WSe2, and MoS2 flakes in sequence. The AC characteristics of the vdW BJT were studied for the first time, in which a maximum common emitter voltage gain of around 3.5 was observed. By investigating the time domain characteristics of the device under various operating frequencies, the frequency response of the device was summarized, which experimentally proved that the MoS2/WSe2/MoS2 BJT has voltage amplification capability in the 0-200 Hz region. In addition, the phase response of the device was also investigated. A phase inversion was observed in the low-frequency range. As the operating frequency increases, the relative phase between the input and output signals gradually shifts until it is in phase at frequencies exceeding 2.3 kHz. This work demonstrates the signal amplification applications of the vdW BJTs for neuromorphic computing and wearable healthcare devices.

Surface-normal illuminated pseudo-planar Ge-on-Si avalanche photodiodes with high gain and low noise

Germanium-on-Silicon (Ge-on-Si) avalanche photodiodes (APDs) are of considerable interest as low intensity light detectors for emerging applications. The Ge absorption layer detects light at wavelengths up to ≈ 1600 nm with the Si acting as an avalanche medium, providing high gain with low excess avalanche noise. Such APDs are typically used in waveguide configurations as growing a sufficiently thick Ge absorbing layer is challenging. Here, we report on a new vertically illuminated pseudo-planar Ge-on-Si APD design utilizing a 2 µm thick Ge absorber and a 1.4 µm thick Si multiplication region. At a wavelength of 1550 nm, 50 µm diameter devices show a responsivity of 0.41 A/W at unity gain, a maximum avalanche gain of 101 and an excess noise factor of 3.1 at a gain of 20. This excess noise factor represents a record low noise for all configurations of Ge-on-Si APDs. These APDs can be inexpensively manufactured and have potential integration in silicon photonic platforms allowing use in a variety of applications requiring high-sensitivity detectors at wavelengths around 1550 nm.

Optical amplification across the whole communication windows in PbS quantum-dot-doped fiber

The surge of big data, cloud computing, and AI bring in explosive requirement of data transmission capacities. However, the transmission capacity of traditional single-mode-fiber already reaches its limit due to the narrow emission bandwidth of rare-earth-ion. Here, we achieved ultra-broadband optical amplification in O + E + S + C + L bands for the first time in PbS quantum-dot-doped glass fiber with the maximum gain of 5 dB at 1370 nm under 100 mW pump. The mechanism of the broadband optical amplification, the advantages of quantum dot-doped fiber amplifier (QDFA), and a new measurement scheme for QDFA are systematically discussed. It is believed that in the future, the further optimization of the composition and architectures of the glass fiber, and the preparation method of quantum dot-doped fiber may lead to important applications in optical interconnection, artificial intelligence, Internet of things, mobile electronics and so on.

A low-profile ultra-wideband hexagonal-patch antenna for UAV-based applications

ABSTRACT A compact, low-profile, and ultra-wideband antenna is always desirable for airborne Unmanned Aerial Vehicles (UAV) applications. In this paper, an ultra-wideband monopole antenna is presented with the benefit of a compact and low-profile design structure. The antenna design enables efficient communication without interfering with the UAV’s other components. The antenna is designed using a slotted-hexagonal-patch fed from a co-planar microstrip feed. The bow-tie-shaped slot along with a few other rectangular-shaped parasitic slots are loaded in the hexagonal patch for bandwidth enhancement. The coplanar feed with top ground offers minimum interference with the UAV structure. The non-conducting bottom plane allows seamless integration without causing any interference to the antenna. An equivalent circuit model (ECM) of the proposed antenna is also developed. The antenna structure is fabricated and the measured results are validated. A good agreement between the measured and simulated results is observed. The antenna covers an ultra-wideband ranging from 3 GHz to 13.5 GHz with a maximum gain of 4.0dBi. The size of the antenna is 0.24λ0 ×0.29λ0 ×0.01λ0. The developed antenna, therefore, demonstrates that it is a strong contender for ultra-wideband UAV-based applications.

A Metasurface Based High Gain Patch Antenna for Future Multiband Wireless Communication

This paper presents a novel, compact, and high gain metasurface (MS) patch antenna. The antenna structure consists of a slotted square patch in a fractal shape, integrated with a metasurface layer stacked on Taconic RF-30 dielectric material. The individual cells are arranged periodically, creating a 5 x 5-layer configuration. The proposed antenna is designed with physical dimensions of 290 x 290 mm² and achieves a maximum gain of 13.3 dBi at a frequency of 2.2 GHz. Moreover, it achieves a satisfactory minimum reflection coefficient of -10.9 dB. The design process and analysis were performed using the CST MWS simulation software. Based on the performance results obtained from this study, the suggested antenna can be considered suitable for applications in 5G communication.

Super-wideband fractal antenna of two-arm structure with broadband balun

ABSTRACT A balanced two-arm antenna has been proposed for super-wideband (SWB) operation to work efficiently over the frequency range (2.95 − 34 GHz ). The antenna proposed for SWB operation can be considered as composed of two main parts. The first part is the radiating surface of the antenna and is composed of two-arms leading to a balanced antenna structure. For wideband operation, each arm has a double-fractal (angular/radial) structure. The second part of the antenna structure is the wideband feeding balun that is responsible for realising maximum power transfer and impedance matching while feeding the balanced radiating two-arm structure from the conventional unbalanced coaxial line. A prototype has been fabricated for experimental characterisation of the proposed antenna. Both the simulation results and the experimental measurements come in good agreement with each other showing that the proposed antenna can be good candidate for many super-wideband applications of future generations of mobile communications. The proposed antenna has overall dimensions of 40.0 mm × 21.0 mm × 1.5 mm . It is shown by simulation and measurement that the proposed antenna has %BW of 168 % , RBW of 11.5 : 1 , and BDR of 2015 . The maximum gain ranges between 2.3 and 6.2 dBi. The radiation efficiency is greater than 98% over the frequency range ( 2 − 24 GHz ) and is greater than 85% over the frequency range ( 24 − 34 GHz ).

A 60 dB gain range programmable gain current amplifier for ultrasound sensing

This article presents a programmable gain current amplifier (CA) for ultrasound sensing applications. The design proposed consists of a current divider and a close-loop current amplifier. The CA utilizes switches to adjust the resistance of the shunt resistors and feedback resistors to achieve variable gain, thus realizing the time gain compensation (TGC) function. The proposed CA implemented in 180-nm BCD technology occupies an active area of 0.059 mm2. Measurement results show that the CA achieves a maximum gain of 36.6 dB and a gain range of 60 dB. The average input-referred noise spectral density is 0.32 pA/√Hz at maximum gain condition while consuming a power of 1.07 mW.

Transparent ionic liquid antenna based on multi-modes using multiple feeding structures

With the rapid development of modern wireless communication technology, there is an increasing demand for the functionality of the communication system carried by a single platform. To improve the utilization of the antenna, a multimode liquid antenna is proposed in this paper. The antenna is fabricated using 3D printing technology and mainly consists of a cylindrical dielectric resonator, a coaxial feeding structure, and a slot-coupling feeding structure. By hollowing out the middle of a resin container and filling it with low-loss ionic liquid with stable dielectric properties, a liquid dielectric resonator antenna (DRA) is formed. The various resonant modes (slot mode, HEM11δ, TM11δ, TM21δ, and TM31δ modes) can be excited by introducing different feeding structures. The operating frequencies and radiation patterns can be modulated by mode switching. Simulated and measured results show that the antenna operates in the frequency bands of 2.25–2.76 GHz (20.4 %) and 4.82–5.73 GHz (17.3 %), and the maximum gain can be up to 10.3 dBi. The proposed antenna structure avoids the complex RF control circuit design, which has various applications including 5G/6G communications, transparent electronic devices, and Internet of Things.

Integrated photonic waveguides for on-chip SBS with OAM modes

Stimulated Brillouin Scattering (SBS) is a nonlinear optical process that can provide significant on-chip gain in various materials and platforms. The utilization of chalcogenide and silicon (Si) waveguides has facilitated the advancement of Brillouin lasers and diverse microwave photonic functionalities. The predominant approach has been centered on interactions between conventional guided modes, specifically TE/TM. This study introduces a novel approach that explores diverse guided-wave configurations capable of sustaining SBS with orbital angular momentum modes (OAM). These configurations include a cross-Si waveguide and a silica/chalcogenide waveguide. The simulations examine the forward and backward SBS utilizing OAM modes up to the 4th order in planar on-chip waveguides. A maximum on-chip SBS gain of up to ∼540W−1m−1 has been observed for pump and Stokes OAM mode numbers satisfying the topological charge conservation law. This OAM multiplexing approach can open new avenues for on-chip integrated nonlinear photonics for various applications, especially where pump and signal beam filtering or separation are critical.

Performance, blood and antioxidant status in dual-purpose laying hens supplemented with aqueous extract of Christ's thorn jujube (Ziziphus spina-christi L.) leaves as phytogenic agent in subtropical conditions.

The potential of aqueous extract of Christ's thorn jujube (Ziziphus spina-christi) leaves (SLAE) to reduce the negative impacts of heat stress on production performance and physiological traits was investigated in dual-purpose layers under subtropical farming. A total of 200, 25-week-old laying hens (Inshas strain) were randomly assigned to four dietary treatments including SLAE at 0, 2.5, 5.0, and 7.5 mL/kg, respectively. The average temperature-humidity index value was 26.69 during the experimental period. The SLAE contained saponin (0.045%), total flavonoid content of 17.9 mg of quercetin equivalent/ 100 g and overall antioxidant capacity concentration of 17.9 mg of ascorbic acid equivalent/100 g. The maximum final body weight (BW), BW gain, egg weight, number, and mass occurred at the level of SLAE7.5 inclusion. The egg quality was significantly higher in SLAE groups than in control, and overall, SLAE7.5 had the most favorable influence at 28 and 32 weeks. Liver and kidney function, as well as lipids profile, improved significantly by SLAE inclusion; the lowest concentrations of these parameters were in SLAE7.5 hens. Treatment with SLAE7.5 increased total antioxidant capacity and endogenous antioxidant enzymes compared to control, whereas no effect on superoxide dismutase was noticed. The addition of SLAE at 7.5 mL/kg diet improved egg laying performance and quality, metabolic profiles, and antioxidant status during hyperthermia conditions.

Omnidirectional circularly polarized base station antenna with high gain and wide band

Omnidirectional circularly polarized base station antenna with high gain and wide band

A high-performance slotted bow-tie nano graphene antenna for optical frequency application with silicon lens and stacked aligning layers

A new Graphene nano-antenna has been designed and proposed in this paper for optical frequency applications with optimized gain performance. The proposed design uses a Silicon Lens and subsequent layers to match the dielectric constant between the antenna and air. The different patch materials are taken and studied for better results. The proposed antenna has been simulated upon a Highly resistive silicon substrate having a high dielectric constant of 11.9. The base of the proposed antenna is designed on a square substrate of 6000μm length and 300μm height. The slotted “bow-tie” antenna is placed on it with an aperture area of 156.8μm×42μm. A silicon layer is placed over it for improved performance. Further, it has been optimized by placing 16 stacked aligning layers to match the dielectric constants. The gain and efficiency improvement are achieved after each layer or coating over the lens. The resonant frequencies obtained are 0.4THz, 1THz, and 2.2THz having triple bands. The maximum gain obtained is 36.89 dB and the maximum radiation efficiency is 97%. HFSS 21.0 software is the used environment for the simulation and optimization.

High gain and low noise O+E bands fiber amplification based on hybrid bismuth-doped fiber

In this paper, we propose and demonstrate a hybrid bismuth-doped fiber approach for broadband amplification in the O + E bands. The bismuth-doped fibers were fabricated by the MCVD process combined with solution doping technique. The amplification performance was investigated by the two pump wavelengths of 1240 nm and 1270 nm combined with different pump configurations. The results show that the maximum gain of 38.2 dB with the NF of 3.7 dB was achieved at 1350 nm by the bi-directional pumping configuration. Furthermore, the hybrid bismuth-doped fiber was demonstrated to improve the gain in E-band and maintain the gain flatness between O-band and E-band. A wide bandwidth of ∼150 nm (1310 nm–1460 nm) was achieved by the hybrid fiber, with a gain >15 dB, gain flatness of 8 dB, and NF of 4.1 dB–5.7 dB.

Improve The Conversion Efficiency and Electrical Output of The Solar PV System by Developing and Implementing a Cooling System

The performance of the grid-connected solar photovoltaic (PV) system in the present study is improved using cooling technology. This technology reduces the temperature of solar PV modules and thus increases their efficiency and lifespan. The current solar PV system has been installed in northern Baghdad in the city of Taji. This study included improving electrical power, conversion efficiency, and performance ratio. All of these improvements are achieved by cooling using water. The performance ratio (PR) and efficiency maximum values of the reference (unimproved) and improved solar PV modules are at 10:10 am at 88.30% & 96.30% and 13.4% & 14.6%, respectively. Improved and reference PV modules maximum solar radiation values occur at 12:00 pm at 1.91 W and 1.566 W, respectively. The maximum solar radiation values of the reference and improved PV modules are at 12:00 pm at 922.9 W/m2 and 1012.22 W/m2, respectively. The maximum daily gain of the power and solar irradiance are 22% and 10%, respectively. The significant innovation in the study is the successful performance optimization of the grid-connected solar PV system. Using different equations to study performance by following different behaviors. Along with improving and studying CIGS PV module performance.