dBi Directivity Research Articles

تصميم ومحاكاة هوائي التصحيح الشريطي الصغير المستطيل بتردد 2.45 جيجا هرتز

Design and simulation of a 2.45GHz Rectangular Microstrip Patch Antenna (RMPA) are presented in this paper. Duroid (RT\5880), a dielectric material with a dielectric constant of 2.2 and a substrate height of 1.6 mm, was chosen for our design. After the simulation was finished, the results showed a 4.746dBi directivity gain and a (-3dB) half power bandwidth of 91.60 at the E-plane and 114.90 at the H-plane. It was found that the return loss (S11) was -8.38dB. It was found that the voltage standing wave ratio, or VSWR, was 2.23. Keywords: Rectangular microstrip patch antenna, Duroid (RT\5880), Return loss, directivity, Half Power Bandwidth, Voltage standing wave ratio, CSTSTUDIO SUITE Software

An easy-to-produce HIS-based MIMO radio altimeter antenna design for aircraft

Purpose The purpose of this study is to design a radio altimeter antenna whose production process is facilitated and can work with multiple-input multiple-output (MIMO) properties to provide space gain on the aircraft. Design/methodology/approach To create an easy-to-produce MIMO, a two-storied structure consisting of a reflector and a top antenna was designed. The dimensions of the reflector were prevented to get smaller to supply easy production. The unit cell nearly with the same dimensions of a lower frequency was protected through the original cell design. The co-planar structure with the use of a via connection was modified and a structure was achieved with no need to via for easy production, too. Finally, the antennas were placed side by side and the distance between them was optimized to achieve a MIMO operation. Findings As a result, an easy-to-produce, compact and successful radio altimeter antenna was obtained with high antenna parameters such as 10.14 dBi gain and 10.55 dBi directivity, and the conical pattern along with proper MIMO features, through original reflector surface and top antenna system. Originality/value Since radio altimeter antennas require high radiation properties, the microstrip antenna structure is generally used in literature. This paper contributes by presenting the radio altimeter application with antenna-reflective structure participation. The technical solutions were developed during the design, focusing on an easy manufacturing process for both the reflective surface and the upper antenna. Also, the combination of International Telecommunication Union’s recommended features that require high antenna properties was achieved, which is challenging to reach. In addition, by operating the antenna as a successful MIMO, two goals of easy production and space gain on aircraft have been attained at the same time.

Antenna Array Performance in Microwave Imaging Technique for Brain Tumor Detection

Recent advancements in microwave tomography (MT) imaging studies have stimulated interest in antenna array development for medical imaging. An antenna and a model of the human head are required for the medical MT system, particularly in detecting brain tumors. Previous studies have shown that antenna arrays are more reliable as compared to a single element of patch antenna in detecting brain tumors. In this study, a single patch antenna is first designed to work at 3.2GHz using CST Studio software. To evaluate the effectiveness of antenna arrays in microwave imaging systems, the patch antenna is then improved into a 2x1 and 4x1 array. The gain, directivity, return loss (S11), Voltage Standing Wave Ratio (VSWR), and bandwidth are compared between single and arrays of antenna models. It has been proved that 2x1 and 4x1 antenna arrays resulted in higher performance. With a maximum gain of 7.11 dB, the 4x1 rectangle patch antenna has 11.3 dBi directivity, -13.88 dB return loss, and 91.1 MHz bandwidth, meanwhile single patch antenna has a gain of 3.34 dB, 5.68 dBi directivity, - 17.33 dB return loss, and 132 MHz bandwidth. Overall, a 4x1 patch antenna is made reliable and sensitive to be used in detecting brain tumors as higher gain and directivity may be useful to penetrate multilayer human head.

Meta-surface (frequency selective surface) loaded high gain directional antenna systems for ultra-wideband applications

<span lang="EN-US">In this work, a meta-surface (frequency selective surface) loaded high gain directional antenna system is presented. The antenna system is developed using ultra-wideband (UWB) antenna element and meta-surface reflector. The UWB antenna element is designed and simulated without meta-surface reflector. The UWB antenna element has poor impedance bandwidth and directivity. A meta-surface is created using unit cell and equal in the size of the antenna substrate. The meta-surface is placed over the UWB antenna element at optimized height (H=30 mm). The impedance bandwidth, directivity and gain of the proposed antenna are improved by the meta-surface reflector. The proposed antenna is fabricated and experimentally validated by the comparison of the simulated and measured results. The antenna has 3 to 6 GHz wide impedance bandwidth, more than 5 dBi gain and maximum 4.6 dBi directivity at 3.5 GHz frequency. Performance of the proposed antenna is also compared with existing carried out work. Comparatively, the proposed antenna with high directivity is most suitable for IEEE 802.15.4a UWB wireless sensor network (WSN) security application.</span>

A Parabolic Planer Monopole Fractal Antenna with Koch

Abstract: Modern telecommunication systems require antenna with wider bandwidth and smaller dimensions. Various antennas for wideband operation have been studied for communication and radar system. The fractal antennas are preferred due to small size, light weight and easy installation. In this paper a parabolic planer monopole antenna using the Koch based fractal geometry is introduced for multiband operation. The design achieves a good input impedance match and linear phase of S11 throughout the pass band (1—3.5 GHz and -10dB criterion for impedance bandwidth). The use of fractal pattern in this paper provides a simple and efficient method for obtaining the compactness. Various bands are 1.2GHz and 2.3 GHz. The antenna has a promising peak gain of 5.3 dBi with 5.5 dBi directivity in pass band. The pass band has VSWR in between 1 and 2. The proposed antenna has enormous high bandwidth (1.124GHz) that suits the many wireless applications like WLAN, Bluetooth, analog radio and GPS system and it can also be used for microwave devices communication.

The Development of Broadband Microstrip Patch Antenna for Wireless Applications

The small volume of microstrip antennas has low production costs and easy production, which has accelerated the work in this area. The disadvantages are narrow bandwidth and low gain. In wireless communication, antennas with low return loss and high bandwidth are required. The bandwidth and power gain of the microstrip patch antennas should be increased optimally. This article presents the design of the broadband microstrip patch antenna operating in the ISM 2.4 GHz band (2400-2485 MHz). The study includes three-dimensional antenna model, simulation phase and fabrication / measurement phase. For the low cost of the antenna, FR-4 with the relative dielectric constant 4.3 and the loss tangent tan 0.02 is preferred as the substrate material. Dielectric material thickness is determined as 1.6 mm. The length of the feed line and the dimensions of the rectangular patch were found by mathematical calculations with the transmission line model. There are slots on the antenna, which is a very simple method in order to improve the bandwidth, gain and directivity parameters of the antenna. In the article, four different designs are presented, the results are compared and the proposed antenna has 979 MHz bandwidth and 2.68 dBi directivity gain at -10 dB at the resonance frequency of 2.316 GHz. The changes made in the antenna design have improved the results such as gain and bandwidth compared to the conventional microstrip patch antenna. The proposed antenna is suitable for use in mobile communication.

Triple-Band Implantable Antenna Design for Biotelemetry Applications in MICS/ISM/Wi-Fi/Bluetooth Bands

Our objective is to design triple-band implantable antennas with wide bandwidths and appropriate sizes for biomedical applications. The targeted design frequencies are 400 MHz, 2.4 GHz, and the new Wi-Fi band of 5.7 GHz. Three triple-band antennas with bandwidth improvements are presented to insure all-time data connection. The proposed triple-band implantable antennas benefit from combining long-distance data transfer at lower frequency bands and a higher effective bandwidth, and high-speed communications at higher frequency bands, which will have flexibility for a variety of applications. A comprehensive explanation of the design procedure to achieve multiple-band implantable antennas is provided. Furthermore, miniaturization techniques are utilized to design antennas in compact sizes suitable for biomedical applications. In this paper, three-layer structures including skin, fat, and muscle are used for the designs, then antennas are placed in the chest, neck, head, and hand of different human voxels to compare antennas’ performance. Additionally, normal and overweight human effects on antenna performance were compared. Antennas have 2 to 6 dBi directivity for telemetry usage, and they are designed to satisfy the absorption limit for the human body to keep the Specific Absorption Rate (SAR) averaged over 1 g of tissue less than 1.6 W/kg and over 10 g of tissue less than 2 W/kg, according to IEEE standard. The antennas include fractal, meandered, and comb types with sizes of 1.4 mm × 10 mm × 10 mm, 3.04 mm × 10 mm × 17.25 mm, and 1.4 mm × 12 mm × 12 mm, respectively. The designed antenna showed an impedance bandwidth of 53 MHz to 120 MHz, 90 MHz to 320 MHz, and 300 MHz to 1200 MHz at the three bands. The meandered antenna was selected for validation of simulations, and its S parameters were measured in the equivalent liquid phantom of body tissues.

5.8 GHz BAND Wi-Fi AND IoT APPLICATIONS ANTENNA DESIGN

Due to the increase in internet-connected devices in daily life, the compact embedded wireless device becomes necessary to meet multiple frequency-based applications on a common platform. Reconfigurability is a good solution for improving device utility in many technical interfaces. Wireless compatibility between different devices over the Internet reveals the importance of the antenna unit. Internet of Things (IoT) based applications requires integration with wireless communication technologies to obtain application data. In this study, a meander-shaped microstrip patch antenna in the 5.8 GHz band is proposed for use in IoT applications. The dimensions of the antenna are 40 x 15 x 1.6 mm3. The antenna design consists of a full circle, a semicircle, and a meander line. In the antenna design, FR-4 has been used as the substrate material, and copper has been used as a conductor on the upper and lower surfaces. Performance parameters have been investigated in the proposed antenna design. In addition, a parametric study is presented to investigate the flexibility of the antenna. The results show that gain and yield can be improved by adjusting the dimensions of the rectangular ground plane. As a result of the improvements, the terminated antenna, return loss below -20 dB in the 5.8 GHz band, 700 MHz wide operating band, 4.35 dBi realized gain, 5.3 dBi directivity, -0.9188 dB radiation efficiency and -0.9445 dB total efficiency have been obtained. In addition, the proposed antenna also operates in the 4.5 GHz, 7 GHz, and 8.5 GHz bands as multi-band.

Gain and Bandwidth Enhanced Optimized Notch Loaded Microstrip Antenna for 5G Applications

In this paper, a rectangular patch antenna is presented loaded with T-shaped notch as well as having truncated corner for the enhancement of gain and bandwidth which is bring into play for mid band of 5G applications. With design frequency of 3 GHz, this prototyped design antenna having 50 Ω microstrip line feed for impedance matching and simulation has been performed using IE3D Mentor Graphics simulation software. Fractional impedance 51.3% has been observed from 2.39 to 4.04 GHz. An enhanced peak gain of 5.05 dBi and maximum directivity of 6.214 dBi has been observed at 4.22 GHz and 4.34 GHz respectively.

Design of a Broadband High-Gain End-Fed Coaxial Collinear Antenna

Omnidirectional antennas are widely used for mobile communications in the base transceiver station. This letter introduces a high-gain coaxial collinear (CoCo) antenna with a stable radiation pattern. To design a wideband end-fed CoCo antenna, we modify the classic center-fed CoCo antenna structure with an appending wire-mesh structure. The proposed CoCo antenna's $-$10 dB impedance bandwidth and gain bandwidth (1 dB variation of maximum gain versus frequency) at a center frequency of 900 MHz is three times higher than the classical center-fed CoCo's equivalent bandwidth, thus retaining 9 dB gain. The unique feeding configuration is designed to create the broadband end-fed antenna and minimize the feeding cable effect on the omnidirectional radiation pattern. We prototype an antenna to evaluate the design performance and confirm the simulation results. The measured results show 8.5 dBi directivity and 125.5 MHz bandwidth at 900 MHz center frequency.

The self- complementary bow-tie vacant dipole with log periodic characteristic quadband antenna design

In this paper, the diagonally symmetrical pair of modified cross dipole inscribed in a circle with equilateral triangular shaped bow-tie log-periodic characteristic quad band antenna is proposed for wireless energy harvesting application. The suggested quad band antenna is capable of satisfying wider bandwidth for available RF frequency bands including GSM 900 (880 MHz-960 MHz), GSM 1800 (1710 MHz-1880 MHz), 3G (1920 MHz-2300 MHz) and Wi-Fi (2.4 GHz-2.45 GHz) in ambient level. The performance characteristic of the antenna is analyzed in terms of scattering parameter, maximum realized gain, total and radiation efficiency, VSWR, surface current distribution and radiation characteristic. The novel configuration of this design achieves directional radiation pattern maintaining a circularly polarized (CP) radiation characteristics. The measurement result of prototype shows that maximum return loss (RL) of this bow-tie antenna is -28 dB, 4.81 dB realized gain and 6.8 dBi directivity at 2.4 GHz, 1.8 GHz resonating frequencies respectively. The excellent characteristic of wider bandwidths over four resonant frequency bands and high gain of the suggested antenna make it promising candidate for multiple wireless communications as well as energy harvesting system

A new inhomogeneous partially reflecting surface for Fabry‐Perot antenna to reduce side lobe level

In this article, an extension of the spatial filter method to study Fabry-Perot antennas with homogeneous or inhomogeneous partially reflecting surface (PRS) of finite size is proposed. This tool was subsequently validated through the study of different Fabry-Perot antennas, with homogeneous PRS and inhomogeneous GRadient-INdex (GRIN) PRS that present very high side lobe level (SLL). Since they are due to structure truncation, a new inhomogeneous PRS to reduce the SLL is designed with the new analytical tool. The new inhomogeneous PRS for Fabry-Perot antenna is characterized by simulations and measurements. Compared to the homogeneous PRS antenna, the proposed PRS allows a SLL reduction of 5 dB without decreasing the 14 dBi directivity.

Pattern-Reconfigurable Array Based on a Circularly Polarized Antenna With Broadband Operation and High Front-to-Back Ratio

A design for single-fed circularly polarized (CP) antennas with broadband operation and high front-to-back ratio is first described. The antenna is mainly composed of a monopole slot, a dipole, and a metallic box. When the monopole slot is operated in its half-wavelength mode, the radiated fields of the slot and dipole have the same amplitudes and 90° phase differences; in addition, the two radiating elements are arranged in an orthogonal configuration. Consequently, a CP radiation is obtained. Then, the CP antenna is adopted as a radiating element of a 3-D array, and a feed network composed of power dividers is used to excite the array. Both the simulated and measured results prove that the CP array can give a nearly omnidirectional pattern, bidirectional patterns with 8 dBi directivity, and scanned beams with a directivity of 11 dBi. Moreover, the half-power beamwidth of the scanned beam can be changed among 48°, 124°, and 240°. The total size of the array is about $1.5\lambda _{0} \times 1.5\lambda _{0} \times 2.5\lambda _{0}$ . Details of the designs for the CP element and array are presented.

Enhanced performance of compact 2 × 2 antenna array with electromagnetic band‐gap

AbstractThe side lobe effects cause the wastage of energy in antenna arrays. In this work, two types of electromagnetic band‐gaps (EBGs) are used to diminish the side lobes in 2 × 2 Patch Antenna Array at 6 GHz through mushroom‐like EBG and triple side slotted (TSS) EBG (TSSEBG). The proposed EBGs are placed on the top surface of the antenna array to eliminate undesired surface currents. The connecting vias in TSSEBG compared with the mushroom‐like EBG structure is decreased from 392 to 92. Accordingly, an easy way in fabrication is guaranteed. The TSSEBG provided triple band gaps of frequencies compared with the structure of mushroom‐like EBG that only had one. The TSSEBG is placed in a flexible structure, which is suitable for antenna applications. The compact EBG and TSSEBG antenna arrays respectively demonstrate 13.77 and 14.68 dB gain, 14.2 and 15.3 dBi directivity, −24 and − 28.5 dB side lobe, and 90.5% and 87% efficiency at the operating frequency of 6 GHz.

A Novel Collapsible Flat-Layered Metamaterial Gradient-Refractive-Index Lens Antenna

With the advent of small-scale satellite technologies, there has been significant interest in developing low-profile antennas. This article presents a novel collapsible flat-layered lens based on gradient-refractive-index (GRIN) metamaterials. The 3-D lens consists of multilayer double-sided microstrip square-rings units of variable sizes distributed on planar dielectric substrates to satisfy the required refractive index distribution. Adjacent layers can be stored compressed in a stacked configuration with minimal height, then deployed to an operational arrangement to their full dimensions and capabilities. The key factor in this design is the judicious choice of the discretized metamaterial unit cell such that neighboring layers are separated by an air gap, which allows the lens to collapse. A proof-of-concept prototype operating at 13.4 GHz with a 11.2 cm diameter and a height of 0.4 and 2.1 cm in collapsed and operational arrangement, respectively, was manufactured within fabrication tolerances. A resonant patch array feed was used and the lens antenna was measured in the UCLA Plane Bi-Polar Near-Field measurement range achieving a 23 dBi directivity and 22.2 dBi gain. The numerical and experimental results agree well and demonstrate that this new lens is advantageous in terms of low packaging height without compromising high-performance.

Passive Front End for LTE TDD Transceiver

In this paper, a passive front end for a 3GPP Long Term Evolution (LTE) TDD transceiver comprising a microstrip antenna and filter is presented. The proposed antenna and filter operates in the LTE band 36 (TDD) which extends from 1930MHz to 1990MHz. A patch antenna and Hairpin filter is fabricated with a total area of 43x36mm for the antenna and 38.6x32.16mm for the filter. The proposed devices are fabricated using FR-4 material substrate and the measuring results show good agreement with the simulation results. The fabricated antenna has 2.67dBi directivity, 1.242dB gain, a minimum return loss of -31.85dB at resonant frequency 1950MHz and 150.3 MHz bandwidth at 6dB return loss, while the filter has -3dB BW of 90MHZ, a center frequency of 1950MHz and a fractional bandwidth of 4.615%.

Broadband Sub-Wavelength Profile High-Gain Antennas Based on Multi-Layer Metasurfaces

A method for designing sub-wavelength-profile and broadband high-gain planar antennas is presented. A novel multi-layer periodic array design is proposed for sub-wavelength Fabry-Perot cavity type antennas with enhanced bandwidth performance. Three double-sided periodic arrays are designed and optimized, each double-sided array consisting of a capacitive artificial impedance surface (AIS) and an inductive partially reflective surface (PRS) printed on either side of a dielectric substrate. They are placed at about sixth of a wavelength from a ground plane and from each other. Thus, three air cavities are created with a total profile of $\lambda/2$ . The proposed antenna has been simulated using CST Microwave Studio and measured achieving 16.9 dBi directivity with 10.7% 3 dB bandwidth. The gain-bandwidth product of the proposed designs outperforms any previous Fabry-Perot antenna design with this profile.

HIGHLY DIRECTIVE HYBRID PLASMONIC LEAKY WAVE OPTICAL NANO-ANTENNA

A novel traveling-wave hybrid plasmonic optical antenna is proposed for operation at the standard telecommunication wavelength of 1550 nm and with the frequency bandwidth of more than 16 THz. A highly directive radiation pattern with 15.2 dBi directivity and 82% efficiency is achieved. The developed antenna benefits from high directivity advantage of leaky-wave antennas, and low loss properties and confinement of hybrid plasmonic structures. The designed device can have applications in inter/intera chip optical interconnect, and absorption enhancement of photodetectors, and solar cells.

Dual Subwavelength Fabry–Perot Cavities for Broadband Highly Directive Antennas

A new concept for designing broadband and subwavelength profile Fabry-Perot-type antennas is introduced. A novel multilayer periodic array design is proposed, yielding two subwavelength-profile Fabry-Perot cavities that significantly enhance the bandwidth performance of the resulting highly directive antenna. The design is based on two optimized double-layer periodic arrays of dissimilar dimensions, each double-layer array consisting of a capacitive artificial magnetic conductor (AMC) layer and an inductive partially reflective surface (PRS) layer printed on either side of a dielectric substrate. They are placed at about a quarter-wavelength distance from a ground plane and from each other. Thus, two air cavities are created with a total profile of less than λ/2. The proposed antenna has been simulated in CST Microwave Studio, achieving 18.3 dBi directivity with 8% bandwidth.

Bipolar dual‐band MPRS‐FSS sectoral antenna for base station applications

AbstractThis article deals specifically with sectoral antennas and focuses on the ability to design a bipolar dual‐band structure by combining double layers metallic partially reflective surface (MPRS) working on orthogonal polarizations as a superstrate with a frequency selective surfaces (FSS) as a substrate , thus making it possible to circumvent the narrow bandwidth problem. The use of metallic structures offers a new approach to industrial partners to reduce costs and to facilitate design techniques. This antenna provides vertical and horizontal polarizations with a sectoral radiation pattern presenting a half power beamwidth of at least 60° in the azimuth plane. We obtain the different operating frequencies by adjusting the distance of MPRS layers from FSS layer. The proposed structure presents more than 15 dBi directivity enhancement at 4.8 and 5.6 GHz as compared to those of a patch antenna with 8 dB directivity. The geometry and characteristics of the antenna are detailed and a design method is proposed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2907‐2912, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26431