Design of a Compact Monopole Antenna for UWB Applications

In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency.To design the proposed structure,three steps are utilized to achieve an UWB response.The bandwidth of the proposed antenna is improved with changing meander lines parameters,miniaturization of the ground width and optimization of the feeding line.The measured and simulated frequency band ranges from 3.2 to 12 GHz,while the radiation patterns are measured at 4,5.3,6 and 8 GHz frequency bands.The overall volume of the proposed antenna is 26×25×1.6 mm^(3);whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025,correspondingly.The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98%for the entire wideband.Design modelling of proposed antenna is performed in ANSYS HFSS 13 software.A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.

A NEW DESIGN METHODOLOGY FOR PRINTED LOG-PERIODIC MONOPOLE ANTENNA

In theory, Log-Periodic Antenna (LPA) is a linearly polarized antenna with frequency independent properties on the input impedance and gain patterns. Owing to these characteristics, LPA has gained research interests and been employed for many wideband applications. A Printed Log-Periodic Dipole Antenna (PLPDA) with multiple notched bands is proposed for Ultra-WideBand (UWB) applications. An antenna with the notched frequencies of 1.03 GHz, 1.28 GHz, 1.72 GHz, 2.24 GHz and 2.51 GHz is designed, fabricated, and measured. An antenna model was established on the substrate of FR4 and feed by a stripline. The simulation results show that the antenna can achieve an impendence wide bandwidth from 0.89 to 2.58 GHz with return loss less than -10 dB and exhibit stable antenna gain. Furthermore, the measurement result is better consistent with simulation result.

FDTD Analysis and Application of Sleeve Monopole Antenna

Based on the symmetry of the structure, a two-dimensional finite difference time domain （FDTD） method is used to analyze the sleeve monopole antenna on the infinite perfect conductor ground fed by a coaxial line. The fields in time domain are then turned into frequency domain through the discrete Fourier Transform to compute the surface current distribution and the input impedance of the sleeve monopole antenna. The gain or pattern of the monopole antenna is also computed, employing the combination of the image theory and the near-to-far transformation in frequency domain. All the computed results agree very well with the results of other methods and measured ones, verifying the application of the FDTD method to analyze the sleeve monopole antennas. The voltage standing wave ratio （VSWR） of the sleeve monopole antennas with different heights and radii of the sleeve are checked to study the influence of the sleeve, which indicates that the height and the radius of the sleeve are both important to the impedance bandwidth of the sleeve monopole antennas.

Monopole Antenna Probe for Density Measurements in Cold Plasmas

A simple diagnostic tool for density measurements in plasma with a certain spatial resolution is proposed in this paper. It uses the emission characteristics of monopole antenna to determine the dielectic property of plasma c = 1 - fp^2/f^2, with the fp electron plasma frequency related to plasma density. We immersed a inonopole antenna probe into plasma and introduced a microwave signal via a network analyzer. When the emitted power is maximized, the reflected power is minimized and there occurs a resonance. Since can be derived from the resonant frequency, this is actually a method to measure the absolute electron density. Validated by a comparison with the amended Langmuir double-probe method, the monopole antenna probe is valuable. In addition, it is free from the difficulties, such as fluctuation in plasma potential.

Super Compact UWB Monopole Antenna for Small IoT Devices

This article introduces a novel,ultrawideband(UWB)planar monopole antenna printed on Roger RT/5880 substrate in a compact size for small Internet of Things(IoT)applications.The total electrical dimensions of the proposed compact UWB antenna are 0.19λo×0.215λo×0.0196λo with the overall physical sizes of 15 mm×17 mm×1.548 mm at the lower resonance frequency of 3.8 GHz.The planar monopole antenna is fed through the linearly tapered microstrip line on a partially structured ground plane to achieve optimum impedance matching for UWB operation.The proposed compact UWB antenna has an operation bandwidth of 9.53 GHz from 3.026 GHz up to 12.556 GHz at−10 dB return loss with a fractional bandwidth(FBW)of about 122%.The numerically computed and experimentally measured results agree well in between.A detailed time-domain analysis is additionally accomplished to verify the radiation efficiency of the proposed antenna design for the ultra-wideband signal propagation.The fabricated prototype of a compact UWB antenna exhibits an omnidirectional radiation pattern with the low peak measured gain required of 2.55 dBi at 10 GHz and promising radiation efficiency of 90%.The proposed compact planar antenna has technical potential to be utilized in UWB and IoT applications.

Novel ladder patch monopole antenna for UWB application

A novel printed microstrip-fed ladder patch monopole antenna is presented for ultrawide band （UWB） application. The antenna consists of rectangular patch elements ladder arrayed at the both sides of the microstrip-fed line on a printed circuit board （PCB） and a rectangular ground plane. The antenna parameters of ladder number N, the rectangular patches geometry of ladder elements, the ladder step length and the length of ground plane are studied to obtain optimized antenna performances. The successfully designed, implemented and measured antenna has a compact size of 12 mm× 12 mm and operation frequency band from 3.1 GHz to 10.6 GHz with voltage standing wave ratio （VSWR） less than 2. Using the ladder patch array in microstrip monopole antenna design makes antennas flexible in terms of controlling resonances, bandwidth, stable radiation patterns, and constant group delay.

Investigations of the Sheath Effect on the Resultant Magnetic Field of a Cylindrical Monopole Plasma Antenna

The functionality of the plasma antenna has been narrowed to types and brand names only. The physics of its operation has been neglected and has stagnated technological innovations. The magnetic field in the sheath and plasma were investigated. Notable specifications were worked out in the proposed improved cylindrical monopole plasma antenna. The occurrence of femto spin demagnetization was discovered between the duration of switch on and switch off of the antenna. This phenomenon seems transient because magnetization is highest at the switch on/off point.

Low-Cost Flexible Graphite Monopole Patch Antenna for Wireless Communication Applications

This research investigates a monopole patch antenna for Wi-Fi applications at 2.45 and 5.2 GHz,and WiMax at 3.5 GHz.A low-cost and flexible graphite sheet with good conductivity,base on graphite conductive powder and glue is used to create a radiator patch and ground plane.Instead of commercially available conductive inks or graphite sheets,we use our selfproduced graphite liquid to create the graphite sheet because it is easy to produce and inexpensive.The antenna structure is formed using a low-cost and easy hand-screen printing approach that involved placing graphite liquid on a bendable polyester substrate.This research focuses on designing and developing a low-cost,thin,light,and flexible patch antenna for wireless communication and smart glass applications.The proposed antenna utilizes CST microwave software for simulations to improve the parameters before fabrication and measurement.The simulation and measurement results for the reflection coefficients at 2.45 GHz,3.5 GHz,and 5.20 GHz are reliable and cover the required resonance frequencies,antennas gain are 1.91,1.98,and 1.87 dB,respectively.Additionally,the radiation patterns of both results are omnidirectional.In the experiments,bending the proposed patch antenna along with the cylinder with the radii of 60,40,and 25 mm yielded the same measurement results as the unbent patch antenna.

An AMC-Based Circularly Polarized Antenna for 5G sub-6 GHz Communications

This paper presents an AMC(artificial magnetic conductor)-based wideband circularly polarized printed monopole antenna for unidirectional radiation.The antenna includes an AMC reflector,a coplanar waveguide(CPW)feed structure to excite the antenna,a ground plane with a rectangular slot on the left side of feedline,and an asymmetrical ground plane on its right side.The induced surface currents on CWP feedline,rectangularly slotted,and asymmetrical ground planes cause circularly polarized radiations.The AMC reflector consisting periodic metallic square patches is used instead of the conventional PEC(perfect electric conductor)reflector,the distance between the antenna and reflector is reduced from 0.25λ0 to 0.18λ0 with performance improvement.By incorporating AMC layer with the monopole antenna,the gain of antenna is increased from 3.3 dBic to 8.7 dBic while the axial ratio bandwidth(ARBW)of antenna is increased from 27.27%to 51.67%.The simulated and measured results show that the proposed antenna has an overlapping 10-dB|S_(11)|and 3-dB ARBW of 51.67%(3.0–5.09 GHz).The overall dimensions of monopole antenna backed by AMC reflector is 1.20_(λ0)×1.20_(λ0)×0.21_(λ0) and covers 5G sub-6 GHz new radio bands(n77/n78/n79)for wireless communication systems.

Ultra-wideband printed antennas for communication applications

A new type of ultra-wideband （UWB） printed monopole antennas is presented, which is composed of a circular or armular patch and a trapeziform ground plane with a tapered CPW feeder in the middle. Both simulated and experimental results are presented, showing good agreement and therefore verifying validity of the design. The proposed antenna with a circular monopole patch achieves an 11.6： 1 measured ratio bandwidth of VSWR ≤2 （ from 0,79 GHz to 9.16 GHz）, while that with an annular patch obtains a measured ratio impedance bandwidth of 10.6：1 （from 0.87 GHz to 9.47 GHz）. In addition, these designs exhibit nearly omnidirectional radiation patterns with simple compact structures, which axe attractive in communications and others UWB applications.

New band-notched UWB antenna

A simple and compact ultra wideband （UWB） printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.

Characteristics Study of Portable Hand-Held Phone Antenna by MoM

The characteristics of one kind of handset antenna are analyzed by the method of moments. By using the Pocklington equation and the Galerkin method, the current distribution on the handset antenna is calculated, the input impedance and radiation patterns are obtained. In addition, the characteristics of monopoles mounted on conducting chassis box with different sizes are analyzed. The results show that the size of the conducting chassis box has significant effect on the performance of the handset antenna. Therefore, appropriately changing the size of the conducting chassis box may improve the performance of the handset antenna.

A UTD SOLUTION FOR THE RADIATED FIELD FROM MONOPOLE ON A CONDUCTING CYLINDER SURFACE WITH A DIELECTRIC COATING

A can0nical problem is investigated for high frequency electromagnetic radiation from amonopo1e on a conducting cylinder with c0ating-At first, the exact solution of this problem is given interms of Dyadic Green's function method. Then, using Watson transformation and high frequency asymptotic approximate technique to the exact soluton, a UTD soultion is obtained. The radiation field excitedby a monopole is expressed in terms of the compound Fock' S functions (CFF), which reduce to the geomertrical optics result in the deep lit region and the creeping waves in the shadow region.

Multi-Mode Frequency Reconfigurable Conformal Antenna for Modern Electronic Systems

The article presents a miniaturized monopole antenna dedicated to modern flexible electronic systems.The antenna combines three fundamental properties in a single structure.Firstly,it is characterized by a compact size compared to the state-of-the-art literature with an overall size of 18×18×0.254 mm3,secondly,the proposed antenna integrates the reconfigurability function of frequency,produced by means of a Positive-IntrinsicNegative(PIN)diode introduced into the radiating element.Thus,the antenna is able to switch between different frequencies and different modes,making it suitable to meet the ever-changing demands of communication systems.third,the antenna is equipped by the property of flexibility.In fact,a conformability test is performed and has demonstrated the stability of the antenna performance under normal and bending conditions.Finally,in order to demonstrate the potential of the proposed antenna,a comparison between the simulated and measured results is made and turned out to be a strong agreement,making the antenna an excellent candidate for future miniaturized rigid and conformal devices.

AMC Integrated Multilayer Wearable Antenna for Multiband WBAN Applications

In this paper,a compact,efficient and easy to fabricate wearable antenna integrated with Artificial Magnetic Conductor(AMC)is presented.Addition of slots and bevels/cuts in the rectangular monopole patch antenna yield a wide bandwidth along with band notches.The proposed antenna is backed with an AMC metasurface that changes the bidirectional radiation pattern to a unidirectional,thus,considerably reducing the Specific Absorption Ratio(SAR).The demonstrated antenna has a good coverage radiating away from the body and presents reduced radiation towards the body with a front-to-back ratio of 13 dB and maximum gain of 3.54 dB.The proposed design operates over a wide frequency band of 2.9 to 12 GHz(exceeding the designated 3.1−10.6 GHz Ultra-Wideband(UWB)band).The band notches were created using slots on the radiating patch in the sub-bands from 5.50 to 5.67 GHz and 7.16 to 7.74 GHz.The overall dimensions of the structure are 33×33×6.75 mm3.The antenna’s radiation performance increased considerably with the addition of the AMC layer.The SAR values for the antenna are reduced by 85.3%when the AMC is used and are 0.083 W/kg which is well below the FCC SAR limits.The simple design,miniaturized profile,low SAR and wide operating bands with multiple band notches make the presented antenna an appealing choice for several UWB wearable body area network(WBAN)applications.

Graphene-Based RFID Tag Antenna for Vehicular Smart Border Passings

Globalization has opened practically every country in the globe to tourism and commerce today.In every region,the volume of vehicles traveling through border crossings has increased significantly.Smartcards and radio frequency identification(RFID)have been proposed as a new method of identifying and authenticating passengers,products,and vehicles.However,the usage of smartcards and RFID tag cards for vehicular border crossings continues to suffer security and flexibility challenges.Providing a vehicle’s driver a smartcard or RFID tag card may result in theft,loss,counterfeit,imitation,or vehicle transmutation.RFID sticker tags would replace RFID tags as vehicle border passes to solve the mentioned problem.The RFID sticker tag adheres to the windscreen,side screen,dash,hood,or door of the vehicle,or any other acceptable location.Any damage or stripping from the installed location may cause data corruption and cannot be reused.Overall,these sticker tags will make the border crossingsmore secure and efficient.This article focuses on designing a rectangular-shaped RFID sticker tag antenna made of graphene sheets as a possible solution for smart border crossings.The proposed antenna is mathematically designed and analyzed with CST software to determine the optimum parameters.The design parameters are then used to create an antenna on a prepared graphene sheet.The performance results are carried out with CST software and a network analyzer.The designed RFID antenna stick on a car windscreen offers approximately 900 MHz bandwidth over the frequency range from 1.8 GHz to 2.7 GHz with an average gain of 1.23 dBi at the frequency to be used of 2.4 GHz microwave RFID band.The radiation is an omnidirectional pattern.The proposed graphene-sheet rectangular-shape monopole antenna is compact,low-cost,and bendable to fit into the windscreen of a car while retaining excellent wave propagation capabilities.These findings illustrate the suggested antenna’s potential as an RFID tag antenna in a vehicular smart border pass system.

Design of Ellipse Antenna Array for Cellular Phone Localization Systems

This paper describes our contribution in the ANR (Agence Nationale de la Recherche) project called GELOCOM (GEo-LOCalisation de telephOnes Mobiles) managed by the THALES Communications company, dedicated to the emergency localization of cellular phones. This contribution takes place in the field of antennas, with the development of broad-band systems: a circular array of six elements with separated outputs for the receiving part. In this paper, we present the design and the characterization of broad-band double ellipse array antenna. This special structure is chosen in order to obtain a good omnidirectional radiation pattern, enhance the gain and maximize the V/H polarization ratio. In comparison with the already existing antenna systems in the wireless market for similar purposes, the proposed antenna has considerably shown better performance which makes it competitive among other antenna models. For the design and optimization of antennas, we use CST MWS software. The antennas have been designed and successfully measured.

Monopole Crescent Elliptical Antenna with Band-Notched Characteristics for UWB Applications

A compact antenna with extended band-notched characteristics was designed for ultra wideband （UWB） communications. The antenna consists of a crescent-shaped elliptical patch with a T-shaped stub and a square ground board plane. The antenna is easily integrated with radio-frequency/microwave circuits to reduce the manufacturing cost. The central frequency and the notch bandwidth can be adjusted by changing the size of the T-shaped stub. Simulations verify the design characteristics. Measurements show that the antenna produces the UWB working bandwidth.