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.

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.

A Self-Consistent Model on Cylindrical Monopole Plasma Antenna Excited by Surface Wave Based on the Maxwell-Boltzmann Equation

The paper analyzes the motion of electron in plasma antenna and the distribution of electromagnetic field power around the plasma antenna, and proposes a self-consistent model according to the structure of cylindrical monopole plasma antenna excited by surface wave;calculation of the model is based on Maxwell-Boltzmann equation and gas molecular dynamics theory. The calculation results show that this method can reflect the relationships between the external excitation power, gas pressure, discharge current and the characteristic of plasma. It is an accurate method to predicate and calculate the parameters of plasma antenna.

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.

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.

ANALYSIS OF MONOPOLE ANTENNA ON CIRCULAR DISC BY MODE MATCHING

Mode matching is used for the analysis of monopole antenna on circular disc, which is achieved by developing a novel model consisting of two artificial ground planes above and bellow the monopole antenna. Using this model, the input impedance is computed and compared with measured data reported in literatures, and excellent agreement is observed.

Design of an 868 MHz Printed S-Shape Monopole Antenna

The purpose of this work is to design and analyze an s-shaped printed circuit board (PCB) monopole antenna. The antenna was analyzed to operate at a resonance frequency band of 868 MHz;acceptable in 915 MHz as well. The s-shape is selected due to the need of reducing the overall size of the normal monopole antenna. The printed antenna was designed with an approximate overall size of 39 × 56 mm2 of which the antenna’s upper side is 26 × 39 mm2 while its reference ground board was sized at 39 × 30 mm2. The antenna is fed by a strip line of 3 × 1.5 mm2, in series with a 4.4 pF capacitance and shunt with an 8.7 nH inductance for purpose of antenna’s impedance matching with the input. A couple of existing publications showed that PCB antenna is not a new technology;however not an old technology for telecommunication industry. The raised problem by this work was duly solved with HFSS as a tool;excellent results are presented. After duly matching the antenna’s impedance with 50 Ω microstrip feed-line, solutions for overall performance were analyzed and demonstrated optimal: radiation patterns were proven omnidirectional, antenna gain optimized. The present antenna prototype’s overall dimensions can be readjusted according to any industrial and manufacturing requests.

A Compact Quad-Band Sickle-Shaped Monopole Antenna for GSM 900/WiMax/WLAN Applications

In this paper a novel,compact,microstrip-fed,quad-band monopole antenna is presented for the application of Global System for Mobile communication(GSM 900),Worldwide Interoperability for Microwave Access(WiMAX)and Wireless Local Area Network(WLAN).The proposed antenna comprises of a sickle-shaped structure with four circular arc strips,and a modified rectangular ground plane.The four strips of the antenna are independently responsible for the four different resonant frequencies of the operating bands and can be tuned separately to control the radiation performance.The proposed quad-band antenna is designed to resonate at 940 MHz for GSM 900,2.5 and 3.5 GHz for WiMAX and 5.85 GHz for WLAN applications.At the four intended operating bands,the antenna exhibits impedance bandwidth of 60 MHz(905–965MHz),80 MHz(2.45–2.53 GHz),110 MHz(3.48–3.59 GHz)and 2.39 GHz(4.82–7.21 GHz),respectively.At the resonance frequency of the four bands,the gain of the proposed antenna is obtained as 4.2,2.5,1.7 and 1.9 dBi,respectively.A prototype of the designed antenna is fabricated and a good agreement between simulated and measured results is observed.Furthermore,the proposed antenna shows good radiation characteristics and gains at all the four operating bands.

Effect of Metal and Magnetic Slab on Radiation Characteristics of Monopole Antenna

The effect of metal and magnetic slab on the radiation characteristic of monopole antenna is studied in this paper. The presence of metal slab changes the antenna radiation pattern and it also increases the gain up to 4.6 dB. The radiation characteristic of monopole antenna is determined by the separation distance between planar monopole and metal slab. In addition, magnetic slab also changes the antenna radiation pattern and it also increases the gain up to 3 dB. Metal slab makes antenna generate reflection, but magnetic slab makes antenna generate refraction is their difference. As to the application slab, the initial pattern of the antenna without materials was omnidirectional. However, when the materials were added, its pattern would change, making the antenna to have other usages and transition effect. They will influence electromagnetic in power systems.

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.

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.

Compact Wideband Rectangular Monopole Antenna for Wireless Applications

This article presents a compact wideband microstrip-fed planar monopole antenna composed of a rectangular patch and slotted ground structure. By placing pair of symmetrical square stubs, making slots in the stubs, putting stubs on the sides of the radiating patch, gives wide-band characteristics. The antenna only one of its kinds in structure, small in size and simple design due to less number of design parameters, compared with the existing UWB antennas in the literature. The bandwidth, radiation pattern and other antenna parameters are at acceptable level. IE3D method of moments based simulation software is used for design and analysis. The simulated results are confirmed by conducting experiments with the help of Rohde and Schwarz, German make ZVK model No.8651 Vector Network Analyzer and discussed.

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.

A novel and simple coplanar waveguide-fed planar monopole antenna for ultra-wideband applications

In this paper, a novel and simple CPW-fed planar monopole antenna is presented for UWB application. The antenna is fabricated on inexpensive FR4 substrate and fed by 50? CPW on the same layer. Measured data show that the antenna provides an impedance bandwidth of about 8GHz for the return loss less than 10dB. It is also observed that the radiation patterns are nearly omni-directional over the entire frequency range. Details of the proposed antenna are presented, and simulated results are presented and discussed.

HYBRID MM/MoL APPROACH FOR ANALYZING A COAXIAL FED MONOPOLE ANTENNA

A new hybrid technique is presented, which combines the Mode Matching (MM) method with the Method of Lines (MoL) to analyze a coaxial fed monopole antenna. The monopole antenna is dealt with using the MoL, while the MM method is used to analyze the coaxial feed system. Then, the two sub-problems are combined by enforcing point matching at the common regional interfaces. The input impedance is computed and compared with the measured data reported in literature, and the excellent agreement is observed.

Multi-Band Antenna with Three Folded Monopoles for Mobile Communication Systems

This paper presents the design and the experimental characterization of a new multi-band antenna consisting of three folded monopoles dedicated to mobile communication systems. The originality of this paper is to get the PMR (Professional or Private Mobile Radio) band with the GSM (Global System for Mobile Communications), DCS (Digital Cellular System) and UMTS (Universal Mobile Telecommunications System) bands. The main lobe of the antenna radiates in the zenith direction with a linear polarization over all bands. It is interesting to design the proposed antenna in order to obtain better performances in terms of directive radiation pattern (especially in the PMR band) in comparison with the already existing antenna systems in the wireless market for similar purposes. The prototype was studied with the software CST-MWS (Micro wave studio 2012). The antenna has been designed and successfully measured.

A NOVEL ULTRA WIDEBAND MONOPOLE ANTENNA WITH BAND-NOTCHED CHARACTERISTICS

A simple and compact microstrip-fed Ultra WideBand(UWB) printed monopole antenna with band-notched characteristic is proposed in this paper.The antenna is composed of a square ring with a small strip bar,so that the antenna occupies about 7.69 GHz bandwidth covering 3.11～10.8 GHz with expected band rejection from 5.12 GHz to 5.87 GHz.A quasi-omnidirectional and quasi-sym-metrical radiation pattern is also obtained.This kind of band-notched UWB antenna requires no ex-ternal filters and thus greatly simplifies the system design of UWB wireless communication.

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.

可用于WLAN的双频MIMO天线设计

设计了一款可用于WLAN的双频MIMO天线。天线的正面为L型单极子,背面为金属接地板。通过在接地板上加载耦合枝节使天线具有双频特性。同时,为了天线的小型化,对耦合枝节进行了弯折处理,减小天线尺寸。在两个天线单元之间加载T型寄生枝节和刻蚀矩形缝隙来提高天线的隔离度。使用电磁仿真软件和矢量网络分析仪对天线进行仿真和实测,结果表明:天线的工作频段为2.4~2.55 GHz和5.1~6.3 GHz,覆盖了WLAN的频段,同时在低频段内隔离度高于19 dB,高频段内隔离度高于25 dB。此外,天线的包络相关系数小于0.01且具有全向辐射特性。天线整体性能较好,可以满足WLAN的需求。