Showing papers in "Progress in Electromagnetics Research Letters in 2010"
TL;DR: In this article, the analytical solution of vector wave equation in fractional space is presented, which is a generalization of wave equation from integer dimensional space to a non-integer dimensional space.
Abstract: This work presents the analytical solution of vector wave equation in fractional space. General plane wave solution to the wave equation for flelds in source-free and lossless media is obtained in fractional space. The obtained solution is a generalization of wave equation from integer dimensional space to a non-integer dimensional space. The classical results are recovered when integer-dimensional space is considered.
96 citations
TL;DR: In this paper, a multiband microstrip antenna array with dumbbell shape defected ground structure (DGS) is presented, which is inserted into the ground plane between the two elements of the antenna array in order to suppress mutual coupling.
Abstract: A novel design of multiband microstrip antenna array with dumbbell shape defected ground structure (DGS) is presented. The DGS is inserted into the ground plane between the two elements of the antenna array in order to suppress mutual coupling. Both simulation and measurement results verifled that the DGS improved the radiation properties of the antenna array. Measurement results of the DGS antenna showed mutual coupling reduction of maximum 5dB and gain enhancement to 3dB.
68 citations
TL;DR: In this article, a triple band coplanar waveguide (CPW) antenna for WLAN/WiMAX applications is proposed, which mainly comprises a ground with a wide square slot in the center, a rectangular feeding strip and two pairs of planar inverted L strips connecting with the slotted ground.
Abstract: In this paper, a wide-slot triple band antenna fed by a coplanar waveguide (CPW) for WLAN/WiMAX applications is proposed. The antenna mainly comprises a ground with a wide square slot in the center, a rectangular feeding strip and two pairs of planar inverted L strips (PIL) connecting with the slotted ground. By introducing the two pairs of PIL's, three resonant frequencies, 2.4/5.5GHz for WLAN, and 3.5GHz for WiMAX, are excited. Prototypes of the antenna are fabricated and tested. The simulated and measured results show that the proposed antenna has three good impedance bandwidths (S11 better than i10dB) of 300MHz (about 12.6% centered at 2.39GHz), 280MHz (about 8% centered at 3.49GHz) and 790MHz (about 14.5% centered at 5.43GHz), which make it easily cover the required bandwidths for WLAN band (2.4{ 2.48GHz, 5.15{5.35GHz, and 5.725{5.825GHz) and WiMAX (3.4- 3.6GHz) applications. Moreover, the obtained radiation patterns demonstrate that the proposed antenna has flgure-eight patterns in E-plane, and is omni-directional in H-plane. The gains of the antenna at operation bands are stable.
60 citations
TL;DR: In this paper, a simple structure for reducing mutual coupling between two diversity planar monopole antennas for WLAN 5.2/5.8GHz applications is presented, which has two slots cut into the ground plane between the two monopoles.
Abstract: This article presents a simple structure for reducing mutual coupling between two diversity planar monopole antennas for WLAN 5.2/5.8GHz applications. The structure has two ‚=4 (‚- wavelength in the substrate) slots cut into the ground plane between the two monopoles. In 0.5‚o (‚o-wavelength in the air) of the antenna spacing, mutual coupling was i33:3, i21:1dB at 5.2, 5.8GHz, respectively. The lowest mutual coupling of i33:3dB was achieved at 5.2GHz, which are 20.8dB improvements over the reference.
43 citations
TL;DR: In this paper, a chiral-coated nihility cylinder with a uniform thickness was used to scatter electromagnetic plane waves from an inflnitely long nhility cylinder.
Abstract: Scattering of electromagnetic plane waves from an inflnitely long nihility cylinder, coated with a chiral layer of uniform thickness, is presented. Cylindrical vector wave functions have been used to express the flelds in difierent regions. The solution is determined by solving the wave equation for difierent regions and applying the appropriate boundary conditions at the discontinuities. Both TM and TE polarizations as incident plane wave have been considered in the analysis. Obtained Numerical results for the chiral-coated nihility cylinder are compared with a chiral-coated PEC cylinder.
41 citations
TL;DR: In this article, a single-feed dual-band circularly polarized (CP) microstrip antenna is evaluated numerically and experimentally, and good agreement is obtained between measured and simulated results.
Abstract: A compact single-feed dual-band circularly polarized (CP) microstrip antenna is evaluated numerically and experimentally. The dual-band performances with small frequency ratio (about 1 : 1.1) are achieved by a circular patch and a narrow annular-ring, which have small difierence in radius. The CP characteristics are achieved by an unequal cross-slot embedded in the circular patch and two orthogonal linear stubs spurred from the annular-ring. The antenna is easy to fabricate. Good agreement is obtained between measured and simulated results.
41 citations
TL;DR: In this article, a novel circularly polarized microstrip rectenna operating on C-band with low proflle was proposed, where the input and output match networks of the rectifying circuit were realized by 4 microstrip lines and open stubs with the harmonics being inhibited.
Abstract: A novel circularly polarized microstrip rectenna operating on C-band with low proflle is proposed. The input and output match networks of the rectifying circuit are realized by ‚=4 microstrip lines and open stubs with the harmonics being inhibited. The circularly polarized receiving antenna is a truncated-corner square patch fed by microstrip line with DGS (Defect Ground Structure) for suppressing high order harmonics further. The voltage of 4.34V on the load of 298› is measured and the overall RF-DC conversion e-ciency of 68.4% is obtained. This kind of rectenna can be extended to large arrays for wireless power transmission applications.
40 citations
TL;DR: In this article, a fractal structure using Koch and Sierpinski fractal shapes is proposed to reduce the resonant frequency of a single-patch microstrip antenna, which can be applied to portable wireless communication systems requiring small devices.
Abstract: A novel fractal structure using Koch and Sierpinski fractal- shapes is proposed. By inserting the Sierpinski carpets into the single patch and etching the inner and outer patch edges according to Koch curves, the resonant frequency of the patch antenna can be lowered signiflcantly. And the higher of the iteration order of the fractal shapes, the lower the resonant frequency becomes. In this paper, a novel small- size single patch microstrip antenna based on the proposed fractal- shapes is designed, fabricated and measured. It is experimentally found that the size reduction can reach 80.3%. Compared to the conventional square single patch antenna, the proposed antenna maintains comparable radiation patterns. Therefore, the small-size single patch microstrip antenna considered here can be applied to portable wireless communication systems requiring small devices.
40 citations
TL;DR: In this paper, a CPW-fed triple-band monopole antenna designed by embedding an S-shaped meander strip into a C-shaped strip is proposed for WLAN and WiMAX applications.
Abstract: A novel CPW-fed triple-band monopole antenna designed by embedding an S-shaped meander strip into a C-shaped strip is proposed for WLAN and WiMAX applications. The antenna with a very simple and compact structure is easy to be fabricated, and the prototype of the proposed antenna has been constructed and measured. The triple operating bands with 10-dB return-loss bandwidths of about 110MHz centered at 2.45GHz, 310MHz centered at 3.55GHz, and 39% ranging from 4.1 to 6.2GHz, covering the required bandwidths of 2.4/5.2/5.8GHz WLAN and 3.5/5.5GHz WiMAX standards, are obtained. In addition, good radiation performance and antenna gain across the three frequency ranges have been obtained.
39 citations
TL;DR: In this paper, a tri-band planar monopole antenna suitable for 2.4/5.8 GHz WLAN and 3.5GHz WiMAX is presented by inserting a U-shaped strip as a parasitic strip into a normal monopole which operates at lower band of WLAN, one more resonance at higher WLAN band comes out.
Abstract: A compact tri-band planar monopole antenna suitable for 2.4/5.2/5.8GHz WLAN and 3.5GHz WiMAX is presented. The antenna employs a U-shaped parasitic strip and a defect ground-plane structure. By inserting a U-shaped strip as a parasitic strip into a normal monopole which operates at lower band of the WLAN, one more resonance at the higher WLAN band comes out. A defect ground-plane composed of two symmetrical L-shaped slits leads to another resonance operating at WiMAX band. The proposed antenna has a compact size of 22 £ 41 £ 0:8mm 3 and ofiers good radiation and re∞ection characteristics in the above frequency bands. The measured VSWR exhibits a good agreement with the simulated one. Detailed design steps, parametric studies and experimental results for the antenna are investigated in this paper.
34 citations
TL;DR: In this paper, a wide-band, polarization-insensitive, wide angle terahertz metamaterial absorber is presented, which can achieve polarization-sensitive, wide-angle absorptions in a wide band from 4.15 to 4.85THz.
Abstract: In this paper, a wide-band, polarization-insensitive, wide- angle terahertz metamaterial absorber is presented. Simulated results show that the absorber can achieve polarization-insensitive, wide-angle absorptions in a wide band from 4.15 to 4.85THz. The retrieved impedance shows that the impedance of the absorber could be tuned, in the absorption band, to match approximatively that of free space on one side and to mismatch on the other side, rendering both the re∞ectance and transmission minimal and thus the corresponding absorbance maximal. The simulated absorbances under three difierent
TL;DR: In this article, a dual-wideband printed monopole antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.
Abstract: A novel dual-wideband printed monopole antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed antenna consists of a T-shaped monopole on top and dual combined G-shaped slots etched symmetrically on the ground plane to achieve a dual-wideband performance. Prototype of the proposed antenna has been constructed and tested. The measured 10dB bandwidths for return loss are 1.76GHz from 2.13 to 3.89GHz and 0.92GHz from 5.03 to 5.95GHz, covering all the 2.4/5.2/5.8GHz WLAN and 2.5/3.5/5.5GHz WiMAX bands. And this antenna also has omni-directional patterns over the lower operating range.
TL;DR: In this paper, a bandpass fractal frequency selective surface (FSS) with excellent angular stability performance is proposed by scheming out a symmetric fractal pattern of continuous slots from the surface of a square-shaped patch, in which each periodic cell consists of incurved slot resonators.
Abstract: A new miniaturized bandpass fractal frequency selective surface (FSS) with excellent angular stability performance is proposed. The miniaturization has been achieved by scheming out a symmetric fractal pattern of continuous slots from the surface of a square-shaped patch, in which each periodic cell consists of incurved slot resonator for reducing the cell size. Reduction in FSS size of up to 74% with respect to the conventional square loop aperture FSS operating at the same frequency of 3.3GHz is obtained. Furthermore, results show excellent angular stability for both vertical and horizontal polarization at difierent incidence angles because of its fractal conflguration. A prototype is fabricated, and the FSS measurement and simulation results are presented and discussed.
TL;DR: In this article, a planar monopole antenna for applications in 2.4GHz WLAN and UWB bands is presented and investigated, which is composed of a gourd-like radiation element fed by a 50Ohm microstrip line and a step-shaped ground plane.
Abstract: In this article, a novel wideband planar monopole antenna for applications in 2.4GHz WLAN and UWB bands is presented and investigated. The proposed antenna is composed of a gourd-like radiation element fed by a 50Ohm microstrip line and a step-shaped ground plane. A pair of slot lines is etched symmetrically on the ground plane to obtain the 5GHz band-notched characteristic, and the notched band can be tuned. The proposed antenna is successfully simulated, designed, and measured. The measured results agree reasonably with the simulated ones. According to the measured results, the proposed antenna yields a wide bandwidth ranging from 2.2 to 11GHz for VSWR less than 2, except the notched band of 5.1{6.2GHz for 5GHz WLAN. Moreover, it exhibits nearly omnidirectional radiation patterns, stable gain, and small group delay variation across the operation band, which meets the requirements of 2.4GHz WLAN and UWB applications.
TL;DR: In this article, a modified UWB power divider formed by implementing one delta stub on each branch is proposed, which makes branch line shorter and stub's size smaller than those of other works based on UWB using radial stub.
Abstract: A modified UWB power divider formed by implementing one delta stub on each branch is proposed. Delta stub is used as a substitution of radial stub that can present wideband characteristic. The proposed structure makes branch line shorter and stub’s size smaller than those of similar works based on UWB power divider using radial stub. It also achieves a compact size of 18 mm by 13 mm. The simulation and measurement results of the developed divider are presented and shown good agreement in the UWB range.
TL;DR: Wu et al. as mentioned in this paper proposed a compact dual-band bandpass filter with wide and narrow bands simultaneously using the stepped impedance resonators (SIRs) in multilayered structure, which achieved 3dB fractional bandwidths of 45% and 10% for 2.4GHz and 5.2 GHz, respectively.
Abstract: Compact dual-band bandpass filter (BPF) with wide and narrow bands simultaneously is presented. By using the stepped impedance resonators (SIRs) in multilayered structure, the dual-band responses with wide and narrow bands simultaneously can be obtained. The filter has 3-dB fractional bandwidths (FBWs) of 45% and 10% for 2.4GHz and 5.2 GHz, respectively. The circuit size is compact due to the multilayered structure. Moreover, multi-path propagation inside the multilayered structure generates transmission zeros at each skirt of the passbands for improving the passband selectivity. Measured results of the filter are in good agreement with the full-wave electromagnetic (EM) simulation. Corresponding author: H.-W. Wu (qqq25q@gmail.com).
TL;DR: In this paper, a wide open slot antenna with a pair of symmetrical L-strip for dual-band WLAN applications is proposed, where a T-shaped monopole is used to cover 5:15 » 5:825GHz.
Abstract: A wide open slot antenna with a pair of symmetrical L- strips for dual-band WLAN applications is proposed in this paper. A T-shaped monopole is used to cover 5:15 » 5:825GHz. To achieve dual-band characteristic, a pair of symmetrical L-strips is embedded in the wide open U-slot to generate another band covering 2:4 » 2:48GHz. The two bands are relatively independent from each other. The proposed antenna has the advantages of simple structure and excellent performance on the WLAN 2.4/5.2/5.8GHz bands. The measured results of the fabricated antenna show that the impedance bandwidths are 150MHz from 2.37 to 2.52GHz and 1270MHz from 4.83 to 6.10GHz, which cover all the desired operating bands. Furthermore, the antenna design and some signiflcant parametric studies are also described in detail.
TL;DR: In this paper, a substrate integrated waveguide (SIW) power divider employing the Wilkinson conflguration for improving the isolation performance of conventional T-junction SIW power dividers was proposed.
Abstract: This work proposes a substrate integrated waveguide (SIW) power divider employing the Wilkinson conflguration for improving the isolation performance of conventional T-junction SIW power dividers. Measurement results at 15GHz show that the isolation (S23, S32) between output ports is about 17dB and the output return losses (S22, S33) are about 14.5dB, respectively. The Wilkinson-type performance has been greatly improved from those (7:0dB » 8:0dB) of conventional T-junction SIW power dividers. The measured input return loss (23dB) and average insertion loss (3.9dB) are also improved from those of conventional ones. The proposed Wilkinson SIW divider will play an important role in high performance SIW circuits involving power divisions.
TL;DR: In this paper, the nucleation suppression could be attributed to the increase of the solid- liquid interfacial energy which might originate from more orderly arrangement of atoms on the solid liquid interface upon applying a magnetic fleld.
Abstract: Solidiflcation of pure aluminum without and with a magnetic fleld has been investigated by difierential thermal analysis (DTA). DTA curves showed that the nucleation temperature of pure aluminum was decreased as a magnetic fleld strength increased although its melting process was almost not in∞uenced. The nucleation suppression could be attributed to the increase of the solid- liquid interfacial energy which might originate from more orderly arrangement of atoms on the solid-liquid interface upon applying a magnetic fleld.
TL;DR: In this article, the authors investigated the properties of water-salt solutions of DNA, irradiated by non thermal coherent millimeter electromagnetic waves with frequency 64.5 GHz using the methods of spectrophotometry and densitometry.
Abstract: The thermostability and density of water-salt solutions of DNA, irradiated by non thermal coherent millimeter electromagnetic waves with frequency 64.5 GHz have been investigated using the methods of spectrophotometry and densitometry. It is shown that the thermostability of DNA and density of its solutions are increased, depending on time of irradiation. It is expected that under the influence of millimeter electromagnetic radiation the hydration of DNA and ions of Na+ that are present in solution decrease. As a result, the physicochemical characteristics of DNA are changed.
TL;DR: This paper addresses the problem of direction of arrival and time delay estimation, and derives multi-invariance MUSIC (MI- MUSIC) algorithm therein, which has better performance than that of ESPRIT and MUSIC, and also can be viewed as a generalization of MUSIC.
Abstract: This paper addresses the problem of direction of arrival and time delay estimation, and derives multi-invariance MUSIC (MI- MUSIC) algorithm therein. The proposed MI-MUSIC, which only requires one-dimension searching, can avoid the high computational cost within two-dimension MUSIC (2D-MUSIC) algorithm. It means that MI-MUSIC algorithm has better performance than that of ESPRIT and MUSIC, and also can be viewed as a generalization of MUSIC. Simulation results verify the usefulness of our algorithm.
TL;DR: In this article, a hybrid dielectric resonator (DR) antenna for UWB short-range wireless communications is proposed, which consists of a microstrip fed monopole loaded with a half cylindrical DR mounted on RT5880 substrate with a flnite ground plane.
Abstract: In this paper, a novel hybrid dielectric resonator (DR) antenna for Ultrawideband (UWB) short-range wireless communications is proposed. The proposed antenna consists of a microstrip fed monopole loaded with a half cylindrical dielectric resonator antenna of Rogers RO3010 mounted on RT5880 substrate with a flnite ground plane. The microstrip line fed monopole antenna is on the other side of the substrate. Compared to the conventional circular cylindrical DR mounted on a flnite ground plane (reference antenna), the proposed antenna has a reduction in the antenna size by about 30% with a bandwidth increase by about 22% than the reference antenna. The proposed antenna has a good impedance bandwidth. In addition, the proposed antenna has a quite higher and more stable gain than that of reference antenna. Moreover, the antenna has a good omni-directional radiation patterns in the H-plane. The proposed antenna is considered a good candidate for UWB short-range wireless communication systems.
TL;DR: In this paper, a broadband circularly polarized (CP) square slot antenna is evaluated numerically and verifled experimentally, which uses a lightening-shaped feedline protruded from the signal line of the feeding coplanar waveguide (CPW).
Abstract: A new broadband circularly polarized (CP) square slot antenna is evaluated numerically and verifled experimentally. The proposed antenna uses a lightening-shaped feedline protruded from the signal line of the feeding coplanar waveguide (CPW). Two symmetrical F-shaped slits embedded in opposite corners of ground plane are designed to obtain an excellent CP bandwidth. By adjusting the dimensions of the lightening-shaped feedline, the CP bandwidth can be further enhanced. Measured results show that the 3dB axial- ratio bandwidth of the proposed antenna can reach 51.7% (2150MHz{ 3650MHz), and the impedance bandwidth is as large as 60.2% (2150MHz{4000MHz) with VSWR • 2. Measured results are in good agreement with the simulation. The proposed antenna can be easily fabricated because of the simple coplanar geometry.
TL;DR: In this article, a microstrip dual-mode dual-band bandpass fllter using stepped impedance resonators (SIRs) is designed for dualband wireless local area networks (WLANs) applications at 2.4/5.2GHz.
Abstract: A microstrip dual-mode dual-band bandpass fllter using stepped impedance resonators (SIRs) is designed for dual-band wireless local area networks (WLANs) applications at 2.4/5.2GHz. By appropriately selecting the impedance ratio (Rz) and length ratio (fi) of the SIRs, the harmonic frequencies can be tuned for generating the dual-bandpass response. Based on SIRs, a dual-mode dual-band bandpass fllter is designed with one transmission zero. To improve the selectivity, another three transmission zeros in stopbands are created by introducing two stubs in input/output (I/O) lines. Two experimental fllters are fabricated. Both simulated and measured results are presented.
TL;DR: In this paper, a racket-shaped slot ultra wideband (UWB) antenna coupled with parasitic strips for band-notched application is proposed, which shows an ultra-wide impedance bandwidth from 3.1 to 10.6GHz for VSWR less than 2 except the bandwidths of 5.15{5.825GHz for WLAN.
Abstract: A racket-shaped slot ultra-wideband (UWB) antenna coupled with parasitic strips for band-notched application is proposed in this paper. By attaching a pair of parasitic rectangular strips on the bottom of the substrate, a band-notched characteristic is well realized. Adjusting the length, width of the two strips and the distance between them, a band-rejected fllter characteristic at the WLAN operation in 5.15{5.825GHz frequency band can be obtained. The fabricated antenna has a small size of 20£37:5mm 2 . Good agreement is achieved between the simulated and measured results, both of which show an ultra-wide impedance bandwidth from 3.1 to 10.6GHz for VSWR less than 2 except the bandwidths of 5.15{5.825GHz for WLAN.
TL;DR: In this paper, a compact ultra-wideband microstrip-fed planar monopole antenna with dual band-notch characteristic is presented, which achieves good omnidirectional radiation patterns in the H-plane, stable antenna gains over the operation band, and perfect group delay in the time domain.
Abstract: A compact ultra-wideband microstrip-fed planar monopole antenna with dual band-notch characteristic is presented. Dual notched frequency bands are achieved by embedding an M-slot in the radiating patch and a W-slot in the ground beneath the feeding line. And the characteristics of the dual band-notched can be controlled by adjusting the length and position of the corresponding slot. Experimental results show that the proposed antenna, with compact size of 35 × 35 mm2, has an impedance bandwidth of 2.75 ∼ 11.30GHz for VSWR less than 2.0, except two notched bands of 3.25 ∼ 4.20 GHz and 5.23 ∼ 6.10GHz. Moreover, this antenna exhibits good omnidirectional radiation patterns in the H-plane, stable antenna gains over the operation band, and perfect group delay in the time-domain.
TL;DR: In this paper, a simple inverted-U-shaped driven element operates frequency bands centered at 1710 and 2350MHz, which achieve a bandwidth based on 6-dB return loss from 1550 to 2490MHz for DCS, PCS, UMTS, and WLAN applications.
Abstract: This paper proposes a novel multi-band monopole antenna for PDA phone. A simple inverted-U-shaped driven element operates frequency bands centered at 1710 and 2350MHz, which achieve a bandwidth based on 6-dB return loss from 1550 to 2490MHz su-cient for DCS, PCS, UMTS, and WLAN applications. A low frequency meander path and an impedance matching stub with a truncated slit located at ground plane operates frequency band centered at 910MHz. The bandwidth from 868 to 995MHz covers the GSM 900 application band. The design procedures and both simulated and measured results are presented and discussed in this paper.
TL;DR: In this paper, a simple electromagnetically coupled broadband printed microstrip antenna suitable for multifunctional wireless communication bands is presented, where V-slots and corner notches are employed in a rectangular patch to achieve broadband operation.
Abstract: A simple electromagnetically coupled broadband printed microstrip antenna suitable for multifunctional wireless communication bands is presented. V-slots and corner notches are employed in a rectangular patch to achieve broadband operation. The proposed antenna has a 2 : 1 VSWR bandwidth of 51% from 3.75GHz to 6.33GHz. The simulated and measured re∞ection characteristics of the antenna along with the radiation patterns and gain are presented and discussed.
TL;DR: In this article, the effect of shaping the ground plane on the performance of a square loop coplanar waveguide (CPW)-fed printed antenna is investigated and simulation results are presented on the current distribution, input impedance and gain.
Abstract: The efiect of shaping the ground plane on the performance of a square loop coplanar waveguide (CPW)-fed printed antenna is reported in this paper. Experimental results are presented on the re∞ection coe-cient and radiation pattern of the investigated antennas. Simulation results are presented on the current distribution, input impedance and gain. It is observed based on the results that shaping the ground plane signiflcantly afiects the re∞ection coe-cients, input impedances and current distributions.
TL;DR: In this article, a tri-band monopole antenna for WLAN/WiMAX applications is proposed, which comprises of two semicircles: one is fed by a microstrip line, and the other is shorted to the ground.
Abstract: A novel tri-band monopole antenna applied to WLAN/WiMAX applications is proposed in this paper. The antenna comprises of two semicircles: one is fed by a microstrip line, and the other is shorted to the ground. By incorporating L-shaped strips, good filter as tri-band performance is achieved. The proposed antenna shows a good multi-band property to satisfy the requirement of WLAN in the 2.4/5.2/5.8 GHz bands and WiMAX in the 2.5/3.5/5.5 GHz bands. In addition, a near omni-directional radiation characteristic is also obtained. Experimental data show that the antenna can provide three separate impedance bandwidths of 400 MHz (centered at 2.6 GHz), 400MHz (centered at 3.4 GHz) and 1100 MHz (centered at 5.3 GHz) with two fine notched bands at the undesired bandwidths.