Showing papers in "Progress in Electromagnetics Research Letters in 2008"
TL;DR: In this article, an ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed, which has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm).
Abstract: An ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed. It has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm). It provides an wide impedance bandwidth ranging from 3.08 GHz to about 12.75 GHz adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and feed and ground plane dimensions. Parametric study is presented. Details of the proposed ultra-wideband design are described. Simulation results are presented and discussed in this paper.
120 citations
TL;DR: In this article, the authors introduce a smart NDI tool using active W-band imaging, which is capable of detecting hidden surface cracks in concrete structures. But this tool is not suitable for non-collapse detection.
Abstract: This paper overviews the latest trends of millimeter- wave (MMW) imaging technologies, focusing mainly on applications of and technical parameter variations for security surveillance and nondestructive inspections (NDI). We introduce a smart NDI tool using active W-band imaging, which is capable of detecting hidden surface cracks in concrete structures.
114 citations
TL;DR: Abbaspour et al. as discussed by the authors proposed a new wideband and small size star shaped patch antennafed capacitively by a small diamond shape patch to enhance the impedance bandwidth, posts are incorporated under the patch antenna.
Abstract: WIDEBANDSTAR-SHAPEDMICROSTRIPPATCHANTENNAM.AbbaspourandH.R.HassaniElectrical Engineering DepartmentShahed UniversityTehran, IranAbstract—A new wideband and small size star shaped patch antennafed capacitively by a small diamond shape patch is proposed.Toenhance the impedance bandwidth, posts are incorporated under thepatch antenna.HFSS high frequency simulator is employed to analyzethe proposed antenna and simulated results on the return loss, the E-and H-plane radiation patterns and Gain of the proposed antenna arepresented at various frequencies.The antenna is able to achieve in therange of 4–8.8GHz an impedance bandwidth of 81% for return loss ofless than
106 citations
TL;DR: In this paper, a new circular ultra-wideband fractal monopole antenna based on descartes circle theorem (DCT) with elliptical iterations is presented, which is optimized for return loss below −15 dB.
Abstract: A new circular ultra-wideband fractal monopole antenna based on descartes circle theorem (DCT) with elliptical iterations is presented. The proposed fractal design is optimized for return loss below −15 dB. The basic structure is slightly modified to ensure an overall smooth current distribution limited by the junction point nature of the fractal geometries. The measured return loss of the proposed design is below −15 dB within its impedance bandwidth along with omni-directional radiation pattern. Moreover due to the fractal shape, the proposed design has less weight and wind loading effect.
103 citations
TL;DR: Anovel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper, which has been demonstrated to provide an UWB with return loss less than −10 dB from 9.5 GHz to 22.4 GHz.
Abstract: Anovel ultra-wideband bow-tie slot antenna fed by CPW is proposed in this paper. This antenna has been demonstrated to provide an UWB with return loss less than −10 dB from 9.5 GHz to 22.4 GHz. The bandwidth is up to 80%, which is quite better than the traditional bow-tie slot antenna. Simulated and measured results are presented.
95 citations
TL;DR: In this paper, a soliton solution of one dimensional modified complex Ginzburg Landau equation is reported and the parametric region where such soliton solutions are possible is also identified.
Abstract: In this paper we have reported soliton solution of one dimensional modified complex Ginzburg Landau equation. The parametric region where such soliton solution is possible is also identified.
79 citations
TL;DR: In this paper, a planar UWB filter with circular slots in ground is presented and the authors used a new technique by etching a wideband circular-shape slot resonator in the ground plane of the filters.
Abstract: In this paper, miniature planar UWB filters with circular slots in ground is presented and we are using a new technique by etching a wideband circular-shape slot resonator in the ground plane of the filters. The proposed filters have compact size of 15 × 12.4 mm2. Two filters are introduced and the final design achieves flat insertion loss and linear phase of S12 throughout the passband (3.14–8.28 GHz) but occasional slight ripple occurs. Two different results are shown and the minimum insertion loss is less than 0.13 dB for both of presented filters.
75 citations
TL;DR: In this article, a very small size microstrip antenna suitable for WLAN application is presented, which consists of an M-shaped slot with shorting wall and a shorted triangular parasitic patch.
Abstract: This paper presents a very small size microstrip antenna suitable for WLAN application. The main patch antenna consists of an M-shaped slot with shorting wall. With a shorted triangular parasitic patch and a folded patch overall antenna size is reduced. The simulated and measured results show that by selecting a proper shorting wall width, the proposed antenna can provide an impedance bandwidth of 21.17% covering the 4.93–6.09 GHz band. The antenna size is of order 0.1094λo × 0.1094λo × 0.0544λo (6 × 6 × 3 mm3). The proposed antenna has 75% surface size reduction compared to a conventional patch antenna operating at the same centre frequency. The Eand H-plane radiation pattern across the entire operating bandwidth is provided.
73 citations
69 citations
TL;DR: In this paper, a compact planar microstrip ultra-wideband (UWB) bandpass filter is realized by cascading a high pass filter (HPF) and a low-pass filter (LPF).
Abstract: A compact planar microstrip ultra-wideband (UWB) bandpass filter is presented in this paper. The proposed UWB filter is realized by cascading a high pass filter (HPF) and a lowpass filter (LPF). HPF with short-circuited stubs is used to realize the lower stopband and a lowpass filter based on a defected ground array in the ground plane employed to attenuate the upper stopband. One such a bandpass filter is designed and simulated.
66 citations
TL;DR: In this article, the authors proposed that the application of defected ground structures (DGS) and electromagnetic bandgap (EBG) reduce the phase velocity, increase effective permittivity of microstrips and reduce the effective the wavelength which eventually lead to the reduction of overall length of Wilkinson power dividers.
Abstract: It is proposed that the application of defected ground structures (DGS) and electromagnetic bandgap (EBG) reduce the phase velocity, increase effective permittivity of microstrips and reduce the effective the wavelength which eventually lead to the reduction of overall length of Wilkinson power dividers. Furthermore, the adjacent strip lines may approach each other, which cause coupling problems. The undesired coupling maybe cancelled by connecting a capacitance in parallel with the isolation resistor of Wilkinson power divider. Application of DGS and EBG will not only reduce the dimensions of the divider, but also improves its scattering parameters.
TL;DR: In this paper, a novel compact Archimedean spiral antenna with gap-loading is investigated, where a circular frame sharing the same center with the spiral elements introduces a capacitive gap.
Abstract: A novel compact Archimedean spiral antenna with gap- loading is investigated in this paper. A circular frame sharing the same centre with the spiral elements introduces a capacitive gap. By adjusting the width of the gap and the width of the circular frame, the initial resonant frequency of the proposed antenna is shifted from 2.79 to 1.93 GHz. Compared with the traditional Archimedean spiral antenna with the same lowest operation frequency, the area of the proposed antenna can be reduced by more than 30simulated radiation pattern results.
TL;DR: In this paper, the authors considered the problem of absorbing the energy of a point source in the presence of an absorbing half-space with the aim of minimizing the signal losses, and proposed new designs of the electromagnetic fleld absorbers and resonators with the use of metamaterials.
Abstract: The problem regarding top possible (hopefully, total) fleld suppression of a fll- amentary source placed above nonuniform impedance plane is discussed New designs of the electromagnetic fleld absorbers and resonators are suggested which may be engineered with the use of metamaterials 1 INTRODUCTION | ABSORPTION OF THE ENERGY OF A POINT SOURCE BY A HALF-SPACE Interest to the fleld propagation along the imperfect surface has about century-old history, the beginnings of which trace back to the Sommerfeld's solution of the classical problem for the dipole radiating above the plane with flnite conductivity Later, as the radio broadcasting evolved, a lot of publications appeared which dealt with electromagnetic fleld propagation in the presence of an absorbing half-space with the aim to minimize the signal losses Now certain practical needs (1) set questions about what value of impedance of a plane should be chosen to absorb the maximum portion of energy radiated by a point source (say, fllamentary current), how much the amount of the absorbed energy is and how to create such an impedance Note, in view of the symmetry of the radiation pattern of the fllament, at the absence of the plate (in the free space) equal power ∞uxes are radiated into upper and lower half-spaces, and exactly one half of the radiated energy penetrates through the plane y = 0, see Fig 1
TL;DR: In this article, a single-pin-shorted microstrip line fed three-dielectric-layer (with different permittivity and thickness) rectangular patch microstrip antenna for all those communication systems whose limited antenna size is premium is simulated.
Abstract: In this paper, we have simulated a single-pin-shorted microstrip line fed three-dielectric-layer (with different permittivity and thickness) rectangular patch microstrip antenna for all those communication systems whose limited antenna size is premium. Low permittivity hard foam has been used as one substrate to achieve wide bandwidth. The simulation of this proposed antenna has been performed by using CST Microwave Studio, which is a commercially available electromagnetic simulator based on the finite difference time domain technique.
TL;DR: This paper presents a novel technique for efficiently combining genetic algorithms (GA's) with method of moments (MOM) for planar inverted-F antennas (PIFAs) and excellent agreement between numerical and measured results is observed.
Abstract: This paper presents a novel technique for efficiently combining genetic algorithms (GA's) with method of moments (MOM) for planar inverted-F antennas (PIFAs). MOM is applied to analyze rectangular patches fed by a coaxial probe and shorted with a shorted pin. The impedance matrix of such a mother structure is, then manipulated by a GA optimization procedure in order to detect the optimal patch shape matching the required frequency properties. GA adoption enables optimal shape detection among all possible shapes allowed by the mother structure dimensions. The design example of dual-band antenna is presented, and measurement result is compared to numerical results. Excellent agreement between numerical and measured results is observed.
TL;DR: In this article, a printed version of the classic volcano smoke antenna is presented and investigated in the design of the proposed antenna, which covers all UWB (3.1-10.6 GHz) and 2.4 GHz WLAN (2.4-2.4835 GHz) bands.
Abstract: A novel printed version of the classic volcano smoke antenna is presented and investigated in this article. The effects of some important parameters on the VSWR of the proposed antenna have been investigated in the design. The measured bandwidth of VSWR< 2 is from 1.80 to 14.35GHz, which covers all UWB (3.1– 10.6 GHz) and 2.4 GHz WLAN (2.4–2.4835 GHz) bands. Moreover, the antenna features near omnidirectional characteristics in the operation range and good radiation efficiency. A gain variation from 2.04 to 7.02 dBi (2–13 GHz) is obtained.
TL;DR: In this paper, a new antenna structure comprising a semicircular microstrip patch alongside a small rectangular shape ground proximity fed by a microstrip line is proposed, which achieves in the range of 5.8-12.9 GHz an impedance bandwidth of almost 75%.
Abstract: A new antenna structure comprising a semicircular microstrip patch alongside a small rectangular shape ground proximity fed by a microstrip line is proposed. On a thin substrate this antenna achieves in the range of 5.8–12.9 GHz an impedance bandwidth of almost 75%. Details of the antenna design, simulation and measured results on the return loss and the E and H -plane radiation pattern of the proposed antenna are presented.
TL;DR: In this paper, the authors proposed a CPW-SL-CPW vertical via transition using gradually stepped vias and embedded air cavities for V-band LTCC System-on-Package (SoP) applications.
Abstract: In this work, CPW-to-stripline (SL) vertical via transitions using gradually stepped vias and embedded air cavities are presented for V-band LTCC System-on-Package (SoP) applications. In order to reduce radiation loss due to abrupt via discontinuities, gradual via transitions are proposed and investigated. In addition, in order to reduce increased parasitic shunt capacitance due to stepped via structures, air cavities are embedded below the transition vias. Using a 3-D EM simulation tool, the proposed transitions are designed and analyzed, compared to the conventional transition. Three-segment transmission lines (CPW-SL-CPW) in 7-layer LTCC dielectrics were fabricated and measured. The two stepped via (STV2) transition embedding air cavities shows an insertion and return losses of 1.6 dB and below −10 dB, respectively, over 60 GHz. The transition loss per one STV2 transition is 0.7 dB at 60 GHz.
TL;DR: In this paper, a radar absorbing cover has been designed with spatial configuration to get maximum performance at the resonant frequency of the fabricated microstrip antenna array, and the measured results of the tested antenna array show a significant reduction of both mutual coupling between array patches and radar cross-section with minimum side effects on the antenna parameters.
Abstract: Improving the performance of a microstrip antenna array has been considered based on the innovative use of an absorbing radar cover.Since the surface wave between antennas array elements plays a major role in mutual coupling and scattering behavior of array antenna. The main objective of this work is to reduce the effect of surface wave between array elements using radar absorbing cover.The absorbing cover has been designed with spatial configuration to get maximum performance at the resonant frequency of the fabricated microstrip antenna array.The measured results of the tested antenna array show a significant reduction of both mutual coupling between array patches and radar cross section of the tested antenna array with minimum side effects on the antenna parameters.
TL;DR: In this paper, the authors presented the calculations of transmission line loss factor by extracting from the Q-factor measurement of the quarterwavelength open stub resonators over the designed frequency and other resonant frequencies.
Abstract: This paper presents the calculations of transmission line loss factor by extracting from the Q-factor measurement of the quarterwavelength open stub resonators over the designed frequency and other resonant frequencies. A comparison of the loss factor of the design frequency with other resonant frequencies of each of the stub’s quarter-wave resonances is provided in this paper. The radiation and discontinuity losses are undesirably included in the unloaded Q-factor measurement and it shows that the unloaded Q-factor is not repeatable at different designed frequency. The implementation of the loss factor measurement by quarter-wavelength open stub resonators is becoming more and more important to be considered with the increase of using the electronic circuits operating at high frequencies. † This author is also with Department of Electronic Engineering, Tam Kang University, 151 Ying-chuan Road, Tamsui, Taipei County, Taiwan 25137, R.O.C.
TL;DR: The results show that though the proposed deembedding method, the error induced by embedding can be eliminated successfully and the propagation constant of the ANUT can be extracted accurately.
Abstract: A new deembedding method in permittivity measurement of ferroelectric thin film material is proposed in this paper. By measuring the two scattering matrixes of the two samples with different length, the propagation constant of the actual network under test (ANUT) can be obtained. Further more, the permittivity would be extracted. The results show that though the proposed deembedding method, the error induced by embedding can be eliminated successfully and the propagation constant of the ANUT can be extracted accurately.
TL;DR: In this article, a novel radiation pattern and frequency reconfigurable microstrip antenna is introduced for wide-band and wide-angle scanning applications on a thin substrate for the application of conformal phased antenna future.
Abstract: A novel radiation pattern and frequency reconfigurable microstrip antenna is introduced in this paper. This antenna is designed on a thin substrate for the application of conformal phased antenna future. The proposed antenna make the operating frequency range 6 times larger than that of a simple rectangular microstrip antenna, and make the beam covering from −70 ◦ ∼70 ◦ compared with the traditional rectangular microstrip antenna beam which only covers −50 ◦ ∼ 50 ◦ . It is potential on the application of wide-band and wide- angle scanning.
TL;DR: In this paper, the authors present an experimental procedure that uses the same equipment for the detec- tion and calibration by means of signal processing procedures for the estimation of the relative permittivity of the soil.
Abstract: Combined ground penetrating radar and metal detector equipment are now avail- able (e.g., MINEHOUND, ERA Technology-Vallon GmbH) for landmine detection. The perfor- mance of the radar detector is in∞uenced by the electromagnetic characteristics of the soil. In this paper we present an experimental procedure that uses the same equipment for the detec- tion and calibration by means of signal processing procedures for the estimation of the relative permittivity of the soil. The experimental uncertainties of this method are also reported.
TL;DR: In this paper, circular polarization (CP) designs of circular and rectangular microstrip patch antennas are demonstrated, which results in excitation of two near degenerate orthogonal modes of near equal amplitudes and 90˚ phase difference, and attempts are made to change the geometry of slots' ends to introduce a novel structure in order to achieve a better matching performance.
Abstract: Circular polarization (CP) designs of circular and rectangular microstrip patch antennas are demonstrated. Proximity coupled feed and aperture coupled feed methods are used. The proposed CP designs are achieved by implementing a suitable crossslot either on the patch (in the case of proximity coupled feed method) or on the ground plane (in the case of aperture coupled feed method), which results in excitation of two near degenerate orthogonal modes of near equal amplitudes and 90◦ phase difference. Attempts are made to change the geometry of slots’ ends to introduce a novel structure in order to achieve a better matching performance.
TL;DR: In this article, a square cylindrical monopole antenna was fabricated using a cross-shaped metal plate for wideband omnidirectional operation with the 802.16e standard in the 2 to 6 GHz.
Abstract: This paper presents a square cylindrical monopole antenna easily fabricated using a cross-shaped metal plate for wideband omnidirectional operation. A prototype of the proposed antenna with a cross-sectional area of 8 × 8 mm2 is implemented, and the antenna provides a wide operating bandwidth of about 7.5 GHz (1.8–9.4 GHz here), making it very promising for WMAN operation with the 802.16e standard in the 2 to 6 GHz. In addition, over the operating bandwidth, the antenna shows very good omnidirectional radiation patterns.
TL;DR: In this article, the authors presented two compact ring slot antennas which are suitable for the PCS-1900 and the 2.4/5-GHz triple-band operations, where the inner most rings, through their Y-shaped slots, create a wide upper operating band by combining the third and fourth modes.
Abstract: This paper presents two compact ring slot antennas which are suitable for the PCS-1900 and the 2.4/5-GHz triple-band operations. The first antenna consists of three annular ring slots. The outer ring is responsible for exciting the first resonant mode whereas the middle ring excites the second resonant mode. The inner most rings, through their Y-shaped slots, create a wide upper operating band by combining the third and fourth resonant modes. To improve this antenna, we have employed circular Photonic Bandgap (PBG) structures in order to obtain a smaller slot antenna with better radiation characteristics. In this design, the cross-polarization level in the E-plane has reduced compared to the first antenna by 5.5 dB, 0.3 dB and 4 dB in the three resonant bands. Also, the cross- polarization in H-plane has reduced by an amount of 3 dB. In addition, the obtained results show that the co-polarization patterns are very similar in all three frequency bands. In both cases we have reduced the size of antennas to 56% and 42% respectively, of conventional microstrip slot antennas. The simulation results are verified by measurements.
TL;DR: In this article, a 3 dB tunable symmetric left-handed coupled line coupler implemented on ferrite substrate is proposed, which is realized in a LH coplanar waveguide configuration constructed using interdigital capacitors and meandered line inductors.
Abstract: This paper introduces a 3 dB tunable symmetric left handed coupled line coupler implemented on ferrite substrate. The proposed coupler is realized in LH coplanar waveguide configuration constructed using interdigital capacitors and meandered line inductors. The analytical analysis and the numerical verification of the proposed couple line coupler are presented. The full wave numerical simulation results for different DC magnetic bias indicate that a tunable left handed coupled line coupler propagation with transmission coefficient up to 3 dB and isolation level more than 25 dB over a wide bandwidth can be achieved.
TL;DR: Triangular patch resonator bandpass filters with tunable operation are developed to perform nicer filter properties of low passband insertion loss, transmission zero, and wide stopband as discussed by the authors, which can bring filters more operation without changing the dielectric substrate or patch size.
Abstract: Triangular patch resonator bandpass filters with tunable operation are developed to perform nicer filter properties of low passband insertion loss, transmission zeros and wide stopband. With tunable fractal-shaped defection acts as perturbation, filter operation frequency and operation band can be controlled, and the responses of undesired resonant modes are greatly weakened even suppressed. The new design can bring filters more operation without changing the dielectric substrate or patch size. The designed filters have outstanding advantages of single patch with compact size and without resonator coupling gaps, simple circuit topology, nicer performances, miniaturization and can be easily tuned for more applications. All these features are well popular for wireless communication systems.