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2013-08-16
PIER
Vol. 141, 769-784, 2013
download: 174
Experimental Study of Efficient Wireless Power Transfer System Integrating with Highly Sub-Wavelength Metamaterials
Yingchun Fan Long Li Shixing Yu Cheng Zhu Chang-Hong Liang
In this paper, an efficient wireless power transfer (WPT) system integrating with highly sub-wavelength metamaterials is proposed. The negative refractive index (NRI) and negative permeability (MNG) metamaterials for operation at radio frequencies are designed and applied to WPT system for improvement of power transfer efficiency. A dual-layer design which consists of a planar spiral on one side and a meander line touching with narrow metallic strips on the other side produces the properties of effective negative permittivity and permeability simultaneously, i.e., negative refractive index. In addition, the structure of double spirals produces a negative permeability. The cell size of the NRI and MNG metamaterials is about 253 times smaller than the operation wavelength. By integrating one, two, three or four metamaterial slabs between the two coupling copper rings, the transfer efficiency is improved significantly. The measured results show that the contribution of high transfer efficiency is due to the property of negative permeability which can make the WPT system work in the mechanism of magnetic resonance.
EXPERIMENTAL STUDY OF EFFICIENT WIRELESS POWER TRANSFER SYSTEM INTEGRATING WITH HIGHLY SUB-WAVELENGTH METAMATERIALS
2013-08-12
PIER
Vol. 141, 751-768, 2013
download: 134
Orbital Angular Momentum Density of an Elegant Laguerre-Gaussian Beam
Guoquan Zhou Guoyun Ru
Based on the method of the vectorial angular spectrum, an analytical expression of the electric field of an elegant Laguerre-Gaussian beam in free space is derived beyond the paraxial approximation, and the corresponding magnetic field is obtained by taking the curl of the electric field. By using the expressions for the electromagnetic fields, the expression of the orbital angular momentum density of the elegant Laguerre.Gaussian beam is derived, which is applicable to both the near and far fields. The effects of the three beam parameters on the distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam are studied. The distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam is also compared with that of the standard Laguerre-Gaussian beam. The result shows that the distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam is more simple and centralized than that of the standard Laguerre-Gaussian beam.
ORBITAL ANGULAR MOMENTUM DENSITY OF AN ELEGANT LAGUERRE-GAUSSIAN BEAM
2013-08-09
PIER
Vol. 141, 739-749, 2013
download: 139
Understand and Realize an ``Invisible Gateway'' in a Classical Way
Xianqi Lin Yuan Jiang Jun Ye Jin Jia Wei Yu Sailing He
We create an invisible gateway simply by putting electric and magnetic superscatterers in a metallic waveguide. The characteristics of the electric and magnetic resonators are analyzed in a metallic hollow waveguide, and the dual-mode superscattering property is discussed in detail to broaden the bandwidth of the invisible gateway. Good agreement is achieved between the simulation and measurement for such an invisible gateway. The present work help readers understand easily how an invisible gateway works (or makes sense) in a classical way without using any complex metamaterial or complicated method of transformation optics.
UNDERSTAND AND REALIZE AN ``INVISIBLE GATEWAY'' IN A CLASSICAL WAY
2013-08-09
PIER
Vol. 141, 727-737, 2013
download: 167
A Coupled-Fed Antenna for 4G Mobile Handset
Jin Dong Yong-Chang Jiao Zi-Bin Weng Qiaona Qiu Yuyu Chen
A novel coupled-fed antenna with compact branch-structure for 4G mobile phone is proposed in this paper. In the proposed design, a driven monopole strip and coupled branch-strips are developed to produce different operation band. The prototype of the proposed antenna was fabricated, tested and discussed. Simulation and measurement results reveal that the proposed antenna can provide two wide frequency bands (698~960 MHz, and 1710~2690 MHz), which covers multi-band for LTE700/GSM850/GSM900/DCS1800/PCS1900/UMTS/LTE2300/LTE2500. The proposed antenna with compact size of 34×12×6.5 mm3 is suitable for today's mobile phone application.
A COUPLED-FED ANTENNA FOR 4G MOBILE HANDSET
2013-08-09
PIER
Vol. 141, 711-726, 2013
download: 230
Complete Propagation Model Structure Inside Tunnels
Ke Guan Zhangdui Zhong Bo Ai Ruisi He Binghao Chen Yuanxuan Li Cesar Briso-Rodriguez
In this paper, a complete model structure for propagation inside tunnels is presented by following the segmentation-based modeling thought. According to the concrete propagation mechanism, totally five zones and four dividing points are modeled to constitute three channel structures corresponding to large-size users and small-size users. Firstly, the propagation characteristics and mechanisms in all the zones are modeled. Then, from the view point of the propagation mechanism, the criterion of judging the type of a user is analytically derived. Afterwards, all the dividing points are analytically localized as well. Finally, a panorama covering all the propagation mechanisms, characteristics, models, and dividing pints for all types of users is presented for the first time. This panorama is very useful to gain a comprehensive understanding of the propagation inside tunnels. Validations show that by using the analytical equations in this paper, designers can easily realize a fast network planning for all types of users in various tunnels at different frequencies.
COMPLETE PROPAGATION MODEL STRUCTURE INSIDE TUNNELS
2013-08-09
PIER
Vol. 141, 693-710, 2013
download: 257
Novel Miniaturized Koch Pentagonal Fractal Antenna for Multiband Wireless Applications
Omar Masood Khan Zain Ul Islam Imran Rashid Farooq Ahmad Bhatti Qamar Ul Islam
A novel reduced size three band Koch Pentagonal fractal antenna is presented. The proposed antenna uses pentagonal shape for the basic fractalization combined with inner sides etched with Koch fractal pattern of the first iteration providing reduction in the overall size of the antenna. For higher order of iterations, more size reduction is achieved, producing equal number of radiation bands. Optimization is done for achieving radiations in the S, C and X bands. Ansoft HFSS, CST Microwave Studio and Solid Works are used for the 3D Modeling, S11 frequency optimization and radiation pattern calculations. The proposed third iteration fractal configuration is fabricated on Rogers RT5870, and measured results are presented. Size reduction up to 43.26 percent in terms of its overall size and 75.18 percent in terms of copper cladding remaining is achieved for the third iteration proposed fractal antenna in comparison to pentagonal patch antenna operating in the first resonant frequency band.
NOVEL MINIATURIZED KOCH PENTAGONAL FRACTAL ANTENNA FOR MULTIBAND WIRELESS APPLICATIONS
2013-08-05
PIER
Vol. 141, 671-692, 2013
download: 121
New Triangular Mass-Lumped Finite Elements of Degree Six for Wave Propagation
William Alexander Mulder
Mass-lumped continuous finite elements allow for explicit time stepping with the second-order wave equation if the resulting integration weights are positive and provide sufficient accuracy. To meet these requirements on triangular and tetrahedral meshes, the construction of higher-degree elements for a given polynomial degree on the edges involves polynomials of higher degrees in the interior. The parameters describing the supporting nodes of the Lagrange interpolating polynomials and the integration weights are the unknowns of a polynomial system of equations, which is linear in the integration weights. To find candidate sets for the nodes, it is usually required that the number of equations equals the number of unknowns, although this may be neither necessary nor sufficient. Here, this condition is relaxed by requiring that the number of equations does not exceed the number of unknowns. This resulted in two new types elements of degree 6 for symmetrically placed nodes. Unfortunately, the first type is not unisolvent. There are many elements of the second type with a large range in their associated time-stepping stability limit. To assess the efficiency of the elements of various degrees, numerical tests on a simple problem with an exact solution were performed. Efficiency was measured by the computational time required to obtain a solution at a given accuracy. For the chosen example, elements of degree 4 with fourth-order time stepping appear to be the most efficient.
NEW TRIANGULAR MASS-LUMPED FINITE ELEMENTS OF DEGREE SIX FOR WAVE PROPAGATION
2013-08-05
PIER
Vol. 141, 659-670, 2013
download: 109
Coherent Anti-Stokes Raman Scattering Microscopy by Dispersive Wave Generations in a Polarization Maintaining Photonic Crystal Fiber
Jinhui Yuan Guiyao Zhou Hongzhan Liu Changming Xia Xinzhu Sang Qiang Wu Chongxiu Yu Kuiru Wang Binbin Yan Ying Han Gerald Farrell Lantian Hou
The polarization maintaining photonic crystal fiber (PM-PCF) with two zero dispersion wavelengths is designed and fabricated by the improved stack-and-draw technology in our laboratory. The broadband blue-shifted and red-shifted dispersive waves (DWs) are efficiently generated from soliton self-frequency shift (SSFS) along the slow axis of PM-PCF. By optimizing the pump parameters and the fiber length, the polarized DWs centered in the normal dispersion region can be used as the pump and Stokes pulses for the high resolution coherent anti-Stokes Raman scattering (CARS) microscopy. Moreover, it is demonstrated that the widely tunable relevant CARS wavelengths can be obtained by adjusting the pump wavelength. The CARS microscopy based on DWs can find important applications in detecting the biological and chemical samples with the C=N, S-H, C-H, and O-H stretch vibration resonances of 2100 to 2400 cm-1, 2500 to 2650 cm-1, 2700 to 3000 cm-1, and 3000 to 3750 cm-1.
COHERENT ANTI-STOKES RAMAN SCATTERING MICROSCOPY BY DISPERSIVE WAVE GENERATIONS IN A POLARIZATION MAINTAINING PHOTONIC CRYSTAL FIBER
2013-08-05
PIER
Vol. 141, 645-657, 2013
download: 150
Multi-Band Circular Polarizer Using Archimedean Spiral Structure Chiral Metamaterial with Zero and Negative Refractive Index
Liyun Xie He-Lin Yang Xiaojun Huang Zhenjun Li
A novel multi-band circular polarizer is proposed by using a bilayered chiral metamaterial (CMM). The unit cell of the CMM is composed of four Archimedean spiral structures, which are twisted 90° to each other in the upper and bottom layers. When a linearly polarized wave incidents on this circular polarizer, the simulation result shows that the transmission of right circularly polarized (RCP) wave can be obtained at 14.28 GHz and 15.96 GHz, while the transmission of left circularly polarized (LCP) wave is emitted at 15.3 GHz and 16.88 GHz. The retrieval results reveal that the effective refractive index of the CMM closes to zero or negative at the vicinity of four resonances. The experimental results are in good agreement with the numerical results.
MULTI-BAND CIRCULAR POLARIZER USING ARCHIMEDEAN SPIRAL STRUCTURE CHIRAL METAMATERIAL WITH ZERO AND NEGATIVE REFRACTIVE INDEX
2013-08-05
PIER
Vol. 141, 619-643, 2013
download: 144
Microwave: Effects and Implications in Transdermal Drug Delivery
Anuar Nor Khaizan Tin Wui Wong
This study investigated transdermal drug delivery mechanisms of pectin and pectin-oleic acid (OA) gels and their effects on skin barrier treated by microwave. Hydrophilic pectin-sulphanilamide gels, with or without OA penetration enhancer, were subjected to drug release and skin permeation studies. The skins were untreated or microwave-treated, and characterized by infrared spectroscopy, raman spectroscopy, thermal, electron microscopy and histology techniques. Unlike solid film, skin treatment by microwave at 2450 MHz demoted drug permeation especially from OA-rich pectin gel. The pectin-skin binding was facilitated by gel with freely soluble pectin molecules instead of solid film with entangled chains. It was promoted when microwave fluidized stratum corneum into structureless domains, or OA extracted endogenous lipid fraction and formed separate phases within intercellular lipid lamellae. This led to a remarkable decrease in transdermal drug permeation. Microwave-enhanced transdermal delivery must not be implemented with pectin gel. In skin treated by microwave, the penetration enhancer in gel can act as a permeation retardant.
MICROWAVE: EFFECTS AND IMPLICATIONS IN TRANSDERMAL DRUG DELIVERY
2013-08-05
PIER
Vol. 141, 607-618, 2013
download: 105
Removal of JEM Signal by Accurate Estimation of Initial Parameters of Chirplet Basis Functions
Joo-Ho Jung Kyung-Tae Kim Sang-Hong Park
The inverse synthetic aperture radar (ISAR) image can be very effective in target recognition because it provides 2-D image that uses frequency data measured at various observation angles. However, the jet engine modulation (JEM) that can occur in the received signal due to the rotation of the blade in the engine may result in image blurring in cross-range direction. In this paper, we propose an efficient method of removing JEM signals by using the existing chirplet basis function and an efficient method to estimate the initial values of the four parameters of the chirplet. Simulations using the measured data provided clear ISAR image of a real Boeing747 aircraft.
REMOVAL OF JEM SIGNAL BY ACCURATE ESTIMATION OF INITIAL PARAMETERS OF CHIRPLET BASIS FUNCTIONS
2013-08-05
PIER
Vol. 141, 591-605, 2013
download: 103
Ultra Wide Band Response of an Electromagnetic Wave Shield Based on a Diode Grid
Yangjun Zhang Mengqing Yuan Qing Huo Liu
This paper investigates Ultra Wide Band (UWB) response of a self-actuated electromagnetic wave shield based on a diode grid both in frequency and time domain. The investigation is first carried out on a shield valid for an incident wave polarized at a specific direction only, then extended to a shield effective for an incident wave polarized at an arbitrary direction. In the frequency domain, two linear analysis methods are used to study the properties of the diode grid over the frequency range from 0.01 to 10 GHz. One method is the microwave network analysis. Another is simulating the diode grid by a linear equivalent circuit instead of a diode. In the time domain, the property of the shield is studied with respect to a broadband impulse, where the diode is described by its SPICE circuit model including the nonlinear property. The results show that the diode grid works well as a self-actuated electromagnetic power selective surface (PSS) in a certain frequency range. The diode grid is strongly frequency dependent. The operating frequency band relies on the reactive elements in the diode grid. In order to extend the operating frequency to a high band, smaller cell size and smaller junction capacitance should be employed.
ULTRA WIDE BAND RESPONSE OF AN ELECTROMAGNETIC WAVE SHIELD BASED ON A DIODE GRID
2013-08-05
PIER
Vol. 141, 577-590, 2013
download: 132
Free-Space and on-Metal Dual-Band Tag for UHF-RFID Applications in Europe and USA
Ferran Paredes Gerard Zamora Simone Zuffanelli Francisco Javier Herraiz-Martinez Ferran Martin Jordi Bonache
In this paper, we present an UHF-RFID tag mountable on metallic surfaces and capable to operate in the assigned frequency bands in Europe (866-869 MHz) and USA (902-928 MHz). Due to the proximity of these frequency bands, the dual-band functionality can be achieved through a perturbation method applied to a single band tag designed to operate at the intermediate frequency. The tag consists of an integrated circuit, an impedance matching network (where the perturbation method is applied) and a patch antenna. The considered antenna has been chosen because it has high efficiency over metallic surfaces. The whole tag has been analyzed, designed and finally fabricated. The read ranges measured in free-space are 9.5 m and 7.5 m at the European and USA frequency bands, respectively. By placing the tag on a metal surface, the read ranges increase up to 14 m and almost 11 m, respectively.
FREE-SPACE AND ON-METAL DUAL-BAND TAG FOR UHF-RFID APPLICATIONS IN EUROPE AND USA
2013-08-01
PIER
Vol. 141, 553-575, 2013
download: 116
A New Parameter Estimation Method for GTD Model Based on Modified Compressed Sensing
Xingwei Yan Jiemin Hu Ge Zhao Jun Zhang Jianwei Wan
The electromagnetic scattering mechanism of radar targets in the high-frequency domain can be characterized exactly by geometrical theory of diffraction (GTD) model. In this paper, we propose a novel parameter estimation method for GTD model based on compressed sensing. The sparse characteristic of radar echoes is analyzed, and the parameter estimation problem is converted to one of sparse signal reconstruction. Furthermore, clustering and linear least-minimum-squares algorithms are utilized to improve the accuracy of the result. Compared with several modern spectral estimation techniques, the proposed method gives a more precise estimation of the GTD model parameters, especially the scattering centers. Simulations with synthetic and measured data in an anechoic chamber confirm the effectiveness of the method.
A NEW PARAMETER ESTIMATION METHOD FOR GTD MODEL BASED ON MODIFIED COMPRESSED SENSING
2013-08-01
PIER
Vol. 141, 537-552, 2013
download: 135
A Bidirectional Circularly Polarized Array of the Same Sense Based on CRLH Transmission Line
Wendong Liu Zhijun Zhang Zhenghe Feng
A bidirectional circularly polarized array of the same sense is proposed. The implementation is a combination of end-fire array, crossed dipoles, and composite right/left-handed transmission line (CRLH-TL). The proposed array consists of four dipoles spaced at a distance equal to λ0/4 (λ0 is the wavelength in free space at the center frequency). For the bidirectional circular polarization of the same sense, the four dipoles are fed in-phase in a series-fed structure. A feed line that exhibits 0° phase shift every λ0/4 is needed. To satisfy the demand for the space distance and phase distribution in a series-fed array, the CRLH unit cell composed of lumped capacitors and inductors is employed and inserted in the feed line. Theoretical analysis is performed based on the balanced parallel stripline and design equations are presented for the determination of the lumped element parameters. The design method can be used in the design of the arrays with more elements. From the experimental results, the array offers a 4.2 dBic bidirectional circular polarization gain. The bandwidth between which the impedance matching is better than -10 dB and the axial-ratio is better than 3 dB is 300 MHz from 2.39 to 2.69 GHz.
A BIDIRECTIONAL CIRCULARLY POLARIZED ARRAY OF THE SAME SENSE BASED ON CRLH TRANSMISSION LINE
2013-08-01
PIER
Vol. 141, 517-535, 2013
download: 162
An Accurate Imaging Algorithm for Millimeter Wave Synthetic Aperture Imaging Radiometer in Near-Field
Jianfei Chen Yuehua Li Jianqiao Wang Yuanjiang Li Yilong Zhang
Due to the fact that the imaging distance is similar to the dimension of synthetic aperture antenna in near-field, the Fourier imaging theory used in the traditional synthetic aperture imaging radiometer (SAIR), which is based on the far-field approximation, is invalid for near-field synthetic aperture imaging. This paper is devoted to establishing an accurate imaging algorithm for near-field millimeter wave SAIR. Firstly, the near-field synthetic aperture imaging theory is deduced and its relationship to the far-field imaging theory analyzed. Then, an accurate imaging algorithm based on the near-field imaging theory is established. In this method, the quadratic phase item and antenna pattern are taken into consideration, and the image reconstruction is performed by minimizing the Total-Variation norm of brightness temperature image, which reduces the influence of the visibility observation error and improves imaging precision. Finally, the effectiveness of the proposed imaging algorithm has been tested by means of several simulation experiments, and the superiority is also demonstrated by the comparison between it and the existing Fourier transform methods. The results demonstrate that the proposed method is an efficient, feasible imaging algorithm for near-field millimeter wave SAIR.
AN ACCURATE IMAGING ALGORITHM FOR MILLIMETER WAVE SYNTHETIC APERTURE IMAGING RADIOMETER IN NEAR-FIELD
2013-07-31
PIER
Vol. 141, 497-516, 2013
download: 109
Azimuth Multichannel SAR Imaging Based on Compressed Sensing
Mingjiang Wang Weidong Yu Robert Wang
Azimuth multichannel is a promising technique of realizing high resolution and wide swath for synthetic aperture radar (SAR) imaging, which consequently leads to extremely high data rate on satellite downlink system and confronts serious ambiguity in subsequent processing due to its strict limitation of pulse repetition frequency (PRF). Ambiguity suppression performance of conventional spectrum construction is disappointing when the samples are approximately overlapped. To overcome these weaknesses, a novel sparse sampling scheme for displaced phase center antennas based on compressed sensing (CS) is proposed in this paper. The imaging strategy sparsely sampled in both range and azimuth direction, leading to a significant reduction of the system data amount beyond the Nyquist theorem, and then operated the CS technique in two dimensions to accomplish target reconstruction. Effectiveness of the proposed approach was validated through simulation and real data experiment. Simulation results and analysis indicated that the new imaging strategy could provide several favorable capability than conventional imaging algorithm such as less sampled data, better ambiguity suppression, higher resolution, and lower integrated side-lobe ratio (ISLR).
AZIMUTH MULTICHANNEL SAR IMAGING BASED ON COMPRESSED SENSING
2013-07-30
PIER
Vol. 141, 479-495, 2013
download: 171
A Compressive Sensing Signal Detection for UWB Radar
Shugao Xia Yuhong Liu Jeffrey Sichina Fengshan Liu
A major challenge in UWB signal processing is the requirement for very high sampling rate under Shannon-Nyquist sampling theorem which exceeds the current ADC capacity. Radar signal is essentially a delayed and scaled version of the transmitted pulse, determined by sparse parameters such as time delays and amplitudes. A system for sampling UWB radar signal at an ultra-low sampling rate based on the Finite Rate of Innovation (FRI) and the estimation of time delays and amplitudes to detect UWB radar signal is presented in the paper. This sampling scheme which acquires the Fourier series coefficients often results in sparse parameter extraction for UWB radar signal detection. The parameters such as time-delays and amplitudes are estimated using the total variation norm minimization. With this system, the UWB radar signal can be accurately reconstructed and detected with overwhelming probability at the rate much lower than Nyquist rate. The simulation results show that the proposed approach offers very good recovery performances for noisy UWB radar signal using very small number of samples, which is effective for sampling and detecting UWB radar signal.
A COMPRESSIVE SENSING SIGNAL DETECTION FOR UWB RADAR
2013-07-29
PIER
Vol. 141, 463-478, 2013
download: 111
Novel Triangular Metamaterial Design for Electromagnetic Absorption Reduction in Human Head
Mohammad Rashed Iqbal Faruque Mohammad Tariqul Islam
In this paper, a novel triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, is developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio®. The technique of specific absorption rate (SAR) reduction is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the novel TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 50.82% reduction for 1 gm SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a cellular phone.
NOVEL TRIANGULAR METAMATERIAL DESIGN FOR ELECTROMAGNETIC ABSORPTION REDUCTION IN HUMAN HEAD
2013-07-28
PIER
Vol. 141, 443-461, 2013
download: 166
A Dual-Band RF Energy Harvesting Using Frequency Limited Dual-Band Impedance Matching
Phirun Kim Girdhari Chaudhary Yongchae Jeong
In this paper, a novel dual-band RF-harvesting RF-DC converter with a frequency limited impedance matching network (M/N) is proposed. The proposed RF-DC converter consists of a dual-band impedance matching network, a rectifier circuit with a villard structure, a wideband harmonic suppression low-pass filter (LPF), and a termination load. The proposed dual-band M/N can match two receiving band signals and suppress the out-of-band signals effectively, so the back-scattered nonlinear frequency components from the nonlinear rectifying diodes to the antenna can be blocked. The fabricated circuit provides the maximum RF-DC conversion efficiency of 73.76% and output voltage of 7.09 V at 881 MHz and 69.05% with 6.86 V at 2.4 GHz with an individual input signal power of 22 dBm. Moreover, the conversion efficiency of 77.13% and output voltage of 7.25 V are obtained when two RF waves with input dual-band signal power of 22 dBm are fed simultaneously.
A DUAL-BAND RF ENERGY HARVESTING USING FREQUENCY LIMITED DUAL-BAND IMPEDANCE MATCHING