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Showing papers in "IEEE Antennas and Wireless Propagation Letters in 2007"


Journal ArticleDOI
TL;DR: In this paper, a novel printed monopole antenna with dual wideband is presented for simultaneously satisfying wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications.
Abstract: A novel printed monopole antenna with dual widebands is presented for simultaneously satisfying wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna structure consists of a rectangular monopole with a microstrip feedline for excitation and a trapezoid conductor-backed plane for band broadening. The measured 10 dB bandwidth for return loss is from 2.01 to 4.27 GHz and 5.06 to 6.79 GHz, covering all the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands

289 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of spatial and pattern diversity on MIMO arrays was analyzed by analyzing the mutual coupling, correlation coefficient, and total active reflection coefficient of multiple-input multiple-output (MIMO) arrays.
Abstract: This paper presents the evaluation of multiple-input-multiple-output (MIMO) arrays by analyzing the mutual coupling, correlation coefficient, and total active reflection coefficient. The meaning and analysis of the three parameters are demonstrated in this paper. We show the effect of spatial and pattern diversity on MIMO arrays. We also attempt to achieve optimization of the array antenna's allocation for wireless broadband MIMO applications by performance evaluation

224 citations


Journal ArticleDOI
TL;DR: In this paper, an aperture-coupled patch antenna (ACPA) was proposed for wearable textile systems. But the antenna was not made out of textile material and it was not integrated into garments.
Abstract: The emergence of wearable textile systems in recent years exhibited the need for wireless communication tools integratable into garments. In literature, several planar antenna designs based on textile materials have been presented, however, without an adapted feeding structure for wearable applications. An aperture-coupled patch antenna (ACPA) meets this requirement since the rigid coaxial feed is replaced by a microstrip feed line that couples its power into the antenna through an aperture in the ground plane. This letter presents the first ACPA entirely made out of textile material. The result is a highly efficient, fully flexible, and wearable antenna that is integratable into garments.

198 citations


Journal ArticleDOI
TL;DR: In this article, a two-element time-modulated array system which can be configured to provide active electronic null scanning is presented, where the received signal from each element of the array is time switched and combined to provide a phase modulated output in which the depth of modulation is dependent on the angle of arrival of received signal.
Abstract: A two-element time-modulated array system which can be configured to provide active electronic null scanning is presented. The received signal from each element of the array is time switched and combined to provide a phase-modulated output in which the depth of modulation is dependent on the angle of arrival of the received signal. The angular response of the array at the first harmonic of the switching frequency exhibits a deep null which can be scanned in angle to plusmn90deg by controlling the mark-space ratio of the element switching waveform

196 citations


Journal ArticleDOI
TL;DR: In this paper, a two-dimensional (2D) periodic array of double-square loops printed on a dielectric substrate is used to absorb the incident electromagnetic wave, which can reduce a conducting plate's RCS greatly over a wide frequency range.
Abstract: This letter presents a design of thin and broadband absorbers using a two-dimensional (2-D) periodic array of double-square loops printed on a dielectric substrate. Lumped resistors are inserted into the four sides of the loops to absorb the incident electromagnetic wave. Simulated and measured results for the radar cross-section (RCS) of a finite 2-D array of double-square loops are in good agreement and both show that the novel absorber can reduce a conducting plate's RCS greatly over a wide frequency range.

189 citations


Journal ArticleDOI
TL;DR: In this paper, a coplanar waveguide fed quasi-Yagi antenna with broad bandwidth is presented, where the antenna is realized on a high dielectric constant substrate and compatible with microstrip circuitry and active devices.
Abstract: In this letter, we present a novel coplanar waveguide fed quasi-Yagi antenna with broad bandwidth. The uniqueness of this design is due to its simple feed selection and despite this, its achievable bandwidth. The 10 dB return loss bandwidth of the antenna is 44% covering X-band. The antenna is realized on a high dielectric constant substrate and is compatible with microstrip circuitry and active devices. The gain of the antenna is 7.4 dBi, the front-to-back ratio is 15 dB and the nominal efficiency of the radiator is 95%.

165 citations


Journal ArticleDOI
TL;DR: In this article, a slot-loaded Yagi patch antenna with dual-band and pattern reconfigurable characteristics is presented, where the beam can scan in the E-plane by switching the modes of the antenna by changing the states of the switches installed in the slots etched on the parasitic patches.
Abstract: This letter presents a slot-loaded Yagi patch antenna with dual-band and pattern reconfigurable characteristics. The beam can scan in the E-plane by switching the modes of the antenna, which is implemented by changing the states of the switches installed in the slots etched on the parasitic patches. Different modes of the antenna have different radiation patterns and operating frequency bands. There are three modes having a common band of 9.15-9.45 GHz and their beams direct to -7deg, +33.5deg, and -40deg in the E-plane. Two among three modes also have another common frequency band around 10.3 GHz and the main beams direct to +58.5deg and -62.5deg, respectively. The third mode also has another frequency band around 10.85 GHz and has a dual-beam pattern. Simulated and measured results are given and they agree well with each other. The antenna can be used in radar, satellite communications, etc

159 citations


Journal ArticleDOI
TL;DR: In this paper, a simple technique is developed to improve the axial ratio (AR)-bandwidth and quality of circularly polarized stacked microstrip antennas (CPSMAs) using a new C-type single feed.
Abstract: A simple technique is developed to improve the axial ratio (AR)-bandwidth and quality of circularly polarized stacked microstrip antennas (CPSMAs) using a new C-type single feed. The proposed antenna has been optimized and fabricated, and the computed results agree very well with measurements. The antenna has a 3 dB AR bandwidth of 13.5%, gain is more than 7.5 dBi over the 3 dB AR bandwidth and the 10 dB return-loss bandwidth is 21%. The proposed feed optimization technique is useful for rapid design of circular polarized stacked microstrip antennas.

140 citations


Journal ArticleDOI
TL;DR: In this article, a planar antenna for ultrawideband (UWB) applications with a bandwidth of 5.5 GHz over 3.7 to 9.2 GHz and return loss values lower than -10 dB is presented.
Abstract: This letter presents the design of a planar antenna for ultrawideband (UWB) applications with a bandwidth of 5.5 GHz over 3.7 to 9.2 GHz and return loss values lower than -10 dB. The antenna geometry is described in terms of a spline-based representation whose control parameters, together with other geometrical descriptive quantities, are determined through a suitable particle swarm optimizer (PSO) in order to fit the UWB requirements. Representative results of both numerical and experimental validations are reported in order to assess the performance of the prototype as well as to give some preliminary indications on the reliability and effectiveness of the whole synthesis approach

138 citations


Journal ArticleDOI
TL;DR: In this paper, a reconfigurable microstrip antenna with switchable circular polarization using a piezoelectric transducer (PET) is presented, where two dielectric perturbers attached to the PETs are used to create perturbations for the desired circular polarizations.
Abstract: This letter presents a novel reconfigurable microstrip antenna with switchable circular polarization using a piezoelectric transducer (PET). Two dielectric perturbers attached to the PETs are used to create perturbations for the desired circular polarizations. Right-hand circular polarization (RHCP) or left-hand circular polarization (LHCP) can be produced by pulling down one of the PETs and lifting up the other one. The full-wave simulation and measured results show good agreement. An axial ratio of less than 1 dB is observed

137 citations


Journal ArticleDOI
TL;DR: In this paper, two designs for three-port orthogonally polarized antennas using dipole antennas and half-slot antennas are proposed, which achieve good isolation and low antenna signal correlation between ports.
Abstract: Two designs for three-port orthogonally polarized antennas using dipole antennas and half-slot antennas are proposed in this letter. Each of the antennas constitutes three mutually perpendicular radiating elements to achieve good isolation and low antenna signal correlation between ports. The antennas are fabricated on FR4 epoxy boards and experimental results are provided. Experimental results show that the antennas resonate at 2.55 GHz and have a mutual coupling of less than -18 dB between elements. In addition, experimental results for the diversity performance and the multiple-input-multiple-output (MIMO) channel capacity are also provided for these antennas and these show that the proposed antennas offer good diversity gain and the channel capacity can be increased by as much as three times by using these antennas.

Journal ArticleDOI
TL;DR: In this article, a miniaturized crescent-shape microstrip antenna is proposed for ultrawideband (3-10 GHz) applications, which is evolved from an elliptical patch antenna by carving a circular hole inside symmetrically.
Abstract: A miniaturized crescent-shape microstrip antenna is proposed for ultrawideband (3-10 GHz) applications. The crescent antenna is evolved from an elliptical patch antenna by carving a circular hole inside symmetrically. The circular aperture introduces an additional antenna in-band resonance and provides wider bandwidth with more design flexibility. The radiation characteristics of this crescent antenna are investigated with full-wave electromagnetic simulations and compared with an elliptical antenna. A crescent antenna prototype that occupies only 60% area of the elliptical patch is fabricated and tested. Antenna pattern and impedance measurements show good performance over the 3-10 GHz band with consistent radiation patterns, low cross polarization, and a substantial gain. The design method is also described

Journal ArticleDOI
TL;DR: A novel automatic pairing scheme for estimating 2-D angle by simultaneous singular value decomposition (SVD) of two cross-correlation matrices of two uniform linear arrays to achieve automatic pairing.
Abstract: Recently, Kikuchi et al. proposed a pair-matching method for two-dimensional (2-D) angle estimation using a cross-correlation matrix. Unlike some classical pair matching methods which require a complex process, Kikuchi's method utilizes the corresponding combinations of the elevation and azimuth angles emerging in the cross-correlation matrix of two uniform linear arrays (ULAs) to achieve automatic pairing. However, Kikuchi's method has some drawbacks such as the pair matching and failure problems when the difference of the corresponding combinations of the 2-D angles {costhetask - cosPhik } k =1 K is small and the signal-to-noise ratio (SNR) is low. Furthermore, this method does not make good use of the cross correlation, where the effect of additive noise is eliminated, to improve the estimation performance. We propose a novel automatic pairing scheme for estimating 2-D angle by simultaneous singular value decomposition (SVD) of two cross-correlation matrices. Computer simulation results are presented to show that the proposed technique can overcome these problems and offer better estimation performance.

Journal ArticleDOI
TL;DR: The obtained architecture is based on a parasitic structure composed by a set of microstrip elements that can be electronically reconfigured by means of radiofrequency (RF) switches, which allows an optimal management of wireless resources.
Abstract: This letter presents the result of the synthesis of a horizontally polarized reconfigurable microstrip antenna. The obtained architecture is based on a parasitic structure composed by a set of microstrip elements that can be electronically reconfigured by means of radiofrequency (RF) switches. As a result, the maximum values and zeros of the antenna radiation pattern can be steered towards an interfering signal or/and desired signals, which allows an optimal management of wireless resources. Representative numerical and experimental results are reported and compared in order to assess the effectiveness and reliability of the proposed prototype.

Journal ArticleDOI
TL;DR: In this article, the finite-difference time-domain (FDTD) method using Berenger's perfectly matched layer absorbing boundary condition (PML-ABC) is employed for simulation and the measurement is carried out in indoor environment.
Abstract: Backscattering of ultrawideband (UWB) antennas is theoretically and experimentally studied in this letter. The finite-difference time-domain (FDTD) method using Berenger's perfectly matched layer absorbing boundary condition (PML-ABC) is employed for simulation and the measurement is carried out in indoor environment. Monostatic radar cross section (RCS) of square-slot antenna and printed circular-disc monopole antenna (PCDMA) terminated with three different kinds of loads are numerically calculated and experimentally verified. They are in good agreement in the frequency range from 3 to 11 GHz. Afterwards, scattering characteristics of the structural and antenna modes of two kinds of UWB antenna structures are extensively characterized in both the frequency domain and time domain

Journal ArticleDOI
TL;DR: In this article, a step-impedance dipole antenna is used to receive the microwave power for a rectenna with a maximum conversion efficiency of 76% at 5.8 GHz with a load resistance of 250 Omega.
Abstract: This letter describes a compact 5.8-GHz rectenna using a stepped-impedance dipole antenna. In comparison to the conventional uniform half-wavelength dipole antenna, the stepped-impedance dipole antenna shows a 23% length reduction. This stepped-impedance dipole antenna is then used to receive the microwave power for a rectenna. The rectenna shows a maximum conversion efficiency of 76% at 5.8 GHz with a load resistance of 250 Omega. Furthermore, the conversion efficiency is better than 67% from 5.725 to 5.875 GHz, which covers the entire 5.8-GHz ISM band.

Journal ArticleDOI
Keum Cheol Hwang1
TL;DR: In this paper, a broadband planar Sierpinski fractal antenna for multiband application is proposed, designed, and tested using perturbation of the perturbed fractal patch and slotted ground plane to achieve broadband characteristics.
Abstract: A broadband planar Sierpinski fractal antenna for multiband application is proposed, designed, and tested. The perturbed Sierpinski fractal patch and slotted ground plane are employed to achieve broadband characteristics. The implemented antenna including the ground plane has a total dimension of 100 times 53.7 times 0.8 mm3. The measured 10-dB return loss bandwidths are 808-1008 MHz (22%) and 1581-2760 MHz (54.3%), which cover the GSM/DCS/PCS/IMT-2000/ISM/satellite DMB bands. The measured return loss, radiation patterns, and gain of the proposed antenna are presented and compared with simulated results.

Journal ArticleDOI
TL;DR: The statistical characterization and modeling of the indoor radio channel for a mobile wireless personal area network operating at 868 MHz found the Nakagami-m cdf beast described fading for bodyworn operation in 60% of all measured channels in anechoic chamber and open office area environments.
Abstract: This letter reports the statistical characterization and modeling of the indoor radio channel for a mobile wireless personal area network operating at 868 MHz. Line of sight (LOS) and non-LOS conditions were considered for three environments: anechoic chamber, open office area, and hallway. Overall, the Nakagami-m cdf beast described fading for bodyworn operation in 60% of all measured channels in anechoic chamber and open office area environments. The Nakagami distribution was also found to provide a good description of Rician distributed channels which predominated in the hallway. Multipath played an important role in channel statistics with the mean recorded m value being reduced from 7.8 in the anechoic chamber to 1.3 in both the open office area and hallway

Journal ArticleDOI
TL;DR: An experimental demonstration and analysis of a dual-state switchable magnetic metamaterial element in which the resonance excitation of the particle is controlled using an RF microelectromechanical (MEMS) switch is presented in this article.
Abstract: An experimental demonstration and analysis of a dual-state switchable magnetic metamaterial element in which the resonance excitation of the particle is controlled using an RF microelectromechanical (MEMS) switch is presented. By controlling the resonant properties of the individual ring, unit cells composed of such elements can be used to realize an effective dual-state switchable medium. Transmission and loss characteristics of the switchable element for two different switch topologies are compared. Experimental data shows that the MEMS switch allows for a switchable resonant particle with reasonably low losses.

Journal ArticleDOI
TL;DR: In this paper, a dual-polarized shorted bowtie antenna integrated with a cross dipole is presented to generate a symmetric radiation pattern and compensate the high back radiation due to the shorted patches.
Abstract: A dual-polarized shorted bowtie antenna integrated with a cross dipole is presented. The electric cross dipole is added to generate a symmetric radiation pattern and to compensate the high back radiation due to the shorted patches. This novel dual-polarized antenna is designed for the existing DCS, PCS, and 3G mobile communication systems working between 1.71 and 2.17 GHz. Stable and symmetric radiation patterns at slanted plusmn45deg polarization have been obtained over the operating frequency bands. Measured isolation between the two input ports is over 28 dB. The gain of the proposed antenna is also stable with frequency. The average is about 6.6 dBi

Journal ArticleDOI
TL;DR: In this paper, a wideband dual-polarized slot-coupled stacked patch antenna operating in the UMTS (1920-2170 MHz), WLAN (2.4-2.484 GHz), and UMTS II (2500-2690 MHz) frequency bands is described.
Abstract: A wideband dual-polarized slot-coupled stacked patch antenna operating in the UMTS (1920-2170 MHz), WLAN (2.4-2.484 GHz), and UMTS II (2500-2690 MHz) frequency bands is described. Measurements on a prototype of the proposed patch antenna confirm good performance in terms of both impedance matching and isolation

Journal ArticleDOI
TL;DR: In this article, a 3D fully integrated filter and antenna function is proposed as a system-on-package (SOP) compact front-end solution for the low-temperature co-fired ceramic (LTCC) based V-band modules.
Abstract: A novel topology implementing a 3-D fully integrated filter and antenna function is proposed as a system-on-package (SOP) compact front-end solution for the low-temperature cofired ceramic (LTCC) based V-band modules. A 4-pole quasi-elliptic bandpass filter composed of four open loop resonators has been developed. It exhibits an insertion loss 15 dB over the pass band (~3.4 GHz) and a 3 dB bandwidth of about 5.46% (~3.4 GHz) at the center frequency of 62.3 GHz. In addition, a series fed 1 4 linear antenna array of four microstrip patches exhibiting high gain and fan-beam radiation pattern has been designed. Its 10 dB bandwidth is experimentally validated to be 55.4-66.8 GHz (~18.5%). The above proposed designs have been combined together, leading to the complete integration of passives with a high level of selectivity over the band of interest. The excellent overall performance of the integrated solution is verified through a 10-dB bandwidth of 4.8 GHz (59.2-64 GHz) and a return loss >10.5 dB over the passband.

Journal ArticleDOI
TL;DR: In this paper, a large amount of data has been gathered in practical environments, for realistic activities, and has been subject to statistical analysis, showing that significant variations of the path gain and fading can occur due to the movements of body.
Abstract: The fading of an on-body transmission channel at 2.45 GHz is investigated. For the first time a large amount of data has been gathered in practical environments, for realistic activities, and has been subject to statistical analysis. It is clear that significant variations of the path gain and fading can occur due to the movements of body. Extensive statistical analysis has shown that fading in on-body channels is a non stationary process. This letter presents results of a number of significant statistical parameters, including level crossing rate and average fade duration.

Journal ArticleDOI
TL;DR: In this article, a 50-MHz DRA that uses water as the dielectric was presented, and an electronic technique for retuning the feed probe is also presented where varactor diodes are biased to provide a good impedance match across a range of approximately 50 to 100 MHz.
Abstract: Dielectric resonator antennas (DRAs) have in the past been used most often at frequencies in the GHz portion of the spectra. This letter presents a novel 50-MHz DRA that uses water as the dielectric. For purposes of keeping the antenna tuned to a specific frequency, ande for using the antenna at different frequencies, this antenna can utilize a pump to alter the level of water in the DRA, thus, altering its resonant frequency. An electronic technique for retuning the feed probe is also presented where varactor diodes are biased to provide a good impedance match across a range of approximately 50 to 100 MHz. These antennas may provide a compact solution at lower frequencies especially where a directional pattern may be required. The liquid dielectric not only provides frequency tuning but simple deployment and a reducible radar cross section.

Journal ArticleDOI
TL;DR: A graphical method based on Green's analysis of scattering antennas to optimize the load impedances for achieving maximum modulated radar cross-section (RCS) of backscattering radio-frequency identification (RFID) tags is presented.
Abstract: In this letter, we present a graphical method based on Green's analysis of scattering antennas to optimize the load impedances for achieving maximum modulated radar cross-section (RCS) of backscattering radio-frequency identification (RFID) tags. A planar tag antenna specifically designed for working in the ultra-high-frequency band is used to experimentally validate the method. The measured RCS of the loaded tag antenna shows acceptable agreement with the theory and simulated results. This method is especially valuable to the design of semipassive RFID tags when the communication range is solely determined by the backscattering modulation efficiency of tags.

Journal ArticleDOI
TL;DR: In this article, the Koch iteration technique has been applied to obtain two fractal versions of a folded-slot antenna, the first iteration and the second iteration of a Koch folded slot antenna were designed, fabricated and characterized on a 30 mil thick RT/Duroid 6002 substrate.
Abstract: In this letter, the Koch iteration technique has been applied to obtain two fractal versions of a folded-slot antenna. A simple folded-slot antenna, first iteration and second iteration versions of a Koch folded-slot antenna were designed, fabricated and characterized on a 30 mil thick RT/Duroid 6002 substrate. The simple folded-slot antenna provides a return loss of 40 dB at the operating frequency of 10.45 GHz and the bandwidth for return loss greater than 10 dB is 1.211 GHz. The return loss of the first iteration of the Koch folded-slot antenna is 34 dB at 8.05 GHz and the bandwidth for 10 dB return loss is 0.4 GHz. The return loss of the second iteration of the Koch folded-slot antenna is 42 dB at 7.9 GHz and the bandwidth for 10 dB return loss is 0.34 GHz

Journal ArticleDOI
TL;DR: In this article, the behavior of a matched electrically small antenna that exhibits two impedance resonances within its defined voltage standing wave ratio (VSWR) bandwidth was examined, and the exact quality factor (Q), computed indirectly from the antenna's input reactance and far field, was compared to twice the inverse of the matched half-power VSWR bandwidth.
Abstract: We examine the behavior of a matched electrically small antenna that exhibits two impedance resonances within its defined voltage standing wave ratio (VSWR) bandwidth. The exact quality factor (Q), computed indirectly from the antenna's input reactance and far field, is compared to twice the inverse of the matched half-power VSWR bandwidth (Q BW) and to an approximate quality factor (Qz) determined from the frequency derivative of the antenna's input impedance. The well-established approximate equalities Q ap Q BW ap Q z for antennas exhibiting an isolated single impedance resonance within their operating band are shown to become highly inaccurate for an electrically small antenna exhibiting two closely spaced impedance resonances.

Journal ArticleDOI
TL;DR: In this article, a planar antenna consisting of an S-strip and a T-strip which are separately printed on the two sides of a thin substrate is developed for global positioning system (GPS), DCS-1800, IMT-2000, and WLAN handsets.
Abstract: A compact broadband planar antenna is developed for global positioning system (GPS), DCS-1800, IMT-2000, and WLAN handsets. The planar antenna consists of an S-strip and a T-strip which are separately printed on the two sides of a thin substrate (no via process is involved in the fabrication). The antenna size is only 18 mm$\,\times\,$7.2 mm $\,\times\,$0.254 mm which is more compact than previously published antenna configurations. The bandwidth of the planar antenna is enhanced by the mutual coupling between the S-strip and the T-strip. It has been demonstrated by simulation and experiment that the compact planar antenna can achieve a bandwidth of more than 50% for return loss $

Journal ArticleDOI
TL;DR: In this paper, a dual-band enhanced-bandwidth microstrip antenna with a frequency separation of f2/f1=1.37 was presented, where a rectangular patch antenna was reactively loaded with a stub placed along one of the radiating edges.
Abstract: A dual-band enhanced-bandwidth microstrip antenna is presented with a frequency separation of f2/f1=1.37. In order to achieve the dual-frequency operation, a rectangular patch antenna is reactively loaded with a stub placed along one of the radiating edges. Then, the bandwidth is enhanced using a stacked parasitic technique, whereas the matching and radiation characteristics are kept constant along each band and similar at two bands.

Journal ArticleDOI
TL;DR: In this paper, the design of a new fractal multiband antenna based on the self-affinity property is presented, and the experimental return loss has been compared with that obtained using the method of moments and the fractal antenna is found to possess predictable multiband characteristics.
Abstract: The design of a new fractal multiband antenna based on the self-affinity property is presented in this letter. Experimental return loss has been compared with that obtained using the method of moments and the fractal antenna is found to possess predictable multiband characteristics