Showing papers on "Slot antenna published in 2003"
TL;DR: In this paper, the effect of antenna shape, length, and sharpness upon the intensity of the optical fields produced by the antenna arrays was investigated. And the FDTD calculated and experimentally measured extinction efficiencies of the antennas were found to be in good agreement.
Abstract: Electromagnetic field enhancement in optical antenna arrays is studied by simulation and experiment at midinfrared wavelengths. The optical antennas are designed to produce intense optical fields confined to subwavelength spatial dimensions when illuminated at the resonant wavelength. Finite difference time domain (FDTD) method simulations are made of the current, charge, and field distributions in the antennas. The influence of antenna shape, length, and sharpness upon the intensity of the optical fields produced is found. Optical antennas arrays are fabricated on transparent substrates by electron beam lithography. Far-field extinction spectroscopy carried out on the antenna arrays shows the dependence of the resonant wavelength on the antenna length and material. The FDTD calculated and experimentally measured extinction efficiencies of the optical antennas are found to be in good agreement.
451 citations
TL;DR: By using a coplanar waveguide (CPW) feed with a widened tuning stub, a square slot antenna for broadband operation is presented in this paper, where the authors show that the impedance matching for the proposed antenna strongly depends on the location of the tuning stub in the square slot, and the impedance bandwidth is mainly determined by the width and length of the tuned stub.
Abstract: By using a coplanar waveguide (CPW) feed with a widened tuning stub, a square slot antenna for broadband operation is presented. Experimental results show that the impedance matching for the proposed antenna strongly depends on the location of the tuning stub in the square slot, and the impedance bandwidth is mainly determined by the width and length of the tuning stub. By properly choosing the location and the size of the tuning stub, a wide impedance bandwidth of 60% can be obtained, which is about 1.9 times that of a conventional CPW-fed square slot antenna with a simple tuning stub. Details of the experimental results are presented and discussed.
394 citations
TL;DR: In this paper, the authors developed principle design procedures for a single-layer coaxially fed rectangular microstrip patch antenna through examination of the structure's multiple resonant frequencies as well as the radiation and impedance properties of different antenna geometries.
Abstract: A wide operating bandwidth for a single-layer coaxially fed rectangular microstrip patch antenna can be obtained by cutting a U-shaped slot on the patch. This antenna structure has recently been found experimentally to provide impedance bandwidths of 10%-40%, even with nonair substrates. However, design rules for this antenna have not yet been presented. This paper develops principle design procedures through examination of the structure's multiple resonant frequencies as well as the radiation and impedance properties of different antenna geometries. The approximate design rules are derived by analysis of former experiments, method of moments (MoM) simulations, and measurement results. Simulations and measurements of several antennas designed using these new rules are presented and directions for further study are discussed.
328 citations
TL;DR: In this paper, a reconfigurable slot antenna architecture allowing polarization switching is presented, which consists of a slot-ring with perturbations which are switched on and off using pin-diodes.
Abstract: A novel reconfigurable slot antenna architecture allowing polarization switching is presented. The antenna shape consists of a slot-ring with perturbations which are switched on and off using pin-diodes. Two antennas allowing switching either between linear and circular polarization or between two circular polarizations are demonstrated. The antenna architecture is interesting for commercial wireless applications because it is compatible with modern fabrication processes and can be realized on low cost dielectric materials.
215 citations
Patent•
24 Apr 2003
TL;DR: In this paper, a wireless communication device contains at least one conductive tab that provides an antenna, and the tab(s) form a pole antenna and the tabs may also be attached across a slot to form a slot antenna.
Abstract: The wireless communication device contains at least one conductive tab that provides an antenna. The tab(s) form a pole antenna, and the tabs may also be attached across a slot to form a slot antenna. The tab(s) may be attached across a slot created in a package to form a slot antenna, or the tab(s) may be attached to a slot that is created as part of the wireless communication device to form a slot antenna. The tab(s) and/or the slot may also contain an adhesive material to attach the wireless communication device to a package, container or other material. More than one slot may be provided to form a circularly polarized antenna. The carrier may be a conductive material in which tabs are formed as part of the carrier before the wireless communication device is attached. The wireless communication device may have an asymmetrical antenna arrangement.
207 citations
TL;DR: In this paper, the authors proposed a method to reduce the area occupied by the resonant antenna by virtual enforcement of the required boundary condition (BC) at the end of a slot antenna.
Abstract: With the virtual enforcement of the required boundary condition (BC) at the end of a slot antenna, the area occupied by the resonant antenna can be reduced. To achieve the required virtual BC, the two short circuits at the end of the resonant slot are replaced by some reactive BC, including inductive or capacitive loadings. The application of these loads is shown to reduce the size of the resonant slot antenna for a given resonant frequency without imposing any stringent condition on the impedance matching of the antenna. A procedure for designing this class of slot antennas for any arbitrary size is presented. The procedure is based on an equivalent circuit model for the antenna and its feed structure. The corresponding equivalent circuit parameters are extracted using a full-wave forward model in conjunction with a genetic algorithm optimizer. These parameters are employed to find a proper matching network so that a perfect match to a 50 /spl Omega/ line is obtained. For a prototype slot antenna with approximate dimensions of 0.05/spl lambda//sub 0//spl times/0.05/spl lambda//sub 0/ the impedance match is obtained, with a fairly high gain of -3dBi, for a very small ground plane (/spl ap/0.20/spl lambda//sub 0/). Since there are neither polarization nor mismatch losses, the antenna efficiency is limited only by the dielectric and ohmic losses.
204 citations
TL;DR: In this article, the U-slot patch antenna and the L-probe-fed patch antenna were proposed to reduce the resonant length of these wideband microstrip-patch antennas.
Abstract: Several designs for small-size wide-bandwidth microstrip antennas are examined through simulation and experiment. Designs are presented based on two wideband patch antennas: the U-slot patch antenna, and the L-probe-fed patch antenna. Several techniques are utilized to reduce the resonant length of these wideband microstrip-patch antennas: increasing the dielectric constant of the microwave substrate material, the addition of a shorting wall between the conducting patch and the ground plane, and the addition of a shorting pin between the conducting patch and the ground plane. Simulation and experimental results confirm that the size of the antennas can be reduced by as much as 94%, while maintaining impedance bandwidths in excess of 20%.
198 citations
Patent•
24 Apr 2003
TL;DR: In this article, a wireless communication device is coupled to an energy source, such as a battery, capacitor, or solar cell, to form a slot antenna for wireless communication, which receives communication signals from an interrogation reader or other communication device.
Abstract: The invention relates to a wireless communication device that is coupled to an energy source, such as a battery, capacitor, or solar cell. The wireless communication device is coupled to a slot in the energy source to form a slot antenna for wireless communication. The slot antenna receives communication signals from an interrogation reader or other communication device. The wireless communication device may be attached to a device or container for purposes such as communicating information regarding identification, manufacturing, tracking, and the like. The wireless communication device may also be coupled to the energy source for power.
198 citations
TL;DR: In this paper, a coplanar waveguide fed square slot antenna loaded with conducting strips is proposed and experimentally studied, and the obtained results show that the impedance bandwidth, determined by 10-dB return loss, of the proposed slot antenna can be greater than 60%.
Abstract: A novel broadband design of a coplanar waveguide fed square slot antenna loaded with conducting strips is proposed and experimentally studied. The obtained results show that the impedance bandwidth, determined by 10-dB return loss, of the proposed slot antenna can be greater than 60%. The design considerations for achieving broad-band operation of the proposed slot antenna are described, and experimental results are presented.
193 citations
TL;DR: In this paper, a dual-polarized slot-coupled microstrip patch antenna is presented, which can achieve high-isolation, low crosspolarization levels, a wide bandwidth, and low backward radiation levels.
Abstract: A new dual-polarized slot-coupled microstrip patch antenna is presented, which can achieve high-isolation, low cross-polarization levels, a wide bandwidth, and low backward radiation levels. The coupling slot is an H-shaped slot. For wide bandwidth and easy integration with active circuits, it uses slot-coupled stacked microstrip patches. The theoretical analysis is based on the finite-difference time-domain (FDTD) method. First, a parametric study on the input impedance of the antenna with a single input port is presented. Based on the results, a dual-polarized microstrip antenna is designed, fabricated, and then measured. The measured return loss exhibits an impedance bandwidth of over 20.9% and the isolation between two polarization ports is better than 36 dB over the bandwidth. The cross-polarization levels in both E and H planes are better than 22 dB. The front-to-back ratio of the antenna radiation pattern is better than 21 dB. Both theoretical and experimental results of return loss, isolation, and radiation patterns are presented and discussed.
193 citations
TL;DR: In this article, a new design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide (CPW) was proposed and experimentally studied.
Abstract: A new design of a broadband circularly polarized square slot antenna fed by a single coplanar waveguide (CPW) is proposed and experimentally studied. The proposed broadband circular polarization (CP) operation is achieved by protruding a T-shaped metallic strip from the ground plane toward the slot center and feeding the square slot antenna using a 50-/spl Omega/ CPW with a protruded signal strip at 90/spl deg/ to the T-shaped strip. Experimental results of constructed prototypes show that the obtained 3-dB and 1-dB axial-ratio bandwidths can reach as large as 18% and 13%, respectively. The proposed antenna also has a peak antenna gain of about 4 dBi, with gain variations less than 1 dBi for frequencies within the CP bandwidth.
16 Nov 2003
TL;DR: In this paper, a method for creating frequency notches in an otherwise ultra-wideband (UWB) antenna element is described, by deliberately introducing a narrow band resonant structure, an antenna may be made insensitive to particular frequencies.
Abstract: This paper describes a method for creating frequency notches in an otherwise ultra-wideband (UWB) antenna element. By deliberately introducing a narrow band resonant structure, an antenna may be made insensitive to particular frequencies. This technique is useful for creating UWB antennas with narrow frequency notches, or for creating multi-band antennas.
TL;DR: In this article, it is shown that the active element pattern of a phased array, obtained by driving a single radiating element of the array while all other elements are match terminated, can be expressed in terms of the scattering matrix parameters of the arrays.
Abstract: It is well known that the active element pattern of a phased array, obtained by driving a single radiating element of the array while all other elements are match terminated, can be expressed in terms of the scattering matrix parameters of the array. It is shown how this relationship can be inverted so that the scattering parameters for all elements of a phased array can be obtained from the active element patterns of the array. In addition, it is also possible to obtain the active input impedance of any element in the fully excited array, at any scan angle, from active element pattern data. The theory is developed for linear and planar arrays and an example is presented for a linear array of slot antenna elements.
07 Sep 2003
TL;DR: The design and realization of a wide band four-port microstrip matrix to feed a switched-beam antenna array for wireless applications at 1.9 GHz is presented and experimental results is presented.
Abstract: This paper presents the design and realization of a wide band four-port microstrip matrix to feed a switched-beam antenna array for wireless applications at 1.9 GHz. The objective of this investigation is to develop an antenna-array feeding network based on Butler with a large bandwidth in order to cover the PCS band: 1900 MHZ to 2200 MHZ. In order to meet these requirements, wide band microwave components such as hybrids and crossovers were designed and used to Butler proposed matrix. The Butler matrix is used as a beamforming network that allows to produce orthogonal beams that can be steered in different directions. To examine the performance of the proposed matrix, simulated and experimental results is presented and discussed.
TL;DR: How the different shape parameters of the DETSA impact antenna performance is described, including how the outside edge of the slot line conductors adds additional antenna design degrees of freedom.
Abstract: The dual exponentially tapered slot antenna (DETSA) is a low-profile slot line radiator that is a modified form of a Vivaldi radiator. The DETSA is created by taking a Vivaldi radiator and tapering the outside edge of the slot line conductors. The shape of the outside edge of the slot line conductors adds additional antenna design degrees of freedom. This paper describes how the different shape parameters of the DETSA impact antenna performance.
TL;DR: In this article, a radial line slot antenna (RLSA) with two simultaneous beams, one broadside beam and one conical beam, is proposed, with the slots placed on the upper plate in concentric rings.
Abstract: The authors propose the design of one radial line slot antenna with two simultaneous beams, one broadside beam and one conical beam. The antenna is a radial line slot antenna (RLSA), with the slots placed on the upper plate in concentric rings. The radiating element is a slot pair, designed for getting left hand circular polarization. The antenna has been designed to work in the range of 13.4 GHz and 14 GHz. Both beams are obtained independently through very simple excitation circuits, realized with microstrip technology. These feeding networks include a Butler Matrix Network. Comparing both radiation patterns, amplitude and phase, theta and phi angles of arrival direction can be obtained. This monopulse performance can be used to orientate the pencil beam for satellite communication antennas. Measurements for a first prototype are presented to validate the design.
TL;DR: The ability of the bow‐tie slot antenna to generate intense optical spots below the diffraction limit is investigated and the effects of material composition, frequency, and antenna geometry on the near‐field radiation pattern using numerical simulations.
Abstract: We investigate the ability of the bow-tie slot antenna to generate intense optical spots below the diffraction limit A commercially available finite-difference time-domain electromagnetic modelling software is used in the numerical simulations The finite-difference time-domain software is first compared to analytical results at optical frequencies to verify its accuracy We then present numerical simulations for various geometries involving apertures on thin films and the bow-tie antenna The transmission efficiency and optical spot size of the bow-tie antenna are compared with those of rectangular and circular apertures on thin metal films We also investigate the effects of material composition, frequency, and antenna geometry on the near-field radiation pattern using numerical simulations
TL;DR: A new built-in quad-band handset antenna for covering GSM900, DCS1800, PCS1900, and UMTS2000 bands is presented and the simulation is based on the finite-difference time-domain (FDTD) method.
Abstract: A new built-in quad-band handset antenna for covering GSM900, DCS1800, PCS1900, and UMTS2000 bands is presented. Details of the antenna are discussed along with measured and simulated results. The simulation is based on the finite-difference time-domain (FDTD) method.
TL;DR: In this article, a compact internal quad-band handset antenna for covering GSM900, DCS1800, PCS1900, and ISM2450 bands is presented, along with measured and simulated results.
Abstract: A novel compact internal quad-band handset antenna for covering GSM900, DCS1800, PCS1900, and ISM2450 bands is presented. Details of the antenna are discussed along with measured and simulated results. The simulation is based on the FDTD method. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 217–223, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11019
TL;DR: In this article, a broadband microstrip-fed slot antenna with double rejection zero was proposed and developed by constructing simultaneously a wide-slot radiator and a quarter-wavelength microstrip line resonator.
Abstract: A novel broadband microstrip-fed slot antenna with double rejection zeros is proposed and developed by constructing simultaneously a wide-slot radiator and a quarter-wavelength microstrip line resonator. A comprehensive explanation of its operating principle is given by using an equivalent two-pole filtering network, in which the radiation resistance is perceived as the output impedance. Extensive numerical results are then obtained using a commercial electromagnetic simulator to demonstrate its attractive broadband feature. Finally, a few antenna samples are designed, fabricated, and measured to verify the predicted performance. Experimental results exhibit that the bandwidth of this proposed antenna configuration is significantly increased, by up to 32.0%, as compared to 9.0% for its traditional counterpart.
TL;DR: In this paper, a dual-band planar-slot antenna that operates through a single coplanar waveguide (CPW) port in two 10% wide-frequency bands, one octave apart, is presented.
Abstract: A dual-band planar-slot antenna that operates through a single coplanar waveguide (CPW) port in two 10% wide-frequency bands, one octave apart is presented. An input T-match circuit is used to match the antenna in both bands, without increasing its size and keeping the CPW feed advantages. A case antenna covering the two Global System for Mobile communications bands (0.88-0.96 GHz and 1.71-1.88 GHz) and the Digital Enhanced Cordless Telecommunications band (1.88-1.9 GHz) has been designed, built, and measured, to demonstrate the technique. A proprietary program, based on the method of moments, has been used to analyze and optimize the antenna.
TL;DR: In this article, a novel hybrid technology where amorphous silicon (a-Si:H) solar cells are either integrated or physically combined with printed slot antennas is presented, which offers advantages in terms of surface coverage, volume, weight and electric performance when compared with a simple juxtaposition of antennas and solar cells.
Abstract: A novel hybrid technology where amorphous silicon (a-Si:H) solar cells are either integrated or physically combined with printed slot antennas is presented. This basic idea is demonstrated with the help of two innovative designs where the solar cells are directly grown on a stainless steel ground-plane or glued onto a standard copper layer printed on a dielectric substrate. To show the compatibility of solar cells and antennas, the concept is used to create a linearly polarized slot antenna, a circularly polarized slot antenna and a slot array. The concept offers advantages in terms of surface coverage, volume, weight and electric performance when compared with a simple juxtaposition of antennas and solar cells.
TL;DR: In this paper, a planar antenna with a resonant narrow slot antenna was designed and tested for a small area as small as 0.12/spl lambda/sub 0/spl times/0.5 dBi on FR4 substrate, which has a losstangent of the order of 0.01.
Abstract: The design aspects and the measured results of a novel miniaturized planar antenna are described. Such architectural antenna design is of great importance in mobile military communications where low visibility and high mobility are required. Slot radiating elements, having a planar geometry and capable of transmitting vertical polarization when placed nearly horizontal, are appropriate for the applications at hand. Slot antennas also have another useful property, so far as impedance matching is concerned. Basically, slot dipoles can easily be excited by a microstrip line and can be matched to arbitrary line impedances simply by moving the feed point along the slot. Antenna miniaturization can be achieved by using a high permittivity or permeability substrate and superstrate materials and/or using an appropriate antenna topology. We demonstrate miniaturization by designing an appropriate geometry for a resonant narrow slot antenna. A very efficient radiating element that occupies an area as small as 0.12/spl lambda//sub 0//spl times/0.12/spl lambda//sub 0/ is designed and tested. Simulation results, as well as the measured input impedance and radiation patterns of this antenna, are presented. This structure shows a measured gain of 0.5 dBi on FR4 substrate, which has a loss-tangent of the order of 0.01. Also, the effect of finite ground plane size on gain and resonant frequency is investigated experimentally.
Patent•
31 Dec 2003
TL;DR: In this paper, a slot is included in the skin of a computing device to form a slot antenna, which can support multiple frequency bands with a single slot and provide directional propagation patterns.
Abstract: The skin of a computing device comprises a conductive material. A slot is included in the skin to form a slot antenna. Various embodiments of the slot antenna can support multiple frequency bands with a single slot and provide directional propagation patterns.
TL;DR: In this article, the authors proposed a tapered slot antenna (TSA) profile and geometry, which is achieved through its modeling by a stepline terminated in free space intrinsic impedance, and the impedance matching of the TSA input impedance to the generator impedance is achieved by minimizing an error criterion constructed as the magnitude squared of the difference between the generator and input impedance over the desired bandwidth.
Abstract: The optimum design of the tapered slot antenna (TSA) profile and geometry is achieved through its modeling by a stepline terminated in free space intrinsic impedance. The impedance matching of the TSA input impedance (obtained by the transmission matrix properties) to the generator impedance is achieved by minimizing an error criterion constructed as the magnitude squared of the difference between the generator and input impedances over the desired bandwidth. The attenuation constant of the stepline is computed by the broadside radiation of TSA (which is an endfire antenna) and the longitudinal power flow. The spectral domain immitance approach is used to compute the broadside radiation, by first determining the electric field components in the slot by the Galerkin's method and then obtaining the equivalent magnetic surface current densities. The power flow in the endfire direction of TSA may be computed by the Poynting's vector in the substrate. The attenuation constant is calculated for various values of slot width. Finally, the minimization procedure gives the slotline widths and lengths.
TL;DR: In this paper, a single-layer capacitive feeding mechanism, consisting of a small rectangular probe-fed patch, which is capacitively coupled to the radiating element, was used to obtain wideband operation for microstrip antennas on thick substrates.
Abstract: In this paper, it is shown how a single-layer capacitive feeding mechanism, consisting of a small rectangular probe-fed patch, which is capacitively coupled to the radiating element, can be used to obtain wideband operation for probe-fed microstrip antennas on thick substrates. The main advantages of this feeding mechanism are that all the elements reside on a single layer and that it is very easy to fine-tune the input impedance. Calculated as well as measured results for rectangular, circular and annular-ring geometries are included.
TL;DR: In this paper, the authors proposed an antenna with cross-shaped or square-shaped lattices for harmonic suppression, which not only exhibited well-behaved bandstop characteristics, but also enhanced the bandwidth of the proposed antennas.
Abstract: Photonic bandgap (PBG) structures with cross-shaped or square-shaped lattices have been incorporated into the antenna feed network for harmonic suppression. Experimental results show that PBG structures not only exhibit well-behaved bandstop characteristics, but also enhance the bandwidth of the proposed antennas. For the proposed antenna with square-shaped lattices, the 10 dB return loss bandwidth could reach 1541 MHz (1525-3066 MHz), which is about 70% with respect to the center frequency of 2200 MHz; for the antenna with cross-shaped lattices, the bandwidth could reach 1320 MHz (1560-2880 MHz), which is about 60% with respect to the center frequency of 2200 MHz.
TL;DR: In this paper, a half-sized U-slot quarter-wave antenna with half the area was proposed and similar performance was maintained such as a broad bandwidth of 28% (SWR < 2), stable far-field radiation patterns and gain.
Abstract: A half-sized U-slot quarter-wave patch antenna is presented. Employing the same parameters as the U-slot quarter-wave patch except with half the area, similar performances are maintained such as a broad bandwidth of 28% (SWR<2), stable far-field radiation patterns and gain. Both measured and simulation results are presented.
05 May 2003
TL;DR: An overview of the DRA is presented to show some of their characteristics, such as geometry, matching bandwidth, radiation patterns, etc. In as mentioned in this paper, the authors highlight the advantages of using DRA in the radar system.
Abstract: Dielectric resonator antennas (DRA) are newly developed antennas that are wideband, small size and have high radiation efficiency. An overview of the DRA is presented to show some of their characteristics, such as geometry, matching bandwidth, radiation patterns, etc. Radiation patterns for some arrays are presented for a linearly polarized linear phased array. The circularly polarized DRA in the array environment is discussed. Advantages of using DRA in the radar system are highlighted indicating that the DRA is an appropriate candidate for radar applications mainly because of high efficiency and wideband performance.
TL;DR: Two different ultra-broadband antenna designs for mobile communications and navigation, which can be integrated conformally into the bodywork of a car are presented, which enables the excitation of two different radiation patterns for terrestrial and satellite services.
Abstract: This paper presents two different ultra-broadband antenna designs for mobile communications and navigation, which can be integrated conformally into the bodywork of a car. Both antennas are based on the frequency-independent spiral structure. One antenna, which is intended to be integrated into the car's window, is an externally fed spiral antenna in order to obtain a flat structure. The second spiral antenna consists of four arms which are fed by a coplanar waveguide transmission line. This enables the excitation of two different radiation patterns for terrestrial and satellite services. With a low cost feed network both radiation modes can be excited simultaneously and independently of each other. Measurement results are presented within and beyond the specifications.