Showing papers on "Coaxial antenna published in 2004"
TL;DR: The planar inverted cone antenna (PICA) as mentioned in this paper provides ultrawideband (UWB) performance with a radiation pattern similar to monopole disk antennas, but is smaller in size.
Abstract: A new antenna, the planar inverted cone antenna (PICA), provides ultrawideband (UWB) performance with a radiation pattern similar to monopole disk antennas , but is smaller in size. Extensive simulations and experiments demonstrate that the PICA antenna provides more than a 10:1 impedance bandwidth (for VSWR<2) and supports a monopole type omnidirectional pattern over 4:1 bandwidth. A second version of the PICA with two circular holes changes the current flow on the metal disk and extends the high end of the operating frequency range, improving the pattern bandwidth to 7:1.
319 citations
TL;DR: In this paper, a printed circular disc monopole antenna for ultra-wideband applications is presented, and the parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.
Abstract: A novel and simple design of a printed circular disc monopole antenna for ultra-wideband applications is presented. The parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.
314 citations
TL;DR: In this article, a new ultra-wideband (UWB) antenna for UWB applications is proposed, which is designed to operate from 3.2 to 12 GHz and consists of a rectangular patch with two steps, a single slot on the patch, and a partial ground plane.
Abstract: In this paper, we propose a new ultra-wideband (UWB) antenna for UWB applications. The proposed antenna is designed to operate from 3.2 to 12 GHz. It consists of a rectangular patch with two steps, a single slot on the patch, and a partial ground plane. Details of the proposed antenna design and measured results are presented and discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 399–401, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11392
304 citations
TL;DR: In this article, the authors present optical measurements of random arrays of aligned carbon nanotubes and show that the response is consistent with conventional radio antenna theory, and demonstrate the polarization effect, the suppression of reflected signal when the electric field of the incoming radiation is polarized perpendicular to the nanotube axis.
Abstract: We present optical measurements of random arrays of aligned carbon nanotubes, and show that the response is consistent with conventional radio antenna theory. We first demonstrate the polarization effect, the suppression of the reflected signal when the electric field of the incoming radiation is polarized perpendicular to the nanotube axis. Next, we observe the interference colors of the reflected light from an array, and show that they result from the length matching antenna effect. This antenna effect could be used in a variety of optoelectronic devices, including THz and IR detectors.
266 citations
TL;DR: In this paper, a dual-polarized L-probe patch antenna is proposed to achieve high isolation between two input ports, achieving an impedance bandwidth of 23.8% and an isolation over 30 dB.
Abstract: An experimental study of a dual-polarized L-probe patch antenna is presented. The antenna is designed to operate at around 1.8 GHz. A "dual-feed" technique is introduced to achieve high isolation between two input ports. The proposed antenna has an impedance bandwidth of 23.8% (SWR/spl les/2), 15% (SWR/spl les/1.5) and an isolation over 30 dB. In array designs, techniques for improving the isolation between two adjacent elements of an antenna array are also investigated. A two-element array with more than 30 dB isolation is designed and tested.
263 citations
Patent•
09 Dec 2004
TL;DR: An adjustable multi-band planar antenna especially applicable in mobile terminals has been proposed in this paper, where a conductive element is placed in the structure of an antenna of PIFA type such that the conductive elements has a significant electromagnetic coupling to the radiating plane.
Abstract: An adjustable multi-band planar antenna especially applicable in mobile terminals. A conductive element is placed in the structure of an antenna of PIFA type such that the conductive element has a significant electromagnetic coupling to the radiating plane. The parasitic element at issue is connected to a matching circuit ( 550 ) consisting of several reactive element. The parasitic element, the matching circuit and a line ( 540 ) between them constitute an adjusting circuit of the antenna. The circuit values of the matching circuit can be chosen from at least two alternatives. Alteration in the circuit values changes the coupling between the parasitic element and the ground, in which case an operation band of the antenna is displaced, because the electric length of the antenna's part corresponding that band is changed, measured from the short-circuit point. Regarding the shiftable operation band, proper impedance matching and a proper efficiency can be arranged for the antenna.
251 citations
TL;DR: A small and low-cost antenna solution for radio frequency identification (RFID) tags is presented that is applicable in many different environments because the impedance of the antenna is immune to the platform.
Abstract: A small and low-cost antenna solution for radio frequency identification (RFID) tags is presented. The impedance of the antenna is designed to match directly to the impedance of the RFID microchip. Also, the impedance of the antenna is immune to the platform. Thus, the antenna is applicable in many different environments. The design and measurement results are reported and discussed.
238 citations
Patent•
02 Feb 2004
TL;DR: In this article, the authors proposed a multi-band planar antenna applicable as an internal antenna in small-sized mobile stations, and to a radio device including an antenna according to the invention, based on a conventional dual band PIFA with its feeding and shorting conductors and a non-conducting slot.
Abstract: A multi-band planar antenna applicable as an internal antenna in small-sized mobile stations, and to a radio device including an antenna according to the invention. The basis is a conventional dual band PIFA with its feeding and shorting conductors and a non-conducting slot. The planar element ( 220 ) has a second slot ( 232 ) known as such, which starts at the edge of the planar element on the other side of the feeding conductor ( 221 ) and shorting conductor ( 211 ) than the above-mentioned slot ( 231 ). In addition the structure comprises a second shorting conductor ( 212 ) on the other side of the second slot, than the feeding conductor. The second slot acts as a radiator, which for instance broadens the upper band of a dual band antenna. The second shorting conductor facilitates a better matching of a multi-band antenna than in corresponding prior art antennas. The antenna is simple, and its manufacturing costs are relatively low.
233 citations
TL;DR: In this paper, an ultrawide-band coplanar waveguide (CPW) fed slot antenna is presented, which is excited by a 50/spl Omega/CPW with a U-shaped tuning stub.
Abstract: An ultrawide-band coplanar waveguide (CPW) fed slot antenna is presented. A rectangular slot antenna is excited by a 50-/spl Omega/ CPW with a U-shaped tuning stub. The impedance bandwidth, from both measurement and simulation, is about 110% (S11<-10 dB). The antenna radiates bi-directionally. The radiation patterns obtained from simulations are found to be stable across the matching band and experimental verification is provided at the high end of the band.
221 citations
TL;DR: The basic concept for the RECAP antenna is verified by comparing theoretical results with measurements for configurations in which the switches are simply wires connecting the patches, and an overview of alternate switch/control strategies, some of which were tested, is given.
Abstract: A reconfigurable aperture (RECAP) antenna is described in which a planar array of electrically small, metallic patches are interconnected by switches. The antenna can be reconfigured to meet different performance goals by changing the switches that are open and closed. The switch configuration for a particular goal is determined using an optimizer, such as the genetic algorithm. First, the basic concept for the RECAP antenna is verified by comparing theoretical results with measurements for configurations in which the switches are simply wires connecting the patches. Next, details are given for a prototype antenna in which field-effect transistor based electronic switches are used with optical control. Theoretical results for the prototype antenna are then compared with measurements for cases in which electronic reconfiguration is used to change the bandwidth of operation or steer the pattern of the antenna. Finally, an overview of alternate switch/control strategies, some of which were tested, is given along with suggestions for improving the next generation of this antenna.
221 citations
TL;DR: In this paper, a Planar Inverted-F Antenna (PIFA) is proposed for cellular telephone applications. But the design of a compact PIFA is not discussed.
Abstract: This letter presents the design of a compact Planar Inverted-F Antenna (PIFA) suitable for cellular telephone applications. The quarter-wavelength antenna combines the use of a slot, shorted parasitic patches and capacitive loads to achieve multiband operation. The commercial electromagnetic software IE3D is used to design and optimize the structure. The resulting antenna can operate from 880 to 960 MHz and 1710 to 2170 MHz covering GSM, DCS, PCS, and UMTS standards with a VSWR better than 2.5. Good agreement is found between simulated and measured results.
Patent•
21 Apr 2004TL;DR: In this article, a controller switchable between a reflecting mode and a direct mode is connected to the arrays, which can cause back-to-back pairs of first antenna elements from the arrays to define a feed-through zone for the first antenna beam.
Abstract: A reflector antenna system may include an arc-shaped antenna reflector defining a first antenna beam, and a phased array antenna positioned in the first antenna beam including first and second arrays of antenna elements coupled together in back-to-back relation. The first array may face the antenna reflector, and the second array may face away from it. A controller switchable between a reflecting mode and a direct mode may be connected to the arrays. The controller, when in the reflecting mode, may cause back-to-back pairs of first antenna elements from the arrays to define a feed-through zone for the first antenna beam, and cause second antenna elements in the first array to define a first active zone for the first antenna beam. Furthermore, when in the direct mode, the controller may cause antenna elements in the second array to define a second active zone for a second antenna beam.
Patent•
29 Mar 2004
TL;DR: In this article, a broadband/multiband circular array antenna is described, which comprises a circular directional array antenna comprising a driven omnidirectional traveling-wave antenna element coupled to a transceiver via a feed and a plurality of surface-waveguide elements symmetrically positioned about and spaced from the antenna element.
Abstract: A broadband/multiband circular array antenna is disclosed. One embodiment comprises a circular directional array antenna comprising a driven omnidirectional traveling-wave antenna element coupled to a transceiver via a feed and a plurality of surface-waveguide elements symmetrically positioned about and spaced from the driven omnidirectional traveling-wave antenna element. Each surface-waveguide element receives a control signal configured to selectively alter its waveguide characteristics to electronically direct a beam to/from the array. The array provides a directionally controllable antenna beam with broadband/multiband frequency performance in a low profile design that is both economical and practical to produce and maintain.
Patent•
28 Oct 2004
TL;DR: An antenna system of coaxial elements and terminating impedances produces controlled bandwidth, broadband, and wideband performance under a variety of near field influences, with capability for simultaneous and alternating reception and radiation of electromagnetic radio energy as mentioned in this paper.
Abstract: An antenna system of coaxial elements and terminating impedances produces controlled bandwidth, broadband, and wideband performance under a variety of near field influences, with capability for simultaneous and alternating reception and radiation of electromagnetic radio energy. The antenna system enables broader bandwidths within miniaturized areas of confinement relative to wavelength. Singular elements of the system enable, and a plurality of elements of the system are combined to form specific bandpass, band reject, duplexing, and diplexing for radio frequencies as a function of the antenna system. The antenna system features complex terminating impedances which combine with characteristic impedances of coaxial structures to yield efficient radiating and matching functions for radio energy over a controlled bandwidth. The antenna system simultaneously utilizes the skin effect of electron flow with different vectors flowing on the internal and the external surfaces of the outside conductor of coaxial antenna elements with different vectors.
TL;DR: In this article, a rectenna designed with a microstrip harmonic-rejecting circular sector antenna at 2.4 GHz was proposed, which exhibits high reflection coefficients at the second and the third harmonics, generated by a diode.
Abstract: A rectenna designed with a microstrip harmonic-rejecting circular sector antenna at 2.4 GHz is proposed. As compared to a conventional microstrip square-patch antenna, the circular sector antenna, using inset feeding, exhibits high reflection coefficients at the second and the third harmonics, generated by a diode. The rectenna with integrated circular sector antenna can eliminate the need for a lowpass filter (LPF) placed between the antenna and the diode as well as producing higher output power, with a maximum conversion efficiency of 77.8% using a 150-/spl Omega/ load resistor.
TL;DR: In this paper, a modified printed Yagi antenna with a simplified feed mechanism is proposed, where the driver dipole is fed by a transmission line formed by two parallel strips printed on opposite sides of the dielectric substrate.
Abstract: A modified printed Yagi antenna with a simplified feed mechanism is proposed. In the new design, the driver dipole is fed by a transmission line formed by two parallel strips printed on opposite sides of the dielectric substrate. This simplified feed structure results in the reduction of the transmission line length, and, consequently, the radiation losses. The analysis of the modified Yagi antenna is performed numerically using Ansoft high frequency structure simulator and is experimentally validated.
TL;DR: In this paper, the aperture's electric field distribution is manipulated to create two fictitious short circuits along the slot, hence creating two additional resonances besides the main one, and the frequencies of these fictitious resonances can be chosen such that the overall bandwidth of the antenna is drastically increased.
Abstract: A technique for designing wideband slot antennas is proposed. By selecting the topology of the microstrip feed network, the aperture's electric field distribution is manipulated to create two fictitious short circuits along the slot, hence creating two additional resonances besides the main one. The frequencies of these fictitious resonances can be chosen such that the overall bandwidth of the antenna is drastically increased. By using this technique, a slot antenna with a 1.8:1 bandwidth ratio is designed and fabricated. The measured results of this antenna show similar radiation patterns at different frequencies in its band of operation. Furthermore, the antenna has a relatively constant gain and, more importantly, it has an excellent polarization purity over the entire bandwidth.
TL;DR: In this paper, a dual-frequency antenna based on the Sierpinski fractal with two parasitic patches to enhance the impedance bandwidth is presented, which has been designed using a method of moment commercial code and has been experimentally tested, obtaining two bands with a broad bandwidth and similar radiation patterns.
Abstract: A dual-frequency antenna based on the Sierpinski fractal with two parasitic patches to enhance the impedance bandwidth is presented. An electrical circuit model formed by RLC resonators is proposed to learn about the antenna physical behavior and to achieve the dual band operation minimizing a trial-and-error numerical/measurement proofs. The antenna has been designed using a method of moment commercial code and has been experimentally tested, obtaining two bands with a broad bandwidth and similar radiation patterns.
TL;DR: In this paper, a broadband multimode antenna system for multiple-input multiple-output (MIMO) and diversity applications is presented, which is not based on spatial diversity, as usual MIMO systems, but a combination of pattern and polarization diversity.
Abstract: This paper presents broadband multimode antennas for multiple-input multiple-output (MIMO) and diversity applications. The antenna system is not based on spatial diversity, as usual MIMO systems, but on a combination of pattern and polarization diversity. Different modes of self-complementary, thus extremely broadband, spiral and sinuous antennas are used to decorrelate the signals. It is shown that only one antenna is necessary to receive three uncorrelated signals, thus the space required to place the MIMO antenna is very small. Simulation results and measurements of a typical indoor scenario are given.
Patent•
20 Dec 2004
TL;DR: In this paper, the IC tag is mounted in the interior of the enclosure of the cable and thus the radio wave intensity of the first antenna can be prevented from being weakened by a metallic member in the cable.
Abstract: In a wireless IC tag, metallic antennas are deposited as thin films on the front and back surfaces of a spacer, made of a heat-resistant glass epoxy material having a desired dielectric constant, to form a first antenna and a second antenna. An IC chip is mounted in the center of the first antenna. The second antenna functions as an auxiliary antenna for resonating to a desired frequency of a transmission radio wave of the first antenna to strengthen the intensity of the radio wave. Accordingly, even when the IC tag is mounted to a cable or the like, the tag can be mounted in the interior of the enclosure of the cable and thus the radio wave intensity of the first antenna can be prevented from being weakened by a metallic member in the cable.
TL;DR: In this paper, a dual broadband rectangular slot antenna for 2.4 and 5 GHz wireless local area network (WLAN) is proposed, which uses a U-shaped strip inset at the center of the rectangular antenna.
Abstract: A novel dual broadband rectangular slot antenna for 2.4 and 5 GHz wireless local area network (WLAN) is proposed. With the use of a U-shaped strip inset at the centre of the rectangular slot antenna, the obtained impedance bandwidths for two operating bands can reach about 10.6% for the 2.4 GHz band and 33.8% for the 5 GHz band, which cover the required bandwidths of IEEE 802.11b/g (2.4-2.484 GHz) and IEEE 802.11a (5.150-5.950 GHz). Details of the antenna design and experimental results are presented and discussed.
TL;DR: A wideband, dual polarized printed antenna is designed and developed in this paper, which is based upon an aperture stacked patch layout and incorporates a simple dual-layered feeding technique to achieve dual-polarized radiation.
Abstract: A wide-band, dual polarized printed antenna is designed and developed in this paper The antenna is based upon an aperture stacked patch layout and incorporates a simple dual-layered feeding technique to achieve dual-polarized radiation The printed antenna has a measured 10 dB return loss bandwidth of 52% and an isolation between the excitation ports of greater than 39 dB over this frequency range The gain of the antenna is 74 dBi /spl plusmn/ 04 dB and the typical issues associated with incorporating an aperture excited solution are resolved by using a cross-shaped reflector patch to ensure the front-to-back ratio is greater than 20 dB
Patent•
06 Feb 2004TL;DR: In this paper, a multi-user wireless communication system for use in an enclosed space includes a distributed aperture antenna having multiple apertures distributed along an outer shield of the antenna, allowing radiated energy to leak from the antenna and form low-power localized electric fields that can couple receivers to the antenna.
Abstract: A multi-user wireless communication system for use in an enclosed space includes a distributed aperture antenna having multiple apertures distributed along an outer shield of the antenna. The apertures allow radiated energy to leak from the antenna and form low-power, localized electric fields that can couple receivers to the antenna. The multiple electric fields ensure that the electric field strength is distributed evenly throughout the communication system. The low-power electric fields also reduce the likelihood of electric field leakage that may cause interference with other communication systems outside the enclosed space.
TL;DR: In this paper, a coplanar waveguide-fed capacitive folded-slot antenna is proposed for the radio frequency identification (RFID) application at 5.8 GHz, where the antenna is fabricated on a 30×30 mm substrate.
Abstract: A coplanar waveguide (CPW)-fed capacitive folded-slot antenna is proposed for the radio frequency identification (RFID) application at 5.8 GHz. The antenna is fabricated on a 30×30 mm substrate. The measured bandwidth and antenna gain are 7.5% and 4.2 dBi, respectively. Radiation patterns are almost omnidirectional in the H-plane. These properties and the compact and uniplanar structure make the antennas suitable for use as RFID tags.
TL;DR: In this paper, a planar dipole array antenna with good omnidirectional radiation in the azimuthal plane is presented, and the measured maximum antenna gain for operating frequencies across the 2.4 GHz band is about 5.0-6.1 dBi.
Abstract: A planar dipole array antenna having good omnidirectional radiation in the azimuthal plane is presented. The planar dipole array antenna comprises two 1 /spl times/ 2 dipole arrays arranged back to back and separated by a narrow rectangular ground plane, and is easily constructed by printing on both sides of a dielectric substrate. Prototypes of the proposed antenna for WLAN operation in the 2.4 GHz band (2400-2484 MHz) were constructed and studied. Good omnidirectional radiation with gain variations less than 2 dBi in the azimuthal plane has been obtained, and the measured maximum antenna gain for operating frequencies across the 2.4 GHz band is about 5.0-6.1 dBi. Effects of the ground-plane width and the array spacing on the performance of the proposed antenna are also studied.
Patent•
30 Jan 2004TL;DR: In this article, a minute loop antenna is provided to be electromagnetically close to a dielectric substrate including a grounding conductor, has a predetermined number N of turns and a predetermined minute length, operates as a magnetic ideal dipole when a predetermined metal plate is located closely to the antenna apparatus, and operate as a current antenna when the metal plate was located apart from the antenna.
Abstract: An antenna apparatus includes a minute loop antenna and at least one antenna element. The minute loop antenna is provided to be electromagnetically close to a dielectric substrate including a grounding conductor, has a predetermined number N of turns and a predetermined minute length, operates as a magnetic ideal dipole when a predetermined metal plate is located closely to the antenna apparatus, and operates as a current antenna when the metal plate is located apart from the antenna apparatus. The antenna element is connected to the minute loop antenna, and operates as a current antenna. In the antenna apparatus, one end of the antenna apparatus is connected to a feeding point, and another end of the antenna apparatus is connected to the grounding conductor of the dielectric substrate.
TL;DR: In this paper, a switched parasitic monopole antenna on a finite ground structure with a conductive sleeve attached to a small, circular ground plane was designed using a genetic algorithm and finite element solver.
Abstract: A switched parasitic monopole antenna on a finite ground structure with a conductive sleeve attached to a small, circular ground plane controls the vertical radiation direction. The antenna was designed using a genetic algorithm and finite element (FEM) solver. At 1.575 GHz, the constructed antenna exhibited a front to back ratio of 10.7 dB and gain of 6.4 dBi with no elevation from the horizontal. The switched parasitic nature of the antenna allowed it to steer a directional beam through 5 locations in the azimuth. Incremented from 0/spl lambda/ to 0.45/spl lambda/, the sleeve was observed to linearly depress the main lobe elevation with little influence on other antenna characteristics such as gain and S/sub 11/.
TL;DR: In this paper, a wide-band L-probe fed circular patch antenna with conical pattern radiation was proposed and the measured gain was in the range of 5.0/spl sim/6.5 dBi in the passband.
Abstract: Experimental results for a wide-band L-probe fed circular patch antenna having conical-pattern radiation are presented. With an antenna thickness of /spl sim/0.13 times the free-space wavelength of the center operating frequency, the proposed antenna can achieve a bandwidth of /spl sim/30% and produce a monopole-like conical radiation patterns. The measured gain is in the range of 5.0/spl sim/6.5 dBi in the passband.
Patent•
01 Oct 2004TL;DR: In this paper, a wideband multi-mode antenna with low VSWR operating characteristics is proposed, where the antenna element is formed from a right-triangularly shaped piece of conductive material, which is rolled along the base dimension.
Abstract: A wideband multi-mode antenna having low VSWR operating characteristics. The antenna element is formed from a right-triangularly shaped piece of conductive material, which is rolled along the base dimension. Operational characteristics may be modified by spacing the antenna element from a ground plane using dielectric spacers, and the antenna element may be shorted to the ground plane.
TL;DR: In this paper, a small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented, where a stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity.
Abstract: A small H-shaped microstrip patch antenna (MPA) with enhanced bandwidth is presented. The H-shaped antenna is first studied by a transmission line model and then is fully analyzed with a MoM code. A stacked patch configuration is proposed to increase the narrow bandwidth, radiation efficiency and directivity. The stacked H-shaped MPA is studied using Chu's fundamental limit for electrically small antennas.