Showing papers on "Fresnel zone antenna published in 2005"
TL;DR: In this article, the ICARA (induced-current analysis of reflector antennas) software is presented, which is able to predict the behavior of reflectors using the physical optics method.
Abstract: The aim of this work is to present the ICARA (induced-current analysis of reflector antennas) software, which is able to predict the behavior of reflector antennas using the physical optics method. The software offers different options for antenna configurations, single and array feed models, and far-field or aperture-field analysis.
49 citations
03 Apr 2005
TL;DR: In this paper, the L-probe is housed under a free space groove between the DRA and the ground plane, and a 32% matching bandwidth is achieved with broadside radiation patterns.
Abstract: Dielectric resonator antennas (DRA) designed for broadband applications and excited by L-shape probe are analyzed numerically. The L-probe is housed under a free space groove between the DRA and the ground plane. A 32% matching bandwidth is achieved with broadside radiation patterns. The new structure is mechanically better than other wideband DRA antennas.
35 citations
Patent•
30 Dec 2005
TL;DR: In this article, a focusing unit includes a Fresnel lens combination, where the Fresnel lenses are oriented to reduce shadowing losses, which is a scattering of light from reflection at the facet walls that separate adjacent Fresnel zones on a given lens.
Abstract: A focusing unit includes a Fresnel lens combination, where the Fresnel lenses are oriented to reduce shadowing losses. Shadowing is a scattering of light from reflection at the facet walls that separate adjacent Fresnel zones on a given Fresnel lens. Two substantially adjacent Fresnel lenses make up the focusing unit, which can be used as a condenser that collects light from a source in a projection system. Both Fresnel lenses have non-faceted sides that face the light source. The first Fresnel lens collimates the light from the source. The second Fresnel lens receives the collimated beam, with a range of incident angles determined by the spatial extent of the source. Components such as reflective polarizers and anti-reflection coatings can be used between the Fresnel lenses and can be applied to the non-faceted side of the second Fresnel lens.
17 citations
TL;DR: In this paper, a linear microstrip array and Fresnel lens combination is proposed for Ka-band satellite communications, where medium-power amplifiers are distributed within the array to achieve a high EIRP required for satellite communications.
Abstract: The design of a linear microstrip array and Fresnel lens combination as a potential candidate for Ka-band satellite communications is presented. Medium-power amplifiers are distributed within the array to achieve a high EIRP required for satellite communications. This architecture may be used as an alternative to the conventional horn-fed reflector antenna with a single high-power amplifier.
16 citations
03 Jul 2005
TL;DR: In this paper, two models of low profile compact disk and sleeve loaded monopole antennas are investigated for broadband applications in the VHF/UHF range Parametric studies of these configurations are performed by method-of-moments simulations Optimized performance (impedance and pattern bandwidths) of these antennas are presented and compared with that of existing designs of similar size.
Abstract: Two models of low profile compact disk and sleeve loaded monopole antennas are investigated for broadband applications in the VHF/UHF range Parametric studies of these configurations are performed by method-of-moments simulations Optimized performance (impedance and pattern bandwidths) of these antennas is presented and compared with that of existing designs of similar size
13 citations
07 Feb 2005
TL;DR: In this article, a fast algorithm using the host Fresnel zone plate was proposed to improve the computational efficiency of computer-generated hologram (CGH) for 3D objects, where the spatial position information of each point of the 3D object was obtained directly.
Abstract: A new fast algorithm using the “host” Fresnel zone plate was proposed to improve the computational efficiency of computer-generated hologram (CGH) for 3D objects. By reading .3DS files, the spatial position information of each point of the 3D object was obtained directly. With the illumination of plane wave, the “host” Fresnel zone plate of a single point could be equal to all points located in the same depth plane - as the Fresnel zone plate was translated and superimposed along the horizontal and vertical axes. Consequently, the hologram of a 3D object could be built up by superimposing different Fresnel zone plates in the corresponding depth planes. For a digital object composed of 1060 points, it cost about 83s to generate a hologram of 1024*768 pixels. The CGH of 3D objects with the results of the reconstruction was presented in this paper, which proved the feasibility of this algorithm.
13 citations
01 Jan 2005
TL;DR: The existence of a free parameter in the design of Fresnel zone plates can be chosen to have non-standard values which are shown to improve important aspects of antenna performance and to add new functionality to zone plate antennas.
Abstract: We call attention to the existence of a free parameter in the design of Fresnel zone plates. Historically, zone plates have been designed with a specific choice for this parameter, which can be taken as a type of phase reference. We present two methods of interpreting the parameter, either in terms of a reference radius or equivalently a reference phase. Importantly, the parameter can be chosen to have non-standard values which are shown to improve important aspects of antenna performance and to add new functionality to zone plate antennas
12 citations
Patent•
22 Aug 2005TL;DR: In this article, an optical device comprising a Fresnel structure is designed such that at least one phase jump is introduced in a radiation beam that passes through said Fresnel structures. And the optical device further comprises a stepped structure for compensating for said phase jump.
Abstract: The invention relates to an optical device comprising a Fresnel structure (101). The Fresnel structure is designed such that at least one phase jump is introduced in a radiation beam that passes through said Fresnel structure. The optical device further comprises a stepped structure (102) for compensating for said phase jump.
12 citations
TL;DR: In this article, a projected image with depth information of the 3D object is prepared to calculate the Fresnel diffraction of the projected image by array operation and distributed parallel processing.
Abstract: Fresnel CGH for a three-dimensional (3-D) object is generated by calculating the Fresnel diffraction, but it requires a huge amount of calculation. This is one reason for the difficulty in realizing real-time holography. We propose fast calculation method of computer-generated Fresnel hologram (Fresnel CGH) utilizing distributed parallel processing and array operation. In our method, a projected image with depth information of the 3-D object is prepared to calculate the Fresnel diffraction. The Fresnel diffraction of the projected image is then calculated with depth information by array operation and distributed parallel processing. Parallel processing is realized using JavaSpaces and many standard computers. In our array operation, calculation error in phase distribution on a hologram occurs more than the strict Fresnel diffraction. However, it was confirmed by experiments that the influence of an error can be controlled and ignored. In this paper, our proposed method and some experimental results are shown.
10 citations
TL;DR: In this paper, a multiphase Fresnel zone plate was used to improve the resolution of near-field optical system with a solid immersion lens by using scalar angular spectrum theory, which can not only decrease the spot size but also decrease the sidelobe intensity and enhance greatly the diffractive efficiency.
Abstract: We propose a method to improve the resolution of near-field optical system with a solid immersion lens by using a multiphase level Fresnel zone plate. The analyses are based on scalar angular spectrum theory. The results show that the multiphase Fresnel zone plate can not only decrease the spot size but also decrease the sidelobe intensity and enhance greatly the diffractive efficiency compared with annular amplitude filter or binary 2-, 3-, 4-zone phase filter.
10 citations
03 Jul 2005
TL;DR: In this article, the authors compared the characteristics of the cylindrical DRA and the rectangular DRA, and showed that by exciting two simultaneous modes, the bandwidth of a DRA can be increased without extensively modifying the geometry.
Abstract: The dielectric resonator antenna (DRA) is quite useful for high frequency applications where ohmic losses become a serious problem for conventional metallic antennas. In addition, they offer higher bandwidths than microstrip patch antennas used in the same frequency range. There are many techniques for increasing the bandwidth of DRAs and many of them increase the complexity of the structure. The paper is concerned with the excitation of two modes with similar radiation characteristics in the same DRA. By adjusting the ratio of the diameter to the height, the modes can be made to resonate close to each other and the bandwidth is thereby increased. The characteristics of the cylindrical DRA and the rectangular DRA are compared. The results show that, by exciting two simultaneous modes, the bandwidth of a DRA can be increased without extensively modifying the geometry.
TL;DR: In this paper, a non-imaging Fresnel lens was designed for a concentrator to collect more sunlight onto the solar cell due to the efficiency and cost, and the optical concentration ratio could reach 15X (2D) and 230X (3D).
Abstract: Design a Fresnel lens for a concentrator to collect more sunlight onto the solar cell due to the efficiency and cost. Since 1970, the non-imaging concentrator was used for solar energy; most of them were reflecting mirrors. The non-imaging optical system provides large aperture and forgiving imaging requirements. The Fresnel lens used in non-imaging optical system was usually called non-imaging Fresnel lens. In this research, the Fresnel lenses were refracting optical elements but diffracting ones. According to the method of Ralf Leutz and Akio Suzuki [2], using minimum deviation and minimum dispersion to design a non-imaging Fresnel lens, which obeys the edge ray principle. Use optical software TracePro to simulate the non-imaging Fresnel lens, and each pitch size was 0.3mm and 200mm focus distant. Discusses the losses of non-imaging Fresnel lens and find out the relation of efficiency and F-Number. The optical concentration ratio could reach 15X (2-D) and 230X (3-D).
05 Mar 2005
TL;DR: In this article, simulation and analysis of the current DSN 34-m antennas in an uplink array mode were discussed together with some preliminary test results with the 34m antenna exciters.
Abstract: Although the technologies for large arrays of distributed reflector antennas with just downlink (receiving) capability have been well defined and proven for deep space applications, a similar architecture, i.e., the arraying of distributed reflector antennas for uplink (transmitting) applications has not been proven, tested, or built yet. In previous papers (Hurd, 2005) the need, feasibility, technology challenges and high-level system issues of a large array of reflector antennas with uplink capability for the future deep space network (DSN) were discussed. In particular, the primary design drivers, cost drivers, and technology challenges for uplink array phase calibration were addressed together with some preliminary test results with the 34-m antenna exciters. It is now of great interest to obtain the key requirements for the current Deep Space Network (DSN) 34-m antennas so that they can operate in an uplink array mode. The successful demonstration of the DSN 34-m antennas in uplink array mode serves as a prototype and a key milestone for the future large array development. In this paper, simulation and analysis of the current DSN 34-m antennas in an uplink array mode were discussed
TL;DR: A generalized vector diffraction theory of the half-open curvilinear Fresnel zone plate (FZP) tens antenna that is valid for any lens profile shape is presented in this article.
Abstract: A generalized vector diffraction theory of the half-open curvilinear Fresnel zone plate (FZP) tens antenna that is valid for any lens profile shape is presented. It is an extension to the vector Kirchhoff diffraction theory for the plane half-open FZP lens antenna and is based on the conical-segment lens profile approximation. An equation for the electric far-field vector is derived from which follow the expressions for the co- and cross-polarization radiation patterns and directive gain. The proposed theory is utilized for a numerical analysis and comparison of 140-GHz curvilinear half-open FZP lens antennas grouped in two distinct sets:
(a)
Set I: antennas with different in shape FZP lenses (plane, conical, parabolic and spherical) having the same number of zones. All eurvilinear FZP antenna lenses are designed for similar gain, co- and cross-polarization performance and bandwidth, regardless of the lens-profile.
(b)
Set II: antennas with different in shape FZP lenses and different number of zones. Since this affects gain, polarization and bandwidth performance, to make the characteristics of these FZP lens antennas practically equal to those of Set I, antenna feeds with different gain patterns have been used.
TL;DR: In this article, the Kirchhoff's scalar formula with reasonable agreement was validated with a three-dimensional vectorial formulation, where the horn aperture was larger than the wavelength and the focal characteristic was obtained not only for the normal incidence but also for the slightly oblique incidence.
Abstract: The application of Fresnel lenses is often made to the receiving antennas for television and radio by way of the satellite communication, for the astronomical observation and so on. Their advantage lies in structural simplicity and low cost. A typical Fresnel zone plate lens (FZPL) consists of coaxial conductive ring bands separately placed over the surface of a dielectric plate. For the antenna application a receiving horn is provided at the focal point. In our previous work, the experiment was carried out for this arrangement, where the horn aperture is larger than the wavelength. Comparison was made with the solution of the Kirchhoff's scalar formula with reasonable agreement (Trans EIC Japan 1998; J-81-B-II(8):823–828; Trans EIC Japan 1996; J-79-B-II(11):959–963). The present work is to validate the numerical treatment. The method of moment and the theory of the physical optics are here considered with three-dimensional vectorial formulation. The focal characteristic is obtained not only for the normal incidence but also for the slightly oblique incidence. Copyright © 2005 John Wiley & Sons, Ltd.
Patent•
09 Mar 2005TL;DR: In this paper, the authors proposed a processing chamber consisting of an energy wave source and a curved spherical surface, where the curved spherical surfaces of the chamber is composed of at least a Fresnel reflector for reflecting the energy wave discharged from the EW source and projecting the same onto a platform as the EEW source is operating in coordination with the spherical surface.
Abstract: The processing chamber comprises an energy wave source and a curved spherical surface, wherein the curved spherical surface of the chamber is composed of at least a Fresnel reflector for reflecting the energy wave discharged from the energy wave source and projecting the same onto a platform as the energy wave source is operating in coordination with the curved spherical surface. In addition, the energy wave source can be a microwave source or a light source. It is noted that the curved spherical surface can be a Fresnel reflector, a wave spherical surface with a portion thereof being replaced by a Fresnel reflector, a curved spherical surface with a portion therof being replaced by at least two Fresnel reflectors, and a surface entirely formed of a plurality of Fresnel reflectors. The processing chamber disclosed in the present invention significantly increases energy density, area, and energy uniformity of the projection region so as to diminish required space of equipment and costs of equipment and manufacture.
TL;DR: In this article, the Kirchhoff's scalar formula with reasonable agreement was validated with a three-dimensional vectorial formulation, where the horn aperture was larger than the wavelength and the focal characteristic was obtained not only for the normal incidence but also for the slightly oblique incidence.
Abstract: The application of Fresnel lenses is often made to the receiving antennas for television and radio by way of the satellite communication, for the astronomical observation and so on. Their advantage lies in structural simplicity and low cost. A typical Fresnel zone plate lens (FZPL) consists of coaxial conductive ring bands separately placed over the surface of a dielectric plate. For the antenna application a receiving horn is provided at the focal point. In our previous work, the experiment was carried out for this arrangement, where the horn aperture is larger than the wavelength. Comparison was made with the solution of the Kirchhoff's scalar formula with reasonable agreement (Trans EIC Japan 1998; J-81-B-II(8):823–828; Trans EIC Japan 1996; J-79-B-II(11):959–963). The present work is to validate the numerical treatment. The method of moment and the theory of the physical optics are here considered with three-dimensional vectorial formulation. The focal characteristic is obtained not only for the normal incidence but also for the slightly oblique incidence. Copyright © 2005 John Wiley & Sons, Ltd.
02 May 2005
03 Jul 2005
TL;DR: In this paper, the possibility of designing rectangular patch antennas with reduced surface wave emissions was investigated, and shorted rectangular patches (SRP) were considered as a possible solution, and a design example was presented to show how effective surface wave suppression can be easily achieved.
Abstract: The paper investigates the possibility of designing rectangular patch antennas with reduced surface wave emissions. As a possible solution, shorted rectangular patches (SRP) are considered. A design example is presented to show how effective surface wave suppression can be easily achieved.
TL;DR: In this paper, a method for observing the propagation-angle displacement of a collimated beam with respect to the travel direction of a moving part by use of a dual-focus Fresnel lens was proposed.
Abstract: We propose a method for observing the propagation-angle displacement of a collimated beam with respect to the travel direction of a moving part by use of a dual-focus Fresnel lens. The fabricated binary-type dual focus Fresnel lens consisting of two portions having a different focal length from each other. 0.5 mrad angular accuracy within a travel range of 16mm was experimentally confirmed and then it was successfully applied to split-type optical head manufacturing.
12 Dec 2005
TL;DR: In this paper, a novel topology of compact dual-band antennas is presented, where wires are integrated in wire antennas for achieving dualband feature and fractal geometry is used for compactness purposes.
Abstract: A novel topology of compact dual-band antennas is presented. Stubs are integrated in wire antennas for achieving dual-band feature and fractal geometry is used for compactness purposes. The design methodology is reported and an excellent agreement with the electromagnetic simulations is obtained
15 Jun 2005
TL;DR: In this paper, the authors presented three novel concepts of ultra-broadband planar antennas with linearly polarized bidirectional radiation patterns, which were developed for multi-band wireless applications especially in open-plan office buildings, airports, trains, and airplanes.
Abstract: This paper presents three novel concepts of ultra-broadband planar antennas with linearly polarized bidirectional radiation patterns. These low-cost and robust printed antennas have been developed for multi-band wireless applications especially in open-plan office buildings, airports, trains, and airplanes.
Journal Article•
TL;DR: In this paper, the authors derived the expressions of non-zero offset Fresnel zone for horizontal and dip reflectors for the ellipse features of the Fresnel ellipses and showed that offset is an important parameter of seismic lateral resolution.
Abstract: Fresnel zone is an important parameter of seismic lateral resolution The expressions of non-zero offset Fresnel zone for horizontal and dip reflectors were deduced Two numerical examples illustrated the theoretical results, and the ellipse features of non-zero offset Fresnel zone expounded the distribution of the main energy of seismic diffracted waves quantitatively The results show that offset is the main factor in changing the size and eccentricity of the Fresnel ellipse But the influence of interface dip is relatively small and can be omitted A considerable declinational departure of the ellipse's center from the reflection point may be caused by the reflector's dip, and the deflection grows rapidly with the dip increasing These results can be used for guiding the design of field survey project and the parameter selection in data processing It is also an expansion to the Fresnel zone in common sense
03 Jul 2005
TL;DR: In this article, a new mechanism for deploying reflector antennas is introduced, and its functionality demonstrated for VSAT and satellite TV reception systems, referred to as DRSAT (deployable reflector for satellite applications), was constructed using sheet aluminum, a fine metal mesh, an existing feed and low noise block, and a directionally adjustable base.
Abstract: A new mechanism for deploying reflector antennas is herein introduced, and its functionality demonstrated for VSAT and satellite TV reception systems. The prototype, herein referred to as DRSAT (deployable reflector for satellite applications), was constructed using sheet aluminum, a fine metal mesh, an existing feed and low noise block, and a directionally adjustable base. The DRSAT design employs a 39-cm offset reflector antenna, which when collapsed occupies less than 0.03 m/sup 3/. Computer simulations performed with the program PRAC (parabolic reflector analysis code) were conducted to validate the design and assess the impact of surface errors during manufacturing.
04 Dec 2005
TL;DR: In this article, three basic types of diffractive antennas and lens are distinguished (according to the principle of their location relative to the direction of electromagnetic wave propagation), they are: a transverse element (implemented primarily on a plane surface), a longitudinal-transverse elements (on an arbitrary curved surface), and a longitudinal element (representing a set of screens situated along the directions of electromagnetic waves propagation).
Abstract: In order to increase the focusing, resolving and scanning properties and to create different shaped radiation patterns the Fresnel zone plate and antenna can be assembled conformable to a curvilinear natural or man-made formation Three basic types of diffractive antennas and lens are distinguished (according to the principle of their location relative to the direction of electromagnetic wave propagation), they are: a transverse element (implemented primarily on a plane surface), a longitudinal-transverse element (on an arbitrary curved surface), and a longitudinal element (representing a set of screens situated along the direction of electromagnetic wave propagation) Diffractive antennas and lens can operate by the principle of "transmission" or "reflection"
TL;DR: In this paper, the feasibility of utilizing large diameter custom designed and fabricated Fresnel lenses as the front optical aperture for Earth-based reception of optical communication signals from remote spacecraft is investigated, including preliminary optical designs, investigation of stray light effects for a particular optical design, effect of temperature variations and mechanical sag on the performance of the photon bucket, and effect of temporal dispersion on the link performance.
Abstract: Feasibility of utilizing large diameter custom designed and fabricated Fresnel lenses as the front optical aperture for Earth-based reception of optical communication signals from remote spacecraft is investigated. This includes preliminary optical designs, investigation of stray-light effects for a particular optical design, effect of temperature variations and mechanical sag on the performance of the photon bucket, and effect of temporal dispersion on the link performance. Experimental results for several commercial off-the-shelf Fresnel lenses with diameters exceeding 1-meter are presented as well as plans for custom diamond turning fabrication of two-meter diameter Fresnel lenses.
19 Sep 2005
TL;DR: Fresnel zone plates are a type of diffractive antenna, used in place of curved lenses, and have seen extensive investigation and application at microwave, millimeter-wave, and terahertz frequencies.
Abstract: Fresnel zone plates are a type of diffractive antenna, used in place of curved lenses. The zone plates offer numerous advantages, and have seen extensive investigation and application at microwave, millimeter-wave, and terahertz frequencies. The difficulties of moving to frequencies above 90 GHz are described.
26 Sep 2005
TL;DR: In this paper, the problem of synthesizing the structure of the diffractive antenna does not have a unique solution and the beampattern can be corrected by choosing the free parameters or/and optical scheme.
Abstract: The problem of synthesizing the structure of the diffractive antenna does not have a unique solution and the beampattern can be corrected by choosing the free parameters or/and optical scheme. All this can be applied to create directivity pattern of unconventional form, for example, conical beampattern. A numerical analysis of the antennas constructions and beampattern calculation is made.
15 Apr 2005
TL;DR: A review of common traveling wave antennas is presented in this paper, where structural characteristics, design trends, and overall performance of several traveling wave antenna types including Beverage antennas (wire and printed), horn antennas, reflectors, and tapered slots are discussed.
Abstract: In this article, a review of common traveling wave antennas is presented. We briefly discuss the structural characteristics, design trends, and overall performance of several traveling wave antennas including Beverage antennas (wire and printed), horn antennas, reflectors, and tapered slots. Some examples of manufactured traveling wave antennas are given. We also attempt to outline the fundamental properties of this general class of antenna and how it can be differentiated from resonant style radiators. It will be shown that traveling wave antennas are essential for a variety of applications ranging from sophisticated radio astronomy platforms to simple low-frequency communications.
Keywords:
traveling wave antennas;
Beverage antennas;
helix antennas;
Yagi Uda antennas;
horn antennas;
corrugated horn antennas;
parabolic reflectors;
lens antennas;
tapered slot antennas;
reflectarrays