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Topic: Radiation pattern


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  Radiation pattern: Definition and Links by Encyclopedian.com - All about Radiation pattern   (Site not responding. Last check: 2007-10-08)
Note: A radiation pattern is usually represented graphically for the far-field[?] conditions in either horizontal or vertical plane.
Note 2: The far-field radiation pattern[?] describes the irradiance[?] as a function of angle in the far-field region of the exit face of an optical fiber.
Note 3: The radiation pattern may be a function of the length of the fiber, the manner in which it is excited, and the wavelength.
www.encyclopedian.com /ra/Radiation-pattern.html   (187 words)

  
 A to Z Weather glossary index- 4WX.COM ¤ Weather Information Center!
the warming of the atmosphere by absorption and reemission of infrared radiation by molecules in the atmosphere
Infrared radiation (energy in the wavelength interval of 3- 80 micrometer) emitted by or being propagated through the atmosphere.
In physical meteorology, a reduction in radiation flow, especially solar radiation by atmospheric gases and aerosols.
www.4wx.com /glossary   (1206 words)

  
 Lithography
by masking some of the radiation) the pattern of the radiation on the material is transferred to the material exposed, as the properties of the exposed and unexposed regions differs (as shown in figure 1).
The first pattern transferred to a wafer usually includes a set of alignment marks, which are high precision features that are used as the reference when positioning subsequent patterns, to the first pattern (as shown in figure 4).
As there is no pattern on the wafer for the first pattern to align to, the first pattern is typically aligned to the primary wafer flat (as shown in figure 8).
www.memsnet.org /mems/beginner/lithography.html   (1995 words)

  
 Antennas and Propagation MSc module 2000 (DJJ questions)
The E-plane radiation pattern is the far field contour of equal power density, such that the distance from the origin of co-ordinates to the pattern surface is proportional to the power radiated in that direction, taken in a plane containing the direction of propagation and the electric field direction.
Array factor: The radiation pattern of a collection of isotropes placed on the element centres and fed with the same amplitudes and phases as are applied to the actual elements of the array.
Pattern multiplication: Pointwise multiplication of the element pattern by the array factor to obtain the total radiation pattern for the array.
www.ee.surrey.ac.uk /Personal/D.Jefferies/antsolns00.html   (1245 words)

  
 Solid stage imaging apparatus - Patent 4129887
Superimposed on the array of radiation sensing and charge storage devices is a two-dimensional pattern of radiation (in dotted outline) having the same number of columns of elements as there are columns in the array and having a greater number of rows of elements than there are rows of devices in the array.
The row to row spacing of the elements of the radiation pattern are equal to the row to row spacing of the devices of the array.
The interval of time elapsed from the movement of a row of elements of the pattern of radiation from registry with a row of devices to registry with an adjacent row of devices is referred to as the interval of scan.
www.freepatentsonline.com /4129887.html   (6949 words)

  
 Understanding and Using Antenna Radiation Patterns - Joseph H. Reisert   (Site not responding. Last check: 2007-10-08)
Radiation plots are most often shown in either the plane of the axis of the antenna or the plane perpendicular to the axis and are referred to as the azimuth or "E-plane" and the elevation or "H-plane" respectively.
The antenna supplier either measures the radiation pattern by rotating the antenna on its axis or calculates the signal strength around the points of the compass with respect to the main beam peak.
Patterns are usually referenced to the outer edge of the plot which is the maximum gain of the antenna.
www.astronantennas.com /radiation_patterns.html   (1223 words)

  
 Ribbon Wavefront Patterns
The main difficulty in representing the radiation patterns is the number of variables involved, frequency, horizontal and vertical directivity as well as magnitude, phase.
I shall start by attempting to define the radiation pattern of a dome or a cone that is treated as a point source and has a hemispherical pattern, then take a look at a ribbon which has a cylindrical pattern.
The lobbing patterns and cone/dome geometry are discussed in Appendix A. This examines the lobbing frequency vs. cone diameter.
www.phy6.net /audio/papers/ribbon_wavefront_patterns/HP001.Wavefronts.htm   (936 words)

  
 RADIATION PATTERNS
The radiation pattern is a graphical depiction of the relative field strength transmitted from or received by the antenna.
Antenna radiation patterns are taken at one frequency, one polarization, and one plane cut.
Patterns are normalized to the maximum graph value, 0 dB, and a directivity is given for the antenna.
www.kyes.com /antenna/navy/rpatterns/radiapat.htm   (326 words)

  
 BROADCASTPAPERS.COM   (Site not responding. Last check: 2007-10-08)
The number of side lobes present varies with the number of radiating elements in the vertical array; that is, the higher the number of elements, the higher the number of side lobes.
If an antenna with this pattern is assumed to be a 1000 ft tower and have an ERP of 5000 kW, a diagram of signal strength vs. distance from the tower can be plotted based on these parameters.
The pattern shown in figure 1 greatly reduces the potential for this type of problem by keeping the side lobe “peak-to-null” range to a minimal magnitude.
www.broadcastpapers.com /tvtran/AndrewsSmoothElevation-print.htm   (1047 words)

  
 Antenna arrays
The array pattern is the polar radiation pattern which would result if the elements were replaced by isotropic radiators, having the same amplitude and phase of excitation as the actual elements, and spaced at points on a grid corresponding to the far field phase centres of the elements.
If we assume that all the polar radiation patterns of the elements taken individually are identical (within a certain tolerance) and that the patterns are all aligned in the same direction in azimuth and elevation, then the total array antenna pattern is got by multiplying the array pattern by the element pattern.
This radiation pattern is similar to that of a vertical dipole, which may roughly be regarded as a "doublet" consisting of two isotropes fed in antiphase.
www.ee.surrey.ac.uk /Personal/D.Jefferies/antarray.html   (1039 words)

  
 Section
The theoretical radiation pattern shall be calculated in accordance with the following mathematical expression: [GRAPHIC] [TIFF OMITTED] TC13NO91.014 where: E([phis],[thetas])th Represents the theoretical inverse distance fields at one kilometer for the given azimuth and elevation.
The horizontal plane pattern shall be plotted on polar coordinate paper, with the zero degree point corresponding to true north.
Patterns for elevation angles above the horizontal plane may be plotted in polar or rectangular coordinates, with the pattern for each angle of elevation on a separate page.
edocket.access.gpo.gov /cfr_2004/octqtr/47cfr73.150.htm   (1587 words)

  
 FVTD — Ridged Horn (animated version)
On the LHS the E-plane patterns are shown and on the RHS the H-plane patterns.
A deformation of the radiation pattern is apparent in the frequency range of 10 GHz ≤ f ≤ 14 GHz and f ≥ 16 GHz, where the broadside gain is much lower than the maximum gain.
The 3D radiation patterns in linear scale at five characteristic frequencies are displayed beside.
www.ifh.ee.ethz.ch /~fvtd/fvtd_horn_anim.html   (468 words)

  
 Decibel Products   (Site not responding. Last check: 2007-10-08)
In lieu of the range pattern, the radiation pattern should be shown in decibels (dB) with 0 dB referenced to a half-wave dipole.
In addition to the spacing between radiators (stacking factor), it is important that the individual radiators be properly fed. Maximum gain in the main lobe of a vertical array at 0° elevation is obtained when all radiators are fed in phase with equal power.
With the top radiator of the 2 stack array started at top of tower, and with 18 ft. (5.49 m) between centers, the bottom end of the bottom radiator will be at the 122 ft. (37.19 m) level on the tower.
www.decibelproducts.com /engineering/eng_elect_chars.htm   (2761 words)

  
 A study into the Assessment of FSS Satellite Antenna Reference Radiation Pattern Envelopes
The aim of the study was to complete the antenna radiation pattern envelope characteristics specified in Recommends 1 of Recommendations ITU-R S.672-2, which relate to single feed for both circular or elliptical beam FSS spacecraft antenna for geostationary and non-geostationary systems.
The patterns given by (3) and (4) of Table 1are applicable to circular beam antennas, but further study is required for elliptical beams.
It is recognised and accepted that tightening the satellite antenna radiation pattern envelope, encourages the use of greater orbit-efficient antennas which should lead to increased orbit capacity.
www.ofcom.org.uk /static/archive/ra/topics/research/topics/archive/satallite/satpage.htm   (2748 words)

  
 米国特許公開公報 20040090385 - Antenna with shaped radiation pattern   (Site not responding. Last check: 2007-10-08)
The gap extends to a transmitting edge of the antenna 1 such that two portions of the outer layer are spaced from a portion of the inner layer 5 along the edge by two insulating portions of the substrate 2.
This shielding layer serves as a field contouring structure which contours the electromagnetic field associated with the antenna so that the transmitted radiation is reflected away from the head of the user.
Such an antenna is designed to reduce the level of transmittal radiation in the vicinity of the user's head where such radiation might present a hazard.
cxp.paterra.com /jp/uspregrant20040090385.html   (144 words)

  
 Interpreting Antenna Performance Parameters for EMC Applications - Part 2
The antenna pattern is defined in the IEEE standard as "The spatial distribution of a quantity which characterizes the electromagnetic field generated by an antenna." This is usually specialized to mean a representation of the angular distribution of one of these quantities.
Thus, the radiation pattern can be simply taken as representation of the tendency of an antenna to radiate electromagnetic energy as a function of direction in the far field region.
When discussing the radiation pattern of a linearly-polarized antenna, it is useful to define the so-called E and H-planes.
www.djmelectronics.com /articles/emc-antenna-parameters-p2.html   (3904 words)

  
 Method and system for forming desired radiation pattern with array antenna - Patent 5081463
A desired radiation pattern with an undesirable sidelobe being suppressed is provided by compensating for the irregular density of antenna elements and by matching the null positions of the actual radiation pattern and an ideal Taylor radiation pattern.
In order to generate a radiation pattern having a desired sidelobe level, it is necessary for an amplitude level from each of the amplitude controllers 4 to be appropriately adjusted.
Thus, in accordance with the present invention, a desired radiation pattern is obtained for a short time even if antenna elements are arranged on a curved surface, whereby the present invention is particularly useful for such an application as a radiation pattern is frequently changed for a short time.
www.freepatentsonline.com /5081463.html   (3408 words)

  
 Chapter 9 figures
Representative plots of the normalized radiation pattern of a microwave antenna in (a) polar form and (b) rectangular form.
Radiation by apertures: (a) an opening in an opaque screen illuminated by a light source through a collimating lens and (b) a parabolic dish reflector illuminated by a small horn antenna.
Radiation patterns of (a) a circular reflector and (b) a cylindrical reflector (side lobes not shown).
www.ee.byu.edu /em/embook/figs/figs9.html   (351 words)

  
 Measurement of radiation patterns. Nordic VHF Meeting, Öland 970606
For a yagi antenna, the significant radiation pattern is the H-Plane.
The reason why the H pattern should be measured is that the E pattern easily is obtained from the H pattern by multiplication with the radiation pattern of a half wave dipole.
It is not possible to calculate the H pattern from the E pattern in directions that are nearly parallell to the elements becausethe H pattern is the E pattern divided by the dipole pattern.
www.sm5bsz.com /oland   (4391 words)

  
 Transmitting on the downlink using one or more weight vectors determined to achieve a desired radiation pattern - ...
The property "low relative radiated power" herein means low radiated power per antenna element relative to the power required to effect a comparable radiation pattern (comparable in range, azimuth and elevation) using a single antenna element of the same gain (e.g., as measured in dBi) as the individual elements of the antenna array.
This omnidirectional radiation pattern appears to be a reasonable choice for mobile cellular system in which the subscriber units can be arbitrarily positioned within the cell area.
Note that the radiated power as a function of azimuth, that is, the sum of the to traces 503 and 505 is still greater than that achievable with a single transmitting element operating at comparable power.
www.freepatentsonline.com /6154661.html   (12125 words)

  
 Section
Following are the possible methods of creating a modified standard pattern: (i) The modified pattern may be computed by making the entire pattern larger than the original pattern (i.e., have a higher RMS value) if the measured fields systematically exceed the confines of the original pattern.
Whereas some pattern smoothing can be accommodated, the extent of the requested span(s) shall be minimized and in no case shall a requested augmentation span extend to a radial azimuth for which the analyzed measurement data does not show a need for augmentation.
Where sector augmentation has been employed in designing the modified pattern, the direction of maximum augmentation (i.e., the central azimuth of augmentation) shall be indicated on the horizontal plane pattern for each augmented sector, and the limits of each sector shall also be shown.
edocket.access.gpo.gov /cfr_2004/octqtr/47cfr73.152.htm   (1233 words)

  
 PATTERN - Definition
Anything proposed for imitation; an archetype; an exemplar; that which is to be, or is worthy to be, copied or imitated; as, a pattern of a machine.
{Pattern box}, {chain}, or {cylinder} (Figure Weaving), devices, in a loom, for presenting several shuttles to the picker in the proper succession for forming the figure.
To make or design (anything) by, from, or after, something that serves as a pattern; to copy; to model; to imitate.
www.hyperdictionary.com /dictionary/pattern   (470 words)

  
 Genesis: Technology: Dipole Radiation Pattern
While the advantages of dipole design are many, the two main benefits are ease of placement in the room and more natural, spacious sound reproduction.
Dipoles achieve their superior performance because they create a radiation pattern where the energy emanating to the sides of the speakers is nearly non-existent.
With very little acoustical energy reaching the side walls of your living room, not only is placement of the speakers easy but, remarkably, the listener is able to experience the music unencumbered by the some of the room interactions which plague most other speaker systems.
www.genesisloudspeakers.com /tech_dipole.html   (237 words)

  
 Fourier-Based Dose Calculation in Radiation Brachytherapy
When a radiating source transmits energy into a medium, the distribution of the resultant energy in the spatial domain is called the source's radiation pattern.
The radiation pattern of a nonideal source can be accurately determined by integrating an infinite number of differential ideal sources (point sources) which make up the nonideal source.
Unlike the current Fourier-based convolution methods which are used for dose calculation in brachytherapy, the proposed method exploits the Fourier decomposition of the source's radiation pattern to avoid the calculation of the nonideal dose function in the spatial domain.
csdl2.computer.org /persagen/DLAbsToc.jsp?resourcePath=/dl/proceedings/&toc=comp/proceedings/icip/1997/8183/02/8183toc.xml&DOI=10.1109/ICIP.1997.638691   (288 words)

  
 BSSA, Volume 92:6   (Site not responding. Last check: 2007-10-08)
The pattern for the combined events may even resemble the pattern for a different type of source.
To examine these effects, we calculate radiation patterns for a number of models consisting of two or three cavities with one or multiple explosive sources located inside the cavities.
We observe that careful selection of distance and delays alters the radiation pattern, which might allow synthesis of a radiation pattern, to boost radiation in a predetermined direction or to make the pattern resemble the radiation from another type of source.
www.seismosoc.org /publications/BSSA_html/bssa_92-6/01214.html   (218 words)

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