Radiation patterns

An emitting dipole, as well as any electromagnetic antenna, can be characterized by its radiation pattern D [9,(p) (where the apex indicates radiation in the vacuum), defined from  

The radiation pattern represents thus the normalized emitted power within an unit solid angle dQ = sm 9)d6d and satisfies  

In the case of a dipole aligned on the x-axis we have instead  

We can also define the integral only over the (p coordinates as 

These definitions will be used later, in section Sec. 1.7.4. 

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We present a novel method, called VIGRAL, to size and position the reflecting surface of a flaw. The method operates on standard B-scan recorded with traditional transducers, to extract Time-of-Flight (ToF) information which is then back-projected to reconstruct the reflecting surface of the flaw and characterize its radiation pattern. The VIGRAL method locates and sizes flaws to within k/2, and differentiates between flat and volumetric defects. 

Figure 4. Radiation pattern emitted from orbiting electrons when the velocities are much smaller than (A) or comparable to (B) the speed of light. (Adapted from Ref. 20.)...

Figure 2.1. Polarization of synchrotron radiation in a hypothetic non-relativistic case. In real ity the toroidal radiation pattern is degenerated to a narrow forwar... 

W. Lukosz and R. E. Kunz, Light emission by magnetic and electric dipoles close to a plane interface. II. Radiation patterns of perpendicularly oriented dipoles, J. Opt. Soc. Am. 67, 1615-1619 (1977). 

S. D. Druger and P. J. McNulty, Radiation pattern of fluorescence from molecules embedded in small particles General case, Appl. Opt. 22, 75-82 (1983). 

D. Gies and T.-C. Poon, Measurement of acoustic radiation pattern in an aconsto-optic modulator, Proceedings of IEEE SoutheastCon, 441-445 (2002). 

Note that the radiation field is dependent on one angle only, namely the angle 9 subtended by the acceleration r and radius arm vector R the dependence enters Eq. 2.60 as (sin 9)2 which is characteristic of the familiar dipole radiation pattern. It is, therefore, straightforward to integrate Eq. 2.60 over a spherical surface R2 f dQ where dQ = sin 9 d9 dtotal power emitted,... 

Data relating to radionuclide deposition (fallout) within a few miles of the Danny Boy, Sedan, and Palanquin nuclear cratering shots are examined for evidence of fractionation. The fractionation index is computed for several fission-product mass chains produced in each event. For the three events studied only Danny Boy showed unambiguous evidence of fractionation in the early fallout, and the degree of fractionation was small. In Danny Boy there was only a factor of four difference between most enriched and most depleted species, compared with the factors of several hundred that have been observed in many late time samples of airborne debris. If this small amount of fractionation proves to be true in general for cratering shots, predictions of early-fallout gamma-radiation patterns will be simplified. 

To summarize, there appears to have been little fractionation in the early fallout from these three cratering events, with Danny Boy being the only one of the three to show unambiguous evidence of fractionation. If this observation proves to be true in general for cratering shots, then predictions of early fallout gamma-radiation patterns will be simplified. 

Figure 15 shows the close-in fallout collection array (NRDL) and the radiation pattern at 1 hour. The first three numbers of the close-in samples correspond to the numbers of the stations shown here. The letters AO and PC indicate always-open collectors and platform collectors, respectively. These collectors were identical, but the PC collectors received better protection from dust prior to shot time. The next number indicates which of the 9 or 16 pans in the array has been taken. Additional numbers indicate sieve sizes retaining the debris. 

Near Field Radiation Pattern—Distribution of the irradiance over an emitting surface in other words, over the cross section of an optical waveguide. 

Gies, D. and Poon, T.-C., Measurement of Acoustic Radiation Pattern in an Acousto-Optic Modulator Proceedings of IEEE SoutheastCon 2002, pp. 441-445. 

FIGURE 2.5. Normalised electroluminescence radiation patterns of die 2-D patterned device measured in die x-(filled circles) and y-directions (filled squares) are shown along with die average of die two (black line, no symbols). The radiation pattern of an unpattemed device is also shown (filled triangles) along with radiation pattern obtained from the lambertian emission (dashed line, no symbols). 

Figure 1. Polar coordinate grid. Papers of this type can be used to show the radiation pattern of an antenna, or the EMI/RFI emissions for a VAX computer or terminal under test for FCC compliance.

Visual comparison of the holographically recorded radiation pattern of a particle with Mie theory has also been used for particle sizing [71]. Holography has also been used to locate sub-micron particles in a 3-dimensional volume [72] and, in conjunction with an image analyzing computer, to size the droplets in sprays [73]. 

Thirdly, the radiation pattern (angular and polarization dependence of the radiated power) may also be modified. We will ignore this aspect, which is in most cases secondary. 

One item overlooked and not evident unless studied spectroradiometricaly, is the contribution of the mercury lines to fluorescent and metal halide radiation patterns. 

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