Aperture Antennas and Diffraction Theory

Jull, E.V.

doi:10.1049/pbew010e

Cited by 89 publications

(33 citation statements)

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“…(4) The radiation pattern of the compound box-horn is derived by plane wave spectra approach for three dimensional fields [19]. The radiation fields for the aperture antenna [19] is given by…”

Section: Analysis Of Radiation Pattern Of Compound Box-horn Antennamentioning

confidence: 99%

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Analysis of Radiation Patterns of Compound Box-Horn Antenna

Gupta¹,

Singh²

2007

PIER

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Abstract-A new type of antenna named as compound box-horn antenna is designed and analyzed for its radiation pattern. The present analysis is based on plane wave spectra for three-dimensional fields. The compound box-horn antenna is obtained by combining modified box-horn and pyramidal horn antennas, in which modified box-horn is coupled to pyramidal horn to excite TE 10 -and TE 30 -modes at the input of pyramidal horn. Thus, the compound boxhorn antenna has properties and advantages of both the modified box-horn and pyramidal horn antennas. The radiation patterns and corresponding half-power beam widths (HPBWs) of compound boxhorn antenna in free-space are computed at 10 GHz and compared for different flare angles in E-and H-planes of larger size pyramidal horn section of the compound box-horn. The results for HPBWs in Eand H-planes demonstrate that the radiation patterns in E-and Hplanes for compound box-horn can be made narrower by decreasing the flare angles in both E-and H-planes of larger size pyramidal horn section of the compound box-horn. The radiation patterns of compound box-horn are also compared with those for TE 10 -mode pyramidal horn of same aperture size and it found that the former horn is narrower in E-as well as H-plane than the latter. The analysis has been validated against the experimental results available in the literature. The work presented here can provide useful design 32 Gupta and Singh guidelines for development of prototypes of compound box-horn which may find potential application as a high-directivity transmitting horn for antenna measurements in the laboratory or as a range illuminator, or in microwave communication etc.

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Section: Analysis Of Radiation Pattern Of Compound Box-horn Antennamentioning

confidence: 99%

“…λ is wavelength in free-space.θ andφ are unit vectors in directions of θ and φ, respectively. F (k x , k y ) is the Fourier transform of the tangential electric field in the aperture [19] and can be evaluated as given below.…”

Section: Analysis Of Radiation Pattern Of Compound Box-horn Antennamentioning

confidence: 99%

Analysis of Radiation Patterns of Compound Box-Horn Antenna

Gupta¹,

Singh²

2007

PIER

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“…A spectral method, described in [7][8], was used to generate a finite sample of a rough surface with desired statistics. In this method, a set of normally distributed (both real and imaginary part) Fourier coefficients is generated and then weighted by a spectral density function in the frequency domain.…”

Section: Random Surface Generationmentioning

confidence: 99%

“…The gain pattern used for the calculations was obtained from [8], using the pattern for a pyramidal horn with the measured antenna dimensions of b = 5.7 cm by a = 7 cm for the aperture dimension and I; = 10 cm and IH = 8.9 cm for the corresponding flare lengths of the horn. Good agreement is observed between the theory and experiment, indicating that the background noise removal procedure was reasonable.…”

Section: Antenna Pattern Effectsmentioning

confidence: 99%

Polarimetric Passive Remote Sensing of Ocean Surface

Kong¹

1993

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$0' ý "t"Cmo'% Wait$ r.$' 1. -7 C4t* W, tm' 10 *01V r-to f'ft-a~fn W-Svb 0' OrAte fot 'AfO-r41-0o O~e'st-or' .ý4 bleoon 11 I ro-ro 9, SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)Office of Naval Research Our work on this project in the past year has concentrated primarily on the phase one goals as outlined in the original proposal. To date, we have performed an experiment in which the polarimetric thermal emission from a sinusoidal water surface was measured and compared against a theoretical model, performed a study of the polarimetric thermal emission from surfaces randomly rough in one direction, and begun work on a model for predicting the polarimetric thermal emission from surfaces randomly rough in two directions. Each of these studies is described in more detail below. Polarimetric Thermal Emission from a Sinusoidal Water SurfaceTo verify further our earlier findings reported in [1,21 for ocean-like surfaces, an experiment was design-,' and carried out in which the polarimetric thermal emission from a sinusoidal water surface was measured [3,4]. This sinusoidal water surface was created by placing a thin sheet of fiberglass with a sinusoidal profile on top of a pool of water and removing the air trapped underneath the fiberglass layer. The resulting surface was actually a 'two-layer' periodic surface whose thermal emission should be close to that of a true sinusoidal water surface if the effect of the fiberglass layer is neglected. The first three Stokes parameters of the thermal emission were measured at both 10 GHz and 14 GHz using a linearly polarized radiometer whose polarzation basis was rotated to perform the polarimetric measurements. Significant values of the brightness temperature corresponding to the third Stokes parameter U were observed at various polar and azimuthal angles (as high as 40 K for certain configurations). A theoretical model for the thermal emission from such a two-layer periodic surface was constructed, and its predictions agreed well with the expermental measurements. This theoretical model also indicated that the fiberglass layer 2 did slightly affect the brightness temperatures in horizontal and vertical polarizations, but had a much smaller effect on U. Polarimetric Thermal Emission from Surfaces Randomnly Rough in One DirectionOur experiment indicated that appreciable values of U could be obtained from a periodic sinusoidal water surface. However, an actual wind generated ocean surface has a very complicated structure and can only be described statistically as a random process.Thus, a numerical experiment in which the polarimetric thermal emission from randomly rough surfaces was investigated was next performed [5].Many approximate theories, such as the Kirchhoff approximation and the small perturbation method, exist for use in predicting the thermal emission from randomly rough surfaces. However, the theoretical predictions of [1] indicate that large surface slopes are needed to obtain appreciable values of U. Since the approximate theories mentioned above are know...

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“…instead of solving (1) by MOM directly, we convert it to the dual series equations [5,, in terms of surface current angular coefficients Then, we extract the static part of the kernel, and also, the part corresponding to the circular shape of the reflector By using the set of eigenfunctions of this partial operator as expansion functions. we obtain finally a regularized matrix equation, i e , that of the Fredholm 2-nd kind…”

mentioning

confidence: 99%