Studies of the Focal Region of a Spherical Reflector: Polarization Effects

Hyde, G.; Spencer, Roy C.

doi:10.1109/tap.1968.1139210

Cited by 10 publications

(6 citation statements)

References 1 publication

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“…The cross-pol field was also calculated in these patterns and as was expected from [15], there is no observable cross-pol field in principal planes. The peak level of the cross-pol in the 45 plane is .…”

Section: Numerical Simulations For the 355-m Spherical Reflectormentioning

confidence: 56%

An array-compensated spherical reflector antenna for a very large number of scanned beams

Bahadori

Rahmat‐Samii

2005

IEEE Trans. Antennas Propagat.

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There are many stringent demands imposed on the applications of spaceborne antenna systems. One of the most challenging demands is the generation of multiple beams with the ability to scan a very large number of beamwidths. Since the parabolic reflectors have limitations in this application, a 35-m spherical reflector antenna is proposed for a geostationary radar antenna at Ka-band (35.6 GHz) due to its inherent capability of scanning the beams to very large number of beamwidths. The utility of using planar array feeds for correcting spherical phase aberrations is investigated to overcome the performance degradation effects. Two different methodologies are developed for the array excitation coefficients determination based on phase conjugate matching and the results are compared. Using the compensating feed array, the radiation characteristics of the compensated spherical reflector are simulated for no scan and large scan cases and the results are compared with the uncompensated case to show performance improvement. In order to demonstrate the technological readiness of the concept a 1.5-m breadboard model is designed to be built for experimental measurements. Some important mechanical design tolerances and realistic array feed topologies are investigated. The antenna concept developed in this paper is advocated to be used in the next generation of geostationary satellite antenna systems for remote sensing radar applications.

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Section: Numerical Simulations For the 355-m Spherical Reflectormentioning

confidence: 56%

An array-compensated spherical reflector antenna for a very large number of scanned beams

Bahadori

Rahmat‐Samii

2005

IEEE Trans. Antennas Propagat.

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“…for the tangential focal point and xc=O yc=O zc=a/(2 cos A ) (13) for the axial caustic corresponding to the second equation of (1 1).…”

Section: Er=ero(u V)j-1'2 Exp [ -J K ( @ + T ) ]mentioning

confidence: 99%

“…The GO field is invalid near the caustic given by (12) and (13). The field expression which is valid near the caustic is (14) where xo and yo are the Cartesian coordinates in (7) which are expressed in terms of hybrid coordinates @, , p y , 2).…”

Section: Er=ero(u V)j-1'2 Exp [ -J K ( @ + T ) ]mentioning

confidence: 99%

“…Hyde [13] has studied the focal region of a spherical reflector using the method of stationary phase for physical regions. Since the numerical integrations of (18) and (19) readily yield the field in the vicinity of the caustic, we will restrict ourselves here to the check that we can derive the GO expressions (8)-( 10) from (16) …”

Section: Stationary Phase Evaluationmentioning

confidence: 99%

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Study of the field around the focal region of spherical reflector antenna

Hongo

1988

IEEE Trans. Antennas Propagat.

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Maslov's method is applied to derive expressions for the wave reflected by a spherical reflector when the plane wave is incident along the axis of the reflector. A relatively simple expression is derived which is valid in the caustic region. An asymptotic my expression is also derived which can be used in the region far from the caustic. Field distributions around the cusp region are calculated numerically and the results are compared with those obtained by other methods when they are available. Agreement among them is fairly good.

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“…T HE DEVELOPMENT of a stationary phase approximation [I] for the fields in the transverse focal region of a spherical reflector builds upon results obtained earlier in geometric optics [2], [3] and polarization [4], [5] studies. Geometric optics was used to locate the focal region of a spherical reflector and map out many of its features, such as the caustic surface, the axial caustic, the paraxial focus, and the circle of least confusion, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Studies of the Focal Region of a Spherical Reflector: Polarization Effects

Cited by 10 publications

References 1 publication

An array-compensated spherical reflector antenna for a very large number of scanned beams

An array-compensated spherical reflector antenna for a very large number of scanned beams

Study of the field around the focal region of spherical reflector antenna

Studies of the focal region of a spherical reflector: Stationary phase evaluation

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