Properties of focused apertures in the fresnel region

Sherman, John W.

doi:10.1109/tap.1962.1137900

Cited by 217 publications

(93 citation statements)

References 2 publications

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“…The main lobes shown in Fig 5 were slightly shifted from the focus and was due to a field spreading factor [11]. This is in line with the results reported in [5], [9], [12]. The calculated shifts of the focus, measured in percentage (%), are given by shift(m) F (m) × 100 and provided in Table I.…”

Section: Analytical Resultssupporting

confidence: 88%

Optimal E-Field Vector Combination for a Highly Focused Antenna-Array

Sharma

Zuazola

Martínez

et al. 2014

Antennas Wirel. Propag. Lett.

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This is an accepted pre-published version of this paper. © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. AbstractA near-field highly focused circular phased-array antenna for 5.8 GHz Radio Frequency IDentification (RFID) applications is presented. The Electric field (E-field) at the focus is enhanced by a constructive vector combination in a three dimensional (3-D) coordinate system. The array dipoles of the antenna are oriented to enhance the energy confinement at the focus, and the radii of the circular array is optimized for lower sidelobe levels. As a result, the proposed design achieves an enhanced focalization of ≈ 4dB with reduced sidelobe levels of ≈ 12dB compared to earlier designs.

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Section: Analytical Resultssupporting

confidence: 88%

Optimal E-Field Vector Combination for a Highly Focused Antenna-Array

Sharma

Zuazola

Martínez

et al. 2014

Antennas Wirel. Propag. Lett.

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“…In Figure 4 a closer look at the field distributions is given, where the main beam, defined by the field values ≥ 0.707 of the maximum value, is shown. It can be seen that the filled array has a 3 dB spot size of 0.84λ × 0.84λ, which is close to the derived value for the 3 dB or Half Power Beam Width HPBW [13]:…”

Section: Computer Simulationssupporting

confidence: 85%

“…The I n values are chosen according to the required amplitude tapering to control the sidelobe level. In order to achieve a spot beam on the normal to the array at a focal distance F from the array antenna, the following quadratic phase distribution need to be used [10,13]: where (x n , y n ) are the coordinates of the nth element of the array. Note that the phase factor in Eq.…”

Section: Analysis Of Focused Arraysmentioning

confidence: 99%

Investigation of Six Array Geometries for Focused Array Hyperthermia Applications

Sayidmarie¹,

Abdulkhaleq²

2012

PIER M

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Abstract-The focusing properties of six array configurations in the form of square, square with interlaced elements, square ring, cross (+) shape, cross (X) shape, and square ring plus diagonals shape arrays are investigated. The performance parameters, such as field distribution in the focal region, size of the focal spot, depth of field, level of field at focal point, and sidelobe structure, are compared. Computer simulations using MTALAB environment are performed in the investigations. The square ring and square ring plus diagonals configurations show favorable focusing properties. The resultant field patterns will help to find the arrays usefulness for hyperthermia and imaging applications.

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“…The beamwidth between 3-dB points in the focal plane is defined as the array spot size. The spot size area radius, W of a NF-focused planar array depends on the interelement distance, array size and geometry, required focal length and phase profile at the antenna aperture [19][20] …”

Section: ×8 Dielectric Resonator Antenna Elements (4×4 Sub-arrays)mentioning

confidence: 99%