Patent US4661820A successfully refreshed from Google Patents.
US4661820A
Expired / Lapsed
US
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Method and equipment for picking up antenna patterns in near-fields
Assignee: Office National d'Études et de Recherches Aérospatiales
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Filing: 1984-07-02
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Granted: 1987-04-28
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Expires: 2004-07-02
Abstract
Abstract Method and equipment are disclosed for picking up the radiation pattern of an antenna to be tested from measurements in near-field. The antenna to be tested is illuminated by a transmit antenna having wavefronts in the shape of circular cylinders. The radiation pattern of the antenna to be tested then is expressed by an integral transform of a unidimensional function which is solved by computing means.
Inventors
- 👤 Christian Pouit
- 👤 Rene Guern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:48
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/08; G01R29/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
234 words
A method for determining the radiation pattern of a test antenna based on near field measurements and on near-to-far field conversion calculations, comprising the steps of (a) rotating the test antenna about a rotation axis; (b) positioning the test antenna at discrete angular positions about said rotation axis; (c) illuminating the test antenna with a transmit antenna, said transmit antenna being arranged sufficiently close to the test antenna, whereby a planar wavefront for the wave transmitted by said transmit antenna is prevented at the location of the test antenna, said transmit antenna having a radiation pattern in the shape of a circular cylinder with the direction of the generating line of the cylinder being parallel to said rotation axis; (d) storing sample signals received by the test antenna at each angular position thereof, whereby the radiation pattern of the test antenna is a Fourier integral transform of the function formed by said sample signals, said function being multiplied by a kernel function; (e) transforming said sample signals by Fourier transform, thereby to obtain Fourier transformed sample signals; (f) generating samples of said kernel function; (g) transforming said kernel function samples by Fourier transform, thereby to obtain Fourier transformed kernel samples; (h) multiplying said Fourier transformed sample signals by said Fourier transformed kernel samples on a term by term basis, thereby to obtain multiplied samples; and (i) transforming said multiplied samples by inverse Fourier transforms.
Claim 2
Independent Claim
234 words
A method for determining the radiation pattern of a test antenna based on near field measurements and on near-to-far field conversion calculations, comprising the steps of (a) rotating the test antenna about a rotation axis; (b) positioning the test antenna at discrete angular positions about said rotation axis; (c) illuminating the test antenna with a transmit antenna, said transmit antenna being arranged sufficiently close to the test antenna, whereby a planar wavefront for the wave transmitted by said transmit antenna is prevented at the location of the test antenna, said transmit antenna having a radiation pattern in the shape of a circular cylinder with the direction of the generating line of the cylinder being parallel to said rotation axis; (d) storing sample signals received by the test antenna at each angular position thereof, whereby the radiation pattern of the test antenna is a Fourier integral transform of the function formed by said sample signals, said function being multiplied by a kernel function; (e) transforming said sample signals by Fourier transform, thereby to obtain Fourier transformed sample signals; (f) generating samples of said kernel function; (g) transforming said kernel function samples by Fourier transform, thereby to obtain Fourier transformed kernel samples; (h) multiplying said Fourier transformed sample signals by said Fourier transformed kernel samples on a term by term basis, thereby to obtain multiplied samples; and (i) transforming said multiplied samples by inverse Fourier transforms.
Claim 3
Dependent Claim
245 words
Apparatus for determining the radiation pattern of a test antenna based on near field measurements and on near-to-far field conversion calculations, comprising: (a) means for rotating the test antenna about a rotation axis and for positioning the test antenna at discrete angular positions about said rotation axis; (b) means for illuminating the test antenna by a transmit antenna, said transmit antenna being arranged sufficiently close to the test antenna, whereby a planar wavefront for the wave transmitted by said transmit antenna is prevented at the location of the test antenna, said transmit antenna having a radiation pattern in the shape of a circular cylinder with the direction of the generating line of the cylinder being parallel to said rotation axis; (c) means for storing sample signals received by the test antenna at every angular position thereof, whereby the radiation pattern of the test antenna is a Fourier integral transform of the function formed by said sample signals, said function being multiplied by a kernel function; (d) means for transforming said sample signals by Fourier transforms, thereby to obtain Fourier transformed sample signals; (e) means for generating samples of said kernel function; (f) means for transforming said kernel function samples by Fourier transform, thereby to obtain Fourier transformed kernel samples; (g) means for multiplying the Fourier transformed sample signals by the Fourier transformed kernel samples on a term-by-term basis, thereby to obtain multiplied samples; and (h) means for transforming said multiplied samples by inverse Fourier transform.
Claim 4
Dependent Claim
245 words
Apparatus for determining the radiation pattern of a test antenna based on near field measurements and on near-to-far field conversion calculations, comprising: (a) means for rotating the test antenna about a rotation axis and for positioning the test antenna at discrete angular positions about said rotation axis; (b) means for illuminating the test antenna by a transmit antenna, said transmit antenna being arranged sufficiently close to the test antenna, whereby a planar wavefront for the wave transmitted by said transmit antenna is prevented at the location of the test antenna, said transmit antenna having a radiation pattern in the shape of a circular cylinder with the direction of the generating line of the cylinder being parallel to said rotation axis; (c) means for storing sample signals received by the test antenna at every angular position thereof, whereby the radiation pattern of the test antenna is a Fourier integral transform of the function formed by said sample signals, said function being multiplied by a kernel function; (d) means for transforming said sample signals by Fourier transforms, thereby to obtain Fourier transformed sample signals; (e) means for generating samples of said kernel function; (f) means for transforming said kernel function samples by Fourier transform, thereby to obtain Fourier transformed kernel samples; (g) means for multiplying the Fourier transformed sample signals by the Fourier transformed kernel samples on a term-by-term basis, thereby to obtain multiplied samples; and (h) means for transforming said multiplied samples by inverse Fourier transform.
Claim 5
Dependent Claim
70 words
A device for determining the radiation pattern of a test antenna according to claim 2, wherein said transmit antenna having a radiation pattern in the shape of a circular cylinder is formed by two parallel metal flanges and a metal reflector in the shape of a parabolic cylinder, said transmit antenna having an open-end in the shape of a flat rectangle and feed means at the center of said rectangle.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-27 | 1990-10-27 | 1991-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-27 | 1994-10-27 | 1995-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-27 | 1998-10-27 | 1999-04-28 | $7700.00 | Window Closed / Lapsed |