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US 6,188,370 B1Granted
Grid antennas and methods with efficient grid spacing
AssigneeCalifornia Amplifier, Inc.
InventorMark J. Lange
Life of this patent
Estimating the term…
Abstract
Paraboloidal grid reflectors and antennas are provided which are lighter and have less wind loading because they efficiently realize selected front-to-back ratios by recognizing the angular distribution in typical differential path losses and feed gains. In particular, the reflectors are formed with adjacent pairs of parallel elongate members that are positioned at respective angles θ from the paraboloidal vertex and spaced apart by respective spaces S that generally increase with increased angle θ. In some reflector embodiments, the spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and may be constant for a contiguous minority that typically adjoins the vertex. In other reflector embodiments, the spaces S increase with increased angle θ for all of the adjacent pairs.
Claims36
A reflector for reflecting an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain wherein said feed signal has a polarization, a wavelength λ and a feed gain Gfθ that angularly varies, the reflector comprising:
- a plurality of conductive elongate members which are substantially parallel and aligned with said polarization and are shaped and positoned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- wherein said elongate members are positioned so that said feed gain Gfθ varies with said angle θ;
- wherein said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determine as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and
- wherein said transmission coefficient Tθ is in accordance with Tθ=F/B−Gml+Gfθ−Ldθ.
3 more elements
An antenna for radiating an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, comprising:
- a plurality of conductive elongate members which are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- and
- a feed positioned at said focus and configured to radiate a feed signal that has a wavelength λ, a feed gain Gfθ that varies with said angle θ and a polarization that is substantially aligned with said elongate members;
- wherein said main lobe gain Gml, said differential path loss Ldq and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and a substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said transmission coefficient Tθ is in accordance with Tθ=F/B−Gml+Gfθ−Ldθ.
3 more elements
A reflector for reflecting an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain wherein said feed signal has a polarization, a wavelength λ and a feed gain Gfθ that angularly varies, the reflector comprising:
- a plurality of conductive elongate members which are substantially parallel and aligned with said polarization and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- wherein said elongate members are positioned so that said feed gain Gfθ varies with said angle θ;
- wherein said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said main lobe gain is substantially in accordance with Gml=10 log {(4πAη)/λ2} wherein A is the area of said paraboloid and η is a total aperture efficiency that is substantially between 0.45 and 0.65.
2 more elements
A reflector for reflecting an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain wherein said feed signal has a polarization, a wavelength λ and a feed gain Gfθ that angularly varies, the reflector comprising:
- a plurality of conductive elongate members which are substantially parallel and aligned with said polarization and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- wherein said elongate members are positioned so that said feed gain Gfθ varies with said angle θ;
- wherein said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said differential path loss Ldθ is substantially in accordance with Ldθ=20 log {sec2 (θ/2)}.
2 more elements
A reflector for reflecting an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain wherein said feed signal has a polarization, a wavelength λ and a feed gain Gfθ that angularly varies, the reflector comprising:
- a plurality of conductive elongate members which are substantially parallel and aligned with said polarization and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- wherein said elongate members are positioned so that said feed gain Gfθ varies with said angle θ;
- wherein said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pair and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said feed gain Gfθ is substantially in accordance with Gfθ=20 log (cosnθ) in which n is between 1 and 10.
2 more elements
An antenna for radiating an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, comprising:
- a plurality of conductive elongate members which are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- and
- a feed positioned at said focus and configured to radiate a feed signal that has a wavelength λ, a feed gain Gfθ that varies with said angle θ and a polarization that is substantially aligned with said elongate members;
- wherein said main lobe gain Gml, said differential path loss Ldq and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said main lobe gain is substantially in accordance with Gml=10 log {(4πAη)/λ2} wherein A is the area of said paraboloid and η is a total aperture efficiency that is substantially between 0.45 and 0.65.
3 more elements
An antenna for radiating an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, comprising:
- a plurality of conductive elongate members which are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- and
- a feed positioned at said focus and configured to radiate a feed signal that has a wavelength λ, a feed gain Gfθ that varies with said angle θ and a polarization that is substantially aligned with said elongate members;
- wherein said main lobe gain Gml, said differential path loss Ldq and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pair and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said differential path loss Ldθ is substantially in accordance with Ldθ=20 log {(sec2 (θ/2)}.
3 more elements
An antenna for radiating an electromagnetic feed signal to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, comprising:
- a plurality of conductive elongate members which are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid with a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- and
- a feed positioned at said focus and configured to radiate a feed signal that has a wavelength λ, a feed gain Gfθ that varies with said angle θ and a polarization that is substantially aligned with said elongate members;
- wherein said main lobe gain Gml, said differential path loss Ldq and said feed gain Gfθ, determine, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- wherein said members have respective cross sections and adjacent pairs of said members are spaced apart by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ and with respective cross sections;
- and wherein said feed gain Gfθ is substantially in accordance with Gfθ=20 log (cosnθ) in which n is between 1 and 10.
3 more elements
A method of transmitting electromagnetic energy with a wavelength λ to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, the method comprising the steps of:
- providing a plurality of conductive elongate members that are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid that has a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- radiating an electromagnetic feed signal from said focus with a polarization substantially parallel to said elongate members and a feed gain Gfθ that varies with said angle θ;
- from said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determining, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- selecting respective cross sections for said elongate members;
- and
- based on their respective cross sections, spacing adjacent pairs of said elongate members by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ;
- wherein said transmission coefficient Tθ is in accordance with Tθ=F/B−Gml+Gfθ−Ldθ.
4 more elements
A method of transmitting electromagnetic energy with a wavelength λ to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, the method comprising the steps of:
- providing a plurality of conductive elongate members that are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid that has a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ said focus that varies with an angle θ from said vertex;
- radiating an electromagnetic feed signal from said focus with a polarization substantially parallel to said elongate members and a feed gain Gfθ that varies with said angle θ;
- from said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determining, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- selecting respective cross sections for said elongate members;
- and
- based on their respective cross sections, spacing adjacent pairs of said elongate members by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ;
- wherein said main lobe gain is substantially in accordance with Gml=10 log {(4πAη)/λ2} wherein A is the area of said paraboloid and η is a total aperture efficiency that is substantially between 0.45 and 0.65.
4 more elements
A method of transmitting electromagnetic energy with a wavelength λ to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, the method comprising the steps of:
- providing a plurality of conductive elongate members that are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid that has a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path loss Ldθ from said focus that varies with an angle θ from said vertex;
- radiating an electromagnetic feed signal from said focus with a polarization substantially parallel to said elongate members and a feed gain Gfθ that varies with said angle θ;
- from said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determining, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- selecting respective cross sections for said elongate members;
- and
- based on their respective cross sections, spacing adjacent pairs of said elongate members by different spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ;
- wherein said differential path loss Ldθ is substantially in accordance with Ldθ=20 log {sec2 (θ/2)}.
4 more elements
A method of transmitting electromagnetic energy with a wavelength λ to realize a front-to-back ratio F/B of main lobe gain to rear lobe gain, the method comprising the steps of:
- providing a plurality of conductive elongate members that are substantially parallel and are shaped and positioned to lie upon the surface of an imaginary paraboloid that has a focus and a vertex, said elongate members thereby having a main lobe gain Gml and a differential path lose Ldθ from said focus that varies with an angle θ from said vertex;
- radiating an electromagnetic feed signal from said focus with a polarization substantially parallel to said elongate members and a feed gain Gfθ that varies with said angle θ;
- from said main lobe gain Gml, said differential path loss Ldθ and said feed gain Gfθ, determining, as a function of said angle θ, a transmission coefficient Tθ that realizes said front-to-back ratio F/B;
- selecting respective cross sections for said elongate members;
- and
- based on their respective cross sections, spacing adjacent pairs of said elongate members by different spaces S wherein said spaces S wherein said spaces S increase with increased angle θ for a contiguous majority of adjacent pairs and are substantially constant for a contiguous minority that typically adjoins said vertex to realize said transmission coefficient Tθ at respective angles θ;
- Gfθ=20 log (cos1.3θ).
4 more elements
Dependencies are inferred from the claim text.