Parabolic antenna system having high-illumination and spillover efficiencies

Claim 2

An antenna system having a main focusing means for redirecting energy having a focus proximate the axis of symmetry of said main focusing means and a feed device having a phase center proximate the axis of symmetry, said antenna system including a dielectric energy refracting means through which a beam transmitted between said main focusing means and said feed device passes, said refracting means having a first irregular surface means at which energy is redirected and substantially wholly comprising segments whose slopes are each a function of beam intensity at the segment to redirect the beam across an intervening space to a boundary at which the intensity of the beam has a relative distribution within the beam different from that of the beam at the first surface means, and a second irregular surface means at said boundary comprising a plurality of segments having slopes which are a function of the directions of the redirected beam at the segments for further redirecting the beam to proceed along a course comprising lines extending from one of said focus and center, said slopes of the segments of one of said irregular surface means of said refracting means being a function of a first angle between the axis of symmetry of said main focusing means and the apparent line of travel of energy through said focus and a second angle formed between the axis of symmetry and the line of travel of said energy through said refracting means, and said slopes of the segments of the other of said irregular surface means being a function of said second angle and of a third angle between the axis of symmetry and the apparent line of travel of energy through said phase center.

Claim 3

The antenna system of claim 1 wherein said energy refracting means is a transparent lens; and the two surface means of the lens are defined by the equations: - (dr/rd theta ) sin ( theta - Alpha )/(1/ Square Root epsilon ) - cos ( theta - Alpha ) (1) da/ad Beta Square Root epsilon sin ( Beta - Alpha )/ Square Root epsilon cos ( Beta - Alpha ) - 1 (2) tan Alpha (a sin Beta - r sin theta )/(P1 P2 + a cos Beta - r cos theta ) (4) wherein: a the distance from said focus to said one surface means epsilon the dielectric constant of said refracting means Beta said first angle Beta m maximum value of Beta Alpha said second angle r the distance from said phase center to said other of said surface means theta said third angle theta m maximum value of theta .

Claim 4

The antenna system of claim 1 wherein said refracting means is located between said feed device and said main focusing means; and wherein substantially all of the energy coupled to said feed device passes through said refracting means.

Claim 5

An antenna system as defined in claim 1 and wherein a relative distribution of intensity of the reflected beam resulting external to the antenna is substantially uniform, and wherein said beam has a first phase front about said focus and has a second phase front about said phase center and at least one of said first and second phase fronts is approximately spherical.

Claim 6

An antenna system having a main focusing means for redirecting energy having a focus proximate the axis of symmetry of said main focusing means and a feed device having a phase center proximate the axis of symmetry, said antenna system including a dielectric energy refracting means through which a beam transmitted between said main focUsing means and said feed device passes, said refracting means having a first irregular surface means at which energy is redirected and substantially wholly comprising segments whose slopes are each a function of beam intensity at the segment to redirect the beam across an intervening space to a boundary at which the intensity of the beam has a relative distribution within the beam different from the beam redirected by the first surface means, and a second irregular surface means at said boundary comprising a plurality of segments having slopes which are a function of the directions of the redirected beam at the segments for further redirecting the beam to proceed along a source comprising lines extending from one of said focus and center, said refracting means including highly reflective means on one of said irregular surface means, said refracting means being arranged so that energy in said beam passes in a first direction through the other of said surface means and through said refracting means and impinges upon said reflective means and passes through aid refracting means in a second direction between said reflective means and through said other surface means, said slopes of said other of said surface means being a function of a first angle formed between said axis of symmetry of the main focusing means and the line of travel of said energy along lines extending from the focal point of said main focusing means and a second angle formed between said axis and the line of travel of said energy as it passes through said refraction means, said slopes of the one of said surface means having said reflective means being a function of said second angle and a third angle formed between said axis and the line of travel of said energy as it passes in said second direction through said refracting means; and said slopes of the other of said surface means of said refracting means being a function of said third angle and a fourth angle formed between the axis of symmetry of said main focusing means and the line of travel of said energy along lines extending from said phase center.

Claim 7

An antenna system having a main focusing means for redirecting energy having a focus proximate the axis of symmetry of said main focusing means and a feed device having a phase center proximate the axis of symmetry, said antenna system including a dielectric energy refracting means through which a beam transmitted between said main focUsing means and said feed device passes, said refracting means having a first irregular surface means at which energy is redirected and substantially wholly comprising segments whose slopes are each a function of beam intensity at the segment to redirect the beam across an intervening space to a boundary at which the intensity of the beam has a relative distribution within the beam different from the beam redirected by the first surface means, and a second irregular surface means at said boundary comprising a plurality of segments having slopes which are a function of the directions of the redirected beam at the segments for further redirecting the beam to proceed along a source comprising lines extending from one of said focus and center, said refracting means including highly reflective means on one of said irregular surface means, said refracting means being arranged so that energy in said beam passes in a first direction through the other of said surface means and through said refracting means and impinges upon said reflective means and passes through aid refracting means in a second direction between said reflective means and through said other surface means, said slopes of said other of said surface means being a function of a first angle formed between said axis of symmetry of the main focusing means and the line of travel of said energy along lines extending from the focal point of said main focusing means and a second angle formed between said axis and the line of travel of said energy as it passes through said refraction means, said slopes of the one of said surface means having said reflective means being a function of said second angle and a third angle formed between said axis and the line of travel of said energy as it passes in said second direction through said refracting means; and said slopes of the other of said surface means of said refracting means being a function of said third angle and a fourth angle formed between the axis of symmetry of said main focusing means and the line of travel of said energy along lines extending from said phase center.

Claim 8

the antenna system of claim 5 wherein said reflective means on said one surface means and said other surface means are defined by the equations: dr/rd theta Square Root epsilon sin ( theta - Alpha )/ Square Root epsilon cos ( theta - Alpha ) - 1 (5) da/ad Beta Square Root epsilon sin ( Beta - xi )/ Square Root epsilon cos ( Beta - xi ) - 1 (6) dx/dy - tan ( xi - Alpha )/2 (8) Alpha tan 1 (y - r sin theta )/P1P2 - x - r cos theta ) (9) xi tan 1 (a sin Beta - y)/(a cos Beta - x) (10) wherein: epsilon the dielectric constant of said refracting means a the distance from said focus to said other of said surfaces along said lines extending from said focal point Beta said first angle Beta m maximum value of Beta xi said second angle theta said fourth angle theta m maximum value of theta Alpha said third angle r the distance from said phase center to said other surface along said lines extending from said phase center x a coordinate of a rectangular coordinate system having its origin at said first focal point, extending along said axis y a coordinate of said coordinate system extending transversely to said axis.

Claim 9

The antenna system of claim 1 wherein said highly reflective means is a metallic surface; and wherein said feed device is located between said refracting means and said main focusing means; said refracting means being situated between said metallic surface and said feed device.

Claim 10

An antenna system as defined in claim 5 and wherein a relative distribution of intensity of the reflecTed beam resulting external to the antenna is substantially uniform, and wherein said beam has a first phase front about said focus and has a second phase front about said phase center and at least one of said first and second phase fronts is approximately spherical.

Claim 11

An antenna apparatus for transmitting or receiving electromagnetic power comprising main focusing means for redirecting power with a principal axis and having a geometric focus, and a feed device having a phase center and a power density pattern F( theta ), comprising lens means having first and second boundary portions for changing the direction of propagation of electromagnetic power received thereon, the power between said phase center and said main focusing means being a beam having a first segment at least a portion of which is between said phase center and lens means and a second segment at least a portion of which is between said lens means and said main focusing means, said first and second boundaries extending generally transversely of the axis and said second boundary being offset a distance along the beam route from the first means in a downstream direction for power flow, said first beam segment being directed along lines emanating from said phase center at various directional angles theta up to an angle theta m, said second beam segment being directed along lines emanating from said focus at various directional angles Beta up to an angle Beta m, both theta and Beta being measured from the principal axis, said apparatus having a first phase wavefront shape and a first power density distribution F( theta ) in the first beam segment up to the angle theta m, and having a substantially spherical second phase wavefront shape and a substantially uniform second power density distribution of said beam as measured with respect to the angle Beta in the second beam segment up to the angle Beta m, said first means receiving one of said beam segments and being configured to be comprised of differential segments for redirecting by differing amounts the portions of received beam power received upon the segments at differing distances from said axis and cooperating with said offset distance to convert the power density distribution within said beam to the distribution in the other of said beam segments, said second boundary being configured to be comprised of a plurality of differential segments for redirecting by differing amounts the portions of beam power received upon segments at differing distances from said axis to follow lines emanating at angles theta and Beta respectively from one of said center and focus, and wherein the portions of beam power flowing at any directional angle theta in the first segment flow at a respective directional angle Beta in accordance with the relationship

Claim 12

An antenna apparatus for transmitting or receiving electromagnetic power comprising main focusing means for redirecting power with a principal axis and having a geometric focus, and a feed device having a phase center and a power density pattern F( theta ), comprising lens means having first and second boundary portions for changing the direction of propagation of electromagnetic power received thereon, the power between said phase center and said main focusing means being a beam having a first segment at least a portion of which is between said phase center and lens means and a second segment at least a portion of which is between said lens means and said main focusing means, said first and second boundaries extending generally transversely of the axis and said second boundary being offset a distance along the beam route from the first means in a downstream direction for power flow, said first beam segment being directed along lines emanating from said phase center at various directional angles theta up to an angle theta m, said second beam segment being directed along lines emanating from said focus at various directional angles Beta up to an angle Beta m, both theta and Beta being measured from the principal axis, said apparatus having a first phase wavefront shape and a first power density distribution F( theta ) in the first beam segment up to the angle theta m, and having a substantially spherical second phase wavefront shape and a substantially uniform second power density distribution of said beam as measured with respect to the angle Beta in the second beam segment up to the angle Beta m, said first means receiving one of said beam segments and being configured to be comprised of differential segments for redirecting by differing amounts the portions of received beam power received upon the segments at differing distances from said axis and cooperating with said offset distance to convert the power density distribution within said beam to the distribution in the other of said beam segments, said second boundary being configured to be comprised of a plurality of differential segments for redirecting by differing amounts the portions of beam power received upon segments at differing distances from said axis to follow lines emanating at angles theta and Beta respectively from one of said center and focus, and wherein the portions of beam power flowing at any directional angle theta in the first segment flow at a respective directional angle Beta in accordance with the relationship