Patent US3541516A successfully refreshed from Google Patents.
US4684952A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microstrip reflectarray for satellite communication and radar cross-section enhancement or reduction
Assignee: Ball Corp
•
Filing: 1982-09-24
•
Granted: 1987-08-04
•
Expires: 2002-09-24
Abstract
Abstract A passive array of resonantly-dimensioned microstrip antenna radiator patches are closely spaced (i.e., less than one-tenth wavelength) above a ground plane and individually associated with transmission line segments terminated so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along the transmission lines and are absorbed by the terminations or reflected therefrom. In the latter case, the reflected r.f. energy is re-transmitted in a predetermined direction as a re-directed r.f. electromagnetic field. The presently preferred embodiment is a relatively thin, flexible and thus conformable layered structure formed by selectively etching conductive material from one side of a metallically cladded dielectric sheet. For satellite communication, a flat reflectarray may be associated with a primary r.f. transmitter/receiver structure disposed at a focal area or spot of the reflectarray having an appropriately phased aperture (e.g., parabolic). For radar cross-section enhancement or reduction, the reflectarray aperture is phased so as to retro-reflect incident r.f. fields or so as to scatter, otherwise misdirect or absorb (e.g., by using lossy resistive transmission line terminations) the incident r.f. field.
Inventors
- 👤 Robert E. Munson
- 👤 Hussain A. Haddad
- 👤 John W. Hanlen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:47
CPC Classifications
H; H01; H01Q; H01Q21/00; H01Q21/06; H01Q21/061; H01Q21/065; H01Q3/00; H01Q3/44; H01Q3/46
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
191 words
A reflectarray of passive microstrip antenna radiators comprising: an electriclally conducted reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antenna radiator elements spaced less than one-tenth wavelength at the intended antenna operating frequency above said reference surface; each of said radiator elements defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlying reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling passive transmission line means, each being coupled to a respective individual one of said radiator elements and having predetermined respective length and terminating impedance of a short or open circuit so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means and to re-transmit in a predetermined direction a re-directed r.f. electromagnetic field in response to substantially complete reflection of r.f. electrical currents from the terminations of said transmission line means.
Claim 2
Dependent Claim
191 words
A reflectarray of passive microstrip antenna radiators comprising: an electriclally conducted reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antenna radiator elements spaced less than one-tenth wavelength at the intended antenna operating frequency above said reference surface; each of said radiator elements defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlying reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling passive transmission line means, each being coupled to a respective individual one of said radiator elements and having predetermined respective length and terminating impedance of a short or open circuit so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means and to re-transmit in a predetermined direction a re-directed r.f. electromagnetic field in response to substantially complete reflection of r.f. electrical currents from the terminations of said transmission line means.
Claim 3
Dependent Claim
120 words
A reflectarray of microstrip antenna radiators as in claim 2 wherein: said array of radiator elements is spaced and physically supported above said reference surface by a layer of dielectric material having said reference surface cladded to one side thereof; said radiator elements and their respectively associated transmission line means are integrally formed from a common metallic layer cladded to the other side of said dielectric material layer by selective removal thereof so as to form individual integrally connected radiator elements and associated microstrip transmission line segments, each radiator element and its connected transmission line segment being electrically isolated from the others; said dielectric layer and its cladded metallic surfaces being sufficiently flexible to be conformable to shaped non-planar surfaces.
Claim 4
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said terminating impedances include open circuits.
Claim 5
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said terminating impedances include short circuits.
Claim 6
Dependent Claim
42 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said terminating impedances include electrically controllable elements which present an r.f. termination short or open circuit impedance that can be changed by application of a controlling electrical signal thereto.
Claim 7
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 5 wherein said electrically controllable impedance elements comprise switchable diodes.
Claim 8
Dependent Claim
33 words
A reflectarrary of microstrip antenna radiators as in claim 1 or 2 wherein said re-directed r.f. electromagnetic field is retro-reflected in a direction back towards the origin of the incident r.f. electromagnetic field.
Claim 9
Dependent Claim
33 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said re-directed r.f. electromagnetic field is directed so as to substantially avoid the origin of the incident r.f. electromagnetic field.
Claim 10
Dependent Claim
47 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 further comprising a primary receiving antenna structure disposed at a predetermined location with respect to said array of radiator elements and wherein said re-directed r.f. electromagnetic field is directed towards said primary receiving antenna structure.
Claim 11
Dependent Claim
20 words
A reflectarray of microstrip antenna radiators as in claim 9 wherein said primary receiving antenna structure comprises a microwave horn.
Claim 12
Dependent Claim
55 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 further comprising a primary transmitting antenna structure disposed at a predetermined location with respect to said array of radiator elements and wherein an r.f. electromagnetic field from said primary transmitting antenna structure incident upon said array is re-transmitted towards a predetermined receiving site.
Claim 13
Dependent Claim
43 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein each of said microstrip antenna radiator elements includes a two-dimensional surface and wherein at least one dimension thereof is substantially equal to one-half wavelength at the intended antenna operating frequency.
Claim 14
Dependent Claim
30 words
A reflectarray of microstrip antenna radiators as in claim 12 wherein the other dimension of said two-dimensional surface is substantially greater than one-half wavelength at the intended antenna operating frequency.
Claim 15
Dependent Claim
23 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said individual phase-controlling transmission line means includes a phase shifter.
Claim 16
Dependent Claim
29 words
A reflectarray of microstrip antenna radiators as in claim 1 or 2 wherein said radiator elements are dimensioned so as to receive/transmit circularly or elliptically polarized r.f. electromagnetic radiation.
Claim 17
Dependent Claim
39 words
A reflectarray of microstrip antenna radiators as in claim 15 wherein said individual phase-controlling transmission line means includes a phase shifter designed to provide/accept two electrical signals having a 90° relative phase difference at the intended antenna operating frequency.
Claim 18
Dependent Claim
116 words
An antenna system for receiving r.f. electromagnetic radiation from an earth satellite station, said antenna system comprising: a passive reflectarray of microstrip antenna radiator patches spaced above an electrical reference surface by less than one-tenth wavelength; said patches having at least one resonant dimension substantially equal to one-half wavelength at the intended antenna operating frequency and having respective individually short or open circuit terminated microstrip transmission lines integrally connected therewith and differently dimensioned across the array aperture so as to reflect and re-direct r.f. electromagnetic radiation incident upon the array towards a predetermined direction; and a primary r.f. electromagnetic radiation receiving structure fixedly disposed with respect to said reflectarray so as to intercept said re-directed radiation.
Claim 19
Dependent Claim
116 words
An antenna system for receiving r.f. electromagnetic radiation from an earth satellite station, said antenna system comprising: a passive reflectarray of microstrip antenna radiator patches spaced above an electrical reference surface by less than one-tenth wavelength; said patches having at least one resonant dimension substantially equal to one-half wavelength at the intended antenna operating frequency and having respective individually short or open circuit terminated microstrip transmission lines integrally connected therewith and differently dimensioned across the array aperture so as to reflect and re-direct r.f. electromagnetic radiation incident upon the array towards a predetermined direction; and a primary r.f. electromagnetic radiation receiving structure fixedly disposed with respect to said reflectarray so as to intercept said re-directed radiation.
Claim 20
Dependent Claim
29 words
An antenna system as in claim 17 wherein said passive reflectarray is approximately planar and suited for affixation to a wall structure generally directed toward the earth satellite station.
Claim 21
Dependent Claim
23 words
An antenna system as in claim 17 or 18 wherein said primary r.f. electromagnetic radiation receiving structure comprises a microwave gude horn structure.
Claim 22
Dependent Claim
42 words
An antenna system as in claim 17 or 18 wherein said terminated transmission lines are dimensioned relative to one another so as to provide a parabolic phase taper across the at least one dimension of the aperture of the arrayed radiator patches.
Claim 23
Dependent Claim
183 words
An array of microstrip antenna radiators for reducing the radar cross-section of an object to which it is affixed, said array comprising: an electrically conducting reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antennna radiator elements spaced less than one-tenth wavelength at the intended antenna operating frequency above said reference surface; each of said passive radiator elements defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlyiing reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling passive transmission line means, each being coupled to a respective individial one of said radiator elements and having predetermined respective length and terminating impedance including electrical resistance to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means and to substantially dissipate said electrical currents by passage through said resistance.
Claim 24
Dependent Claim
183 words
An array of microstrip antenna radiators for reducing the radar cross-section of an object to which it is affixed, said array comprising: an electrically conducting reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antennna radiator elements spaced less than one-tenth wavelength at the intended antenna operating frequency above said reference surface; each of said passive radiator elements defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlyiing reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling passive transmission line means, each being coupled to a respective individial one of said radiator elements and having predetermined respective length and terminating impedance including electrical resistance to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means and to substantially dissipate said electrical currents by passage through said resistance.
Claim 25
Dependent Claim
120 words
An array of microstrip antenna radiators as in claim 21 wherein: said array of radiator elements is spaced and physically supported above said reference surface by a layer of dielectric material having said reference surface cladded to one side thereof; said radiator elements and their respectively associated transmission line means are integrally formed from a common metallic layer cladded to the other side of said dielectric material layer by selective removal thereof so as to form individual integrally connected radiator elements and associated microstrip transmission line segments, each radiator element and its connected transmission line segment being electrically isolated from the others; said dielectric layer and its cladded metallic surfaces being sufficiently flexible to be conformable to shaped non-planar surfaces.
Claim 26
Dependent Claim
19 words
An array of microstrip antenna radiators as in claim 22 wherein said dielectric material includes resistive material embedded therewithin.
Claim 27
Dependent Claim
37 words
A reflectarray of microstrip antenna radiators as in claim 21 or 22 wherein said terminating impedance electrically controllable elements which present an r.f. termination condition that can be changed by application of a controlling electrical signal thereto.
Claim 28
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 24 wherein said electrically controllable impedance elements comprise switchable diodes.
Claim 29
Dependent Claim
33 words
A reflectarray of microstrip antenna radiators as in claim 21 or 22 wherein said re-directed r.f. electromagnetic field is directed so as to substantially avoid the origin of the incident r.f. electromagnetic field.
Claim 30
Dependent Claim
222 words
A reflectarray of passive microstrip antenna radiators for enhancing the radar cross-section of an object to which it is attached, said reflectarray comprising: an electrically conducting reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antenna radiator elements spaced less than one-thenth wavelength at the intended antenna operating frequency above said reference surface; each of said passive radiator elements thus defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlying reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling transmission line means, each being coupled to a respective individual one of said radiator elements and having predetermined respective length and terminating open or short circuit impedance so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means, to reflect substantially all of said currents from said termination and to re-transmit in a predetermined direction substantially toward the source of said incident r.f. field a re-directed r.f. electromagnetic field in response to reflection of r.f. electrical currents from the terminations of said transmission line means.
Claim 31
Dependent Claim
222 words
A reflectarray of passive microstrip antenna radiators for enhancing the radar cross-section of an object to which it is attached, said reflectarray comprising: an electrically conducting reference surface; an array of resonantly-dimensioned electrically conducting passive microstrip antenna radiator elements spaced less than one-thenth wavelength at the intended antenna operating frequency above said reference surface; each of said passive radiator elements thus defining a resonant cavity between it and the underlying reference surface and also defining at least one radiation slot between at least one edge of the radiator element and the underlying reference surface, said slot coupling r.f. energy to/from said element and the resonant cavity at the intended antenna operating frequency; and a plurality of individual phase-controlling transmission line means, each being coupled to a respective individual one of said radiator elements and having predetermined respective length and terminating open or short circuit impedance so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r.f. electrical currents which flow along said transmission line means, to reflect substantially all of said currents from said termination and to re-transmit in a predetermined direction substantially toward the source of said incident r.f. field a re-directed r.f. electromagnetic field in response to reflection of r.f. electrical currents from the terminations of said transmission line means.
Claim 32
Dependent Claim
120 words
A reflectarray of microstrip antenna radiators as in claim 27 wherein: said array of radiator elements is spaced and physically supported above said reference surface by a layer of dielectric material having said reference surface cladded to one side thereof; said radiator elements and their respectively associated transmission line means are integrally formed from a common metallic layer cladded to the other side of said dielectric material layer by selective removal thereof so as to form individual integrally connected radiator elements and associated microstrip transmission line segments, each radiator element and its connected transmission line segment being electrically isolated from the others; said dielectric layer and its cladded metallic surfaces being sufficiently flexible to be conformable to shaped non-planar surfaces.
Claim 33
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 27 or 28 wherein said terminating impedances include open circuits.
Claim 34
Dependent Claim
19 words
A reflectarray of microstrip antenna radiators as in claim 27 or 28 wherein said terminating impedances include short circuits.
Claim 35
Dependent Claim
43 words
A reflectarray of microstrip antenna radiators as in claim 27 or 28 wherein each of said microstrip antenna radiator elements includes a two-dimensional surface and wherein at least one dimension thereof is substantially equal to one-half wavelength at the intended antenna operating frequency.
Claim 36
Dependent Claim
30 words
A reflectarray of microstrip antenna radiators as in claim 31 wherein the other dimension of said two-dimensional surface is substantially greater than one-half wavelength at the intended antenna operating frequency.
Claim 37
Dependent Claim
23 words
A reflectarray of microstrip antenna radiators as in claim 27 or 28 wherein said individual phase-controlling transmission line means includes a phase shifter.
Claim 38
Dependent Claim
29 words
A reflectarray of microstrip antenna radiators as in claim 27 or 28 wherein said radiator elements are dimensioned so as to receive/transmit circularly or elliptically polarized r.f. electromagnetic radiation.
Claim 39
Dependent Claim
127 words
An antenna system for transmitting r.f. electromagnetic radiation to an earth satellite station, said antenna system comprising: a passive reflectarray of microstrip antenna radiator patches spaced above an electrical reference surface by less than one-tenth wavelength; said patches having at least one resonant dimension substantially equal to one-half wavelength at the intended antenna operating frequency and having respective individually open or short circuit terminated microstrip transmission lines integrally connected therewith and differently dimensioned across the array aperture so as to re-direct r.f. electromagnetic radiation incident upon the array from a first predetermined direction towards a second predetermined direction; and a primary r.f. electromagnetic radiation transmitting structure fixedly disposed with respect to said reflectarray so as to direct r.f. radiation towards said reflectarray along said first predetermined direction.
Claim 40
Dependent Claim
127 words
An antenna system for transmitting r.f. electromagnetic radiation to an earth satellite station, said antenna system comprising: a passive reflectarray of microstrip antenna radiator patches spaced above an electrical reference surface by less than one-tenth wavelength; said patches having at least one resonant dimension substantially equal to one-half wavelength at the intended antenna operating frequency and having respective individually open or short circuit terminated microstrip transmission lines integrally connected therewith and differently dimensioned across the array aperture so as to re-direct r.f. electromagnetic radiation incident upon the array from a first predetermined direction towards a second predetermined direction; and a primary r.f. electromagnetic radiation transmitting structure fixedly disposed with respect to said reflectarray so as to direct r.f. radiation towards said reflectarray along said first predetermined direction.
Claim 41
Dependent Claim
29 words
An antenna system as in claim 35 wherein said passive reflectarray is approximately planar and suited for affixation to a wall structure generally directed toward the earth satellite station.
Claim 42
Dependent Claim
23 words
An antenna system as in claim 35 or 36 wherein said primary r.f. electromagnetic radiation transmitting structure comprises a microwave guide horn structure.
Claim 43
Dependent Claim
42 words
An antenna system as in claim 35 or 36 wherein said terminated transmission lines are dimensioned relative to one another so as to provide a parabolic phase taper across the at least one dimension of the aperture of the arrayed radiator patches.
References Cited (Backward Citations)
US29296A
Cited
US29911A
Cited
US3408653A
Cited
US3713162A
Cited
US3810183A
Cited
USRE29296E
Cited
US3811128A
Cited
US3921177A
Cited
USRE29911E
Cited
US3938161A
Cited
US3971032A
Cited
US4070676A
Cited
US4012741A
Cited
US4051477A
Cited
US4180817A
Cited
US4079268A
Cited
US4110751A
Cited
US4131894A
Cited
US4233607A
Cited
US4320404A
Cited
US4259670A
Cited
US4320401A
Cited
US4220956A
Cited
US4358771A
Cited
US4287518A
Cited
US4445121A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |