US4307404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dichroic scanner for conscan antenna feed systems
Assignee: Harris Corp
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Filing: 1980-02-19
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Granted: 1981-12-22
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Expires: 2000-02-19
Abstract
Abstract A dichroic antenna scanner is comprised of transmission or reflection surfaces that impart to an incoming wave a phase shift which varies across the surface of the antenna. For this purpose, a multilayer dichroic structure may be configured to have a controlled tapered spacing between the various layers or a variable reflectance across the dichroic surface, thereby varying the cut-off frequency of the dichroic surface across its surface. Since the phase of a transmitted or reflected wave varies rapidly in the vicinity of the cut-off frequency, a variation in the cut-off frequency across the dichroic surface yields a varying phase characteristic across the antenna. Because the phase shift characteristic of the dichroic is frequency-dependent and varies sharply in the vicinity of the cut-off frequency, an incoming wave, the frequency of which is far from cut-off, will not be as greatly affected as one near cut-off, so that selection of effectively scanned and nonscanned frequencies is possible merely by adjusting the insertion loss characteristic of the multilayer dichroic structure. Selective scanning of different frequencies may be accomplished by rotating the dichroic surface structure.
Inventors
- 👤 Lock R. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:16
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/0006; H01Q15/0013; H01Q3/00; H01Q3/12; H01Q3/14; H01Q5/00; H01Q5/40; H01Q5/45
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
95 words
An antenna system comprising: a dichroic antenna structure the cut-off frequency of which varies across its surface, said dichroic structure having the property such that the degree of phase shift imparted by said structure to incident frequency signals in the vicinity of cut-off varies in dependence upon frequency; first means for directing at least one signal, the frequency of which is in the vicinity of the cut-off frequency of the dichroic antenna structure, at said dichroic antenna structure; and second means for moving said dichroic antenna structure relative to at least said one directed signal.
Claim 2
Dependent Claim
95 words
An antenna system comprising: a dichroic antenna structure the cut-off frequency of which varies across its surface, said dichroic structure having the property such that the degree of phase shift imparted by said structure to incident frequency signals in the vicinity of cut-off varies in dependence upon frequency; first means for directing at least one signal, the frequency of which is in the vicinity of the cut-off frequency of the dichroic antenna structure, at said dichroic antenna structure; and second means for moving said dichroic antenna structure relative to at least said one directed signal.
Claim 3
Dependent Claim
28 words
An antenna system according to claim 1, wherein said structure comprises a plurality of layers of artificial dielectric material the spacing between which varies across the antenna structure.
Claim 4
Dependent Claim
30 words
An antenna system according to claim 1, wherein said antenna structure comprises a plurality of layers of artificial dielectric material the sheet susceptance of which varies across the antenna structure.
Claim 5
Dependent Claim
22 words
An antenna system according to claim 3, wherein the spacing between said layers of artificial dielectric material varies across the antenna structure.
Claim 6
Dependent Claim
24 words
An antenna system according to claim 2, wherein the sheet susceptance of the layers of artificial dielectric material is constant across the antenna structure.
Claim 7
Dependent Claim
42 words
An antenna system according to claim 1, wherein said first means comprises means for directing a plurality of signals, the frequency of which is in the vicinity of the cut off frequency of said dichroic antenna structure, at said dichroic antenna structure.
Claim 8
Dependent Claim
41 words
An antenna system according to claim 1, wherein said first means comprises means for directing a signal the frequency of which is remote from the vicinity of the cut off frequency of said dichroic antenna structure, at said dichroic antenna structure.
Claim 9
Dependent Claim
26 words
An antenna system according to claim 7, wherein the frequency remote from the vicinity of the cut off frequency is lower than the cut off frequency.
Claim 10
Dependent Claim
26 words
An antenna system according to claim 7, wherein the frequency remote from the vicinity of the cut off frequency is greater than the cut off frequency.
Claim 11
Dependent Claim
28 words
An antenna system according to claim 6, wherein said antenna comprises a plurality of layers of artificial dielectric material the spacing between which varies across the antenna structure.
Claim 12
Dependent Claim
30 words
An antenna system according to claim 6, wherein said antenna structure comprises a plurality of layers of artificial dielectric material the sheet susceptance of which varies across the antenna structure.
Claim 13
Dependent Claim
22 words
An antenna system according to claim 11, wherein the spacing between said layers of artificial dielectric material varies across the antenna structure.
Claim 14
Dependent Claim
24 words
An antenna system according to claim 10, wherein the sheet susceptance of the layers of artificial dielectric material is constant across the antenna structure.
Claim 15
Dependent Claim
41 words
An antenna system according to claim 1, wherein said first means comprises means for directing a plurality of respectively different frequency signals at said dichroic antenna structure such that said different frequency signals appear to have originated from the same point.
Claim 16
Independent Claim
74 words
A method of scanning at least one frequency signal over a prescribed space comprising the steps of: directing said at least one frequency signal at a dichroic antenna structure the cut-off frequency of which varies across its surface, said dichroic antenna structure having the property such that the degree of phase shift imparted by said structure to incident frequency signals in the vicinity of cut-off varies in dependence upon frequency; and moving said surface.
Claim 17
Independent Claim
74 words
A method of scanning at least one frequency signal over a prescribed space comprising the steps of: directing said at least one frequency signal at a dichroic antenna structure the cut-off frequency of which varies across its surface, said dichroic antenna structure having the property such that the degree of phase shift imparted by said structure to incident frequency signals in the vicinity of cut-off varies in dependence upon frequency; and moving said surface.
Claim 18
Dependent Claim
28 words
A method according to claim 15, wherein said antenna structure comprises a plurality of layers of artificial dielectric material the spacing between which varies across the antenna structure.
Claim 19
Dependent Claim
29 words
A method according to claim 15, wherein said antenna structure comprises a plurality of layers of artificial dielectric material the sheet susceptance of which varies across the antenna structure.
Claim 20
Dependent Claim
21 words
A method according to claim 17, wherein the spacing between said layers of artificial dielectric material varies across the antenna structure.
Claim 21
Dependent Claim
23 words
A method according to claim 16, wherein the sheet susceptance of the layers of artificial dielectric material is constant across the antenna structure.
Claim 22
Dependent Claim
24 words
A method according to claim 15, wherein said directing step includes the step of directing a plurality of frequency signals at said antenna structure.
Claim 23
Dependent Claim
23 words
A method according to claim 20, wherein one of said frequency signals has a frequency in the vicinity of the cut off frequency.
Claim 24
Dependent Claim
27 words
A method according to claim 20, wherein more than one of said plurality of frequency signals has a frequency in the vicinity of the cut off frequency.
Claim 25
Dependent Claim
24 words
A method according to claim 21, wherein one of said frequency signals has a frequency remote from the vicinity of the cut off frequency.
Claim 26
Dependent Claim
25 words
A method according to claim 23, wherein the frequency remote from the vicinity of the cut off frequency is lower than the cut off frequency.
Claim 27
Dependent Claim
25 words
A method according to claim 23, wherein the frequency remote from the vicinity of the cut off frequency is greater than the cut off frequency.
Claim 28
Dependent Claim
24 words
A method according to claim 16, wherein said directing step includes the step of directing a plurality of frequency signals at said antenna structure.
Claim 29
Dependent Claim
23 words
A method according to claim 26, wherein one of said frequency signals has a frequency in the vicinity of the cut off frequency.
Claim 30
Dependent Claim
24 words
A method according to claim 27, wherein one of said frequency signals has a frequency remote from the vicinity of the cut off frequency.
Claim 31
Dependent Claim
37 words
A method according to claim 20, wherein said directing step comprises directing a plurality of respectively-different frequency signals at said dichroic antenna structure such that said different frequency signals appear to have originated from the same point.
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) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |