US4476471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
Assignee: NEC Corp
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Filing: 1982-02-08
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Granted: 1984-10-09
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Expires: 2002-02-08
Abstract
Abstract An antenna having a frequency separator of the type comprising plural lattice structures of a periodic conductive pattern. Each lattice structure exhibits an inherent resonance frequency and an inductance-capacitance effect at frequencies below the inherent resonance frequency. The periodic conductive patterns are selected so that each of the lattice structures exhibits substantially the same inherent resonance frequency, and when placed at selected intervals, the plurality of lattice structures exhibit interactive resonance at frequencies below the inherent resonance frequencies. Each lattice also exhibits substantially equal inductance and capacitance with respect to obliquely incident electromagnetic waves in the TE and TM modes.
Inventors
- 👤 Ikuro Sato
- 👤 Susumu Tamagawa
- 👤 Ryuichi Iwata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:28
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/0006; H01Q15/0013; H01Q15/0033; H01Q5/00; H01Q5/40; H01Q5/45
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
129 words
A frequency separator means for use in an antenna apparatus, said means comprising, a plurality of frequency-selective reflecting surface members for separating electromagnetic waves, each of said surface members composed of a lattice of conductive material having a periodic pattern, said lattice exhibiting the effect of an inductive-capacitive circuit element in a first relatively low frequency region and having an inherent resonance frequency at a frequency higher than said first region, said lattice being shaped to exhibit substantially equal inductance and capacitance with respect to obliquely incident TE and TM mode electromagnetic waves at said inherent resonance frequency and said first region, all of said surface members having substantially equal inherent resonance frequencies, and said surface members being disposed to have interactive resonance at frequencies within said first region.
Claim 2
Dependent Claim
129 words
A frequency separator means for use in an antenna apparatus, said means comprising, a plurality of frequency-selective reflecting surface members for separating electromagnetic waves, each of said surface members composed of a lattice of conductive material having a periodic pattern, said lattice exhibiting the effect of an inductive-capacitive circuit element in a first relatively low frequency region and having an inherent resonance frequency at a frequency higher than said first region, said lattice being shaped to exhibit substantially equal inductance and capacitance with respect to obliquely incident TE and TM mode electromagnetic waves at said inherent resonance frequency and said first region, all of said surface members having substantially equal inherent resonance frequencies, and said surface members being disposed to have interactive resonance at frequencies within said first region.
Claim 3
Dependent Claim
27 words
A frequency separator means as claimed in claim 1, wherein said frequency separator means is transmissive at both said inherent resonance frequency and said interactive resonance frequency.
Claim 4
Dependent Claim
28 words
A frequency separator means as claimed in claim 2, wherein said periodic pattern of conductive material defines apertures having any one of rectangular, elliptical, crossed and circular shapes.
Claim 5
Dependent Claim
29 words
A frequency separator means as claimed in claim 2, wherein said periodic pattern defines rows of apertures, the aperatures in each row being displaced from those in adjacent rows.
Claim 6
Dependent Claim
24 words
A frequency separator means as claimed in claim 4, wherein said adjacent rows of apertures are displaced half the period of said periodic pattern.
Claim 7
Dependent Claim
28 words
A frequency separator means as claimed in claim 1, wherein said frequency separator means is reflective at said inherent resonance frequency and transmissive at said interactive resonance frequency.
Claim 8
Dependent Claim
53 words
An antenna apparatus comprising a frequency separator means as claimed in claim 1, a reflector means disposed on one side of said surface members for reflecting one of said electromagnetic waves, and two horn means disposed on the other side of said surface members to feed said electromagnetic waves to said surface members.
Claim 9
Dependent Claim
20 words
An antenna apparatus as claimed in claim 7, wherein said periodic pattern of conductive material is defined by rectangular apertures.
Claim 10
Dependent Claim
25 words
An antenna apparatus as claimed in claim 8, wherein said apertures are mutually displaced in one dimension by half the period of said periodic pattern.
Claim 11
Dependent Claim
19 words
An antenna apparatus as claimed in claim 7, wherein said periodic pattern of conductive material is of rectangular shape.
Claim 12
Dependent Claim
26 words
An antenna apparatus as claimed in claim 10, wherein said periodic pattern of conductive material is mutually displaced by half the period of said periodic pattern.
Claim 13
Dependent Claim
55 words
An antenna apparatus comprising a frequency separator means as claimed in claim 1, said antenna apparatus further comprising reflector means disposed on one side of said surface members for reflecting said electromagnetic waves, and two horn means disposed on opposite sides, respectively, of said surface members, to feed said electromagnetic waves to said surface members.
Claim 14
Dependent Claim
20 words
An antenna apparatus as claimed in claim 12, wherein said periodic pattern of conductive material is defined by rectangular apertures.
Claim 15
Dependent Claim
22 words
An antenna apparatus as claimed in claim 13, wherein said apertures are mutually displaced by half the period of said periodic pattern.
Claim 16
Dependent Claim
19 words
A frequency separator as claimed in claim 12, wherein said periodic pattern of conductive material is of rectangular shape.
Claim 17
Dependent Claim
26 words
A frequency separator as claimed in claim 15, wherein said periodic pattern of conductive material is mutually displaced by half the period of said periodic pattern.
Claim 18
Dependent Claim
31 words
A frequency separator means as claimed in claim 6 wherein each said lattice comprises a plurality of rows and columns of shaped conductive material positioned periodically in said rows and columns.
Claim 19
Dependent Claim
24 words
A frequency separator means as claimed in claim 17 wherein said shaped conductive material has any one of rectangular, elliptical, crossed or circular shape.
Claim 20
Dependent Claim
27 words
A frequency separator means as claimed in claim 17 wherein the shaped conductive materials in each row are displaced from the shaped conductive materials in adjacent rows.
Claim 21
Dependent Claim
30 words
A frequency separator means as claimed in claim 19 wherein the adjacent rows of shaped conductive materials are displaced from one another by half the period of said periodic pattern.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-09 | 1988-04-09 | 1988-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-09 | 1992-04-09 | 1992-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-09 | 1996-04-09 | 1996-10-09 | $7700.00 | Window Closed / Lapsed |