US3883875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Endfire commutated antenna array
Assignee: International Standard Electric Corp
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Filing: 1974-01-02
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Granted: 1975-05-13
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Expires: 1994-01-02
Abstract
Abstract A commutated linear antenna array of general utility in simulated Doppler guidance systems. The array operates as an entire array of n elements in which n-1 elements are successively excited in accordance with a commutation (scan) program. As each element is excited, the immediately adjacent element to the rear (opposite the radiation direction) has a base loading circuit activated such that it acts as a short circuit and therefore the element itself acts as a reflector in cooperation with the excited element. At the same time all other elements are provided with base loadings so that they are open circuited and appear transparent for radiation purposes. A dummy parasite reflector is provided behind the first element of the array (not commutated) and has a fixed short-circuit loading at its base. Thus the radiation pattern is substantially the same in the forward direction during the successive exitation of each of the commutated elements.
Inventors
- 👤 Ian W Mcclymont
- 👤 Sharad V Parekh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:18
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02; G01S1/08; G01S1/38; G01S1/40; H; H01; H01Q; H01Q21/00; H01Q21/06; H01Q21/08; H01Q21/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
150 words
A Doppler navigation beacon system having a commutated linear array of n radiator elements for radiating in substantially equal radiation patterns during the successive excitation of corresponding elements of said array, comprising the combination of: transmitter means for generating a radio frequency signal; radio frequency energy commutator means for discretely switching said radio frequency signal among at least a first portion of said elements according to a predetermined sequence, said elements thereby becoming driven elements; and switching means operating synchronously with said commutatoR means, for causing an element of said array adjacent to the driven element at any time, to act as a reflecting element, said switching means also operating to cause a second portion of the other elements of said array to be substantially electrically transparent, said driven elements thereby providing substantially equal radiation patterns maximized in the direction opposite said reflecting element with respect to each excited element.
Claim 2
Dependent Claim
150 words
A Doppler navigation beacon system having a commutated linear array of n radiator elements for radiating in substantially equal radiation patterns during the successive excitation of corresponding elements of said array, comprising the combination of: transmitter means for generating a radio frequency signal; radio frequency energy commutator means for discretely switching said radio frequency signal among at least a first portion of said elements according to a predetermined sequence, said elements thereby becoming driven elements; and switching means operating synchronously with said commutatoR means, for causing an element of said array adjacent to the driven element at any time, to act as a reflecting element, said switching means also operating to cause a second portion of the other elements of said array to be substantially electrically transparent, said driven elements thereby providing substantially equal radiation patterns maximized in the direction opposite said reflecting element with respect to each excited element.
Claim 3
Dependent Claim
77 words
Apparatus according to claim 1 in which said array includes one electrically fixed element at the end of said array opposite said direction maximum radiation, said fixed element being electrically connected to always act as a reflector; in which the other n - 1 of said elements are sequentially energized through n - 1 outputs of said commutator; and in which said other elements which are electrically transparent at any time are n - 2 in number.
Claim 4
Dependent Claim
25 words
Apparatus according to claim 2, in which said n radiator elements are monopoles spaced from each other by one quarter wavelength at the excitation frequency.
Claim 5
Dependent Claim
147 words
Apparatus according to claim 3 in which said n - 1 radiators controlled by said commutator are each connected to said commutator by transmission lines each comprising a first section having a length of an even number of quarter wavelengths and a second section an odd number of quarter wavelengths long, said first section extending from said corresponding monopole to an outer control point and said second section extending from said outer control point to an inner control point, said inner control point being connected to said commutator by a further length of transmission line; and first shorting RF means responsive to said switching means are included for short circuiting said outer control point to ground to effect short circuiting of the base of the corresponding monopole, and second RF shorting means also responsive to said switching means are included for short circuiting said inner control point.
Claim 6
Dependent Claim
94 words
Apparatus according to claim 4 in which said first and second shorting means comprise PIN diodes, said switching means are arranged to bias only said first shorting means into RF conduction to cause the corresponding monopole to act as a reflector, said switching means are also arranged to bias only said second shorting means into RF conduction to cause said corresponding monopole to appear electrically transparent, and said switching means are also arranged to bias both said first and second shorting means out of conduction during the time said commutator energizes said corresponding monopole.
References Cited (Backward Citations)
US3054105A
Cited
US3047864A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |