US4313121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compact monopole antenna with structured top load
Assignee: United States Department of the Army
•
Filing: 1980-03-13
•
Granted: 1982-01-26
•
Expires: 2000-03-13
Abstract
Abstract A VHF monopole antenna unit, particularly adapted for operation in the 30 MHz frequency range, yet capable of embodiment in a compact structure only approximately 11/2 feet in height is described. Coarse tuning is accomplished in a number of switched bands, for each of which is provided a specially designed matching network comprised of inexpensive L-networks of inductors and capacitors. Tuning is accomplished through adjustment of inductor elements. The simple, inexpensive design of the matching circuits eliminates need for intricate mechanisms typically used for automatic impedance matching over a wide band and also for a broadband impedance matching transformer. The compactness made available by the unique top-load structure design is further made possible by provision of a specially designed dielectric filled vertical antenna element, accomplishing the same range and efficiency in an even more compact antenna.
Inventors
- 👤 Donn V. Campbell
- 👤 Charles M. DeSantis
- 👤 John R. Wills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:36
CPC Classifications
H; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/06; H01Q9/14; H01Q9/145; H01Q9/30; H01Q9/32; H01Q9/36
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
122 words
A compact survivable VHF, monopole antenna with top fed capacitive top load having one or more conductive portions and one or more insulating portions, the antenna having a vertical element for supporting the said capacitive top load, one or more of the conductive portions being electrically fed at a point where feedpoint resistance approximately equals characteristic line impedance with one or more conductive portions grounded, said antenna further comprising a matching circuit for impedance matching over a broad frequency range, the circuit comprising: a number of adjustable inductors and limited band matching units comprising broadband circuits each designed for a given portion of the band, a positional switch manually operable to switch the individual matching units as required for a particular frequency.
Claim 2
Dependent Claim
122 words
A compact survivable VHF, monopole antenna with top fed capacitive top load having one or more conductive portions and one or more insulating portions, the antenna having a vertical element for supporting the said capacitive top load, one or more of the conductive portions being electrically fed at a point where feedpoint resistance approximately equals characteristic line impedance with one or more conductive portions grounded, said antenna further comprising a matching circuit for impedance matching over a broad frequency range, the circuit comprising: a number of adjustable inductors and limited band matching units comprising broadband circuits each designed for a given portion of the band, a positional switch manually operable to switch the individual matching units as required for a particular frequency.
Claim 3
Dependent Claim
22 words
The antenna of claim 1 wherein the switching of the matching networks and the adjustment of the said inductors are mechanically synchronized.
Claim 4
Dependent Claim
49 words
The antenna of claim 2 having a metal tube sleeve for enclosing the vertical member of the antenna structure having the effect of improving its operation by further loading the top regions of the vertical element, and improving its impedance characteristic by reducing the number of switched bands required.
Claim 5
Dependent Claim
10 words
The antenna of claim 3 with the sleeve dielectrically filled.
Claim 6
Dependent Claim
19 words
The antenna of claim 2 with base choke for inductive loading of the signal line feeding the top load.
Claim 7
Dependent Claim
36 words
The antenna of claim 5 where the adjustable inductors are connected to a vertical tube member within the sleeve so as to provide further inductive loading of the signal feed line which passes through the tube.
Claim 8
Dependent Claim
43 words
The antenna of claims 2,3,4,5 or 6 wherein the capacitive top load comprises a central disc conductive portion surrounded by a concentric conductive ring portion spaced at a distance by insulator portions the outer ring being electrically fed and the inner disc grounded.
References Cited (Backward Citations)
US3100893A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |