US3689928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-band tunable halfwave whip antenna
Assignee: TDK Micronas GmbH
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Filing: 1970-12-30
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Granted: 1972-09-05
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Expires: 1990-12-30
Abstract
Abstract A physically shortened halfwave antenna of the whip type is disclosed. The antenna includes a main antenna rod, a pair of helices, one helix coupled to each end of the rod, and a capacitive top load coupled to the upper one of the helices. An RF terminal is inductively coupled to the lower one of the helices to supply RF energy to or remove RF energy from the antenna. A variable capacitance means is coupled between the lower helix and a capacitive bottom load, which may be ground, a small ground plane or an equivalent arrangement, to resonate the antenna. A plurality of lower helices and an associated variable capacitance means for each are selectively connected to the rod to enable the antenna to cover a relatively broadband frequency range. In one embodiment an inductive coupling to the lower helix is accomplished by a single tuned arrangement for the lower frequency band of the frequency range and by a doubled tuned arrangement for the middle and upper frequency band of the frequency range. Other embodiments may include all single tuned arrangements, all double tuned arrangements or a different combination of single and double tuned arrangements than that used for said one embodiment. A directional coupler and capacitance control arrangement are provided to adjust the capacitance of the variable capacitance means for reresonating the antenna when the resonance of the antenna is changed by an object coming into the proximity of the antenna.
Inventors
- 👤 Robert A Felsenheld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:49
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/38; H03H7/40; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/06; H01Q9/14; H01Q9/145; H01Q9/16
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
98 words
A physically shortened halfwave antenna of the whip type comprising: a main antenna rod having an upper and lower end; a first helix having one end connected to the upper end of said rod; a capacitive top load connected to the other end of said first helix; a second helix having one end connected to the lower of said rod; first means coupled to the other end of said second helix to resonate said antenna; and second means inductively coupled to said second helix to feed radio frequency energy to and remove radio frequency energy from said antenna.
Claim 2
Dependent Claim
98 words
A physically shortened halfwave antenna of the whip type comprising: a main antenna rod having an upper and lower end; a first helix having one end connected to the upper end of said rod; a capacitive top load connected to the other end of said first helix; a second helix having one end connected to the lower of said rod; first means coupled to the other end of said second helix to resonate said antenna; and second means inductively coupled to said second helix to feed radio frequency energy to and remove radio frequency energy from said antenna.
Claim 3
Dependent Claim
16 words
An antenna according to claim 1, wherein said top load includes at least one conductive element.
Claim 4
Dependent Claim
34 words
An antenna according to claim 1, wherein said first means includes a capacitive bottom load, and a capacitance means coupled in series between the other end of said second helix and said bottom load.
Claim 5
Dependent Claim
39 words
An antenna according to claim 1, wherein said second means includes a capacitive bottom load, a radio frequency terminal, an inductor having one end coupled to said bottom load and the other end coupled to said radio frequency terminal.
Claim 6
Dependent Claim
48 words
An antenna according to claim 1, wherein said secoNd means includes a capacitive bottom load, an inductor having one end coupled to said bottom load, a capacitance means coupled in parallel with said inductor, and a radio frequency terminal connected to a selected impedance point along said inductor.
Claim 7
Dependent Claim
115 words
An antenna according to claim 1, wherein said first means includes a capacitive bottom load, and a variable capacitance means coupled in series between the other end of said second helix and said bottom load; and said second means includes a radio frequency terminal, an inductor having one end coupled to said bottom load and the other end coupled to said radio frequency terminal; said variable capacitance means, said second helix and said inductor providing a single tuned circuit to resonate said antenna and to provide a narrow band impedance match to said antenna; the adjustment of said variable capacitance means enabling an impedance match and resonance of said antenna over a given frequency range.
Claim 8
Dependent Claim
107 words
An antenna according to claim 1, wherein said first means includes a capacitive bottom load,and a first variable capacitance means coupled in series between the other end of said second helix and said bottom load; and said second means includes an inductor having one end coupled to said bottom load; a second variable capacitance means coupled in parallel with said inductor, and a radio frequency terminal connected to a selected impedance point along said inductor; said first and second variable capacitance means, said second helix and said inductor providing a double tuned circuit to resonate said antenna and to provide a broadband impedance match to said antenna.
Claim 9
Dependent Claim
46 words
An antenna according to claim 1, further including third means coupled between said second means and said first means, said third means responding to reflected power, due to an object altering the resonance of said antenna, to automatically control said first means and reresonate said antenna.
Claim 10
Dependent Claim
87 words
An antenna according to claim 8, wherein said first means includes a capacitive bottom load, and a first variable capacitance means coupled in series between the other end of said second helix and said bottom load; and said third means includes a directional coupler coupled to said second means, and a capacitance control means coupled to said directional coupler and said first variable capacitance means, said control means responding to said reflected power to alter the capacitance of said first variable capacitance means to reresonate said antenna.
Claim 11
Dependent Claim
83 words
An antenna according to claim 9, wherein said second means includes an inductor having one end coupled to said bottom load and the other end coupled to said directional coupler; said first variable capacitance means, said second helix and said inductor providing a single tuned circuit to resonate said antenna and to provide a narrow band impedance match to said antenna; the control of said first variable capacitance means enabling an impedance match and resonance of said antenna over a given frequency range.
Claim 12
Dependent Claim
79 words
An antenna according to claim 9, wherein said second means includes an inductor having one end coupled to said bottom load, a second variable capacitance means coupled in parallel to said inductor; and means to couple said directional coupler to a selected impedance point along said inductor; said first and second variable capacitance means, said second helix and said inductor providing a double tuned circuit to resonate said antenna and to provide a broadband impedance match to said antenna.
Claim 13
Dependent Claim
169 words
An antenna according to claim 1, further including a capacitive bottom load; three of said second helix; three of said first means each coupled between an end of a different one of said three of said second helix and said bottom load; first switch means to selectively couple the other end of each of said Three of said second helix to the lower end of said rod; three of said second means each inductively coupled to an associated one of said three second helix; a radio frequency terminal; and second switch means ganged to said first switch means to selectively couple each of said three of said second means to said terminal; said three of said second helix, said three of said first means and three of said second means cooperating to resonate said antenna over a given broad frequency range, each of said three of said second helix, said first means and said second means covering a different given adjacent frequency bands within said given broad frequency range.
Claim 14
Dependent Claim
228 words
An antenna according to claim 12, wherein each of said three of said first means includes a first variable capacitance means; one of said three of said second means includes a first inductor having one end coupled to said bottom load and the other end coupled to said second switch means; said first inductor, the associated one of said first variable capacitance means and the associated one of said second helix providing a single tuned circuit, an adjustment of said associated one of said first variable capacitance means enabling the resonance of said antenna and an impedance match to said antenna over the lower one of said frequency bands; and each of the other two of said three of said second means includes a second inductor having one end coupled to said bottom load, a second variable capacitance means coupled in parallel to said second inductor; and means to couple said second switch means to a selected impedance point along said second inductor; each of the associated one of said first variable capacitance means, each of said second variable capacitance means, the associated one of said second helix and each of said second inductor providing a double tuned circuit to resonate said antenna and to provide a broadband impedance match to said antenna over the associated one of the middle one and higher one of said frequency bands.
Claim 15
Dependent Claim
173 words
An antenna according to claim 1, further including a capacitive bottom load; a plurality of said second helix; a plurality of said first means each coupled between and end of a different one of said plurality of said second helix and said bottom load; first switch means to selectively couple the other end of each of said plurality of said second helix to the lower end of said rod; a plurality of said second means each inductively coupled to an associated one of said plurality of second helix; a radio frequency terminal; and second switch means ganged to said first switch means to selectively couple each of said plurality of said second means to said terminal; said plurality of said second helix, said plurality of said first means and plurality of said second means cooperating to resonate said antenna over a given broad frequency range, each of said plurality of said second helix, said first means and said second means covering a different given adjacent frequency band within said given broad frequency range.
Claim 16
Dependent Claim
215 words
An antenna according to claim 14, wherein each of said plurality of said first means includes a first variable capacitance means; certain ones of said plurality of said second means includes a first inductor having one end coupled to said bottom load and the other end coupled to said second switch means; said first inductor, the associated one of said first variable capacitance means and the associated one of said second helix providing a single tuned circuit, an adjustment of said associated one of said first variable capacitance means enabling the resonance of said antenna and an impedance match to said antenna over certain ones of said frequency bands; and others of said plurality of said second means includes a second inductor having one end coupled to said bottom load, a second variable capacitance means coupled in parallel to said second inductoR; and means to couple said second switch means to a selected impedance point along said second inductor; each of the associated one of said first variable capacitance means, each of said second variable capacitance means, the associated one of said second helix and each of said second inductor providing a double tuned circuit to resonate said antenna and to provide a broadband impedance match to said antenna over others of said frequency bands.
Claim 17
Dependent Claim
107 words
An antenna according to claim 14, wherein each of said plurality of said first means includes a first variable capacitance means; each of said plurality of said second means includes a first inductor having one end coupled to said bottom load and the other end coupled to said second switch means; said first inductor, the associated one of said first variable capacitance means and the associated one of said second helix providing a single tuned circuit, an adjustment of said associated one of said first variable capacitance means enabling the resonance of said antenna and an impedance match to said antenna over each of said frequency bands.
Claim 18
Dependent Claim
124 words
An antenna according to claim 14, wherein each of said plurality of said first means includes a first variable capacitance means; each of said plurality of said second means includes an inductor having one end coupled to said bottom load, a second variable capacitance means coupled in parallel to said inductor; and means to couple said second switch means to a selected impedance point along said inductor; each of the associated one of said first variable capacitance means, each of said second variable capacitance means, the associated one of said second helix and each of said inductors providing a double tuned circuit to resonate said antenna and to provide a broadband impedance match to said antenna over the associated one of said frequency bands.
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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |