Patent US3579113A successfully refreshed from Google Patents.
US3579113A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Antenna coupling circuit
Assignee: Motorola Solutions Inc
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Filing: 1969-03-14
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Granted: 1971-05-18
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Expires: 1989-03-14
Abstract
Abstract A high impedance capacitive antenna is coupled in series with a low impedance resistive load in the form of the input circuit of an RF transistor amplifier through a series-tuned circuit including a varactor diode connected in series with an inductor. A source of DC biasing potential is provided to vary the biasing voltage on the diode in order to change its capacitance to tune the circuit over a predetermined band of frequencies. The circuit operates to transfer constant power at constant bandwidth from the antenna to the load over a wide range of frequencies, utilizing only a restricted range of capacitance change of the diode capacitance.
Inventors
- 👤 Kamil Y Jabbar
- 👤 Ole K Nilssen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:06
CPC Classifications
H; H03; H03H; H03H2/00; H03H2/005; H03H2/008
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
146 words
A coupling circuit for connecting an antenna to a load including in combination: a capacitive antenna operating as a high impedance reactive source of AC signals; a transistor having at least base and emitter electrodes, with the base-emitter circuit of the transistor comprising a low impedance resistive load to input signals applied thereto, the value of the impedance of the capacitive antenna being at least an order of magnitude greater than the value of impedance presented by the emitter-base circuit of the transistor; a series-tuned LC circuit connected in series between the antenna and the emitter-base circuit of the transistor and including a variable capacitor for tuning the coupling circuit over a predetermined range of frequencies, the series-tuned LC circuit operating to couple substantially constant power at substantially constant bandwidth from the antenna to the emitter-base circuit of the transistor over said predetermined range of frequencies.
Claim 2
Dependent Claim
146 words
A coupling circuit for connecting an antenna to a load including in combination: a capacitive antenna operating as a high impedance reactive source of AC signals; a transistor having at least base and emitter electrodes, with the base-emitter circuit of the transistor comprising a low impedance resistive load to input signals applied thereto, the value of the impedance of the capacitive antenna being at least an order of magnitude greater than the value of impedance presented by the emitter-base circuit of the transistor; a series-tuned LC circuit connected in series between the antenna and the emitter-base circuit of the transistor and including a variable capacitor for tuning the coupling circuit over a predetermined range of frequencies, the series-tuned LC circuit operating to couple substantially constant power at substantially constant bandwidth from the antenna to the emitter-base circuit of the transistor over said predetermined range of frequencies.
Claim 3
Dependent Claim
37 words
The combination according to claim 1, wherein the capacitor is a voltage variable capacitor and further including means for supplying a biasing voltage to the capacitor to cause its capacitance to be changed over a predetermined range.
Claim 4
Dependent Claim
26 words
The combination according to claim 2, wherein the voltage variable capacitor is a voltage variable diode capacitor which is back-biased by the biasing voltage applied thereto.
Claim 5
Dependent Claim
151 words
A circuit for coupling an antenna to a load including in combination: a frequency dependent, high impedance capacitive antenna having an output; a low impedance resistive load; a first voltage variable capacitor included in a series-tuned circuit connected in series between the antenna and the load, said series-tuned circuit being the only tuned circuit connected between the antenna and the load; a second voltage variable capacitor connected in shunt across the antenna output; and means for applying DC bias potential to the fIrst and second voltage variable capacitors for tuning the capacitors over a predetermined range, with the first variable capacitor operating to tune the antenna circuit across a predetermined range of frequencies and with the second voltage variable capacitor causing an increase in the power transfer from the antenna to the load as the range of frequencies to which the antenna is tuned by the first voltage variable capacitor increases.
Claim 6
Dependent Claim
151 words
A circuit for coupling an antenna to a load including in combination: a frequency dependent, high impedance capacitive antenna having an output; a low impedance resistive load; a first voltage variable capacitor included in a series-tuned circuit connected in series between the antenna and the load, said series-tuned circuit being the only tuned circuit connected between the antenna and the load; a second voltage variable capacitor connected in shunt across the antenna output; and means for applying DC bias potential to the fIrst and second voltage variable capacitors for tuning the capacitors over a predetermined range, with the first variable capacitor operating to tune the antenna circuit across a predetermined range of frequencies and with the second voltage variable capacitor causing an increase in the power transfer from the antenna to the load as the range of frequencies to which the antenna is tuned by the first voltage variable capacitor increases.
Claim 7
Dependent Claim
19 words
The combination according to claim 4 wherein the first and second voltage variable capacitor are voltage variable diode capacitors.
Claim 8
Dependent Claim
22 words
The combination according to claim 5 wherein the first and second voltage variable capacitors are provided with the same DC biasing potential.
Claim 9
Dependent Claim
33 words
The combination according to claim 6 wherein the voltage variable capacitor diodes are connected at a junction in a back-to-back relationship, with the biasing potential being applied to the junction between the diodes.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |