US3701057A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Broad-band lumped-element directional coupler
Assignee: United States Department of the Navy
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Filing: 1971-05-20
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Granted: 1972-10-24
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Expires: 1991-05-20
Abstract
Abstract A broad-band lumped element directional coupler for measuring either the forward or reflected power in a coaxial transmission line. A resistive voltage divider is coupled to the center conductor of a transmission line with a capacitor to keep the phase of the voltage sampling circuit equal to the phase of the current sampling circuit. Capacitors shunting the resistors make the voltage ratio of the resistive voltage divider independent of frequency over a large frequency range. Directivity greater than 50 dB is achieved over a large frequency range for coupling ratios of 30, 40 and 50 dB.
Inventors
- 👤 Cletus A Hoer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/213; H03; H03H; H03H2/00; H03H2/005
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
125 words
A broad-band directional coupler comprising: a transmission line having a center conductor and an outer conductor; a resistive voltage divider comprising first and second resistances in series for sampling the voltage on the transmission line, the second resistance being connected to the outer conductor; a capacitance in series with the resistive voltage divider connecting the voltage divider to the center conductor; means electrically connected to the second resistance and physically disposed between the center conductor and the outer conductor for sampling the current on the transmission line; and, means for making the impedance of the resistive voltage divider substantially independent of frequency, said means including a metal tube at least partially surrounding the first resistance and a capacitor connected in parallel with the second resistance.
Claim 2
Dependent Claim
125 words
A broad-band directional coupler comprising: a transmission line having a center conductor and an outer conductor; a resistive voltage divider comprising first and second resistances in series for sampling the voltage on the transmission line, the second resistance being connected to the outer conductor; a capacitance in series with the resistive voltage divider connecting the voltage divider to the center conductor; means electrically connected to the second resistance and physically disposed between the center conductor and the outer conductor for sampling the current on the transmission line; and, means for making the impedance of the resistive voltage divider substantially independent of frequency, said means including a metal tube at least partially surrounding the first resistance and a capacitor connected in parallel with the second resistance.
Claim 3
Dependent Claim
14 words
The directional coupler of claim 1 wherein the metal tube is a brass tube.
Claim 4
Dependent Claim
38 words
The directional coupler of claim 1 wherein: said second resistance of the resistive voltage divider is a potentiometer; said current sampling means is a toroidal coil; and said toroidal coil is connected to the wiper of the potentiometer.
Claim 5
Dependent Claim
28 words
The directional coupler of claim 3 further comprising: a shield between the toroidal coil and the center conductor whereby the current sampling means is maintained independent of voltage.
Claim 6
Dependent Claim
31 words
The directional coupler of claim 4 wherein the capacitance connecting the resistive voltage divider to the center conductor is provided by a brass sleeve between the center conductor and the shield.
Claim 7
Dependent Claim
25 words
The directional coupler of claim 5 wherein resistances are added to the center conductor to maintain the voltage standing wave ratio less than about 1.04.
Claim 8
Dependent Claim
30 words
The directional coupler of claim 5 wherein the ratio of the inductance to the capacitance of the transmission line is kept constant throughout the region of the current sampling means.
Claim 9
Dependent Claim
52 words
The directional coupler of claim 6 wherein the voltage across the second resistance comprises the coupled output, and further including an inductance connected in parallel with a resistance at the coupled output whereby the coupled output impedance can be made equal to the impedance of a load and substantially independent of frequency.
Claim 10
Dependent Claim
45 words
The directional coupler of claim 8 further including an adjustable capacitor in the coupled output connected in parallel with the potentiometer of the resistive voltage divider whereby the impedance of the coupled output may be more readily made equal to the impedance of a load.
Claim 11
Dependent Claim
11 words
The directional coupler of claim 8 wherein the inductance is variable.
References Cited (Backward Citations)
US2588390A
Cited
US3550042A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |