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Patent US4216445A successfully refreshed from Google Patents.
US4216445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable resistance attenuator
Assignee: United States Department of the Army
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Filing: 1978-12-22
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Granted: 1980-08-05
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Expires: 1998-12-22
Abstract
Abstract Four PIN diodes are connected, two in parallel oppositely directed at eachf two ports of a 3 dB, quadrature hybrid which equally divide the power from an input port. The mismatch produced by the PIN diode resistance in parallel with the matching load resistance reflects part of the power, which combines at the two ports and exits at a fourth port of the hybrid. Direct-current bias to the PIN diodes is adjusted to vary the attenuation. There is also variable resistance and capacitance which serves as variable adjustments on the terminations of the hybrid when the diodes are unbiased.
Inventors
- 👤 Anthony Abajian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:00
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/22; H03; H03H; H03H7/00; H03H7/24; H03H7/25; H03H7/253; H03H7/255
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
179 words
A variable resistance attenuator comprising: quadrature hybrid means having an input port, an output port, and at least first and second other ports, such that radio frequency power applied at the input port divides equally between the first and second other ports, and the output port is isolated; at least four PIN type diodes whose radio-frequency resistance is a function of their direct-current bias coupled to said first and second other ports, with first and second of said diodes in parallel coupled between the first other port and ground, and third and fourth of said diodes in parallel between the second other port and ground, adjustable bias means to supply direct current through said diodes to control the resistance thereof; and termination impedance means coupled between said first and second other ports and ground, comprising a plurality of impedance elements, including an adjustable resistor coupled to said first other port, and an adjustable capacitor in parallel with a fixed resistor coupled to said second other port, to match the characteristic impedance of the hybrid when the diodes are unbiased.
Claim 2
Dependent Claim
179 words
A variable resistance attenuator comprising: quadrature hybrid means having an input port, an output port, and at least first and second other ports, such that radio frequency power applied at the input port divides equally between the first and second other ports, and the output port is isolated; at least four PIN type diodes whose radio-frequency resistance is a function of their direct-current bias coupled to said first and second other ports, with first and second of said diodes in parallel coupled between the first other port and ground, and third and fourth of said diodes in parallel between the second other port and ground, adjustable bias means to supply direct current through said diodes to control the resistance thereof; and termination impedance means coupled between said first and second other ports and ground, comprising a plurality of impedance elements, including an adjustable resistor coupled to said first other port, and an adjustable capacitor in parallel with a fixed resistor coupled to said second other port, to match the characteristic impedance of the hybrid when the diodes are unbiased.
Claim 3
Dependent Claim
20 words
An attenuator according to claim 1, wherein said quadrature hybrid means comprises a single quadrature hybrid having said four ports.
Claim 4
Dependent Claim
138 words
An attenuator according to claim 2, wherein said biase means is connected with one pole coupled to the junction of said first and third diodes and the other pole to the junction of said second and fourth diodes, with one of said junctions connected directly to ground, and the other of said junctions coupled via a capacitor to ground for radio frequency, and coupled to the bias source via an inductor, the diodes being directed so that the bias current flows in the forward direction through the first and second in series, and in the forward direction through the third and fourth in series; there further being two direct current blocking capacitors connected respectively between the diodes and said first and second other ports, the termination impedance means being connected directly to said first and second other ports.
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) | 1983-08-05 | 1984-02-04 | 1984-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-05 | 1988-02-04 | 1988-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-05 | 1992-02-04 | 1992-08-05 | $7700.00 | Window Closed / Lapsed |