US4835499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Voltage tunable bandpass filter
Assignee: Motorola Solutions Inc
•
Filing: 1988-03-09
•
Granted: 1989-05-30
•
Expires: 2008-03-09
Abstract
Abstract A voltage tunable bandpass filter consisting of a plurality of parallel resonators electromagnetically coupled and having tuning diodes coupled to a first end. The resonators are DC isolated at a second or RF grounded end of each resonator. A voltage source reverse biases the tuning diodes from the second or less critical end of the resonators.
Inventors
- 👤 Michael N. Pickett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:38
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/201; H01P1/203; H01P1/20327; H01P1/20336
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
128 words
A method of biasing a voltage tunable bandpass filter to decrease distortion and eliminate DC parasitics, said method comprising the steps of: coupling each one of a plurality of varactors to a first end of an associated one of a plurality of resonators; coupling a first end of each of a plurality of capacitors to a second end of the associated one of said plurality of resonators; coupling a second end of each one of said plurality of capacitors to a ground potential; and coupling each one of a plurality of resistors between adjacent resonators, said plurality of resistors coupled to said second end of said plurality of resonators adjacent to said first end of said plurality of capacitors, said plurality of resistors coupled to a voltage source.
Claim 2
Independent Claim
128 words
A method of biasing a voltage tunable bandpass filter to decrease distortion and eliminate DC parasitics, said method comprising the steps of: coupling each one of a plurality of varactors to a first end of an associated one of a plurality of resonators; coupling a first end of each of a plurality of capacitors to a second end of the associated one of said plurality of resonators; coupling a second end of each one of said plurality of capacitors to a ground potential; and coupling each one of a plurality of resistors between adjacent resonators, said plurality of resistors coupled to said second end of said plurality of resonators adjacent to said first end of said plurality of capacitors, said plurality of resistors coupled to a voltage source.
Claim 3
Dependent Claim
134 words
A voltage tunable bandpass filter which incorporates a unique biasing scheme to eliminate parasitics caused by biasing, said filter comprising: at least one resonator means for creating a resonating frequency, each one of said at least one resonator means having a first port and a second port; at least one tuning means to tuning said resonator means, each of said tuning means including a first port electrically coupled to an electrical ground, and a second port electrically coupled to said first port of an associated one of said resonator means; and at least one biasing means for reverse biasing said tuning means, each of said biasing means including a first port electrically coupled to said second port of an associated one of said resonator means, and a second port electrically coupled to said ground.
Claim 4
Dependent Claim
134 words
A voltage tunable bandpass filter which incorporates a unique biasing scheme to eliminate parasitics caused by biasing, said filter comprising: at least one resonator means for creating a resonating frequency, each one of said at least one resonator means having a first port and a second port; at least one tuning means to tuning said resonator means, each of said tuning means including a first port electrically coupled to an electrical ground, and a second port electrically coupled to said first port of an associated one of said resonator means; and at least one biasing means for reverse biasing said tuning means, each of said biasing means including a first port electrically coupled to said second port of an associated one of said resonator means, and a second port electrically coupled to said ground.
Claim 5
Dependent Claim
17 words
A voltage tunable bandpass filter according to claim 2 wherein said tuning means comprises a varactor capacitor.
Claim 6
Dependent Claim
110 words
A voltage tunable bandpass filter according to claim 2 wherein said biasing means comprises: at least one capacitor means for direct current isolating said resonator means and for radio frequency grounding said resonator means, each of said capacitor means including a first port electrically coupled to said second port of an associated one of said resonator means, and a second port electrically coupled to said ground; and at least one resistor means for biasing said biasing means, each of said resistor means including a first port electrically coupled to said first port of the associated one of said capacitor means, and a second port electrically coupled to a voltage source.
Claim 7
Dependent Claim
16 words
A voltage tunable bandpass filter according to claim 2 wherein said filter comprises a microstrip filter.
Claim 8
Dependent Claim
39 words
A voltage tunable bandpass filter according to claim 2 wherein said at least one resonator means comprises a plurality of resonator means for filtering a radio frequency, said plurality of resonator means electrically coupled in parallel to each other.
Claim 9
Dependent Claim
88 words
A voltage tunable bandpass filter according to claim 6 wherein said filter further comprises: first coupling means for coupling said filter to an input, said coupling means including a first port electrically coupled to a first of said plurality of resonator means, and a second port coupled to said input; and second coupling means for coupling said filter to an output, said coupling means including a first port electrically coupled to a last of said plurality of resonator means, and a second port electrically coupled to said output.
Claim 10
Dependent Claim
19 words
A voltage tunable bandpass filter according to claim 7 wherein said first and second coupling means each comprise capacitors.
Claim 11
Dependent Claim
185 words
A voltage tunable bandpass filter which incorporates a unique biasing scheme to eliminate parasitics caused by biasing, said filter comprising: at least one resonator means for creating a resonating frequency, each of said at least one resonator means having a first port and a second port; at least one tuning means for tuning said resonator means, each of said tuning means including a first port electrically coupled to an electrical ground, and a second port electrically coupled to said first port of an associated one of said resonator means; at least one capacitor means for direct current isolating said resonator means and for radio frequency grounding and resonator means, each of said capacitor means including a first port electrically coupled to said second port of the associated one of said resonator means, and a second port electrically coupled to said ground; and at least one resistor means for biasing said tuning means, each of said resistor means including a first port electrically coupled to said first port of the associated one of said capacitor means, and a second port electrically coupled to a voltage source.
Claim 12
Dependent Claim
185 words
A voltage tunable bandpass filter which incorporates a unique biasing scheme to eliminate parasitics caused by biasing, said filter comprising: at least one resonator means for creating a resonating frequency, each of said at least one resonator means having a first port and a second port; at least one tuning means for tuning said resonator means, each of said tuning means including a first port electrically coupled to an electrical ground, and a second port electrically coupled to said first port of an associated one of said resonator means; at least one capacitor means for direct current isolating said resonator means and for radio frequency grounding and resonator means, each of said capacitor means including a first port electrically coupled to said second port of the associated one of said resonator means, and a second port electrically coupled to said ground; and at least one resistor means for biasing said tuning means, each of said resistor means including a first port electrically coupled to said first port of the associated one of said capacitor means, and a second port electrically coupled to a voltage source.
Claim 13
Dependent Claim
17 words
A voltage tunable bandpass filter according to claim 9 wherein said tuning means comprises a varactor capacitor.
Claim 14
Dependent Claim
16 words
A voltage tunable bandpass filter according to claim 9 wherein said filter comprises a microstrip filter.
Claim 15
Dependent Claim
39 words
A voltage tunable bandpass filter according to claim 9 wherein said at least one resonator means comprises a plurality of resonator means for filtering a radio frequency, said plurality of resonator means electrically coupled in parallel to each other.
Claim 16
Dependent Claim
88 words
A voltage tunable bandpass filter according to claim 12 wherein said filter further comprises: first coupling means for coupling said filter to an input, said coupling means including a first port electrically coupled to a first of said plurality of resonator means, and a second port coupled to said input; and second coupling means for coupling said filter to an output, said coupling means including a first port electrically coupled to a last of said plurality of resonator means, and a second port electrically coupled to said output.
Claim 17
Dependent Claim
19 words
A voltage tunable bandpass filter according to claim 13 wherein said first and second coupling means each comprise capacitors.
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) | 1992-05-29 | 1992-11-28 | 1993-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-29 | 1996-11-28 | 1997-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-29 | 2000-11-28 | 2001-05-30 | $7700.00 | Window Closed / Lapsed |