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US5455545A
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Compact low-loss microwave balun
Assignee: Philips North America LLC
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Filing: 1993-12-07
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Granted: 1995-10-03
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Expires: 2013-12-07
Abstract
Abstract A microwave balun is constructed by combining a four-transmission-line branch-line coupler with a single-transmission-line delay element. This construction results in a simplified, compact arrangement for combining first and second signals applied to respective first and second ports, phase shifted by 180°, and providing the combined signal at a third port. The balun is a reciprocal device and may be operated in reverse with a signal applied to the third port to obtain outputs at the first and second ports.
Inventors
- 👤 Jose M. Garcia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:30
CPC Classifications
H; H01; H01P; H01P5/00; H01P5/08; H01P5/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
202 words
A microwave balun comprising: a. a branch-line coupler having: i. first and second inputs; ii. first and second outputs; iii. a first delay element having a characteristic impedance of Z 0 /√2 and coupling the first input to the first output through a phase shift of 90°; iv. a second delay element having a characteristic impedance of Z 0 /√2 and coupling the second input to the second output through a phase shift of 90°; v. a third delay element having a characteristic impedance of Z 0 and coupling the first and second inputs through a phase shift of 90°; vi. a fourth delay element having a characteristic impedance of Z 0 and coupling the first and second outputs through a phase shift of 90°; b. a fifth delay element having a characteristic impedance of Z 0 and coupling the first input of the branch-line coupler to a first input of the balun through a phase shift of 90°; and c. impedance means having a characteristic impedance of Z 0 terminating the first output; said second input of the branch-line coupler comprising a second input of the balun and said second output of the branch-line coupler comprising an output of the balun.
Claim 2
Dependent Claim
202 words
A microwave balun comprising: a. a branch-line coupler having: i. first and second inputs; ii. first and second outputs; iii. a first delay element having a characteristic impedance of Z 0 /√2 and coupling the first input to the first output through a phase shift of 90°; iv. a second delay element having a characteristic impedance of Z 0 /√2 and coupling the second input to the second output through a phase shift of 90°; v. a third delay element having a characteristic impedance of Z 0 and coupling the first and second inputs through a phase shift of 90°; vi. a fourth delay element having a characteristic impedance of Z 0 and coupling the first and second outputs through a phase shift of 90°; b. a fifth delay element having a characteristic impedance of Z 0 and coupling the first input of the branch-line coupler to a first input of the balun through a phase shift of 90°; and c. impedance means having a characteristic impedance of Z 0 terminating the first output; said second input of the branch-line coupler comprising a second input of the balun and said second output of the branch-line coupler comprising an output of the balun.
Claim 3
Dependent Claim
222 words
A microwave balun including a dielectric substrate supporting a conductive layer forming a ground plane and further supporting: a. a conductive pattern defining a branch-line coupler, said coupler having: i. first and second inputs; ii. first and second outputs; iii. first transmission line means having a characteristic impedance of Z 0 /√2 and coupling the first input to the first output through a phase shift of 90°; iv. second transmission line means having a characteristic impedance of Z 0 /√2 and coupling the second input to the second output through a phase shift of 90°; v. third transmission line means having a characteristic impedance of Z 0 and coupling the first and second inputs through a phase shift of 90°; vi. fourth transmission line means having a characteristic impedance of Z 0 and coupling the first and second outputs through a phase shift of 90°; b. fifth transmission line means having a characteristic impedance of Z 0 and coupling the first input of the branch-line coupler to a first input of the balun through a phase shift of 90°; and c. impedance means having a characteristic impedance of Z 0 terminating the first output; said second input of the branch-line coupler comprising a second input of the balun and said second output of the branch-line coupler comprising an output of the balun.
Claim 4
Dependent Claim
222 words
A microwave balun including a dielectric substrate supporting a conductive layer forming a ground plane and further supporting: a. a conductive pattern defining a branch-line coupler, said coupler having: i. first and second inputs; ii. first and second outputs; iii. first transmission line means having a characteristic impedance of Z 0 /√2 and coupling the first input to the first output through a phase shift of 90°; iv. second transmission line means having a characteristic impedance of Z 0 /√2 and coupling the second input to the second output through a phase shift of 90°; v. third transmission line means having a characteristic impedance of Z 0 and coupling the first and second inputs through a phase shift of 90°; vi. fourth transmission line means having a characteristic impedance of Z 0 and coupling the first and second outputs through a phase shift of 90°; b. fifth transmission line means having a characteristic impedance of Z 0 and coupling the first input of the branch-line coupler to a first input of the balun through a phase shift of 90°; and c. impedance means having a characteristic impedance of Z 0 terminating the first output; said second input of the branch-line coupler comprising a second input of the balun and said second output of the branch-line coupler comprising an output of the balun.
Claim 5
Dependent Claim
19 words
A microwave balun as in claim 1 or 2 where at least the branch-line coupler is formed in stripline.
Claim 6
Dependent Claim
19 words
A microwave balun as in claim 1 or 2 where at least the branch-line coupler is formed in microstrip.
Claim 7
Dependent Claim
26 words
A microwave balun as in claim 2 where at least one of the transmission line means comprises a meander conductive pattern formed on the dielectric substrate.
Claim 8
Dependent Claim
66 words
A microwave balun as in claim 2 where at least the first, second, third and fourth transmission line means each comprise a conductive pattern formed on the dielectric substrate and including a meander pattern and a linear segment, said meander patterns being arranged adjacent to each other and at least one of said linear segments being disposed between each meander pattern and each adjacent meander pattern.
Claim 9
Dependent Claim
51 words
A microwave balun as in claim 2 where at least the first, second, third and fourth transmission line means each comprise a conductive pattern formed on the dielectric substrate and including a meander pattern including adjacent linear segments having a predetermined width which are spaced apart by at least said width.
Claim 10
Dependent Claim
30 words
A microwave balun as in claim 6 or 7 where the meander patterns of the first, second, third and fourth transmission lines are arranged symmetrically with respect to each other.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-10-02 | 1999-04-03 | 1999-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-02 | 2003-04-03 | 2003-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-02 | 2007-04-03 | 2007-10-03 | $7700.00 | Window Closed / Lapsed |