US6150897A
Expired / Lapsed
US
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Balun circuit with a cancellation element in each coupled line
Assignee: NTT Inc
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Filing: 1998-03-27
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Granted: 2000-11-21
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Expires: 2018-03-27
Abstract
Abstract A Marchand balun cirucit having a pair of coupled lines of quarter wavelength for dividing and/or combining signals with the same amplitude and opposite phase with each other is improved by inserting a cancellation element between said pair of coupled lines. Said cancellation element may be a transmission line, a capacitor, or an inductor which improves amplitude difference error and phase difference error of a pair of outputs by controlling phase velocity for an even mode so that phase velocity for an even mode becomes equal to that for an odd mode. Thus, a balun circuit with wide operation band, and less error of amplitude difference and phase difference is obtained.
Inventors
- 👤 Kenjiro Nishikawa
- 👤 Ichihiko Toyoda
- 👤 Tsuneo Tokumitsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:54
CPC Classifications
H; H01; H01P; H01P5/00; H01P5/08; H01P5/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
211 words
A balun circuit having an input port and a pair of output ports which provide output signals having the same amplitude and opposite phase to each other relating to an input signal input into said input port, comprising: a first coupled line and a second coupled line each equal to or shorter than a quarter wavelength, and each having an input port, a through port, a coupled port and an isolation port, each defined in accordance with a reference port; a reference port of the first coupled line and a reference port of the second coupled line being coupled, an isolation port of the first coupled line being grounded, and an isolation port of the second coupled line being grounded; a through port of the second coupled line being open; a through port of the first coupled line being an input port of the balun circuit; coupling ports of the first and second coupled lines respectively being output ports of the balun circuit; a cancellation element being coupled with each coupled line for compensating amplitude difference and phase difference error of output signals on said output ports; wherein said cancellation element comprises a transmission line inserted in one of the lines of each coupled line between ground and an output port.
Claim 2
Dependent Claim
211 words
A balun circuit having an input port and a pair of output ports which provide output signals having the same amplitude and opposite phase to each other relating to an input signal input into said input port, comprising: a first coupled line and a second coupled line each equal to or shorter than a quarter wavelength, and each having an input port, a through port, a coupled port and an isolation port, each defined in accordance with a reference port; a reference port of the first coupled line and a reference port of the second coupled line being coupled, an isolation port of the first coupled line being grounded, and an isolation port of the second coupled line being grounded; a through port of the second coupled line being open; a through port of the first coupled line being an input port of the balun circuit; coupling ports of the first and second coupled lines respectively being output ports of the balun circuit; a cancellation element being coupled with each coupled line for compensating amplitude difference and phase difference error of output signals on said output ports; wherein said cancellation element comprises a transmission line inserted in one of the lines of each coupled line between ground and an output port.
Claim 3
Dependent Claim
215 words
A balun circuit having an input port and a pair of output ports which provide output signals having the same amplitude and opposite phase to each other relating to an input signal input into said input port, comprising: a first coupled line and a second coupled line each equal to or shorter than a quarter wavelength, and each having an input port, a through port, a coupled port and an isolation port, each defined in accordance with a reference port; a reference port of the first coupled line and a reference port of the second coupled line being coupled, an isolation port of the first coupled line being grounded, and an isolation port of the second coupled line being grounded; a through port of the second coupled line being open; a through port of the first coupled line being an input port of the balun circuit; coupling ports of the first and the second coupled lines respectively being output ports of the balun circuit; a cancellation element being coupled with each coupled line for compensating amplitude difference and phase difference error of output signals on said output ports; wherein said cancellation element comprises an inductor inserted in one of the lines of each coupled line between ground and an output port in each coupled line.
Claim 4
Dependent Claim
215 words
A balun circuit having an input port and a pair of output ports which provide output signals having the same amplitude and opposite phase to each other relating to an input signal input into said input port, comprising: a first coupled line and a second coupled line each equal to or shorter than a quarter wavelength, and each having an input port, a through port, a coupled port and an isolation port, each defined in accordance with a reference port; a reference port of the first coupled line and a reference port of the second coupled line being coupled, an isolation port of the first coupled line being grounded, and an isolation port of the second coupled line being grounded; a through port of the second coupled line being open; a through port of the first coupled line being an input port of the balun circuit; coupling ports of the first and the second coupled lines respectively being output ports of the balun circuit; a cancellation element being coupled with each coupled line for compensating amplitude difference and phase difference error of output signals on said output ports; wherein said cancellation element comprises an inductor inserted in one of the lines of each coupled line between ground and an output port in each coupled line.
Claim 5
Dependent Claim
63 words
A balun circuit according to claims 1 or 2 further comprising a balanced frequency mixer comprising a divider for dividing a local frequency into a pair of the same amplitude and opposite phase signals, frequency conversion means for converting an IF signal to radio frequency by using outputs of said divider, and a signal combiner for combining outputs of said frequency conversion means.
Claim 6
Dependent Claim
21 words
A balun circuit according to claims 1 or 2 wherein each of said coupled lines is produced on multi-layered dielectric layers.
Claim 7
Dependent Claim
25 words
A balun circuit according to claim 1, wherein length of said coupled lines is in the range between a quarter wavelength and 0.65×(a quarter wavelength).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-11-21 | 2004-05-22 | 2004-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-21 | 2008-05-22 | 2008-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-21 | 2012-05-22 | 2012-11-21 | $7700.00 | Window Closed / Lapsed |