US3863181A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mode suppressor for strip transmission lines
Assignee: AT&T Inc
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Filing: 1973-12-03
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Granted: 1975-01-28
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Expires: 1993-12-03
Abstract
Abstract If strip transmission lines are enclosed in a conducting shield, the shield acts as a waveguide and spurious waveguide modes, which interfere with stripline transmission, are excited. A waveguide mode suppressing structure is disclosed which selectively suppresses the waveguide modes over a certain frequency range and also physically provides support for a dielectric substrate. The structure has at least one groove, having an approximate electrical depth one-quarter of the wavelength of the stripline operating frequency, positioned in the shield side wall. This structure provides suppression without restricting cross sectional dimensions of the channel, thereby allowing more circuits on a substrate and greater freedom in strip transmission line circuit design than in the prior art. Additionally, at least one resistive thin film may be deposited on the dielectric substrate in the vicinity of the groove to increase suppression capability.
Inventors
- 👤 Bernard Glance
- 👤 Martin Victor Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:34
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/16; H01P1/162
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
115 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; a resistive thin film being positioned between the dielectric substrate and shield and extending partially into the groove and partially into the channel.
Claim 2
Dependent Claim
115 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; a resistive thin film being positioned between the dielectric substrate and shield and extending partially into the groove and partially into the channel.
Claim 3
Dependent Claim
22 words
A device as described in claim 1 wherein the electrical depth of the groove varies along the length of the siDe member.
Claim 4
Dependent Claim
120 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the shape of the groove being rectangular and the electrical depth of the groove being approximately one-quarter lambda where lambda is the operating frequency of the transmission device.
Claim 5
Dependent Claim
120 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the shape of the groove being rectangular and the electrical depth of the groove being approximately one-quarter lambda where lambda is the operating frequency of the transmission device.
Claim 6
Dependent Claim
20 words
A device as described in claim 3 wherein the portion of the dielectric substrate adjacent to the channel is lossy.
Claim 7
Dependent Claim
31 words
A device as described in claim 3 wherein a resistive thin film is positioned between the dielectric substrate and shield and extends partially into the groove and partially into the channel.
Claim 8
Dependent Claim
165 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the groove of approximate electrical depth one-quarter lambda being positioned vertically in the side member and said groove opening onto the dielectric substrate, said center of the opening of the groove being an electrical distance one-half lambda , where lambda is the operating frequency of the transmission device, from the edge of the side member bounding the channel space and an electrical distance one-half lambda from the exterior edge of the side member.
Claim 9
Dependent Claim
165 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the groove of approximate electrical depth one-quarter lambda being positioned vertically in the side member and said groove opening onto the dielectric substrate, said center of the opening of the groove being an electrical distance one-half lambda , where lambda is the operating frequency of the transmission device, from the edge of the side member bounding the channel space and an electrical distance one-half lambda from the exterior edge of the side member.
Claim 10
Dependent Claim
165 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the groove of approximate electrical depth one-half lambda being positioned vertically in the side member and said groove opening onto the dielectric substrate, the center of said opening of the groove being an electrical distance one-quarter lambda , where lambda is the operating frequency of the transmission device, from the edge of the side member bounding the channel space and an electrical distance one-quarter lambda from the exterior edge of the side member.
Claim 11
Dependent Claim
165 words
A transmission device comprising: a ground plane member; a dielectric substrate; a conductor pattern supported by the dielectric; a shield having two parallel side members, a top member and the ground plane member parallel to the top member, the shield being positioned to enclose the dielectric and the conductor pattern within a channel space; means for suppressing modes associated with vertical currents, said means including a groove in at least one side member of the shield, said groove being dimensioned and positioned to appear as an open circuit to the vertical currents; the groove of approximate electrical depth one-half lambda being positioned vertically in the side member and said groove opening onto the dielectric substrate, the center of said opening of the groove being an electrical distance one-quarter lambda , where lambda is the operating frequency of the transmission device, from the edge of the side member bounding the channel space and an electrical distance one-quarter lambda from the exterior edge of the side member.
References Cited (Backward Citations)
US3329898A
Cited
US3768048A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |