US3319194A - Variable attenuator employing internal switching - Google Patents

Variable attenuator employing internal switching Download PDF

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US3319194A
US3319194A US493985A US49398565A US3319194A US 3319194 A US3319194 A US 3319194A US 493985 A US493985 A US 493985A US 49398565 A US49398565 A US 49398565A US 3319194 A US3319194 A US 3319194A
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signal
conductor
ground plane
signal transmission
plane conductor
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US493985A
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Stephen F Adam
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HP Inc
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Hewlett Packard Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/22—Attenuating devices
    • H01P1/225—Coaxial attenuators

Definitions

  • This invention relates to a high frequency signal attenuator which provides discrete steps of attenuation using separate attenuator elements which are all disposed in a transmission line configuration adjacent a common and continuous ground plane.
  • An attenuator of this type obviates the need for complex mechanisms for switching both the signal and ground plane conductors of the transmission line structure and thus eliminates the introduction of unknown contact irnpedances in the ground plane conductor at the junctions of attenuator sections.
  • a strip line structure is formed in a continuous ground plane conductor using a number of switchable sections, each including a resistive card attenuator and a straight-through conductor. Selection of either of the two signal paths is accomplished by defiecting the signal conductor from contact with one signal path to contact with the other signal path using magnetic or mechanical actuators. The effects of leakage paths ⁇ around the selected attenuating signal path may be overcome by establishing shorting paths simultaneously with the deflection of the signal conductor.
  • FIGURE 1 is a front sectional view of the attenuator according to the present invention.
  • FIGURE 2 is an end sectional view of the attenuator of FIGURE 1;
  • FIGURE 3 is a top sectional view of the attenuator of FIGURE 1.
  • FIGURES 1, 2 and 3 of the drawing there is shown a body 9 which forms the ground plane conductor of a strip line.
  • Coaxial connectors 11, 13 at the ends of the body 9 each include a center .conductor 15 which is matched coupled to the strip line conductor 17 and an outer conductor 19 which is connected to the body 9.
  • the strip line conductor 17 is supported on a dielectric slab 21 which is mounted in longitudinal grooves 23 in the side walls of the ground plane conductor or body 9.
  • a parallel pair of signal conductive elements 25 and 27 are disposed within the ground plane conductor 9 above and below the plane of the strip line conductor 17.
  • the lower conductive element 25 forms a straight-through transmission path and includes a conductive strip line 29 supported by a dielectric slab 31 which is mounted in longitudinal slots 33.
  • the width of the strip line 29 is decreased to maintain the characteristic impedance of the transmission line which is formed with closer spacing to the ground plane conductor 9.
  • the upper conductive element forms an attenuating transmission path and includes a resistive film 35 which is disposed on a dielectric slab 37 mounted in longitudinal slots 39 and which is connected to the ground plane conductor 9 along its longitudinal edges 41.
  • a resistive card attenuator of this type is described in connection with a coaxial transmission line in pending .U.S. patent application Ser. No. 393,127 tiled Aug. 31, 1964 by W. R. Hewlett and W. B. Wholey and issued on Jan. 4, 1966 as U.S. Patent 3,227,975.
  • the strip line conductor 17 includes a iiexible portion 47 at each side of the parallel pair of signal transmission paths which serves as a switching element and which is tapered to maintainthe characteristic impedance of the transmission line.
  • the switching element 47 is actuated either magnetically by suitable electromagnetics 49 and programming ⁇ power source 50 or mechanically by an actuator 51 and programming cam assembly 53.
  • the actuator 51 may be any dielectric material which passes through an aperture in the ground plane conductor 9 that has dimensions which cause the aperture to operate as a waveguide beyond cutoi at the frequencies of signal applied to the attenuator so that signal leakage is negligible.
  • a selected step of attenuation is provided by switching the strip line conductor 47 at both ends of the parallel pair of signal transmission paths to the resistive card path.
  • each with an attenuator card of selected value such as 5 db, 10 db, 20 db and 40 db a number of attenuation steps in 5 db increments from 5 db to 75 db may be provided by selectively switching in either an attenuation transmission path or a straightthrough transmission path.
  • This selection is provided in a conventional manner either by the programmed power source 50 (used with the magnetic actuators) or the cam assembly 53 (used with the mechanical actuator 51) in response to the position of the attenuation selector dial 55.
  • spurious transmission paths around the attenuator card are formed along the closely-spaced straight-through transmission path of the parallel pair. This disturbs the attenuation vs. frequency response of the attenuator and may readily be suppressed by shorting slugs 57 which are brought into contact with the straight-through transmission path simultaneously with the magnetic or mechanical actuation of the switching elements of that attenuation section.
  • Signal apparatus comprising:
  • a transmission line including a ground plane conductor
  • a first signal transmission path of said transmission line within said ground plane conductor including a resistance layer on a dielectric
  • actuator means for simultaneously deecting said switching elements to the same one of said first and second signal transmission paths.
  • Signal apparatus comprising: 3. Signal apparatus as in claim 2 wherein:
  • each of said switching elements has a width which disposed in spaced relationship within a ground plane decreases with length from the signal conductor.

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  • Attenuators (AREA)

Description

5. F. ADAM May 9, 1967 y' VARIABLE ATTENUATOR EMPLOYING INTERNAL SWITCHING Filed Oct. 8, 1965' myENToR STEPHEN F. ADAM BY' Q .CQ m
ATTORNEY United States Patent O Y 3,319,194 VARIABLE ATTENUATOR EMPLOYING INTERNAL SWITCHING Stephen F. Adam, Los Altos, Calif., assignor to Hewlett- Packard Company, Palo Alto, Calif., a corporation of California Filed Oct. 8, 1965, Ser. No. 493,985 3 Claims. (Cl. 333--S1) This invention relates to a high frequency signal attenuator which provides discrete steps of attenuation using separate attenuator elements which are all disposed in a transmission line configuration adjacent a common and continuous ground plane. An attenuator of this type obviates the need for complex mechanisms for switching both the signal and ground plane conductors of the transmission line structure and thus eliminates the introduction of unknown contact irnpedances in the ground plane conductor at the junctions of attenuator sections.
Accordingly, it is an object of the present invention to provide an improved step attenuator for high frequency signals.
In accordance with the illustrated embodiment of the present invention, a strip line structure is formed in a continuous ground plane conductor using a number of switchable sections, each including a resistive card attenuator and a straight-through conductor. Selection of either of the two signal paths is accomplished by defiecting the signal conductor from contact with one signal path to contact with the other signal path using magnetic or mechanical actuators. The effects of leakage paths `around the selected attenuating signal path may be overcome by establishing shorting paths simultaneously with the deflection of the signal conductor.
'I'hese and other objects of the present invention will be apparent from a reading of this specification and an inspection of the accompanying drawing in which:
FIGURE 1 is a front sectional view of the attenuator according to the present invention;
FIGURE 2 is an end sectional view of the attenuator of FIGURE 1; and
FIGURE 3 is a top sectional view of the attenuator of FIGURE 1.
In FIGURES 1, 2 and 3 of the drawing, there is shown a body 9 which forms the ground plane conductor of a strip line. Coaxial connectors 11, 13 at the ends of the body 9 each include a center .conductor 15 which is matched coupled to the strip line conductor 17 and an outer conductor 19 which is connected to the body 9. The strip line conductor 17 is supported on a dielectric slab 21 which is mounted in longitudinal grooves 23 in the side walls of the ground plane conductor or body 9.
At selected intervals along the length of the strip line conductor, a parallel pair of signal conductive elements 25 and 27 are disposed within the ground plane conductor 9 above and below the plane of the strip line conductor 17. The lower conductive element 25 forms a straight-through transmission path and includes a conductive strip line 29 supported by a dielectric slab 31 which is mounted in longitudinal slots 33. The width of the strip line 29 is decreased to maintain the characteristic impedance of the transmission line which is formed with closer spacing to the ground plane conductor 9. The upper conductive element forms an attenuating transmission path and includes a resistive film 35 which is disposed on a dielectric slab 37 mounted in longitudinal slots 39 and which is connected to the ground plane conductor 9 along its longitudinal edges 41. Contacts 43, 45 with the resistive film at restricted areas 3,3l9,l94 Patented May 9, 1967 ice at the ends of the slab 37 provide connection points for the signal transmission path. A resistive card attenuator of this type is described in connection with a coaxial transmission line in pending .U.S. patent application Ser. No. 393,127 tiled Aug. 31, 1964 by W. R. Hewlett and W. B. Wholey and issued on Jan. 4, 1966 as U.S. Patent 3,227,975. The strip line conductor 17 includes a iiexible portion 47 at each side of the parallel pair of signal transmission paths which serves as a switching element and which is tapered to maintainthe characteristic impedance of the transmission line. The switching element 47 is actuated either magnetically by suitable electromagnetics 49 and programming `power source 50 or mechanically by an actuator 51 and programming cam assembly 53. The actuator 51 may be any dielectric material which passes through an aperture in the ground plane conductor 9 that has dimensions which cause the aperture to operate as a waveguide beyond cutoi at the frequencies of signal applied to the attenuator so that signal leakage is negligible. A selected step of attenuation is provided by switching the strip line conductor 47 at both ends of the parallel pair of signal transmission paths to the resistive card path. When a plurality of such paths are provided, each with an attenuator card of selected value such as 5 db, 10 db, 20 db and 40 db, a number of attenuation steps in 5 db increments from 5 db to 75 db may be provided by selectively switching in either an attenuation transmission path or a straightthrough transmission path. This selection is provided in a conventional manner either by the programmed power source 50 (used with the magnetic actuators) or the cam assembly 53 (used with the mechanical actuator 51) in response to the position of the attenuation selector dial 55.
For higher attenuation sections, (e.g. 40 db or higher) spurious transmission paths around the attenuator card are formed along the closely-spaced straight-through transmission path of the parallel pair. This disturbs the attenuation vs. frequency response of the attenuator and may readily be suppressed by shorting slugs 57 which are brought into contact with the straight-through transmission path simultaneously with the magnetic or mechanical actuation of the switching elements of that attenuation section.
I claim:
1. Signal apparatus comprising:
a transmission line including a ground plane conductor;
a first signal transmission path of said transmission line within said ground plane conductor including a resistance layer on a dielectric;
means connecting the ground plane conductor and said resistive lm along the longitudinal edges thereof;
contacts at each end of said resistive film within a restricted area intermediate the longitudinal edges of the resistive film;
a second signal transmission path within the ground plane conductor in spaced plane-parallel relation to the resistance layer on a dielectric in the iirst signal transmission path;
another signal conductor at each end of the first and second signal transmission paths disposed intermediate the spacing thereof and within the ground plane conductor;
a switching element at each of the signal conductor adjacent the first and second signal transmission paths forming a portion of the length of said signal conductor; and
actuator means for simultaneously deecting said switching elements to the same one of said first and second signal transmission paths.
2. Signal apparatus comprising: 3. Signal apparatus as in claim 2 wherein:
a signal attenuating path and a signal conduction path each of said switching elements has a width which disposed in spaced relationship within a ground plane decreases with length from the signal conductor. conductor; t
a signal conductor at each end of the signal attenuat- 5 References Cited by the Examiner ing and signal conduction paths disposed inter- UNITED STATES PATENTS mediate the spacing thereof and within the ground 2 597 090 5/1952 Freeman 333 81 plane conductor;
a switching element attached at the end of each of the gnclelman signal conductors adjacent the signal attenuating and l0 3 087125 4/1963 shle 333:97
signal conduction paths forming a portion of the length of each of said signal conductors, each of ELI LIEBERMAN Primary Examiner the switching elements being capable of flexing over the length thereof; and HERMAN KARL SAALBACH, Examiner. actuator means for simultaneously deecting said 15 REHUNT, Assistant Examnen switching elements to the same one of said signal attenuating and vsignal conduction paths.

Claims (1)

1. SIGNAL APPARATUS COMPRISING: A TRANSMISSION LINE INCLUDING A GROUND PLANE CONDUCTOR; A FIRST SIGNAL TRANSMISSION PATH OF SAID TRANSMISSION LINE WITHIN SAID GROUND PLANE CONDUCTOR INCLUDING A RESISTANCE LAYER ON A DIELECTRIC; MEANS CONNECTING THE GROUND PLANE CONDUCTOR AND SAID RESISTIVE FILM ALONG THE LONGITUDINAL EDGES THEREOF; CONTACTS AT EACH END OF SAID RESISTIVE FILM WITHIN A RESTRICTED AREA INTERMEDIATE THE LONGITUDINAL EDGES OF THE RESISTIVE FILM; A SECOND SIGNAL TRANSMISSION PATH WITHIN THE GROUND PLANE CONDUCTOR IN SPACED PLANE-PARALLEL RELATION TO THE RESISTANCE LAYER ON A DIELECTRIC IN THE FIRST SIGNAL TRANSMISSION PATH; ANOTHER SIGNAL CONDUCTOR AT EACH END OF THE FIRST AND SECOND SIGNAL TRANSMISSION PATHS DISPOSED INTERMEDIATE THE SPACING THEREOF AND WITHIN THE GROUND PLANE CONDUCTOR; A SWITCHING ELEMENT AT EACH OF THE SIGNAL CONDUCTOR ADJACENT THE FIRST AND SECOND SIGNAL TRANSMISSION PATHS FORMING A PORTION OF THE LENGTH OF SAID SIGNAL CONDUCTOR; AND ACTUATOR MEANS FOR SIMULTANEOUSLY DEFLECTING SAID SWITCHING ELEMENTS TO THE SAME ONE OF SAID FIRST AND SECOND SIGNAL TRANSMISSION PATHS.
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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753170A (en) * 1971-02-10 1973-08-14 Tektronix Inc Step attenuator apparatus having attenuator stages selectively connected in cascade by cam actuated switches
JPS5365043A (en) * 1976-11-20 1978-06-10 Tektronix Inc Attenuator unit
DE2206350C3 (en) 1971-02-10 1979-05-10 Tektronix, Inc., Beaverton, Oreg. (V.St.A.) Damping arrangement
DE2265361B1 (en) * 1971-02-10 1980-09-04 Tektronix Inc Electrical switch device for high frequency with a support plate made of insulating material and a coupling element extending through a hole in the support plate
DE3417658A1 (en) * 1983-05-24 1985-04-25 Adret Electronique S.A., Trappes INSERTION SWITCH FOR A HIGH-FREQUENCY TRANSMISSION LINE
US4695811A (en) * 1986-07-28 1987-09-22 Tektronix, Inc. High frequency coaxial switch
US4734661A (en) * 1986-12-04 1988-03-29 Tektronix, Inc. Coax to slab line connector and programmable attenuator using the same
US5039961A (en) * 1989-12-21 1991-08-13 Hewlett-Packard Company Coplanar attenuator element having tuning stubs
US5061909A (en) * 1988-04-12 1991-10-29 Marconi Instruments Limited Attenuator switchably coupled to transmission path and means for switchably breaking the path
DE4226106C1 (en) * 1992-08-07 1993-09-16 Rohde & Schwarz Gmbh & Co Kg, 81671 Muenchen, De Programmable calibration line between 2 conductor planes - has gap in inner conductor bridged by 2 alternate 4-pole networks by deflection of free inner conductor ends
US5315273A (en) * 1992-10-30 1994-05-24 Teledyne Industries Inc. Attenuator relay
DE4401068A1 (en) * 1993-08-30 1995-03-02 Rohde & Schwarz Network analyser
US20020153980A1 (en) * 2001-04-24 2002-10-24 Freeman James A. Relay
US6621391B2 (en) 2001-04-24 2003-09-16 Agilent Technologies, Inc. Relay
US20080283379A1 (en) * 2007-05-18 2008-11-20 Teledyne Technologies Incorporated Coaxial switch with reduced tribo-electric charge accumulation
US20090273420A1 (en) * 2008-05-05 2009-11-05 Teledyne Technologies Incorporated Electromagnetic switch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597090A (en) * 1949-05-19 1952-05-20 Daven Company Variable attenuator
US2958054A (en) * 1958-11-24 1960-10-25 Amphenol Borg Electronics Corp Impedance terminated coaxial line switch apparatus
US2997669A (en) * 1958-02-03 1961-08-22 Thompson Ramo Wooldridge Inc Broad band lobing switch
US3087125A (en) * 1961-07-13 1963-04-23 Gen Electric Coaxial reed relay for interrupting the center conductor and simultaneously terminating its opened ends

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2597090A (en) * 1949-05-19 1952-05-20 Daven Company Variable attenuator
US2997669A (en) * 1958-02-03 1961-08-22 Thompson Ramo Wooldridge Inc Broad band lobing switch
US2958054A (en) * 1958-11-24 1960-10-25 Amphenol Borg Electronics Corp Impedance terminated coaxial line switch apparatus
US3087125A (en) * 1961-07-13 1963-04-23 Gen Electric Coaxial reed relay for interrupting the center conductor and simultaneously terminating its opened ends

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753170A (en) * 1971-02-10 1973-08-14 Tektronix Inc Step attenuator apparatus having attenuator stages selectively connected in cascade by cam actuated switches
DE2206350C3 (en) 1971-02-10 1979-05-10 Tektronix, Inc., Beaverton, Oreg. (V.St.A.) Damping arrangement
DE2265361B1 (en) * 1971-02-10 1980-09-04 Tektronix Inc Electrical switch device for high frequency with a support plate made of insulating material and a coupling element extending through a hole in the support plate
DE2265361C3 (en) * 1971-02-10 1981-09-24 Tektronix, Inc., 97005 Beaverton, Oreg. Electrical switch device for high frequency with a carrier plate made of insulating material and a coupling element extending through a hole in the carrier plate
JPS5365043A (en) * 1976-11-20 1978-06-10 Tektronix Inc Attenuator unit
JPS5714602B2 (en) * 1976-11-20 1982-03-25
DE3417658A1 (en) * 1983-05-24 1985-04-25 Adret Electronique S.A., Trappes INSERTION SWITCH FOR A HIGH-FREQUENCY TRANSMISSION LINE
US4695811A (en) * 1986-07-28 1987-09-22 Tektronix, Inc. High frequency coaxial switch
DE3724445A1 (en) * 1986-07-28 1988-02-11 Tektronix Inc HIGH FREQUENCY COAXIAL SWITCH
US4734661A (en) * 1986-12-04 1988-03-29 Tektronix, Inc. Coax to slab line connector and programmable attenuator using the same
US5061909A (en) * 1988-04-12 1991-10-29 Marconi Instruments Limited Attenuator switchably coupled to transmission path and means for switchably breaking the path
US5039961A (en) * 1989-12-21 1991-08-13 Hewlett-Packard Company Coplanar attenuator element having tuning stubs
DE4226106C1 (en) * 1992-08-07 1993-09-16 Rohde & Schwarz Gmbh & Co Kg, 81671 Muenchen, De Programmable calibration line between 2 conductor planes - has gap in inner conductor bridged by 2 alternate 4-pole networks by deflection of free inner conductor ends
US5315273A (en) * 1992-10-30 1994-05-24 Teledyne Industries Inc. Attenuator relay
DE4401068A1 (en) * 1993-08-30 1995-03-02 Rohde & Schwarz Network analyser
US6081125A (en) * 1993-08-30 2000-06-27 Rohde & Schwarz Gmbh & Co. Kg Network analyzer
US20020153980A1 (en) * 2001-04-24 2002-10-24 Freeman James A. Relay
US6621391B2 (en) 2001-04-24 2003-09-16 Agilent Technologies, Inc. Relay
US6707356B2 (en) 2001-04-24 2004-03-16 Agilent Technologies, Inc. Method of constructing a relay
US6853273B2 (en) 2001-04-24 2005-02-08 Agilent Technologies, Inc. Relay
US20050030135A1 (en) * 2001-04-24 2005-02-10 Freeman James A. Relay
US6933816B2 (en) 2001-04-24 2005-08-23 Agilent Technologies, Inc. Relay
US20050248425A1 (en) * 2001-04-24 2005-11-10 Freeman James A Relay
US20080283379A1 (en) * 2007-05-18 2008-11-20 Teledyne Technologies Incorporated Coaxial switch with reduced tribo-electric charge accumulation
US20090273420A1 (en) * 2008-05-05 2009-11-05 Teledyne Technologies Incorporated Electromagnetic switch
US7876185B2 (en) 2008-05-05 2011-01-25 Teledyne Technologies Incorporated Electromagnetic switch

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