US2819452A - Microwave filters - Google Patents

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US2819452A
US2819452A US286763A US28676352A US2819452A US 2819452 A US2819452 A US 2819452A US 286763 A US286763 A US 286763A US 28676352 A US28676352 A US 28676352A US 2819452 A US2819452 A US 2819452A
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conductor
line
conductors
obstacles
susceptance
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US286763A
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Arditi Maurice
Georges A Deschamps
Elefant Jack
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TDK Micronas GmbH
International Telephone and Telegraph Corp
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Deutsche ITT Industries GmbH
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Priority to US286763A priority Critical patent/US2819452A/en
Priority to GB12112/53A priority patent/GB761763A/en
Priority to CH316535D priority patent/CH316535A/en
Priority to DEI7222A priority patent/DE1139928B/en
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01PWAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P3/00Waveguides; Transmission lines of the waveguide type
    • H01P3/02Waveguides; Transmission lines of the waveguide type with two longitudinal conductors
    • H01P3/08Microstrips; Strip lines
    • H01P3/081Microstriplines
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01PWAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00Auxiliary devices
    • H01P1/20Frequency-selective devices, e.g. filters
    • H01P1/201Filters for transverse electromagnetic waves
    • H01P1/203Strip line filters
    • H01P1/2039Galvanic coupling between Input/Output

Definitions

  • This invention relates to microwave transmission systems and more particularly to microwave filters specially applicable to microwave printed transmission lines and circuitry.
  • a type :of microwave transmission line comprising, in one of its simplest forms, two conductors printed or otherwise disposed in substantially parallel relation on opposite sides of a strip or layer of dielectric material a small fraction of a quarter wavelength thick.
  • One conductor is made narrower than the other, so that the wider planar conductor appears as an infinite conducting surface to the narrower conductor, thereby insuring the mode of propagation tof microwave energy therealong in the TEM mode.
  • the dielectric between the two conductors may be of substantially the same Width as the narrowest of the two conductors or wider according to the relationships desired.
  • filter arrangements utilizing a section of the aforementioned parallel strip type of line and spaced susceptances in the form of conductor obstacles projecting either partway or all the way across the space between the paralle'l strip conductors.
  • An object of this invention is to provide still other microwave filter arrangements which are small, light in Weight, and relatively simple and inexpensive to make, also utilizing a section of the aforementioned parallel type of line.
  • One of the features of this invention is the manner of providing in a parallel strip type of line spaced susceptances of large value disposed as reflecting shunt impedances to define a resonant section or cavity in the parallel strip line.
  • the susceptances may comprise the placing of two obstacles or Iother discontinuity structures in or on one or the other or both of the conductors of the line at spaced points to form a resonant cavity section therebetween. These discontinuities may comprise either a conductor or dielectric obstacle.
  • susceptances may be introduced in the line by placing a piece of conductor cross-wise of the line as ⁇ a lumped impedance.
  • the cross-wise conductor would be in contact with one of the line conductors with its ends either open or shorted to the other line conductor. Also such obstacles may be printed directly on the strip of dielectric along with the line conductors, and if desired, may comprise variations in the shape of the line conductors.
  • Another feature of the invention is the method and means for tuning the resonant spacing formed by such line conductor configurations.
  • this tuning of the resonant spacing or cavity may be accomplished in various ways, including Vernier capacitive screws, line compressors or stretches, lateral line projections or protuberances and the size and position of interconnecting portions of the line conductor configurations.
  • Fig. 1 is a plan view of ⁇ one forni of filter in accordance with the principles of this invention
  • Fig. 2 is a cross-sectional View taken along line 2-2 of Fig. l; l
  • Fig. 3 isa plan view of an alternate form of filter
  • Fig. 4 is a cross-sectional view taken along line 4 -4 of Fig. 3;
  • Fig. 5 is a cross-sectional view similar to Fig. 4 showing another modification of the invention.
  • Fig. 6 is a plan view of another embodiment of the invention.
  • Fig. 7 is a cross-sectional view taken along line 7 7 of Fig. 6;
  • Fig. 8 is a circle diagram based upon the Smith admittance chart used in explaining the susceptance characteristics of the plate-'like obstacles used in the filters of the character disclosed herein;
  • Fig. 9 is a plan View of a directly coupled filter in accordance with the principles of this invention.
  • Fig. 10 is a cross-sectional View taken along line 10- 10 of Fig. 9;
  • Figs. l1 and 12 show still other modifications of this invention.
  • the microwave transmission line shown is of the printed circuit type comprising a first or line conductor 1 and a second or base conductor 2 with a layer 3 of dielectric material therebetween.
  • the conductive material may be applied and/ or shaped or etched on a layer of dielectric material, such as polystyrene, polyethylene, quartz, Teflon, fiberglass, or other suitable material of high dielectric quality, in the form of conductive paint or ink, or the conductive material may be chemically deposited, sprayed through a stencil, or dusted onto selected prepared surfaces of thedielectric, or by any other of the known printed circuit techniques.
  • the spacing of the two conductors is preferably selected a small fraction in the order of about 1/10 ⁇ to about 1/s of a quarterwavelength of the microwave propagated therealong.
  • the microwave line of Figs. l and 2 is shown. provided. with spaced obstacles as lumped impedances in the form of short pieces of conductors 4, S, 6, and 7 disposed crosswise of the line conductor l.
  • These crosswise conductor obstacles provide two resonant cavity sections of lengths 1, the cavity sections being coupled by quarter wavelength sections of line.
  • the crosswise conductors 4 through 7 are shown to be of the same width as the line conductor 1, they may be of other widths either wider or narrower as desired, but always a small fraction of a quarter wavelength, depending upon the susceptance value desired.
  • the lengths of the crosswise conductors may also vary depending upon the susceptance value dev sired.
  • the susceptance value may also be varied by adjusting the position of the crosswise conductor. After the crosswise conductors have been suitably located, they may be secured to the line conductor by means of solder 8. After securing the crosswise pieces, it may be desirable to further tune the susceptances, the cavities idened thereby or the quarter wavelength spaced therebetween by ⁇ some form of Vernier trimming device. Such a trimming device is shown in Figs. l and 2 to comprise a piece of small wire as indicated at 9 and 10. Such piece of wire may be positioned either on the cross pieces 4 to 7 or on the line conductor 1 as may be desired. By adjusting the position of the wire, proper matching may be obtained.
  • the optimum position of trimming pieces or wire may be determined by use of any suitable measuring technique, one satisfactory method of making such measurements being disclosed in the pending application of G. A. Deschamps, Serial No. 333,164, tiled January 26, 1953.
  • a piece of solder which is maintained soft by a ysoldering iron whereby the Wire is nudged from one position to another until an optimum reading is obtained whereupon the solder is permitted to freeze.
  • the filter When the proper location of the crosswise conductors is obtained, the filter may be reproduced with reasonable accuracy by photographic and printed circuit techniques. Such a filter when produced by these techniques may have the appearance shown in Figs. 3 and 4.
  • the line conductor 1a and the cross-conductors 4a through 7a are made integral. While the cross pieces 4a through 7a are shown to extend completely across the dielectric 3, it will be clear that they need not be so extended but may fall short of the Width of the dielectric similarly as illustrated in Fig. 1.
  • the use of small pieces of Wire may also be practiced on this form of printed filter as well as several other methods. As shown in Figs.
  • one such method comprises conductive posts 11 and 12 disposed in the dielectric 3 in the resonant cavity section of the line.
  • Another method of varying the length of line between adjacent cross pieces is that of compressing or stretching the width of the line conductor. This method is best employed by providing the line conductor with extended width with gradual curvature as indicated at 13. If this width provides in effect too long a section, that section may be shortened in effect by slicing away edge portions of the line conductor, thus compressing it as indicated between broken lines 14. This lengthening and shortening of the line has reference to line wavelength.
  • the cross pieces 4a through 7a shown in Fig. 3 may be open ⁇ or closed at their ends.
  • the cross pieces are shown to be open.
  • the cross pieces are shown to be closed with respect to the other line conductor 2a, the line conductor 4a for example being continued by a conductor for connection with conductor 2a.
  • the conductor 2a may comprise a planar conductor extending the full width of the dielectric 3 or it may be of substantially the same width as the line conductor 1a as indicated in Fig. 5.
  • the conductor 2a may also be provided with cross pieces the same as 4a through 7a.
  • Figs. 6 and 7 show another form of ilter arrangement comprising two ribbon-like conductors 16 and 17 of substantially equal width separated by a similar region of dielectric 18.
  • the susceptance obstacles of lumped impedance in this iilter comprise strips of conductive material 19, 20 and 21, 22 disposed on opposite sides of the line conductors.
  • the susceptance values of these obstacles may be adjusted by adjusting relative positions, one being offset with respect to the other.
  • the ends of these cross pieces may be either open as shown or may be closed similarly as indicated in Fig. 5.
  • a Smith admittance chart is shown onto which a circle has been applied corresponding to test data with respect to a susceptance obstacle illustrated at 24 in Fig. 8.
  • the line section ⁇ is of the same character illustrated in Fig. l and is provided with like reference characters.
  • the obstacle comprises a crosswise strip 25 which is shorted at its ends to conductor 2 as indicated at 26. It will be observed that the circle is large thereby indicating that the insertion loss of this type of obstacle is small. It also shows that the obstacle is substantially symmetrical.
  • a directly coupled lter comprising a line conductor 27 printed on a strip ⁇ of dielectric 3 which in turn is provided with a second conductor 2 on the opposite Vside thereof.
  • the line conductor 27 is provided with a series of susceptance obstacles of dilerent lengths, the obstacles 28, 29, 30,
  • the susceptance obstacles 32, 33, and 34 determine the susceptance of the resonant sections.
  • These crosswise obstacles may each be tuned by any one of the tuning or trimming means herein described but for purposes of illustration the tuning means is shown to be in the form of a capacitive post 35 which may be adjusted with respect to the opposite line conductor. It should also be observed that While the second conductor 2 is illustrated as a planar conductor that it may in fact correspond substantially to the shape of the line conductor 27 together with the obstacle susceptance projections thereof.
  • the iilter may follow various line configurations incorporating susceptance obstacles of lumped impedances.
  • the line conductor 36 is shown with obstacle projections along :one side thereof as indicated Iat 37, the projections being of a width less than ⁇ a quarter wavelength.
  • the printed configuration may also incorporate trimming projections ⁇ as indicated at 38 -and 39. These trimming projections correspond substantially to the small pieces of wire 9 and 10 illustrated in Fig. 1. Final trimming of the resonant sections and the susceptance obstacles may be accomplished by cutting away portions of these small projections 38 and 39 until the optimum lsusceptance is obtained. Should too much be removed, conductive material may be added by soldering.
  • Fig. 11 the line conductor 36 is shown with obstacle projections along :one side thereof as indicated Iat 37, the projections being of a width less than ⁇ a quarter wavelength.
  • the printed configuration may also incorporate trimming projections ⁇ as indicated at 38 -and 39. These trimming projections correspond substantially to the small pieces of wire 9 and 10
  • 12 obstacles may comprise cutouts such as indicated at 40 in the line conductor 41.
  • the susceptance values of these recesses in the line 41 are also in the nature of lumped impedances or reflection obstacles, since the width ⁇ of the slots are a small fraction of a quarter wavelength.
  • These recesses may be tuned by means of small pieces ⁇ of wire las indicated at 42 and 43. By adjusting the position of these wires optimum tuning may be had, the Wires being thereafter secured by soldering or other suitable fastening means.
  • a microwave filter comprising first and second ribbonlike conductors, means disposing said conductors in dielectrically spaced substantially parallel relation a small fraction of a quarter wavelength vapart to provide a waveguide, ⁇ said fir-st conductor being of a width equal to a fraction of a quarter wavelength, said second conductor being wider than said first conductor to present thereto a planar conducting surface for propagation ⁇ of microwave energy in a mode approximating the TEM mode, said irst conductor having laterally disposed projections extending in overlying parallel relation to the planar conducting surface of said second conductor, the width of said lateral projections being asmall fraction of a quarter wavelength to present reflecting lump impedances spaced apart longitudinally of said conductors to form a resonant section therebetween, and means for adjusting the susceptance value :of certain of said lateral projections, said means including a conductive screw carried by the projection for adjustment into the space between saidprojection and said planar conducting surface.

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Description

Jan. 7, 1958 M. ARDlTl ETAL 2,819,452
MICROWAVE FILTERS Filed May 8. 1952 2 Sheets-Sheet 1 ELEFANT lNvENToRs MAUR/CE AKD/T EORL-'JES A. DESCHAMPS JACK )122,7 /1d ATTORNEY Jan. 7, 1958 M. ARD|T1 ET' AL 2,819,452
MICROWAVE FILTERS :filed May 8. 1952 2 sheets-Sweet 2 Vfl/ 1544 u l I l E /l 3 36 @W1 2 L 32 44x z5/@H12 .2 nl f n im fg \40 l I INVENTORS MAURICE ARDTI GEORES A. DESCHAMPS JACK ELEFANT United States Patent O MICROWAVE FILTERS Maurice Arditi, Clifton, N. J., and Georges A. Deschamps,
New York, and Jack Elefant, Brooklyn, N. Y., assignors to International Telephone and Telegraph Corporation, a corporation of Maryland Application May 8, 1952, Serial No. 286,7 63
1 Claim. (Cl. S33-73) This invention relates to microwave transmission systems and more particularly to microwave filters specially applicable to microwave printed transmission lines and circuitry.
In the copending applications of D. D. Grieg and H. F. Englemann, Serial No. 234,503, led June 30, 1951, now Patent No. 2,721,312, and M. Arditi and P. Parzen Serial No. 286,764, filed May 8, 1952, now Patent No. 2,774,046 a type :of microwave transmission line is disclosed comprising, in one of its simplest forms, two conductors printed or otherwise disposed in substantially parallel relation on opposite sides of a strip or layer of dielectric material a small fraction of a quarter wavelength thick. One conductor is made narrower than the other, so that the wider planar conductor appears as an infinite conducting surface to the narrower conductor, thereby insuring the mode of propagation tof microwave energy therealong in the TEM mode. The dielectric between the two conductors may be of substantially the same Width as the narrowest of the two conductors or wider according to the relationships desired. In our copending application Serial No. 286,761, iiled May 8, 1952, we disclose filter arrangements utilizing a section of the aforementioned parallel strip type of line and spaced susceptances in the form of conductor obstacles projecting either partway or all the way across the space between the paralle'l strip conductors.
An object of this invention is to provide still other microwave filter arrangements which are small, light in Weight, and relatively simple and inexpensive to make, also utilizing a section of the aforementioned parallel type of line.
One of the features of this invention is the manner of providing in a parallel strip type of line spaced susceptances of large value disposed as reflecting shunt impedances to define a resonant section or cavity in the parallel strip line. The susceptances, broadly speaking, may comprise the placing of two obstacles or Iother discontinuity structures in or on one or the other or both of the conductors of the line at spaced points to form a resonant cavity section therebetween. These discontinuities may comprise either a conductor or dielectric obstacle. For example, susceptances may be introduced in the line by placing a piece of conductor cross-wise of the line as `a lumped impedance. The cross-wise conductor would be in contact with one of the line conductors with its ends either open or shorted to the other line conductor. Also such obstacles may be printed directly on the strip of dielectric along with the line conductors, and if desired, may comprise variations in the shape of the line conductors.
Another feature of the invention is the method and means for tuning the resonant spacing formed by such line conductor configurations. As more fully described hereinafter, this tuning of the resonant spacing or cavity may be accomplished in various ways, including Vernier capacitive screws, line compressors or stretches, lateral line projections or protuberances and the size and position of interconnecting portions of the line conductor configurations.
ICC
The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, wherein:
Fig. 1 is a plan view of `one forni of filter in accordance with the principles of this invention;
Fig. 2 is a cross-sectional View taken along line 2-2 of Fig. l; l
Fig. 3 isa plan view of an alternate form of filter;
Fig. 4 is a cross-sectional view taken along line 4 -4 of Fig. 3;
Fig. 5 is a cross-sectional view similar to Fig. 4 showing another modification of the invention;
Fig. 6 is a plan view of another embodiment of the invention;
Fig. 7 is a cross-sectional view taken along line 7 7 of Fig. 6;
Fig. 8 is a circle diagram based upon the Smith admittance chart used in explaining the susceptance characteristics of the plate-'like obstacles used in the filters of the character disclosed herein;
Fig. 9 is a plan View of a directly coupled filter in accordance with the principles of this invention;
Fig. 10 is a cross-sectional View taken along line 10- 10 of Fig. 9; and
Figs. l1 and 12 show still other modifications of this invention.
Referring to Figs. 1 and 2, the microwave transmission line shown is of the printed circuit type comprising a first or line conductor 1 and a second or base conductor 2 with a layer 3 of dielectric material therebetween. The conductive material may be applied and/ or shaped or etched on a layer of dielectric material, such as polystyrene, polyethylene, quartz, Teflon, fiberglass, or other suitable material of high dielectric quality, in the form of conductive paint or ink, or the conductive material may be chemically deposited, sprayed through a stencil, or dusted onto selected prepared surfaces of thedielectric, or by any other of the known printed circuit techniques. The spacing of the two conductors is preferably selected a small fraction in the order of about 1/10` to about 1/s of a quarterwavelength of the microwave propagated therealong.
The microwave line of Figs. l and 2 is shown. provided. with spaced obstacles as lumped impedances in the form of short pieces of conductors 4, S, 6, and 7 disposed crosswise of the line conductor l. These crosswise conductor obstacles provide two resonant cavity sections of lengths 1, the cavity sections being coupled by quarter wavelength sections of line. While the crosswise conductors 4 through 7 are shown to be of the same width as the line conductor 1, they may be of other widths either wider or narrower as desired, but always a small fraction of a quarter wavelength, depending upon the susceptance value desired. The lengths of the crosswise conductors may also vary depending upon the susceptance value dev sired. The susceptance value may also be varied by adjusting the position of the crosswise conductor. After the crosswise conductors have been suitably located, they may be secured to the line conductor by means of solder 8. After securing the crosswise pieces, it may be desirable to further tune the susceptances, the cavities idened thereby or the quarter wavelength spaced therebetween by `some form of Vernier trimming device. Such a trimming device is shown in Figs. l and 2 to comprise a piece of small wire as indicated at 9 and 10. Such piece of wire may be positioned either on the cross pieces 4 to 7 or on the line conductor 1 as may be desired. By adjusting the position of the wire, proper matching may be obtained. The optimum position of trimming pieces or wire may be determined by use of any suitable measuring technique, one satisfactory method of making such measurements being disclosed in the pending application of G. A. Deschamps, Serial No. 333,164, tiled January 26, 1953. During this adjustment of the wire pieces, it is preferable to have applied thereto a piece of solder which is maintained soft by a ysoldering iron whereby the Wire is nudged from one position to another until an optimum reading is obtained whereupon the solder is permitted to freeze.
When the proper location of the crosswise conductors is obtained, the filter may be reproduced with reasonable accuracy by photographic and printed circuit techniques. Such a filter when produced by these techniques may have the appearance shown in Figs. 3 and 4. The line conductor 1a and the cross-conductors 4a through 7a are made integral. While the cross pieces 4a through 7a are shown to extend completely across the dielectric 3, it will be clear that they need not be so extended but may fall short of the Width of the dielectric similarly as illustrated in Fig. 1. In order to provide for susceptance trimming, the use of small pieces of Wire may also be practiced on this form of printed filter as well as several other methods. As shown in Figs. 3 and 4, one such method comprises conductive posts 11 and 12 disposed in the dielectric 3 in the resonant cavity section of the line. Another method of varying the length of line between adjacent cross pieces is that of compressing or stretching the width of the line conductor. This method is best employed by providing the line conductor with extended width with gradual curvature as indicated at 13. If this width provides in effect too long a section, that section may be shortened in effect by slicing away edge portions of the line conductor, thus compressing it as indicated between broken lines 14. This lengthening and shortening of the line has reference to line wavelength.
The cross pieces 4a through 7a shown in Fig. 3 may be open `or closed at their ends. In Fig. 4 the cross pieces are shown to be open. In Fig. 5 the cross pieces are shown to be closed with respect to the other line conductor 2a, the line conductor 4a for example being continued by a conductor for connection with conductor 2a. The conductor 2a may comprise a planar conductor extending the full width of the dielectric 3 or it may be of substantially the same width as the line conductor 1a as indicated in Fig. 5. The conductor 2a may also be provided with cross pieces the same as 4a through 7a.
Figs. 6 and 7 show another form of ilter arrangement comprising two ribbon- like conductors 16 and 17 of substantially equal width separated by a similar region of dielectric 18. The susceptance obstacles of lumped impedance in this iilter comprise strips of conductive material 19, 20 and 21, 22 disposed on opposite sides of the line conductors. The susceptance values of these obstacles may be adjusted by adjusting relative positions, one being offset with respect to the other. The ends of these cross pieces may be either open as shown or may be closed similarly as indicated in Fig. 5.
Referring to Fig. 8, a Smith admittance chart is shown onto which a circle has been applied corresponding to test data with respect to a susceptance obstacle illustrated at 24 in Fig. 8. The line section `is of the same character illustrated in Fig. l and is provided with like reference characters. The obstacle, however, comprises a crosswise strip 25 which is shorted at its ends to conductor 2 as indicated at 26. It will be observed that the circle is large thereby indicating that the insertion loss of this type of obstacle is small. It also shows that the obstacle is substantially symmetrical.
Referring to Figs. 9 and 10, a directly coupled lter is therein shown comprising a line conductor 27 printed on a strip `of dielectric 3 which in turn is provided with a second conductor 2 on the opposite Vside thereof. The line conductor 27 is provided with a series of susceptance obstacles of dilerent lengths, the obstacles 28, 29, 30,
and 31 representing transformer couplingsoflumpedimpedance between adjacent resonant sections while the susceptance obstacles 32, 33, and 34 determine the susceptance of the resonant sections. These crosswise obstacles may each be tuned by any one of the tuning or trimming means herein described but for purposes of illustration the tuning means is shown to be in the form of a capacitive post 35 which may be adjusted with respect to the opposite line conductor. It should also be observed that While the second conductor 2 is illustrated as a planar conductor that it may in fact correspond substantially to the shape of the line conductor 27 together with the obstacle susceptance projections thereof.
Referring now to Figs. 11 and 12, the iilter may follow various line configurations incorporating susceptance obstacles of lumped impedances. In Fig. 11, for example, the line conductor 36 is shown with obstacle projections along :one side thereof as indicated Iat 37, the projections being of a width less than `a quarter wavelength. The printed configuration may also incorporate trimming projections `as indicated at 38 -and 39. These trimming projections correspond substantially to the small pieces of wire 9 and 10 illustrated in Fig. 1. Final trimming of the resonant sections and the susceptance obstacles may be accomplished by cutting away portions of these small projections 38 and 39 until the optimum lsusceptance is obtained. Should too much be removed, conductive material may be added by soldering. In Fig. 12 obstacles may comprise cutouts such as indicated at 40 in the line conductor 41. The susceptance values of these recesses in the line 41 are also in the nature of lumped impedances or reflection obstacles, since the width `of the slots are a small fraction of a quarter wavelength. These recesses may be tuned by means of small pieces `of wire las indicated at 42 and 43. By adjusting the position of these wires optimum tuning may be had, the Wires being thereafter secured by soldering or other suitable fastening means.
While we have -described above the principles of `our invention in connection with specific apparatus, it is to be `clearly understood that this description is madeonly by way :of example Iand not as a limitation to the scope of our invention as set forth in the objects thereof and Iin the `accompanying claim.
We claim:
A microwave filter comprising first and second ribbonlike conductors, means disposing said conductors in dielectrically spaced substantially parallel relation a small fraction of a quarter wavelength vapart to provide a waveguide, `said fir-st conductor being of a width equal to a fraction of a quarter wavelength, said second conductor being wider than said first conductor to present thereto a planar conducting surface for propagation `of microwave energy in a mode approximating the TEM mode, said irst conductor having laterally disposed projections extending in overlying parallel relation to the planar conducting surface of said second conductor, the width of said lateral projections being asmall fraction of a quarter wavelength to present reflecting lump impedances spaced apart longitudinally of said conductors to form a resonant section therebetween, and means for adjusting the susceptance value :of certain of said lateral projections, said means including a conductive screw carried by the projection for adjustment into the space between saidprojection and said planar conducting surface.
References Cited in the tile of this patent UNITED STATES PATENTS 2,411,555 Rogers Nov. 26, 1946I 2,540,488 Mumford Feb. 6,'1951 2,558,748 Haeft` July 3, 1951v 2,721,312 Grieg et al. Oct. 18, 1955 OTHER REFERENCES Radio-Electronic Engineering; Sept. 1951, pages 16, 31, S33-84M.
US286763A 1952-05-08 1952-05-08 Microwave filters Expired - Lifetime US2819452A (en)

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GB12112/53A GB761763A (en) 1952-05-08 1953-05-01 Microwave filters
CH316535D CH316535A (en) 1952-05-08 1953-05-07 Ultra-shortwave filter
DEI7222A DE1139928B (en) 1952-05-08 1953-05-07 Microwave filters

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US2915716A (en) * 1956-10-10 1959-12-01 Gen Dynamics Corp Microstrip filters
US2919441A (en) * 1955-04-15 1959-12-29 Chu Lan Jen Radio-frequency-energy transmission line and antenna
US2962716A (en) * 1957-06-21 1960-11-29 Itt Antenna array
US2984802A (en) * 1954-11-17 1961-05-16 Cutler Hammer Inc Microwave circuits
US3327255A (en) * 1963-03-06 1967-06-20 Bolljahn Harriette Interdigital band-pass filters
US3345589A (en) * 1962-12-14 1967-10-03 Bell Telephone Labor Inc Transmission line type microwave filter
US3348173A (en) * 1964-05-20 1967-10-17 George L Matthaei Interdigital filters with capacitively loaded resonators
US3391356A (en) * 1964-06-30 1968-07-02 Bolljahn Harriette Strip-line filter
US3497835A (en) * 1965-12-10 1970-02-24 Hughes Aircraft Co Microwave filter
US3534301A (en) * 1967-06-12 1970-10-13 Bell Telephone Labor Inc Temperature compensated integrated circuit type narrowband stripline filter
US3670270A (en) * 1968-04-15 1972-06-13 Technitrol Inc Electrical component
US3749473A (en) * 1971-11-04 1973-07-31 T Stewart Landing gear lever knob
US3959749A (en) * 1973-10-29 1976-05-25 Matsushita Electric Industrial Co., Ltd. Filter of the distributed constants type
EP0028403A1 (en) * 1979-11-05 1981-05-13 CSELT Centro Studi e Laboratori Telecomunicazioni S.p.A. Stub for matching microstrip circuits
EP0037421A1 (en) * 1979-10-15 1981-10-14 Motorola Inc Thin film structure for ceramic substrates.
FR2580118A1 (en) * 1985-04-03 1986-10-10 Singer Co
US5734307A (en) * 1996-04-04 1998-03-31 Ericsson Inc. Distributed device for differential circuit
CN1050703C (en) * 1992-09-24 2000-03-22 松下电器产业株式会社 Electric filter
US6621382B2 (en) * 2000-12-11 2003-09-16 Sharp Kabushiki Kaisha Noise filter and high frequency transmitter using noise filter

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IT1160736B (en) * 1983-03-18 1987-03-11 Telettra Lab Telefon RESONER CIRCUIT FOR A SYSTEM OF EXTRACTION FROM THE FLOW OF THE SWING DATA AT THE TIMING FREQUENCY
EP1298757A1 (en) * 2001-09-29 2003-04-02 Marconi Communications GmbH High frequency bandpass filter and tuning method thereof

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Cited By (21)

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US2984802A (en) * 1954-11-17 1961-05-16 Cutler Hammer Inc Microwave circuits
US2919441A (en) * 1955-04-15 1959-12-29 Chu Lan Jen Radio-frequency-energy transmission line and antenna
US2915716A (en) * 1956-10-10 1959-12-01 Gen Dynamics Corp Microstrip filters
US2962716A (en) * 1957-06-21 1960-11-29 Itt Antenna array
US3345589A (en) * 1962-12-14 1967-10-03 Bell Telephone Labor Inc Transmission line type microwave filter
US3327255A (en) * 1963-03-06 1967-06-20 Bolljahn Harriette Interdigital band-pass filters
US3348173A (en) * 1964-05-20 1967-10-17 George L Matthaei Interdigital filters with capacitively loaded resonators
US3391356A (en) * 1964-06-30 1968-07-02 Bolljahn Harriette Strip-line filter
US3497835A (en) * 1965-12-10 1970-02-24 Hughes Aircraft Co Microwave filter
US3534301A (en) * 1967-06-12 1970-10-13 Bell Telephone Labor Inc Temperature compensated integrated circuit type narrowband stripline filter
US3670270A (en) * 1968-04-15 1972-06-13 Technitrol Inc Electrical component
US3749473A (en) * 1971-11-04 1973-07-31 T Stewart Landing gear lever knob
US3959749A (en) * 1973-10-29 1976-05-25 Matsushita Electric Industrial Co., Ltd. Filter of the distributed constants type
EP0037421A1 (en) * 1979-10-15 1981-10-14 Motorola Inc Thin film structure for ceramic substrates.
EP0037421A4 (en) * 1979-10-15 1982-01-26 Motorola Inc Thin film structure for ceramic substrates.
EP0028403A1 (en) * 1979-11-05 1981-05-13 CSELT Centro Studi e Laboratori Telecomunicazioni S.p.A. Stub for matching microstrip circuits
FR2580118A1 (en) * 1985-04-03 1986-10-10 Singer Co
US4654668A (en) * 1985-04-03 1987-03-31 The Singer Company Microstrip circuit temperature compensation with stub means
CN1050703C (en) * 1992-09-24 2000-03-22 松下电器产业株式会社 Electric filter
US5734307A (en) * 1996-04-04 1998-03-31 Ericsson Inc. Distributed device for differential circuit
US6621382B2 (en) * 2000-12-11 2003-09-16 Sharp Kabushiki Kaisha Noise filter and high frequency transmitter using noise filter

Also Published As

Publication number Publication date
DE1139928B (en) 1962-11-22
GB761763A (en) 1956-11-21
CH316535A (en) 1956-10-15

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