US2512468A - Wave guide with mode suppression means - Google Patents

Wave guide with mode suppression means Download PDF

Info

Publication number
US2512468A
US2512468A US688165A US68816546A US2512468A US 2512468 A US2512468 A US 2512468A US 688165 A US688165 A US 688165A US 68816546 A US68816546 A US 68816546A US 2512468 A US2512468 A US 2512468A
Authority
US
United States
Prior art keywords
waves
guide
slots
mode
wave guide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US688165A
Inventor
Percival William Spencer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EMI Ltd filed Critical EMI Ltd
Application granted granted Critical
Publication of US2512468A publication Critical patent/US2512468A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
    • H01P1/162—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion absorbing spurious or unwanted modes of propagation

Definitions

  • This invention relates to electric waveguides and has for its object to provide means whereby waves of the so-called E mode, such as E waves, can be propagated along a guide and undesired waves of the so-called H mode, such as H; waves, can be eliminated from the guide or substantially attenuated.
  • the present invention pro vides a simple and effective meanswhereby such elimination can be accomplished.
  • the present invention is based on the fact that a narrow longitudinal slot in a guide will allow waves of H mode to escape while having a negligible effect upon waves of E mode, so that waves of the latter mode will be transmitted along the guide while Waves of H mode will be attenuated.
  • an electric waveguide for the transmission of waves of the E mode coupled to a source of said waves and having undesired waves of the H mode present in said guide, wherein said guide is provided with one or a plurality of slots arranged longitudinally of said guide, the size of said slot or slots being such as to afiord substantial attenuation of said undesired waves.
  • a plurality of said slots may be provided spaced equidistantly around the circumference of said guide and, if desired, a plurality of sets of said slots are provided each set being spaced longitudinally of said guide.
  • a conducting sleeve or sleeves may be provided axially movable with respect to said tube for the purpose of adjusting the length of said slot or lots.
  • Figure 1 illustrates a portion of a waveguide provided with means in accordance with the preferred form of the invention
  • Figure 2 illustrates a portion of a waveguide provided with means in accordance with another embodiment of the invention.
  • the section of the waveguide illustrated is intended to transmit waves of E0 mode and to eliminate or substantially attenuate waves of H1 mode.
  • the waveguide illustrated comprises a conducting tube 3 of circular form in cross-section having an internal diameter of one and one-eighth inches and a wall thickness of one-sixteenth of I an inch, and is,intended to mode which in air have .a-wavelengthgoi ,3,2 cms.,
  • the guide is provided witl;1;.;giour .filter sections each comprising aplurality of setsof longitudinal slots 4-, 5, 6 and], eight slots being provided in each sectionequidistantly spaced around the circumference of the guide. .
  • the optimum length of each slot is found to be-about 1.5 times the wavelength of the waves to be propagatedin-the guide and where waves of a, wavelengthof 3.2 cms. are required to be transmitted, the optimum length of each slot is 4.5 cms.
  • the width of each slot is one-sixteenth of an inch and the spacing between the slots in the adjacent sections is 3 cms., although this spacing is not critical.
  • H waves when travelling along a guide set up circumferential currents in the guide due to their axial magnetic field and the effect of the slots above described is to present a high impedance to the circumferential currents which thus set up a potential difierence across the slots and hence causes radiation of H1 waves.
  • the filter acts like an impedance in the guide which has no measurable effect on E0 waves but reflects or absorbs nearly all the power of the H1 waves. Since a considerable fraction of the power of the H1 waves is absorbed this is advantageous compared with a filter which operates entirely by reflection since, in general, it is not possible to build up high H1 voltages in the guide on the source side of the filter.
  • the length of the slots forming the filter section nearest the source may be adjusted by the provision of an axially movable conducting sleeve 8.
  • the guide 3 is provided with two filter sections each comprising a plurality of slots 9 and I0 spaced apart as indicated. Each section has four slots arranged longitudinally with respect to the axis of the guide and equidistantly spaced around its circumference.
  • the slots 9 and ID are substantially longer than the slots shown in Fi ure 1 and are partially covered by conducting sleeves H and I2 which are arranged for axial movement along the length of the slots 9 and I ll.
  • the length of the slots 9 and I 0 are five and one-eighth inches, the two sections being spaced apart by one and one-quarter inches, although this latter distance is not believed to be critical.
  • each sleeve II and I2 is one inch and with transmit waves of the sleeves l I and I2 arranged 1.79 inches from the left and right hand ends of the sections respectivel'y,Imaximurri attenuation ofithe Hr'waves occurredalthoughmot'to" the same extent as the attenuation obtained with the arrangement of Figure 1.
  • the present invention is of particulanuse-:irr-
  • An electric wave guide for the transmission of waves of the E mode to the exclusion of waves 'of" the H mode comprising a hollow conducting tube havinga plurality of sets of slots open to free space arranged longitudinally of said tube,
  • said sleeves being axially moveable with respect to said tubes to present openings of said slots having lengths atwhich undesired waves of the H mode present in said guide are substantially completely attenuated.

Landscapes

  • Control Of Motors That Do Not Use Commutators (AREA)
  • Non-Reversible Transmitting Devices (AREA)

Description

JuneZO, 1950 w. s. PERCIVAL 2,512,468
.WAVE GUIDE WITH MADE SUPPRESSION MEANS Filed Aug. 2, 1946 INVENTOR Wat/AM 6T pfAC/VAL ATTORNEY Patented June 20, 1950 WAVE GUIDE WITH MODE SUPPRESSION William Spencer Percival, Ealing, London,,E ng- ,land, assignor to Electric & Musical Industries Limited, Hayes, Middlesex, England, a corn+ 'pany of Great Britain v Application August 2, 1946, Serial No. 688,165
r In GreatBritain May 12, 1943 1 Section 1, Public Law 690, August 8,1946
Patent expires May 12, 1963 2 Claims. (Cl. 178-44) This invention relates to electric waveguides and has for its object to provide means whereby waves of the so-called E mode, such as E waves, can be propagated along a guide and undesired waves of the so-called H mode, such as H; waves, can be eliminated from the guide or substantially attenuated. The present inventionpro vides a simple and effective meanswhereby such elimination can be accomplished.--
The present invention is based on the fact that a narrow longitudinal slot in a guide will allow waves of H mode to escape while having a negligible effect upon waves of E mode, so that waves of the latter mode will be transmitted along the guide while Waves of H mode will be attenuated.
According to the invention there is provided an electric waveguide for the transmission of waves of the E mode coupled to a source of said waves and having undesired waves of the H mode present in said guide, wherein said guide is provided with one or a plurality of slots arranged longitudinally of said guide, the size of said slot or slots being such as to afiord substantial attenuation of said undesired waves. A plurality of said slots may be provided spaced equidistantly around the circumference of said guide and, if desired, a plurality of sets of said slots are provided each set being spaced longitudinally of said guide. Where the said slot or slots is or are provided in a guide formed of a conducting tube, a conducting sleeve or sleeves may be provided axially movable with respect to said tube for the purpose of adjusting the length of said slot or lots.
In order that the said invention may be clearly understood and readily carried into effect, it will now be more fully described with reference to the accompanying drawings, in which:
Figure 1 illustrates a portion of a waveguide provided with means in accordance with the preferred form of the invention, and
Figure 2 illustrates a portion of a waveguide provided with means in accordance with another embodiment of the invention.
In the embodiments of the invention shown in Figures 1 and 2', the section of the waveguide illustrated is intended to transmit waves of E0 mode and to eliminate or substantially attenuate waves of H1 mode.
Referring first to Figure l of the drawings, the waveguide illustrated comprises a conducting tube 3 of circular form in cross-section having an internal diameter of one and one-eighth inches and a wall thickness of one-sixteenth of I an inch, and is,intended to mode which in air have .a-wavelengthgoi ,3,2 cms.,
The guide is provided witl;1;.;giour .filter sections each comprising aplurality of setsof longitudinal slots 4-, 5, 6 and], eight slots being provided in each sectionequidistantly spaced around the circumference of the guide. .The optimum length of each slot is found to be-about 1.5 times the wavelength of the waves to be propagatedin-the guide and where waves of a, wavelengthof 3.2 cms. are required to be transmitted, the optimum length of each slot is 4.5 cms. The width of each slot is one-sixteenth of an inch and the spacing between the slots in the adjacent sections is 3 cms., although this spacing is not critical.
H waves when travelling along a guide set up circumferential currents in the guide due to their axial magnetic field and the effect of the slots above described is to present a high impedance to the circumferential currents which thus set up a potential difierence across the slots and hence causes radiation of H1 waves. The filter acts like an impedance in the guide which has no measurable effect on E0 waves but reflects or absorbs nearly all the power of the H1 waves. Since a considerable fraction of the power of the H1 waves is absorbed this is advantageous compared with a filter which operates entirely by reflection since, in general, it is not possible to build up high H1 voltages in the guide on the source side of the filter. If desired, it is possible by suitably choosing the length of the slots forming the filter section nearest the source to adjust the impedance of the filter to match the impedance of the source of H1 waves. The length of the slots may be adjusted by the provision of an axially movable conducting sleeve 8.
In the embodiment of the invention shown in Figure 2 the guide 3 is provided with two filter sections each comprising a plurality of slots 9 and I0 spaced apart as indicated. Each section has four slots arranged longitudinally with respect to the axis of the guide and equidistantly spaced around its circumference. The slots 9 and ID are substantially longer than the slots shown in Fi ure 1 and are partially covered by conducting sleeves H and I2 which are arranged for axial movement along the length of the slots 9 and I ll. In one specific example for waves with an air wavelength of approximately 3.2 cms., the length of the slots 9 and I 0 are five and one-eighth inches, the two sections being spaced apart by one and one-quarter inches, although this latter distance is not believed to be critical. The length of each sleeve II and I2 is one inch and with transmit waves of the sleeves l I and I2 arranged 1.79 inches from the left and right hand ends of the sections respectivel'y,Imaximurri attenuation ofithe Hr'waves occurredalthoughmot'to" the same extent as the attenuation obtained with the arrangement of Figure 1.
The present invention is of particulanuse-:irr-
apparatus for measuring impedances. appreciated that in such apparatus it. is necessary to isolate the impedance meas'uringrapparatus from possible s0urces of"l- I1 "waves1in theff 7 source of E0 waves and in the impedance'to be measured. By inserting a filter as described above between the measuring apparatus and the; source and between the measuring apparatus and the impedance to be measured, thisrisolation can be readily accomplished.
Although in the above description the filters V described each employ a.. ,plurality of sections, it
moveable-with respect to said member to ad-' just the apertures of said slots to lengths at which undesired waves of the H mode present in said guide are substantially attenuated.
2; An electric wave guide for the transmission of waves of the E mode to the exclusion of waves 'of" the H mode, comprising a hollow conducting tube havinga plurality of sets of slots open to free space arranged longitudinally of said tube,
the slots of each set of slots being spaced equidistantly about the: circumference of said tube,
and conducting sleeves surrounding said tube,
said sleeves being axially moveable with respect to said tubes to present openings of said slots having lengths atwhich undesired waves of the H mode present in said guide are substantially completely attenuated.
' WILLIAM: SPENCER PERCIVAL.
REFERENGES CITED vFlhe:followingreferences are of record in the file of.-tthis; patent:-
I UNITED STATES PATENTS Number Name Date 2,151,118 King Mar. 21, 1939 2,239,905 Trevor 'Apr. 29, 1941 2,241,119 -Dallenbach Ma 6, 1941 2,423,526 Sontheimer July 8, 194'! Southworth Feb. 8,v 1949
US688165A 1943-05-12 1946-08-02 Wave guide with mode suppression means Expired - Lifetime US2512468A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7601/43A GB582179A (en) 1943-05-12 1943-05-12 Improvements in or relating to electric waveguides

Publications (1)

Publication Number Publication Date
US2512468A true US2512468A (en) 1950-06-20

Family

ID=9836247

Family Applications (1)

Application Number Title Priority Date Filing Date
US688165A Expired - Lifetime US2512468A (en) 1943-05-12 1946-08-02 Wave guide with mode suppression means

Country Status (2)

Country Link
US (1) US2512468A (en)
GB (1) GB582179A (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2656513A (en) * 1949-12-29 1953-10-20 Bell Telephone Labor Inc Wave guide transducer
US2711440A (en) * 1944-10-09 1955-06-21 Rines Robert Harvey Microwave scanning system
US2779006A (en) * 1949-12-02 1957-01-22 Bell Telephone Labor Inc Spurious mode suppressing wave guides
US2786982A (en) * 1952-12-19 1957-03-26 Gen Electric Resonator structure
US2819451A (en) * 1951-07-12 1958-01-07 Gen Electric Co Ltd Electromagnetic-wave generating system
US2901698A (en) * 1955-09-21 1959-08-25 Sperry Rand Corp Microwave frequency meter
US2907962A (en) * 1953-02-11 1959-10-06 Polarad Electronics Corp Signal generator apparatus
US2921224A (en) * 1954-12-06 1960-01-12 Bell Telephone Labor Inc Traveling wave tube amplifier
US2983919A (en) * 1957-10-16 1961-05-09 Rca Corp Tuning means for slot radiator
US3087089A (en) * 1957-10-26 1963-04-23 Telefunken Gmbh Line to travelling wave tube coupling
US3205462A (en) * 1962-02-23 1965-09-07 Gen Electric Low-loss waveguide for propagation of h10 wave
US3516032A (en) * 1967-04-14 1970-06-02 Siemens Ag Albis Apparatus for filtering and dissipating microwave energy possessing undesired wave modes
US4926145A (en) * 1988-12-16 1990-05-15 Flam & Russell, Inc. Radial power combiner/divider with mode suppression

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2151118A (en) * 1935-10-30 1939-03-21 Bell Telephone Labor Inc Termination for dielectric guides
US2239905A (en) * 1938-02-19 1941-04-29 Rca Corp Filter circuits
US2241119A (en) * 1936-09-15 1941-05-06 Pintsch Julius Kg Ultra-short-wave apparatus
US2423526A (en) * 1944-03-30 1947-07-08 Rca Corp Reflectometer for waveguide transmission lines
US2461005A (en) * 1940-04-05 1949-02-08 Bell Telephone Labor Inc Ultra high frequency transmission

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2151118A (en) * 1935-10-30 1939-03-21 Bell Telephone Labor Inc Termination for dielectric guides
US2241119A (en) * 1936-09-15 1941-05-06 Pintsch Julius Kg Ultra-short-wave apparatus
US2239905A (en) * 1938-02-19 1941-04-29 Rca Corp Filter circuits
US2461005A (en) * 1940-04-05 1949-02-08 Bell Telephone Labor Inc Ultra high frequency transmission
US2423526A (en) * 1944-03-30 1947-07-08 Rca Corp Reflectometer for waveguide transmission lines

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2711440A (en) * 1944-10-09 1955-06-21 Rines Robert Harvey Microwave scanning system
US2779006A (en) * 1949-12-02 1957-01-22 Bell Telephone Labor Inc Spurious mode suppressing wave guides
US2656513A (en) * 1949-12-29 1953-10-20 Bell Telephone Labor Inc Wave guide transducer
US2819451A (en) * 1951-07-12 1958-01-07 Gen Electric Co Ltd Electromagnetic-wave generating system
US2786982A (en) * 1952-12-19 1957-03-26 Gen Electric Resonator structure
US2907962A (en) * 1953-02-11 1959-10-06 Polarad Electronics Corp Signal generator apparatus
US2921224A (en) * 1954-12-06 1960-01-12 Bell Telephone Labor Inc Traveling wave tube amplifier
US2901698A (en) * 1955-09-21 1959-08-25 Sperry Rand Corp Microwave frequency meter
US2983919A (en) * 1957-10-16 1961-05-09 Rca Corp Tuning means for slot radiator
US3087089A (en) * 1957-10-26 1963-04-23 Telefunken Gmbh Line to travelling wave tube coupling
US3205462A (en) * 1962-02-23 1965-09-07 Gen Electric Low-loss waveguide for propagation of h10 wave
US3516032A (en) * 1967-04-14 1970-06-02 Siemens Ag Albis Apparatus for filtering and dissipating microwave energy possessing undesired wave modes
US4926145A (en) * 1988-12-16 1990-05-15 Flam & Russell, Inc. Radial power combiner/divider with mode suppression

Also Published As

Publication number Publication date
GB582179A (en) 1946-11-07

Similar Documents

Publication Publication Date Title
US2512468A (en) Wave guide with mode suppression means
US2155508A (en) Wave guide impedance element and network
US4114121A (en) Apparatus and methods for launching and screening electromagnetic waves in the dipole mode
US2106769A (en) Transmission of guided waves
US2503549A (en) Impedance matching in wave guides
US3581243A (en) Directional coupler wherein dielectric media surrounding main line is different from dielectric media surrounding coupled line
GB687203A (en) Travelling wave tube
US2567210A (en) Ultra-high-frequency attenuator
JPS58642B2 (en) Hiragata Cable
US2588103A (en) Wave guide coupling between coaxial lines
US2643296A (en) High-frequency energy dividing apparatus
US2514544A (en) High-frequency attenuating device
US2670461A (en) Electromagnetic wave attenuator
US2760171A (en) Wave-guide mode filter
US4019162A (en) Coaxial transmission line with reflection compensation
US2558385A (en) Branch guide coupler
US2605400A (en) High stability radio wave frequency converter
US2605356A (en) Radio-frequency power divider circuit
GB786986A (en) Travelling wave tube
US4066927A (en) Wide-band low-reflection attenuated delay line
GB952338A (en) Improvements in or relating to travelling wave tubes
US2985852A (en) Apparatus of the kind including a waveguide
GB609333A (en) Impedance matching devices
US2567718A (en) Tapered corrugated line
US3251011A (en) Filter for passing selected te circular mode and absorbing other te circular modes