US2675524A - Electrical wave guide provided with tuning pistons - Google Patents

Electrical wave guide provided with tuning pistons Download PDF

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Publication number
US2675524A
US2675524A US81656A US8165649A US2675524A US 2675524 A US2675524 A US 2675524A US 81656 A US81656 A US 81656A US 8165649 A US8165649 A US 8165649A US 2675524 A US2675524 A US 2675524A
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US
United States
Prior art keywords
piston
waveguide
cross
tuning
section
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
US81656A
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English (en)
Inventor
Collard John
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 US2675524A publication Critical patent/US2675524A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/24—Terminating devices
    • H01P1/28—Short-circuiting plungers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • H01P7/06—Cavity resonators

Definitions

  • This invention relates to electrical waveguides of the kind having a rectangular or other noncireular cross-section.
  • a piston having a shape conforming to the cross-sectional area of the waveguide and to cause the piston to move axially along the waveguide by the provision of a suitable screw.
  • a piston for use in a non-circular waveguide is difficult to construct and, moreover, since it is guided by the sides of the waveguide which are not usually verysmooth the travel of the piston is often erratic and, furthermore, since it is usual to employ a-screw to cause axial movement of the piston it is necessary, since the piston cannot rotate relatively to the waveguide to provide a joint. between the screw and the piston to allow the piston to move axially without rotating. The provision. of such a joint, however, often introduces back-lash.
  • the piston can be of any shape in cross-section and can therefore be of such a shape that it can rotate within the waveguide and hence avoid the necessity of providing a joint which permits relative
  • the piston is necessary'to provide the latter with some form of wave trap to prevent power from passing through the coaxial circuit which is formed by the piston and the waveguide.
  • a waveguide of non-circular cross-section having a tuning piston of such a shape that it can rotate within the waveguide and having a cross-sectional area to cause attenuation of waves within the free space and between the piston and the wall of the waveguide, said piston also having means for preventing power from passing along the circuit formed by the piston and the waveguide.
  • a waveguide having a rectangular cross-section and having a tuning piston of circular form in cross-section so that it can rotate within the waveguide and having a cross-sectional area to cause attenuation of waves within the free space between the piston and the wall of the waveguide, said piston also having means for preventing power from passing along the circuit formed by said piston and waveguide.
  • Figure 1 is a transverse section through a waveguide and a tuning piston arranged therein
  • Figure 2 is a cross-sectional view takenal'ong the line 22 of Figure 1, and
  • Figure 3 is a View similar to Figure 2 showing a modified form of piston.
  • the reference numeral 1 indicates a waveguide of rectangular cross-section, the longer dimension of the cross-sectional area of the waveguide being chosen so as to pass power at a desired operating frequency and usually in the H10 mode so that the electric vector will be directed perpendicularly to the longer Walls of the waveguide as seen in cross-section.
  • a tuning piston 2 is employed which is of circular cylindrical form, as shown, and having a diameter slightly less than the smaller dimension of the waveguide cross-section, the piston being disposed centrally between the walls of the waveguide.
  • the piston is provided with a suitable adjusting screw 3 supported in any convenient manner relatively to the waveguide.
  • the circumferential surface of the piston 2 is provided with one or more grooves 4 having a depth of a quarter of wavelength at the operating frequency and if more than one of said grooves are provided, as shown in Figures 2 and 3, successive grooves are spaced apart a quarter of an operating wavelength.
  • Each groove 4 presents at its open end a high impedance which is transformed to a low impedance bythe preceding length of piston and thus presents a low impedance and hence an effective short circuit between the piston and the wall of the waveguide.
  • the grooves 4 as shown in Figure 2 are disposed obliquely to the longitudinal axis of the piston so as to avoid such merging.
  • the grooves can be disposed in planes at right-angles to the longitudinal axis of said piston and the grooves filled with a suitable dielectric materal, such as for example, a phenolic synthetic resin so that the wavelength in the dielectric material is less than in air whereby the depth of the grooves can be reduced.
  • the length of the piston and the number of grooves employed may be varied to suit particular circumstances. If the piston is used in a Wavemeter having a high Q it will preferably be desirable to employ three or more grooves, whereas for a simple reactance tuner in a matched wave guide a single groove will usually be sufficient.
  • a waveguide of rectangular cross section and excitable in the H10 mode a tuning piston, means rotatably mounting said piston for axial movement in the waveguide with its axis of rotation parallel to the longitudinal axis of the waveguide, said piston having a circular form in cross section and disposed centrally between the walls of the waveguide which are disposed closer together and having a diameter slightly less than the smaller dimension of the waveguide cross section, said piston having means for effectively short circuiting the piston to said walls of said Wave guide, and a screw-threaded rod fixed to said piston and engaging a screwthreaded support for rotating the piston to move it axially of said waveguide with the axis of rotation of said piston parallel to the longitudinal axis of the waveguide.
  • a waveguide of elongated cross-section having a tuning piston rotatable within the waveguide, said piston having such cross-sectional area in relation to the internal dimensions of the waveguide that a pair of opposite surfaces on said piston are disposed close to but out of contact with areas adjacent said piston on the internal surface of said waveguide Where maximum voltage exists, other surfaces on said piston being more widely spaced from said waveguide, said piston also having means for effectively short-circuiting the piston "to said areas of said waveguide, an a screw-threaded rod fixed to said piston and engaging a screw-threaded support for rotating the piston to move it axially of said waveguide with the axis of rotation of said piston parallel to the longitudinal axis of the waveguide.
  • a waveguide of elongated cross-section having a tuning piston rotatable within the waveguide, said piston having such cross-sectional area in relation to the internal dimension of the waveguide that a pair of opposite surfaces on said piston are disposed close to but out of contact with areas adjacent said piston on the internal surface of said waveguide where maxi.- mum voltage exists, other surfaces on said piston being more widely spaced from said waveguide, said piston having a circumferential groove spaced from one end of said piston to provide an effective short circuit between the piston and the said areas of said waveguide, and a screwthreaded rod fixed to said piston and engaging a screw-threaded support for rotating the piston to move it axially of said waveguide with the axis of rotation of said piston parallel to the longitudinal axis of the waveguide.

Landscapes

  • Pistons, Piston Rings, And Cylinders (AREA)
  • Non-Reversible Transmitting Devices (AREA)
US81656A 1948-03-25 1949-03-16 Electrical wave guide provided with tuning pistons Expired - Lifetime US2675524A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8746/48A GB649732A (en) 1948-03-25 1948-03-25 Improvements in or relating to electrical waveguides

Publications (1)

Publication Number Publication Date
US2675524A true US2675524A (en) 1954-04-13

Family

ID=9858479

Family Applications (1)

Application Number Title Priority Date Filing Date
US81656A Expired - Lifetime US2675524A (en) 1948-03-25 1949-03-16 Electrical wave guide provided with tuning pistons

Country Status (4)

Country Link
US (1) US2675524A (xx)
FR (1) FR983312A (xx)
GB (1) GB649732A (xx)
NL (2) NL145326B (xx)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1211298B (de) * 1963-10-28 1966-02-24 Philips Patentverwaltung Abstimmbarer Hohlleiter-Resonator fuer hochfrequente elektrische Schwingungen
US3806842A (en) * 1972-11-13 1974-04-23 Harvard Ind Inc Re-entrant radial choke for cavity resonator with displacing mechanism
US3975695A (en) * 1975-06-10 1976-08-17 The United States Of America As Represented By The Secretary Of The Army Waveguide beyond cutoff coupler for coupling to resonant cavity
US4688008A (en) * 1986-02-03 1987-08-18 Motorola, Inc. Locking, adjustable waveguide shorting piston
US5138289A (en) * 1990-12-21 1992-08-11 California Institute Of Technology Noncontacting waveguide backshort
EP0616382A1 (en) * 1993-03-19 1994-09-21 ALENIA SPAZIO S.p.A. Planar variable power divider
US20100301973A1 (en) * 2009-05-28 2010-12-02 James Stanec Systems, Devices, and/or Methods Regarding Waveguides

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2106769A (en) * 1935-08-23 1938-02-01 American Telephone & Telegraph Transmission of guided waves
US2441598A (en) * 1944-06-16 1948-05-18 Bell Telephone Labor Inc Wave transmission
US2451876A (en) * 1943-06-05 1948-10-19 Winfield W Salisbury Radio-frequency joint
USRE23131E (en) * 1949-06-28 Tuned microwave wattmeter
US2518092A (en) * 1945-07-24 1950-08-08 Philco Corp Ultra high frequency band-pass circuits
US2530248A (en) * 1945-04-16 1950-11-14 Western Electric Co Method and apparatus for measuring electrical properties
US2543721A (en) * 1944-02-09 1951-02-27 Emi Ltd High-frequency electrical transmission line and wave guide
US2548655A (en) * 1946-04-26 1951-04-10 Bell Telephone Labor Inc Directive dielectric guide antenna

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE23131E (en) * 1949-06-28 Tuned microwave wattmeter
US2106769A (en) * 1935-08-23 1938-02-01 American Telephone & Telegraph Transmission of guided waves
US2451876A (en) * 1943-06-05 1948-10-19 Winfield W Salisbury Radio-frequency joint
US2543721A (en) * 1944-02-09 1951-02-27 Emi Ltd High-frequency electrical transmission line and wave guide
US2441598A (en) * 1944-06-16 1948-05-18 Bell Telephone Labor Inc Wave transmission
US2530248A (en) * 1945-04-16 1950-11-14 Western Electric Co Method and apparatus for measuring electrical properties
US2518092A (en) * 1945-07-24 1950-08-08 Philco Corp Ultra high frequency band-pass circuits
US2548655A (en) * 1946-04-26 1951-04-10 Bell Telephone Labor Inc Directive dielectric guide antenna

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1211298B (de) * 1963-10-28 1966-02-24 Philips Patentverwaltung Abstimmbarer Hohlleiter-Resonator fuer hochfrequente elektrische Schwingungen
US3806842A (en) * 1972-11-13 1974-04-23 Harvard Ind Inc Re-entrant radial choke for cavity resonator with displacing mechanism
US3975695A (en) * 1975-06-10 1976-08-17 The United States Of America As Represented By The Secretary Of The Army Waveguide beyond cutoff coupler for coupling to resonant cavity
US4688008A (en) * 1986-02-03 1987-08-18 Motorola, Inc. Locking, adjustable waveguide shorting piston
US5138289A (en) * 1990-12-21 1992-08-11 California Institute Of Technology Noncontacting waveguide backshort
EP0616382A1 (en) * 1993-03-19 1994-09-21 ALENIA SPAZIO S.p.A. Planar variable power divider
US20100301973A1 (en) * 2009-05-28 2010-12-02 James Stanec Systems, Devices, and/or Methods Regarding Waveguides
US8823471B2 (en) 2009-05-28 2014-09-02 James Stenec Waveguide backshort electrically insulated from waveguide walls through an airgap

Also Published As

Publication number Publication date
NL145326B (nl)
GB649732A (en) 1951-01-31
NL78957C (xx)
FR983312A (fr) 1951-06-21

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