US3353122A - Waveguide filters having adjustable tuning means in narrow wall of waveguide - Google Patents

Waveguide filters having adjustable tuning means in narrow wall of waveguide Download PDF

Info

Publication number
US3353122A
US3353122A US303481A US30348163A US3353122A US 3353122 A US3353122 A US 3353122A US 303481 A US303481 A US 303481A US 30348163 A US30348163 A US 30348163A US 3353122 A US3353122 A US 3353122A
Authority
US
United States
Prior art keywords
waveguide
conductive
posts
filter
tuning
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
US303481A
Other languages
English (en)
Inventor
Manoochehri Hussein Hamid
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.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co 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 Marconi Co Ltd filed Critical Marconi Co Ltd
Application granted granted Critical
Publication of US3353122A publication Critical patent/US3353122A/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
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/207—Hollow waveguide filters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/207—Hollow waveguide filters
    • H01P1/208—Cascaded cavities; Cascaded resonators inside a hollow waveguide structure

Definitions

  • This invention relates to waveguide filters and more particularly to waveguide filters of the kind comprising a length of waveguide of rectangular cross-section having therein at least one effectively resonant length whose ends are defined by conductive posts extending between and in contact with the broad faces of the guide.
  • the operating frequency is determined, inter alia, by the cross-sectional dimensions of the conductive posts which place a limit on the frequency range over which the filter may be tuned, with the result that such filters as at present known suffer from the defect that they may be tuned over only a relatively narrow frequency band. It is the object of the present invention to provide improved waveguide filters of the kind referred to which shall be free of this defect.
  • a waveguide filter of the kind referred to is provided with at least one conductive member alongside each conductive post and adapted adjustably to extend into said guide from a narrow face thereof towards or away from said post.
  • each conductive member is constituted by a metallic screw screwed into the guide Wall.
  • a filter in accordance with the invention may comprise a number of effectively resonant lengths of waveguide which may be immediately adjacent one another or, spaced apart by quarter wave coupling sections of waveguide.
  • each resonant length of waveguide is provided in known manner with a conductive tuning member position between said posts and extending into the guide through one of its broad faces.
  • FIGURES 1 and 2 are mutually perpendicular views of a preferred embodiment of waveguide filter in accordance with the invention, FIGURE 2 being a cross-sectional view taken on the centre line of FIGURE 1', while FIGURE 3 shows a further embodiment.
  • the waveguide filter therein shown comprises a length 1 of waveguide of rectangular cross-section having end flanges 2 and 3.
  • the waveguide length 1 includes three resonant lengths or cavities C1, C2 and C3 each having a nominal length of half a guide wavelength at the operating frequency, the ends of each length or cavity being defined by conductive posts which extend between and are fixed in contact with the broad faces of the waveguide.
  • the conductive posts are thus arranged parallel to the electric field excited in the waveguide at the dominant H mode propagated therein.
  • cavity C1 is terminated by the posts P1 and P2, cavity C2 by posts P2 and P3 and cavity C3 by posts P3 and P4.
  • Each of the posts P2 and P3 thus acts as a terminating post for two adjacent resonant lengths or cavities and provides coupling therebetween.
  • posts P2 and P3 are larger in diameter than posts P1 and P4 while the length of cavity C2 is greater than the lengths of cavities C1 and C3.
  • the dimensioning of the lengths of 3,353,122 Patented Nov. 14, 1967 the cavities and the diameters of the posts is in accord with well known practice and does not require further description here.
  • capacitive tuning screws TS1, TS2 and T83 Centrally situated between adjacent pairs of posts are capacitive tuning screws TS1, TS2 and T83 each of which is in conductive contact with and adjustably extends through a broad face of waveguide 1 into the interior of the guide.
  • the waveguide filter is a band pass filter whose operating frequency is adjustable within certain small limits by means of the adjustment of screws T81, T52 and T83 whose adjustment, as is well known also permits the achievement of a desired overall band pass characteristic.
  • each of the posts P1, P2, P3 and P4 a pair of adjustable tuning members constituted by a pair of metallic screws TM1-TM'1, TMZ-TMZ, TM3TM'3 or TM4- TM4, which are screwed through and are in conductive contact with the narrow faces of the waveguide 1, the axes of each pair of screws and the axis of the associated post lying in a common transverse cross-sectional plane of the guide.
  • the lengths of the resonant lengths or cavities of the filter are chosen to have optimum values at the upper frequency to which the filter is to be tuned, while the diameters of the posts P1, P2, P3 and P4 are chosen to have optimum values at the lower frequency of the range of tuning of the filter.
  • the pairs of screws TM1TM'1, TM2-TM2, TM3-TM'3 or TM4-TM'4 adjusted so that their innermost faces are flush with the narrow walls of waveguide 1 the filter is tuned at the lower frequency of its tuning range.
  • the pairs of screws TMll-TM'I are screwed into the guide the operating frequency of the filter increases.
  • the screws of each pair are adjusted to extend into the guide by equal amounts but this again is not essential so long as the total extension of each pair of screws into the guide is at a desired value.
  • each of the tuning posts is provided with a pair of tuning screws, this again is not essential and a single tuning member positioned in the same cross-sectional plane as its associated post and extending through one of the narrow faces of the waveguide may be used. Such a single tuning member will not, of course, provide tuning over as great a frequency range as will a pair of tuning members.
  • each of the tuning screws TM1 TMI is made to have as large a diameter as the size of the waveguide will conveniently permit.
  • the tuning members TMl- 'IM'l are extended into the waveguide the operating frequency of the filter is increased but, in practice, it is found that if these tuning members are extended into the waveguide beyond a certain predetermined limit their effeet is reversed and the frequency of the filter decreases. This, however, is nOt a serious defect in practice and it is found that large variations in the tuning of the filter may be obtained before the above effect operates.
  • waveguide 1 had internal dimenisons of 2.37” x 1.12", the lengths of cavities C1, C2 and C3 were 1.75", 2" and 1.75 respectively, the diameters of posts P1, P2, P3 and P4 were 0.184", 0.583", 0.583, and 0.184 respectively and the external diameter of each of the tuning screws TMl-TMI was 1.1".
  • this filter was capable of being tuned over frequency range 3,600 mc./s.-4,200 mc./s.
  • FIGURE 3 shows a further embodiment of a band-pass waveguide filter in accordance with the invention the filter comprising a waveguide length 10 including therein two resonant lengths or cavities C4 and C5 each having a nominal length of half a guided wavelength at the operating frequency and each having its ends defined by a pair of conductive posts P5 and P6 or P7 and P8. Each post extends between and is'fixed in contact with the broad faces of waveguide 10. PostsP6 and P7 are spaced apart in known manner by a distance approximately equal to a quarter of a guide wavelength at the operating frequency of the filter to provide a coupling section be tween the cavities C4 and C5.
  • each post is provided, in the same cross-sectional plane of the waveguide, with a pair of metallic tuning members or screws TMlll-TMIO, TMll-TM11, TM12-TM12 or TM13-TM13 which are screwed through and in contact with the narrow faces of waveguide 10.
  • TMlll-TMIO metallic tuning members or screws
  • TMll-TM11 metallic tuning members or screws
  • TM12-TM12 or TM13-TM13
  • each post is provided, in the same cross-sectional plane of the waveguide, with a pair of metallic tuning members or screws TMlll-TMIO, TMll-TM11, TM12-TM12 or TM13-TM13 which are screwed through and in contact with the narrow faces of waveguide 10.
  • adjustment of the extent to which the tuning screws TM-TM10 extend into the waveguide provides adjustment of the operating frequency of the filter.
  • cavities C4 and C5 are provided in known manner with capacitive tuning screws T84 and T85.
  • tuning screws TM10- TM'10 being similar. to that of the tuning screws TMl-TMI of the embodiment of FIGURES 1 and 2.
  • a waveguide filter comprising a length of rectangular waveguide having a pair of opposing broad faces joined together by a pair of opposing narrow faces, a pair of spaced conductive inductive posts, each extending fully between and in contact with said broad faces and positioned to lie generally parallel to the electric field upon excitation of the filter, said conductive posts being spaced to define a resonant length within said waveguide between said posts, and a plurality of adjustable conductive members each attached to a narrow face of said waveguide adjacent to a corresponding conductive post and movable within said waveguide toward and away from the corresponding conductive post to adjust the resonant frequency of said resonant length within said waveguide.
  • a waveguide filter as defined in claim 1 wherein a pair of adjustable conductive members are provided adjacent to each of said conductive posts, one of said adjustable conductive members being attached to a narrow face of said waveguide on one side of said conductive post, and the other adjustable conductive member being attached to the opposing narrow face of said waveguide on the other side of said conductive post.
  • each of said adjustable conductive members comprises a metallic screw engaged in a threaded opening formed in said narrow face adjacent to said corresponding conductive post, and means for moving each of said adjustable conductive members comprising means on the outer end of each of said screws for engaging a screwdriver.
  • each of said adjustable conductive members comprises a metallic screw engaged in a threaded opening formed in said narrow face adjacent to said corresponding conductive post, and means for moving each of said adjustable conductive members comprising means on theouter end of each of said screws for engaging a screwdriver.
  • each of said adjustable conductive members comprises a metallic screw engaged in a threaded opening formed in said narrow face adjacent to said corresponding conductive post, and means for moving each of said adjustable conductive members comprising means on the outer end of each of said screws for engaging a screwdriver.
  • each of said adjustable conductive members comprises a metallic screw engaged in a threaded opening formed in said narrow face adjacent to said corresponding conductive post, and means for moving each of said adjustable conductive members comprising means on the outer end of each of said screws for engaging a screwdriver.

Landscapes

  • Control Of Motors That Do Not Use Commutators (AREA)
US303481A 1962-08-24 1963-08-21 Waveguide filters having adjustable tuning means in narrow wall of waveguide Expired - Lifetime US3353122A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB32632/62A GB989386A (en) 1962-08-24 1962-08-24 Improvements in or relating to waveguide filters

Publications (1)

Publication Number Publication Date
US3353122A true US3353122A (en) 1967-11-14

Family

ID=10341661

Family Applications (1)

Application Number Title Priority Date Filing Date
US303481A Expired - Lifetime US3353122A (en) 1962-08-24 1963-08-21 Waveguide filters having adjustable tuning means in narrow wall of waveguide

Country Status (3)

Country Link
US (1) US3353122A (enrdf_load_stackoverflow)
GB (1) GB989386A (enrdf_load_stackoverflow)
NL (1) NL297026A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496498A (en) * 1965-08-11 1970-02-17 Nippon Electric Co High-frequency filter
US3680012A (en) * 1969-02-17 1972-07-25 Thomson Csf Microwave band-pass filter having constant bandwidth as filter is tuned
US3737816A (en) * 1970-09-15 1973-06-05 Standard Telephones Cables Ltd Rectangular cavity resonator and microwave filters built from such resonators
US3748604A (en) * 1971-04-21 1973-07-24 Bell Telephone Labor Inc Tunable microwave bandstop resonant cavity apparatus
US3798578A (en) * 1970-11-26 1974-03-19 Japan Broadcasting Corp Temperature compensated frequency stabilized composite dielectric resonator
US4143344A (en) * 1976-06-14 1979-03-06 Murata Manufacturing Co., Ltd. Microwave band-pass filter provided with dielectric resonator
US4374154A (en) * 1981-11-10 1983-02-15 General Foods Corporation Soft, frozen dessert formulation
EP0167302A3 (en) * 1984-06-07 1987-09-09 Spar Aerospace Limited Antenna feed networks
US4868575A (en) * 1986-12-04 1989-09-19 Mok Chuck K Phase slope equalizer for satellite antennas

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2510288A (en) * 1947-12-05 1950-06-06 Bell Telephone Labor Inc Microwave band reflection filter
US2518092A (en) * 1945-07-24 1950-08-08 Philco Corp Ultra high frequency band-pass circuits
US2531447A (en) * 1947-12-05 1950-11-28 Bell Telephone Labor Inc Hybrid channel-branching microwave filter
US2540488A (en) * 1948-04-30 1951-02-06 Bell Telephone Labor Inc Microwave filter
US2585563A (en) * 1949-09-17 1952-02-12 Bell Telephone Labor Inc Wave filter
US2594037A (en) * 1946-08-28 1952-04-22 Rca Corp Ultrahigh-frequency filter
US2645679A (en) * 1947-11-29 1953-07-14 Standard Telephones Cables Ltd Method of controlling susceptance of a post type obstacle
US2686902A (en) * 1950-07-24 1954-08-17 Bell Telephone Labor Inc Microwave branching arrangement
US2749523A (en) * 1951-12-01 1956-06-05 Itt Band pass filters
US3164792A (en) * 1962-01-31 1965-01-05 Gen Electric Microwave switch utilizing waveguide filter having capacitance diode means for detuning filter

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518092A (en) * 1945-07-24 1950-08-08 Philco Corp Ultra high frequency band-pass circuits
US2594037A (en) * 1946-08-28 1952-04-22 Rca Corp Ultrahigh-frequency filter
US2645679A (en) * 1947-11-29 1953-07-14 Standard Telephones Cables Ltd Method of controlling susceptance of a post type obstacle
US2510288A (en) * 1947-12-05 1950-06-06 Bell Telephone Labor Inc Microwave band reflection filter
US2531447A (en) * 1947-12-05 1950-11-28 Bell Telephone Labor Inc Hybrid channel-branching microwave filter
US2540488A (en) * 1948-04-30 1951-02-06 Bell Telephone Labor Inc Microwave filter
US2585563A (en) * 1949-09-17 1952-02-12 Bell Telephone Labor Inc Wave filter
US2686902A (en) * 1950-07-24 1954-08-17 Bell Telephone Labor Inc Microwave branching arrangement
US2749523A (en) * 1951-12-01 1956-06-05 Itt Band pass filters
US3164792A (en) * 1962-01-31 1965-01-05 Gen Electric Microwave switch utilizing waveguide filter having capacitance diode means for detuning filter

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3496498A (en) * 1965-08-11 1970-02-17 Nippon Electric Co High-frequency filter
US3680012A (en) * 1969-02-17 1972-07-25 Thomson Csf Microwave band-pass filter having constant bandwidth as filter is tuned
US3737816A (en) * 1970-09-15 1973-06-05 Standard Telephones Cables Ltd Rectangular cavity resonator and microwave filters built from such resonators
US3798578A (en) * 1970-11-26 1974-03-19 Japan Broadcasting Corp Temperature compensated frequency stabilized composite dielectric resonator
US3748604A (en) * 1971-04-21 1973-07-24 Bell Telephone Labor Inc Tunable microwave bandstop resonant cavity apparatus
US4143344A (en) * 1976-06-14 1979-03-06 Murata Manufacturing Co., Ltd. Microwave band-pass filter provided with dielectric resonator
US4374154A (en) * 1981-11-10 1983-02-15 General Foods Corporation Soft, frozen dessert formulation
EP0167302A3 (en) * 1984-06-07 1987-09-09 Spar Aerospace Limited Antenna feed networks
US4868575A (en) * 1986-12-04 1989-09-19 Mok Chuck K Phase slope equalizer for satellite antennas

Also Published As

Publication number Publication date
NL297026A (enrdf_load_stackoverflow)
GB989386A (en) 1965-04-14

Similar Documents

Publication Publication Date Title
US2530691A (en) Wave filter
US4216448A (en) Microwave distributed-constant band-pass filter comprising projections adjacent on capacitively coupled resonator rods to open ends thereof
US2749523A (en) Band pass filters
US3737816A (en) Rectangular cavity resonator and microwave filters built from such resonators
US4620168A (en) Coaxial type tunable hyperfrequency elimination band filter comprising of dielectric resonators
US20030006866A1 (en) Waveguide group branching filter
US3657670A (en) Microwave bandpass filter with higher harmonics rejection function
US3353122A (en) Waveguide filters having adjustable tuning means in narrow wall of waveguide
US3516030A (en) Dual cavity bandpass filter
US2851666A (en) Microwave filter with a variable band pass range
US20120293282A1 (en) Waveguide filter having coupling screws
US3451014A (en) Waveguide filter having branch means to absorb or attenuate frequencies above pass-band
JPS62204601A (ja) 二重モ−ドフイルタ
US20130169384A1 (en) Frequency-tunable microwave bandpass filter
US3496498A (en) High-frequency filter
US3693115A (en) Mechanical tunable bandpass filter
US2585563A (en) Wave filter
US3538463A (en) Microwave filter
US3611214A (en) Waveguide reflective harmonic filter
US3579153A (en) Microwave filter
US3680012A (en) Microwave band-pass filter having constant bandwidth as filter is tuned
US3634788A (en) Waveguide filter
US2510288A (en) Microwave band reflection filter
US5105174A (en) Wave-guide band rejection filter having a short circuited coaxial tuning screw
US3315183A (en) Ridged waveguide magic tee