US3701959A - Microwave cavity resonator with printed circuit interior walls and modulation coils - Google Patents

Microwave cavity resonator with printed circuit interior walls and modulation coils Download PDF

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Publication number
US3701959A
US3701959A US127745A US3701959DA US3701959A US 3701959 A US3701959 A US 3701959A US 127745 A US127745 A US 127745A US 3701959D A US3701959D A US 3701959DA US 3701959 A US3701959 A US 3701959A
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United States
Prior art keywords
printed circuit
cavity
cavity resonator
circuit board
walls
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Expired - Lifetime
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US127745A
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English (en)
Inventor
Stuart C Hansen
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Varian Medical Systems Inc
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Varian Associates Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/345—Constructional details, e.g. resonators, specially adapted to MR of waveguide type
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49016—Antenna or wave energy "plumbing" making
    • Y10T29/49018—Antenna or wave energy "plumbing" making with other electrical component

Definitions

  • ABSTRACT A microwave cavity resonator useful in electron paramagnetic resonance spectrometers made from a printed circuit board having an electrically conductive surface printed on one side thereof and folded so as to form a plurality of the walls of a parallelepipedon 3 Claims, 6 Drawing Figures [72] Inventor: Stuart C. Hansen, Santa Clara County, Calif. 73 Assignee: Varian Associates, Palo Alto, Calif.
  • the modulation coils mounted on the sides of the cavity are hand wound and consist of many turns of electrically insulated wire, with the individual windings side-by-side and also stacked one level upon another.
  • the coil is then made integral with and affixed to the cavity side wall by a suitable glue such as epoxy.
  • a suitable glue such as epoxy.
  • repulsive forces are set up between the unidirectional magnetic field produced by the magnet in which the cavity resonator is immersed and the alternating current passing through the modulation coils.
  • This force extends in the direction of the plane of the coil, i.e. parallel to the surface of the cavity wall on which the coil is affixed, and alternates in direction at the frequency of modulation.
  • the force thus tends to shear the windings from the wall surface and from each other, thus setting up vibrations in the coil windings and cavity walls, producing an undersired spurious effect called potatoe.”
  • the present invention provides a microwave cavity the upper side, -by a layer of electrically conductive material, the board being folded so that a plurality of the inner walls of a parallelepipedon cavity resonator are formed by said conductive surface of the circuit board.
  • the two side walls and the top and bottom walls of a cavity resonator are formed by folding the circuit board along three folds which form three of the juncturesof the inner walls, the fourth juncture being formed by an electrically conducting seam.
  • the two end walls may be formed by suitable electrically conducting end plates.
  • the two modulation coils are formed by printed circuit techniques on the under surface of the circuit board and in alignment with the two side wall segments on the upper surface, such that, with the board folded toform the cavity, the modulation coils are positioned on the outer surfaces of the two side walls of the cavity.
  • Theinner side-wall surfaces are made suitably pervious such that the modulation magnetic field may penetrate into the cavity while substantial current paths are retained on the inner wall surfaces for the How of microwave current.
  • the single layer modulation coils formed by the printed circuit techniques are very strong in shear due to the tenacity of the bond of each winding to the circuit board, and the vibrations which normally produce the undesired potatoe effect are effectively eliminated.
  • FIG. 1 is a plan view of the under surface of the printed circuit board prior to folding into a cavity resonator configuration.
  • FIG. 2 is a plan view of the upper surface of the cir cuit board of FIG. 1.
  • FIG. 3 is a perspective view of the completed cavity resonator formed by the folded circuit board with end walls affixedthereto.
  • FIG. 4 is a cross-section view of the cavity resonator taken along section line 4-4 of FIG. 3.
  • FIG. 5 is an enlarged plan view of a portion of the mesh area of the cavity side wall taken at section line 55 of FIG. 2.
  • FIG. 6 is a cross-section of the wall portion of FIG. 5 taken along section line 6-6.
  • the novel cavity resonator of the present invention is formed from a printed circuit board (of well known construction) manufactured by standard photographic techniques.
  • the board is a glass epoxy sheet or base ll which is one-sixteenth inch thick with 2 A mil thick copper coating for the circuit elements, i.e. 2 02. copper clad, with a gold flash surface.
  • the conductive coating 12 on the upper surface of board 11 covers the entire surface, except for two sections 13 and 14 where a plurality of small spaced-apart openings exist in the coat, described more fully below.
  • the under surface of board 11 carries a number of plated areas including two areas 15 and 16 extending along the edges of the two long sides of the board and two coil windings l7 and 18 spaced-apart along the length of the board and approximately'midway across the board.
  • Two rectangular-shaped areas 21 and 22 are aligned with the coils l7 and 18, one area 21 being positioned between the coils and the other area located on the other side of coil 18.
  • a number of additional small pads 23 are provided on the surface.
  • the under surface of the board 11 is scored or cut along the three lines 26, 27, 28 extending across the width of the surface and between the coils and pads, and the board folded along these lines with the upper coated surface 12 on the inner side of the folded structure.
  • the coating 12 remains intact or integral at the three folds and serves as a hinge for the wall sections.
  • the fourth juncture 29 formed where the two ends of the board are brought together is closed with a solder seam of good electrically conducting material.
  • the folded sheet 11 thusforms a four walled box structure with open ends and having two side walls 31 and 32 and top and bottom walls 33 and 34 respective- A pair of cup-shaped end plates 35 and 36 of electrically conductive material are sealed in and close the ends of the cavity structure.
  • the base of a U-shaped clip member 37 is affixed to one end plate 35, an iris opening 38 extending through the base and the end plate to communicate with the interior of the cavity.
  • the legs of the clip member 37 are arranged to slip into the open end of a wave guide 39 to couple the cavity resonator to the microwave bridge circuit.
  • the side walls 31 and 32 carry the coils 17 and 18, respectively, utilized as the modulation coils to modulate the magnetic field extending normal to these side walls when the cavity is placed in the magnet of the system.
  • Tubular members 41 and 42 are affixed to the two pads 21 and 22 over the openings therein to permit the sample under investigation and carried in a vial to be inserted into the cavity resonator.
  • the small holes 45 e.g. 0.030-inch diameter, in areas 13 and 14 on the inner surfaces of the two side walls and aligned with the modulation coils 17, 18 provide a pervious mesh surface which allows the modulation fields to penetrate into the cavity, thus improving the modulation substantially.
  • the porosity of the mesh areas 13, 14 is established at about 40 percent so that sufficient conductive surface is provided around the openings 44 to give a good current path for the microwave currents.
  • the circumferential resistance of each of the holes 45 is maintained sufficiently high so thatthe small bucking magnetic fields established by the eddy currents set up in the surface around the holes do not significantly reduce the strength of the polarizing magnetic field passing through the mesh.
  • the single level winding of the modulation coil affixed to the circuit board surface is very strong in the direction of shear, i.e. parallel to the wall surface, because of the strong adhesion of the printed circuit to the board.
  • the coils l7, 18 therefore withstand the forces applied thereto, which tend to move the windingtsJ sideways, b interaction of the magnet fields set up y the modu ating current and the magnets field.
  • the potatoe effect produced by hand wound, multilayer coils. is substantially eliminated by the use of these printed circuit coils.
  • a microwave cavity resonator comprising a para]- lelepipedon cavity including two side walls, a top and bottom wall and two end walls having electrically conducting inner wall surfaces, at least four of said walls being formed by a unitary sheet of printed circuit board having one surface coated with an electrically conductive film which forms said electrically conducting inner wall surfaces, said circuit board being folded along a plurality of lines each fold forming the juncture of a different two of said inner wall surfaces wherein two of said four walls comprise said two side walls, said inner electrically conducting wall surfaces on said two side walls having a portion thereof previous to magnetic flux, and a modulation coil formed by a printed circuit on the outer surface of each of two side walls aligned with said pervious portions of the inner wall surfaces.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)
US127745A 1971-03-24 1971-03-24 Microwave cavity resonator with printed circuit interior walls and modulation coils Expired - Lifetime US3701959A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12774571A 1971-03-24 1971-03-24

Publications (1)

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US3701959A true US3701959A (en) 1972-10-31

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US127745A Expired - Lifetime US3701959A (en) 1971-03-24 1971-03-24 Microwave cavity resonator with printed circuit interior walls and modulation coils

Country Status (8)

Country Link
US (1) US3701959A (https=)
JP (1) JPS5418591B1 (https=)
AU (1) AU463492B2 (https=)
CA (1) CA939025A (https=)
CH (1) CH539342A (https=)
DE (1) DE2207547C3 (https=)
FR (1) FR2130338B1 (https=)
GB (1) GB1355143A (https=)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3931569A (en) * 1974-02-19 1976-01-06 Varian Associates Narrow cavity low cost EPR spectrometer
US4398149A (en) * 1981-02-02 1983-08-09 Varian Associates, Inc. NMR Probe coil system
EP0574813A3 (https=) * 1992-06-09 1994-04-27 Nikkiso Co Ltd
US5739690A (en) * 1996-04-04 1998-04-14 Colorado Seminary Crossed-loop resonator structure for spectroscopy
US20090230962A1 (en) * 2006-10-31 2009-09-17 James Robert White Method and apparatus for in-situ measurement of soot by electron spin resonance ( esr) spectrometry
RU2691996C1 (ru) * 2018-08-28 2019-06-19 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Чувствительный элемент сканирующего спектрометра ферромагнитного резонанса

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4706042A (en) * 1986-05-23 1987-11-10 Ball Corporation Atomic or molecular maser cavity resonator
JPH02502039A (ja) * 1986-09-19 1990-07-05 モナシユ・ユニバーシテイ 電子スピン共振分光計

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2262020A (en) * 1938-01-15 1941-11-11 Bell Telephone Labor Inc Frequency stabilization at ultrahigh frequencies
US2636125A (en) * 1948-04-10 1953-04-21 Bell Telephone Labor Inc Selective electromagnetic wave system
US3122703A (en) * 1959-12-21 1964-02-25 Varian Associates Gyromagnetic resonance method and apparatus
US3172035A (en) * 1961-05-08 1965-03-02 Varian Associates Probe for a gyromagnetic resonance apparatus
US3195079A (en) * 1963-10-07 1965-07-13 Burton Silverplating Built up nonmetallic wave guide having metallic coating extending into corner joint and method of making same
US3197692A (en) * 1962-04-02 1965-07-27 Varian Associates Gyromagnetic resonance spectroscopy
US3205432A (en) * 1962-05-25 1965-09-07 Edward L Cochran Cavity resonators
US3331017A (en) * 1962-12-13 1967-07-11 Varian Associates Frequency-compensated access structure for cavity resonator
US3466580A (en) * 1965-07-30 1969-09-09 Emi Ltd Circuit elements especially for use as scanning coils

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1135677A (fr) * 1955-02-28 1957-05-02 Siemens Ag Circuit oscillant pour des hautes fréquences
FR1372288A (fr) * 1962-10-23 1964-09-11 Varian Associates Cavité résonnante pour micro-ondes
FR1377538A (fr) * 1963-09-26 1964-11-06 Thomson Houston Comp Francaise Procédé de réalisation de guides minces non fendus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2262020A (en) * 1938-01-15 1941-11-11 Bell Telephone Labor Inc Frequency stabilization at ultrahigh frequencies
US2636125A (en) * 1948-04-10 1953-04-21 Bell Telephone Labor Inc Selective electromagnetic wave system
US3122703A (en) * 1959-12-21 1964-02-25 Varian Associates Gyromagnetic resonance method and apparatus
US3172035A (en) * 1961-05-08 1965-03-02 Varian Associates Probe for a gyromagnetic resonance apparatus
US3197692A (en) * 1962-04-02 1965-07-27 Varian Associates Gyromagnetic resonance spectroscopy
US3205432A (en) * 1962-05-25 1965-09-07 Edward L Cochran Cavity resonators
US3331017A (en) * 1962-12-13 1967-07-11 Varian Associates Frequency-compensated access structure for cavity resonator
US3195079A (en) * 1963-10-07 1965-07-13 Burton Silverplating Built up nonmetallic wave guide having metallic coating extending into corner joint and method of making same
US3466580A (en) * 1965-07-30 1969-09-09 Emi Ltd Circuit elements especially for use as scanning coils

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3931569A (en) * 1974-02-19 1976-01-06 Varian Associates Narrow cavity low cost EPR spectrometer
US4398149A (en) * 1981-02-02 1983-08-09 Varian Associates, Inc. NMR Probe coil system
EP0574813A3 (https=) * 1992-06-09 1994-04-27 Nikkiso Co Ltd
US5596276A (en) * 1992-06-09 1997-01-21 Nikkiso Co., Ltd. Cavity resonator for an electron spin resonator
US5739690A (en) * 1996-04-04 1998-04-14 Colorado Seminary Crossed-loop resonator structure for spectroscopy
US6046586A (en) * 1996-04-04 2000-04-04 Colorado Seminary Crossed-loop resonator structure for spectroscopy
US20090230962A1 (en) * 2006-10-31 2009-09-17 James Robert White Method and apparatus for in-situ measurement of soot by electron spin resonance ( esr) spectrometry
US8212563B2 (en) * 2006-10-31 2012-07-03 Active Spectrum, Inc. Method and apparatus for in-situ measurement of soot by electron spin resonance (ESR) spectrometry
US9546970B2 (en) 2006-10-31 2017-01-17 Active Spectrum, Inc. Method of and apparatus for in-situ measurement of soot by electron spin resonance (ESR) spectrometry
RU2691996C1 (ru) * 2018-08-28 2019-06-19 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Чувствительный элемент сканирующего спектрометра ферромагнитного резонанса

Also Published As

Publication number Publication date
AU463492B2 (en) 1975-07-11
AU3941872A (en) 1973-08-30
FR2130338B1 (https=) 1977-12-23
FR2130338A1 (https=) 1972-11-03
CH539342A (de) 1973-07-15
GB1355143A (en) 1974-06-05
DE2207547C3 (de) 1980-10-16
CA939025A (en) 1973-12-25
DE2207547B2 (de) 1980-02-28
JPS5418591B1 (https=) 1979-07-09
DE2207547A1 (de) 1972-10-05

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