US3676808A - Resonator for electromagnetic waves of the millimetric and submillimetric band - Google Patents

Resonator for electromagnetic waves of the millimetric and submillimetric band Download PDF

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US3676808A
US3676808A US50428A US3676808DA US3676808A US 3676808 A US3676808 A US 3676808A US 50428 A US50428 A US 50428A US 3676808D A US3676808D A US 3676808DA US 3676808 A US3676808 A US 3676808A
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resonator
reflectors
electromagnetic waves
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millimetric
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Evgeny Alexandrovic Vinogradov
Nataliya Alexandrovna Irisova
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type

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  • a resonator for electromagnetic waves of the millimetric submillimetric band comprising main reflectors in the for: mountings wherein parallel conductors are strung at a spa smaller than the length of electromagnetic waves in selected band, and at least one additional reflector ident to, and disposed between, said main deflectors, the plan: said additional reflector being parallel to the planes of main reflectors.
  • the present invention relates to radio measuring techniques, and, more particularly to resonance devices, and can be employed for filtration of electromagnetic waves in millimetric and submillimetric bands and for stabilization and frequency calibration of the sources which radiate such waves.
  • the planes of the reflectors are parallel to each other and perpendicular to the optical axis.
  • the existing resonators of millimetric and submillimetric wavebands have essential disadvantages.
  • One of such disadvantages lies in the fact that the shape of the resonance curve of such a resonator is anything but rectangular, and this is especially undesirable when the resonator is to be used as a filter.
  • the attempt to increase the Q of the resonator by placing the reflectors at greater distances from each other results in the increased number of resonant frequencies in the natural frequency spectrum of the resonator, which may affect the quality of filtration or the frequency output of the oscillator being stabilized.
  • An object of the present invention is to provide a multiplecoupled resonator for electromagnetic waves of the millimetric and submillimetric bands.
  • a resonator for electromagnetic waves of the millimetric and submillimetric band in which reflectors are in the form of mountings with parallel conductors, the shortest spacing between which is smaller than the length of electromagnetic waves in the selected band, comprises, according to the present invention, at least one additional reflector, identical to, and disposed between, said reflectors, the plane of said additional reflector being parallel to the planes of the main reflectors.
  • FIG. 1 is a view showing the arrangement of reflectors in a multiple-coupled resonator
  • FIG. 2 shows an embodiment of the reflector.
  • a multiple-coupled resonator for electromagnetic waves of the millimetric and submillimetric band comprises at least three reflectors 1, 2 and 3 (FIG. 1), the planes of which are parallel to one another and perpendicular to their common optical axis.
  • the reflectors disposed as above form two coupled resonators l and Il.
  • Each reflector (FIG. 2) is a mounting 4 which may be shaped as ring wherein conductors 5 are strung parallel to one another.
  • the diameter a of the mounting 4 is made greater than the maximum wavelength A of the selected band.
  • the conductors 5 strung in the mount ing 4 must be made from a material possessing the highest possible conductance or a coating must be used the thickness of which is not smaller than the skin layer for the selected.
  • the conductors 5 may have a section of any geometrical shape though a roundsection is preferable.
  • a spacing 1 between the conductors 5 must be smaller the the maximum wavelength in the selected band.
  • the greatt the ratio Ale and d/e where d is the width of the CO1 ductor in the plane of the mounting, the greater is the Q of ti resonator. However, this is true only so long as the 1055! caused by the resistance of the conductors do n predominate.
  • the Q of th resonator and the amount of coupling between separal resonators I and II may vary with the geometrical parameter of separate reflectors l, 2 and 3 (the diameter of the refle tors, spacing between the conductors, section and size of th conductors) or, for the given geometrical parameters, with th angle by which the reflectors are turned with respect to th optical axis.
  • the resonant frequencies common to the two resonators and II can be selected by varying the distance from the add: tional reflector 2 to either of the main reflectors.
  • the reflectors 1,2 are spaced at definite distances by means of calibrated inserts for arbitrary selection of scales at least two reflectors may b provided with devices for their displacement and accurat measurement of their relative position (the inserts and th measuring devices are not shown in the drawing).
  • the resonator operates as follows.
  • the electromagnetic radiation generated by a source 6 o millimetric and submillimetric waves is directed by a radiatin; aerial along the axis of the resonator onto a reflector 1 tht aerial is not shown in the drawing).
  • the ratir between the part of the electromagnetic flux that is reflectet from the resonator and the part that passes through it depend: on whether the resonators l and [I are tuned to the frequenc of radiation generated by the source of electromagnetk waves, on the amount of coupling between the resonators am on the transmission of the reflectors l and 3.
  • the part of the electromagnetic flux passing through the multiple-coupled resonator is picked up by a radiatior receiver 7 disposed behind the reflector 3.
  • the source 6 of electromagnetic radiation, the multiple coupled resonator and the radiation receiver 7 are all alignec along one optical axis.
  • the part of the electromagnetic flux reflected from the reflector 1 can be picked up by an additional radiatior receiver 8, the axis of which is perpendicular to the main optical axis.
  • the part of the electromagnetic flux reflected frorr the reflector l is directed onto this additional receiver by z semi-transparent mirror 9 disposed between the multiple-coupled resonator and the source 6 of electromagnetic radiatior so that the plane of the mirror is at an angle of 45 to the mair optical axis.
  • the resonator l is tuned to the radiation frequency while the resonator II is not tuned to this frequency part of the incident electromagnetic flux is absorbed in the resonator l and the reflected part of the electromagnetic flux diminishes. if the resonator l is tuned to the same frequency as the resonator ll. the reflected part of the electromagnetic flux becomes greater.
  • This property of the resonator is used to provide calibration frequency marks when the source 6 of electromagnetic waves operates in frequency scanning mode.
  • the spacing between the reflectors 2 and 3 is made several times smaller than the spacing between the reflectors l and 2.
  • the spacing between the natural frequencies of the resonator 11 becomes several times greater than the spacing between the natural frequencies of the resonator I, and the frequency marks of the resonator l coinciding with the natural frequencies of the resonator II will have a much smaller amplitude in the reflected signal than all other marks, or will disappear altogether.
  • the amplitude of the marks obtained as above can be adjusted by turning the reflector 3 about its axis.
  • the last reflector can be substituted with a solid mirror having a flat or spherical surface.
  • the multiple-coupled resonator described herein is also a convenient means for measuring refractive index of various substances, when the thickness of the test specimen (in the case of hard specimens) considerably exceeds the wavelength of electromagnetic radiation.
  • the operating procedure is as follows.
  • the two resonators l and II are adjusted so that their resonant frequencies coincide, then a test specimen is placed in one of the resonators and the resonant frequencies of the resonators are gain caused to coincide by displacing one of the end reflectors l or 3.
  • the distance by which one of these reflectors has to be displaced represents the difference in the beam travel caused by the specimen. Knowing this difference one can easily calculate the refractive index of the specimen.
  • the second resonator ll may be tuned to the same frequencies as the first one.
  • the spacings L and L between the reflectors 1, 2 and 3 of the resonators l and ll are made multiple of M2 only for those wavelengths which are to be left in the frequency spectrum.
  • a resonator for electromagnetic waves of the millimetric and submillimetric band comprising main reflectors and at least one additional reflector, the plane of said additional reflector being parallel to the planes of said main reflectors, said reflectors having mountings and conductors strung in the mountings parallel to one another, the shortest spacing between said conductors being smaller than the length of electromagnetic waves in the selected band.

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Abstract

A resonator for electromagnetic waves of the millimetric and submillimetric band, comprising main reflectors in the form of mountings wherein parallel conductors are strung at a spacing smaller than the length of electromagnetic waves in the selected band, and at least one additional reflector identical to, and disposed between, said main deflectors, the plane of said additional reflector being parallel to the planes of the main reflectors.

Description

United States Patent Vinogradov et al.
[151 3,676,8 [451 July 11,1!
[54] RESONATOR FOR ELECTROMAGNETIC WAVES OF THE MILLIMETRIC AND SUBMILLIMETRIC BAND [72] Inventors: Evgeny Alexandrovich Vinogradov, Kozhevnicheskaya ulitsa, lb, kv. 33; Nataliya Alexandrovna Irisova, ulitsa Vavilova, 44, korpus 4, kv. 74, both of Moscow, U.S.S.R.
[22] Filed: June 29,1970
[21] Appl.No.: 50,428
[52] US. Cl. ..333/83, 330/4.5, 324/58, 356/1 12 [51] Int. Cl. ..H01p 7/06 [58] Field ofSearch ..333/83; 330/4.5,4.5 G; 350/160 [56] References Cited UNITED STATES PATENTS 3,187,270 6/1965 Kogelnik et al. ..333/83 X 3,316,511 4/1967 Schulten.... .....333/83 X 3,487,230 12/1969 Costich ..330/4.5 X
3,055,257 9/1962 Boyd et al. ..333/l 3,201,709 8/1965 Boyd ..33(
3,530,301 9/1970 Boyd et a1. ..330/4 OTHER PUBLICATIONS High Resolution Millimeter Wave Fabry- Perot 1| ferometer by Culshaw, 3/60, pp. 183- 189, IRE Trans'ac on Microwave Theory and Techniques.
Resonators for Millimeter and Submillimeter Wavelengt BY Culshaw, 3/61, pp. 136- 144, IRE Transaction Microwave Theory and Techniques, Vol. 9, No. 2.
Primary Examiner-Herman Karl Saalbach Assistant Examiner-Saxfield Chatmon, Jr. AnomeyWaters, Roditi, Schwartz & Nissen ABSTRACT A resonator for electromagnetic waves of the millimetric submillimetric band, comprising main reflectors in the for: mountings wherein parallel conductors are strung at a spa smaller than the length of electromagnetic waves in selected band, and at least one additional reflector ident to, and disposed between, said main deflectors, the plan: said additional reflector being parallel to the planes of main reflectors.
3 Claims, 2 Drawing Figures RESONATOR FOR ELECTROMAGNETIC WAVES OF THE MILLIMETRIC AND SUBMILLIMETRIC BAND The present invention relates to radio measuring techniques, and, more particularly to resonance devices, and can be employed for filtration of electromagnetic waves in millimetric and submillimetric bands and for stabilization and frequency calibration of the sources which radiate such waves.
There exist resonators similar to a F abry-Perot interferometer employing flat reflectors in the form of mountings wherein conductors are strung parallel to one another, the shortest spacing L between the conductors being smaller than the length of electromagnetic waves in the selected band.
The planes of the reflectors are parallel to each other and perpendicular to the optical axis.
However, the existing resonators of millimetric and submillimetric wavebands have essential disadvantages. One of such disadvantages lies in the fact that the shape of the resonance curve of such a resonator is anything but rectangular, and this is especially undesirable when the resonator is to be used as a filter.
Besides, the attempt to increase the Q of the resonator by placing the reflectors at greater distances from each other results in the increased number of resonant frequencies in the natural frequency spectrum of the resonator, which may affect the quality of filtration or the frequency output of the oscillator being stabilized.
The use of a two-reflector resonator for marking equidistant frequencies on a small scale makes it rather difficult directly to find the absolute value of the frequency.
An object of the present invention is to provide a multiplecoupled resonator for electromagnetic waves of the millimetric and submillimetric bands.
With this object in view, a resonator for electromagnetic waves of the millimetric and submillimetric band, in which reflectors are in the form of mountings with parallel conductors, the shortest spacing between which is smaller than the length of electromagnetic waves in the selected band, comprises, according to the present invention, at least one additional reflector, identical to, and disposed between, said reflectors, the plane of said additional reflector being parallel to the planes of the main reflectors.
It is preferable to make at least one additional reflector or capable of displacement. v
[t is possible to make at least one of the main reflectors capable of displacement.
The present invention will be best understood from the following detailed description of its embodiment when read in connection with the accompanying drawings, in which:
FIG. 1 is a view showing the arrangement of reflectors in a multiple-coupled resonator;
FIG. 2 shows an embodiment of the reflector.
A multiple-coupled resonator for electromagnetic waves of the millimetric and submillimetric band comprises at least three reflectors 1, 2 and 3 (FIG. 1), the planes of which are parallel to one another and perpendicular to their common optical axis. The reflectors disposed as above form two coupled resonators l and Il.
Each reflector (FIG. 2) is a mounting 4 which may be shaped as ring wherein conductors 5 are strung parallel to one another.
To reduce diffraction losses the diameter a of the mounting 4 is made greater than the maximum wavelength A of the selected band. The higher the ratio a/ A, the greater the Q of the resonator and the more strictly equidistant is the distribution of the natural frequencies of the resonator.
To reduce the losses caused by the resistance of the conductors 5 and increase the Q and the resonant oscillation amplitude of the resonator the conductors 5 strung in the mount ing 4 must be made from a material possessing the highest possible conductance or a coating must be used the thickness of which is not smaller than the skin layer for the selected.
band.
The conductors 5 may have a section of any geometrical shape though a roundsection is preferable.
A spacing 1 between the conductors 5 must be smaller the the maximum wavelength in the selected band. The greatt the ratio Ale and d/e," where d is the width of the CO1 ductor in the plane of the mounting, the greater is the Q of ti resonator. However, this is true only so long as the 1055! caused by the resistance of the conductors do n predominate.
In a multiple-coupled resonator (FIG. 1) the Q of th resonator and the amount of coupling between separal resonators I and II may vary with the geometrical parameter of separate reflectors l, 2 and 3 (the diameter of the refle tors, spacing between the conductors, section and size of th conductors) or, for the given geometrical parameters, with th angle by which the reflectors are turned with respect to th optical axis.
The resonant frequencies common to the two resonators and II can be selected by varying the distance from the add: tional reflector 2 to either of the main reflectors.
This makes it possible to considerably space out the nature frequency spectrum of the first resonator or intensify resonan frequencies multiple of some integral number to provid frequency marks of a greater scale.
To provide reference scale marks the reflectors 1,2 and are spaced at definite distances by means of calibrated inserts for arbitrary selection of scales at least two reflectors may b provided with devices for their displacement and accurat measurement of their relative position (the inserts and th measuring devices are not shown in the drawing).
The resonator operates as follows.
The electromagnetic radiation generated by a source 6 o millimetric and submillimetric waves is directed by a radiatin; aerial along the axis of the resonator onto a reflector 1 tht aerial is not shown in the drawing).
Part of the electromagnetic flux is reflected from the reflec tor 1 and the remainder of the flux reaches the resonator 1 Owing to the presence of coupling between the resonators and II the electromagnetic flux then reaches the resonator l and leaves this resonator through a reflector 3. The ratir between the part of the electromagnetic flux that is reflectet from the resonator and the part that passes through it depend: on whether the resonators l and [I are tuned to the frequenc of radiation generated by the source of electromagnetk waves, on the amount of coupling between the resonators am on the transmission of the reflectors l and 3.
The part of the electromagnetic flux passing through the multiple-coupled resonator is picked up bya radiatior receiver 7 disposed behind the reflector 3.
The source 6 of electromagnetic radiation, the multiple coupled resonator and the radiation receiver 7 are all alignec along one optical axis.
The part of the electromagnetic flux reflected from the reflector 1 can be picked up by an additional radiatior receiver 8, the axis of which is perpendicular to the main optical axis. The part of the electromagnetic flux reflected frorr the reflector l is directed onto this additional receiver by z semi-transparent mirror 9 disposed between the multiple-coupled resonator and the source 6 of electromagnetic radiatior so that the plane of the mirror is at an angle of 45 to the mair optical axis.
Let us see how the magnitude of the signal reflected frorr the multiple-coupled resonator varies if all three reflectors l 2 and 3 have the same geometrical dimensions, and the conductors of the reflectors l, 2 and 3 are parallel to one another and to the intensity vector E of the electric field.
As was mentioned above, a greater part of the flux will be reflected from the resonator I if this resonator is tuned to the frequency of the incident radiation.
If the resonator l is tuned to the radiation frequency while the resonator II is not tuned to this frequency part of the incident electromagnetic flux is absorbed in the resonator l and the reflected part of the electromagnetic flux diminishes. if the resonator l is tuned to the same frequency as the resonator ll. the reflected part of the electromagnetic flux becomes greater.
This property of the resonator is used to provide calibration frequency marks when the source 6 of electromagnetic waves operates in frequency scanning mode.
In this case the spacing between the reflectors 2 and 3 is made several times smaller than the spacing between the reflectors l and 2.
As a result the spacing between the natural frequencies of the resonator 11 becomes several times greater than the spacing between the natural frequencies of the resonator I, and the frequency marks of the resonator l coinciding with the natural frequencies of the resonator II will have a much smaller amplitude in the reflected signal than all other marks, or will disappear altogether.
The amplitude of the marks obtained as above can be adjusted by turning the reflector 3 about its axis. To facilitate measurement of the reflected signal the last reflector can be substituted with a solid mirror having a flat or spherical surface.
The multiple-coupled resonator described herein is also a convenient means for measuring refractive index of various substances, when the thickness of the test specimen (in the case of hard specimens) considerably exceeds the wavelength of electromagnetic radiation.
The operating procedure is as follows.
The two resonators l and II are adjusted so that their resonant frequencies coincide, then a test specimen is placed in one of the resonators and the resonant frequencies of the resonators are gain caused to coincide by displacing one of the end reflectors l or 3.
The distance by which one of these reflectors has to be displaced represents the difference in the beam travel caused by the specimen. Knowing this difference one can easily calculate the refractive index of the specimen.
If the only object is to make the resonance curve of the resonator as nearly rectangular as possible the second resonator ll may be tuned to the same frequencies as the first one.
If the object is to space out the natural frequencies of the first resonator I, the spacings L and L between the reflectors 1, 2 and 3 of the resonators l and ll are made multiple of M2 only for those wavelengths which are to be left in the frequency spectrum.
What is claimed is:
1. A resonator for electromagnetic waves of the millimetric and submillimetric band, comprising main reflectors and at least one additional reflector, the plane of said additional reflector being parallel to the planes of said main reflectors, said reflectors having mountings and conductors strung in the mountings parallel to one another, the shortest spacing between said conductors being smaller than the length of electromagnetic waves in the selected band.
2. A resonator as claimed in claim 1, comprising at least one additional reflector capable of displacement.
3. A resonator as claimed in claim 1, comprising at least one main reflector capable of displacement.

Claims (3)

1. A resonator for electromagnetic waves of the millimetric and submillimetric band, comprising main reflectors and at least one additional reflector, the plane of said additional reflector being parallel to the planes of said main reflectors, said reflectors having mountings and conductors strung in the mountings parallel to one another, the shortest spacing between said conductors being smaller than the length of electromagnetic waves in the selected band.
2. A resonator as claimed in claim 1, comprising at least one additional reflector capable of displacement.
3. A resonator as claimed in claim 1, comprising at least one main reflector capable of displacement.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4298990A (en) * 1978-11-04 1981-11-03 Polska Akademia Nauk Instytut Fizyki Frequency converter of electromagnetic radiation in millimeter and submillimeter wavelength range
US5012212A (en) * 1987-10-07 1991-04-30 Communications Research Laboratory Ministry Of Posts And Telecommunications Open resonator for electromagnetic waves having a polarized coupling region

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3055257A (en) * 1960-10-07 1962-09-25 Bell Telephone Labor Inc Optical maser cavity
US3201709A (en) * 1963-12-19 1965-08-17 Bell Telephone Labor Inc Tunable optical resonator for harmonic generation and parametric amplification
US3316511A (en) * 1962-12-05 1967-04-25 Philips Corp Passive gas cell frequency standard in the millimeter wave range
US3487230A (en) * 1966-11-04 1969-12-30 Spectra Physics Optical resonator apparatus
US3530301A (en) * 1968-03-14 1970-09-22 Bell Telephone Labor Inc Nonlinear optical devices employing optimized focusing

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3055257A (en) * 1960-10-07 1962-09-25 Bell Telephone Labor Inc Optical maser cavity
US3187270A (en) * 1960-10-07 1965-06-01 Bell Telephone Labor Inc Optical maser mode selector
US3316511A (en) * 1962-12-05 1967-04-25 Philips Corp Passive gas cell frequency standard in the millimeter wave range
US3201709A (en) * 1963-12-19 1965-08-17 Bell Telephone Labor Inc Tunable optical resonator for harmonic generation and parametric amplification
US3487230A (en) * 1966-11-04 1969-12-30 Spectra Physics Optical resonator apparatus
US3530301A (en) * 1968-03-14 1970-09-22 Bell Telephone Labor Inc Nonlinear optical devices employing optimized focusing

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
High Resolution Millimeter Wave Fabry Perot Interferometer by Culshaw, 3/60, pp. 183 189, IRE Transaction on Microwave Theory and Techniques. *
Resonators for Millimeter and Submillimeter Wavelengths, by Culshaw, 3/61, pp. 136 144, IRE Transactions on Microwave Theory and Techniques, Vol. 9, No. 2. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4298990A (en) * 1978-11-04 1981-11-03 Polska Akademia Nauk Instytut Fizyki Frequency converter of electromagnetic radiation in millimeter and submillimeter wavelength range
US5012212A (en) * 1987-10-07 1991-04-30 Communications Research Laboratory Ministry Of Posts And Telecommunications Open resonator for electromagnetic waves having a polarized coupling region

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