US2724112A - Energy absorber - Google Patents

Energy absorber Download PDF

Info

Publication number
US2724112A
US2724112A US147500A US14750050A US2724112A US 2724112 A US2724112 A US 2724112A US 147500 A US147500 A US 147500A US 14750050 A US14750050 A US 14750050A US 2724112 A US2724112 A US 2724112A
Authority
US
United States
Prior art keywords
strips
energy
energy absorber
lossy
wave length
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
US147500A
Inventor
Curtis M Hepperle
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.)
Collins Radio Co
Original Assignee
Collins Radio Co
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 Collins Radio Co filed Critical Collins Radio Co
Priority to US147500A priority Critical patent/US2724112A/en
Application granted granted Critical
Publication of US2724112A publication Critical patent/US2724112A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q17/00Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
    • H01Q17/008Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems with a particular shape

Definitions

  • This invention relates in general to energy absorbers, and in particular to a high frequency broad-band nonreflecting attenuator.
  • a further object is to provide a broad band non-reflecting absorber for magnetic waves which will substantially absorb all of the impinging energy.
  • Yet another object is to provide a non-reflective energy absorber to be used as a calibration device for a radiometry receiver.
  • a feature of this invention is found in the provision for a supporting frame adapted to hold a plurality of lossy strips spaced laterally apart in a position so as to intercept electromagnetic waves.
  • Figure l is a front isometric view of the energy absorber of this invention.
  • Figure 2 is a sectional view taken on a line 22 of Figure 1.
  • a frame of dielectric material such as wood comprises the upper and lower members 11 and 12, respectively, and the side members 13 and 14.
  • a plurality of lossy sheets or strips 16 of a width L substantially equal to the width of the frame 10 are supported between the members 11 and 12 parallel to the side walls 13 and 14.
  • the strips 16 are spaced equidistant apart, as shown in Figure 2.
  • the material is lossy and may be, for example, coarse fabric strips.
  • the United States Rubber Company manufactures a cloth named Uskon which may be used, for example.
  • the term lossy is an adjective which indicates that the loss in a material is appreciable when compared to incident energy. See second paragraph, page 274, Fields and Waves in Modern Radio, Ramo and Whinnery, published by John Wiley 1944.
  • the ends of the strips 16 are attached to the end walls 11 and 12 by gluing or other suitable holding means. If the distance between each of the lossy strips 16 is designated as d, electromagnetic waves impinging on the front of the energy absorber will be shorted and attenuated if the wave length of the energy is greater than the d dimension and less than 2d.
  • the attenuator is broad band in that it attenuates over a range of wave lengths from d to 2d.
  • energy absorbers which comprise a flat piece of lossy material supported in front of a metal sheet, with the distance between them being A wave length. It is seen in this instance that the attenuator must be tuned, in that the A wave length distance will change for each frequency.
  • the broad band characteristic of the present invention is a major improvement over this type of energy absorber. Another advantage, which is a corollary of the above one, is that the dimension d need not be maintained to a very small tolerance.
  • the dimension L of the strip 16 affects the attenuating characteristic of the energy absorber. Another variable is the type of material used in the strips, and if the resistivity of the material is 377 ohms per square, optimum performance is obtained. If any energy passes through the attenuator and is reflected through it from the reverse direction, it will be decreased again as it passes through it from the reverse direction, and should be negligible when it arrives at the transmitter once again.
  • the lossy strips might be mounted on the four walls and roof of a room to obtain a space room from which no reflection will be forthcoming between the wave length from d to 2d.
  • this invention provides means for terminating an antenna in a non-reflecting manner over a relatively broad band of frequencies, and thus makes it possible to calibrate antennas and radiometric receivers within the confines of a building.
  • An electromagnetic wave attenuator comprising a frame member defining an axially extending opening, and a plurality of laterally disposed, equally spaced lossy strips of electrically conductive material having the impedance of free space extending across said opening, each strip supported at each end by said frame member parallel to the remaining strips.
  • a broad band non-reflecting absorber for electromagnetic waves comprising, a frame member, a plurality of laterally disposed lossy strips extending across said frame member with each strip parallel to the remaining strips, the lateral distance between eachstrip substantially constant and the distance between strips being greater than one-half wave length of the energy to be absorbed and less than one wave length of the energy to be absorbed.
  • a broad band non-refiecting absorber of electromagnetic radiant energy comprising, a frame member, a plurality of electrically resistive strips of cloth having the impedance of free space, each of said strips being supported by said frame member with the broad sides of the strips parallel and laterally spaced apart between the limits of a half wave length and one Wave length of the energy to be absorbed.

Description

United States Patent ENERGY ABSORBER Curtis M. Hepperle, Cedar Rapids, Iowa, assignor to Co!- Radio Company, Cedar Rapids, Iowa, a corporation 0 owa Application March 3, 1950, Serial No. 147,500
3 Claims. (Cl. 343-18) This invention relates in general to energy absorbers, and in particular to a high frequency broad-band nonreflecting attenuator.
It is often desirable in testing antennas and transmitters to terminate in a non-reflective load. One method of obtaining such a termination is to point the antenna toward open space so that none of the energy which is transmitted will be reflected. At times this becomes inconvenient in that the radiating antenna must always be placed in the open, and at times even the transmitter must be placed outside. In radiometry it is usually necessary to calibrate the receiver by directing the antenna toward a non-reflecting surface of known temperature.
It is an object of this invention, therefore, to provide means for terminating an antenna in a manner so that it may be tested inside a building.
A further object is to provide a broad band non-reflecting absorber for magnetic waves which will substantially absorb all of the impinging energy.
Yet another object is to provide a non-reflective energy absorber to be used as a calibration device for a radiometry receiver.
A feature of this invention is found in the provision for a supporting frame adapted to hold a plurality of lossy strips spaced laterally apart in a position so as to intercept electromagnetic waves.
Further objects, features, and advantages of this invention will become apparent from the following description and claims when read in view of the drawings, in which:
Figure l is a front isometric view of the energy absorber of this invention; and,
Figure 2 is a sectional view taken on a line 22 of Figure 1.
Referring to Figure 1, a frame of dielectric material such as wood comprises the upper and lower members 11 and 12, respectively, and the side members 13 and 14. A plurality of lossy sheets or strips 16 of a width L substantially equal to the width of the frame 10 are supported between the members 11 and 12 parallel to the side walls 13 and 14. The strips 16 are spaced equidistant apart, as shown in Figure 2.
The material is lossy and may be, for example, coarse fabric strips. The United States Rubber Company manufactures a cloth named Uskon which may be used, for example. As used herein, the term lossy is an adjective which indicates that the loss in a material is appreciable when compared to incident energy. See second paragraph, page 274, Fields and Waves in Modern Radio, Ramo and Whinnery, published by John Wiley 1944. The ends of the strips 16 are attached to the end walls 11 and 12 by gluing or other suitable holding means. If the distance between each of the lossy strips 16 is designated as d, electromagnetic waves impinging on the front of the energy absorber will be shorted and attenuated if the wave length of the energy is greater than the d dimension and less than 2d. In other words, the attenuator is broad band in that it attenuates over a range of wave lengths from d to 2d. Thus no tuning is required within this range, as is necessary in the conventional type of 2,724,112 Patented Nov. 15, 1955 energy absorbers which comprise a flat piece of lossy material supported in front of a metal sheet, with the distance between them being A wave length. It is seen in this instance that the attenuator must be tuned, in that the A wave length distance will change for each frequency. The broad band characteristic of the present invention is a major improvement over this type of energy absorber. Another advantage, which is a corollary of the above one, is that the dimension d need not be maintained to a very small tolerance.
The dimension L of the strip 16 affects the attenuating characteristic of the energy absorber. Another variable is the type of material used in the strips, and if the resistivity of the material is 377 ohms per square, optimum performance is obtained. If any energy passes through the attenuator and is reflected through it from the reverse direction, it will be decreased again as it passes through it from the reverse direction, and should be negligible when it arrives at the transmitter once again. The lossy strips might be mounted on the four walls and roof of a room to obtain a space room from which no reflection will be forthcoming between the wave length from d to 2d.
It is seen that this invention provides means for terminating an antenna in a non-reflecting manner over a relatively broad band of frequencies, and thus makes it possible to calibrate antennas and radiometric receivers within the confines of a building.
Although this invention has been described with respect to a particular embodiment thereof, it is not to be so limited as changes and modifications may be made therein which are within the full intended scope as defined by the appended claims.
I claim:
1. An electromagnetic wave attenuator comprising a frame member defining an axially extending opening, and a plurality of laterally disposed, equally spaced lossy strips of electrically conductive material having the impedance of free space extending across said opening, each strip supported at each end by said frame member parallel to the remaining strips.
2. A broad band non-reflecting absorber for electromagnetic waves comprising, a frame member, a plurality of laterally disposed lossy strips extending across said frame member with each strip parallel to the remaining strips, the lateral distance between eachstrip substantially constant and the distance between strips being greater than one-half wave length of the energy to be absorbed and less than one wave length of the energy to be absorbed.
3. A broad band non-refiecting absorber of electromagnetic radiant energy comprising, a frame member, a plurality of electrically resistive strips of cloth having the impedance of free space, each of said strips being supported by said frame member with the broad sides of the strips parallel and laterally spaced apart between the limits of a half wave length and one Wave length of the energy to be absorbed.
References Cited in the file of this patent UNITED STATES PATENTS 2,461,005 Southworth Feb. 8, 1949 2,464,006 Tiley Mar. 8, 1949 2,464,269 Smith Mar. 15, 1949 2,474,384 Sunstein June 28, 1949 2,491,662 Houghton Dec. 20, 1949 2,508,479 Wheeler May 23, 1950 2,526,573 Mason Oct. 17, 1950 2,527,918 Collard Oct. 31, 1950 2,538,035 Pickles Jan. 16, 1951 2,588,249 Kock Mar. 4, 1952 FOREIGN PATENTS 802,728 France June 13, 1936
US147500A 1950-03-03 1950-03-03 Energy absorber Expired - Lifetime US2724112A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US147500A US2724112A (en) 1950-03-03 1950-03-03 Energy absorber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US147500A US2724112A (en) 1950-03-03 1950-03-03 Energy absorber

Publications (1)

Publication Number Publication Date
US2724112A true US2724112A (en) 1955-11-15

Family

ID=22521811

Family Applications (1)

Application Number Title Priority Date Filing Date
US147500A Expired - Lifetime US2724112A (en) 1950-03-03 1950-03-03 Energy absorber

Country Status (1)

Country Link
US (1) US2724112A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2977591A (en) * 1952-09-17 1961-03-28 Howard A Tanner Fibrous microwave absorber
US3078461A (en) * 1958-04-07 1963-02-19 Walter J Dwyer Dished, annular, radio frequency absorber and method of manufacture
US3124798A (en) * 1954-06-11 1964-03-10 Reflection-free damping structure for
US3152328A (en) * 1957-11-21 1964-10-06 Mcmillan Corp Of North Carolin Microwave radiation absorber comprising spaced parallel resistance discs
US3281848A (en) * 1964-06-29 1966-10-25 Sylvania Electric Prod Attenuator for radiant electromagnetic energy
US4743887A (en) * 1983-11-07 1988-05-10 Sanders Associates, Inc. Fault locating system and method
US4794396A (en) * 1985-04-05 1988-12-27 Sanders Associates, Inc. Antenna coupler verification device and method

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR802728A (en) * 1935-02-19 1936-09-14 Meaf Mach En Apparaten Fab Nv Apparatus and method for improving devices for producing and receiving ultra-short electric waves
US2461005A (en) * 1940-04-05 1949-02-08 Bell Telephone Labor Inc Ultra high frequency transmission
US2464006A (en) * 1944-04-28 1949-03-08 Philco Corp Radio wave absorption device
US2464269A (en) * 1942-06-12 1949-03-15 Raytheon Mfg Co Method and means for controlling the polarization of radiant energy
US2474384A (en) * 1944-04-28 1949-06-28 Philco Corp High-frequency radiant energy absorbing device
US2491662A (en) * 1945-03-30 1949-12-20 Bell Telephone Labor Inc Attenuator
US2508479A (en) * 1944-11-16 1950-05-23 Hazeltine Research Inc High-frequency electromagneticwave translating arrangement
US2526573A (en) * 1947-08-15 1950-10-17 Bell Telephone Labor Inc Frequency selective system
US2527918A (en) * 1950-10-31 Method of minimizing reflection of
US2538035A (en) * 1948-04-03 1951-01-16 Int Standard Electric Corp Absorbing screen for directive radiation
US2588249A (en) * 1946-01-22 1952-03-04 Bell Telephone Labor Inc Wave polarization shifter systems

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527918A (en) * 1950-10-31 Method of minimizing reflection of
FR802728A (en) * 1935-02-19 1936-09-14 Meaf Mach En Apparaten Fab Nv Apparatus and method for improving devices for producing and receiving ultra-short electric waves
US2461005A (en) * 1940-04-05 1949-02-08 Bell Telephone Labor Inc Ultra high frequency transmission
US2464269A (en) * 1942-06-12 1949-03-15 Raytheon Mfg Co Method and means for controlling the polarization of radiant energy
US2464006A (en) * 1944-04-28 1949-03-08 Philco Corp Radio wave absorption device
US2474384A (en) * 1944-04-28 1949-06-28 Philco Corp High-frequency radiant energy absorbing device
US2508479A (en) * 1944-11-16 1950-05-23 Hazeltine Research Inc High-frequency electromagneticwave translating arrangement
US2491662A (en) * 1945-03-30 1949-12-20 Bell Telephone Labor Inc Attenuator
US2588249A (en) * 1946-01-22 1952-03-04 Bell Telephone Labor Inc Wave polarization shifter systems
US2526573A (en) * 1947-08-15 1950-10-17 Bell Telephone Labor Inc Frequency selective system
US2538035A (en) * 1948-04-03 1951-01-16 Int Standard Electric Corp Absorbing screen for directive radiation

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2977591A (en) * 1952-09-17 1961-03-28 Howard A Tanner Fibrous microwave absorber
US3124798A (en) * 1954-06-11 1964-03-10 Reflection-free damping structure for
US3152328A (en) * 1957-11-21 1964-10-06 Mcmillan Corp Of North Carolin Microwave radiation absorber comprising spaced parallel resistance discs
US3078461A (en) * 1958-04-07 1963-02-19 Walter J Dwyer Dished, annular, radio frequency absorber and method of manufacture
US3281848A (en) * 1964-06-29 1966-10-25 Sylvania Electric Prod Attenuator for radiant electromagnetic energy
US4743887A (en) * 1983-11-07 1988-05-10 Sanders Associates, Inc. Fault locating system and method
US4794396A (en) * 1985-04-05 1988-12-27 Sanders Associates, Inc. Antenna coupler verification device and method

Similar Documents

Publication Publication Date Title
CA1121912A (en) Half-wave communications antenna assembly
KR860000331B1 (en) A small loop antenna
US2588610A (en) Directional antenna system
Severin Nonreflecting absorbers for microwave radiation
US2724112A (en) Energy absorber
US3789404A (en) Periodic surface for large scan angles
US6340951B1 (en) Wideband microstrip leaky-wave antenna
US3274603A (en) Wide angle horn feed closely spaced to main reflector
US2425585A (en) Wave-signal antenna
US4716389A (en) Millimeter wave microstrip surface mounted attenuator
US2856605A (en) Antenna
US3727230A (en) Antenna having a combined dipole and loop portion
US2972147A (en) Circularly polarized slot antenna
US2573460A (en) Antenna
US2281429A (en) Antenna
JP2011009836A (en) Multi-frequency shared antenna
US3945016A (en) Wide-band spiral antenna
US3848256A (en) Waveguide antenna
US3508271A (en) Folded monopole antenna
Yi et al. Design of miniaturized and ultrathin absorptive/transmissive radome based on interdigital square loops
WO2015145392A1 (en) Antenna with absorbent device
US2963704A (en) Antenna
Menon et al. Guided and leaky mode characteristics of solid dielectric horn: Analytical and numerical solutions
Paulotto et al. A microstrip periodic leaky-wave antenna optimized for broadside scanning
Geterud et al. Radome design for hat-fed reflector antenna