US3633131A - Water load - Google Patents

Water load Download PDF

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Publication number
US3633131A
US3633131A US31710A US3633131DA US3633131A US 3633131 A US3633131 A US 3633131A US 31710 A US31710 A US 31710A US 3633131D A US3633131D A US 3633131DA US 3633131 A US3633131 A US 3633131A
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United States
Prior art keywords
line
wave
loss section
liquid
delay
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Expired - Lifetime
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US31710A
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English (en)
Inventor
Richard B Nelson
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PREMIER MICROWAVE OF CALIFORNIA Inc
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Varian Associates Inc
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Assigned to TECHNOLOGY FUNDING SECURED INVESTORS II reassignment TECHNOLOGY FUNDING SECURED INVESTORS II SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GAMMA MICROWAVE, INC.
Assigned to GAMMA MICROWAVE, INC., A CORP OF CA reassignment GAMMA MICROWAVE, INC., A CORP OF CA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: VARIAN ASSOCIATES, INC.
Assigned to TECHNOLOGY FUNDING SECURED INVESTORS II, A CALIFORNIA LIMITED PARTNERSHIP reassignment TECHNOLOGY FUNDING SECURED INVESTORS II, A CALIFORNIA LIMITED PARTNERSHIP SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GAMMA MICROWAVE, INC. A CORP. OF CALIFORNIA
Assigned to TECHNOLOGY FUNDING SECURED INVESTORS II reassignment TECHNOLOGY FUNDING SECURED INVESTORS II ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: GAMMA MICROWAVE, INC.
Assigned to TECHNOLOGY FUNDING SEC. IN. II reassignment TECHNOLOGY FUNDING SEC. IN. II RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: GAMMA MICROWAVE, INC.
Assigned to PREMIER MICROWAVE OF CALIFORNIA, INC. reassignment PREMIER MICROWAVE OF CALIFORNIA, INC. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: TECHNOLOGY FUNDING SECURED INVESTORS II
Assigned to TECHNOLOGY FUNDING SECURED INVESTORS II reassignment TECHNOLOGY FUNDING SECURED INVESTORS II SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PREMIER MICROWAVE OF CALIFORNIA, INC.
Assigned to PREMIER MICROWAVE OF CALIFORNIA, INC. reassignment PREMIER MICROWAVE OF CALIFORNIA, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TECHNOLOGY FUNDING SECURED INVESTORS II
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/24—Terminating devices
    • H01P1/26—Dissipative terminations
    • H01P1/262—Dissipative terminations the dissipative medium being a liquid or being cooled by a liquid

Definitions

  • a radio frequency water load having a loss section of transmission line.
  • the loss section of transmission line includes a delay line portion for slowing the group velocity of wave energy traveling in the loss section.
  • Conduits are arranged for directing a stream of wave-attenuative liquid through the loss section in wave-energy-exchanging relation with wave energy on the delay line for attenuating the wave energy, whereby the physical length of the loss section is reduced for a given amount of attenuation.
  • the loss section is a section of coaxial line and the inner conductor is a helical delay line.
  • the principal object of the present invention is the provision of an improved water load.
  • One feature of the present invention is the provision of a water load having a loss section of transmission line including a delay line portion for slowing'the group velocity of the wave energy to be attenuated and including means for directing a stream of wave energy attenuative liquid through the loss section in wave-energy-exchanging relation with the wave energy on the delay line.
  • Another feature of the present invention is the same as the preceding feature wherein the loss section of transmission line is a section of coaxial line and'the delay line portion of the transmission line is formed by the inner conductor.
  • Another feature of the present invention is the same as the immediately preceding feature wherein the delay line inner conductor is a helix or topological equivalent of a helix, whereby a broad band load is obtained.
  • Another feature of the present invention is the same as any one or more of the preceding features including the provision of a dielectric structure disposed within the delay line portion of the loss section for displacing some of the wave'energy attenuative liquid for reducing the dielectric loading of the loss section of transmission line.
  • Another feature of the present invention is the same as any one or more of the preceding features including the provision of a transition section at the input end of the loss section for gradually'decreasing the axial group velocity of wave energy traveling in the direction of power flow on the delayline for reducing wave reflection from the delay line.
  • Another feature of the present invention is the provision of an abrupt impedance matching transition at the partitioning wall between the attenuative liquid filled loss section and the transmission line input to the loss section.
  • the DRAWING is a longitudinal sectional view of a coaxial water load incorporating features of the present invention.
  • the water load 1 includes an input section of air-filled coaxial line 2 connected to a loss section of coaxial line 3 via the intermediary of an abrupt impedance-matching transition section 4 formed by a wave-permeable water-impervious dielectric disc 5, as of teflon, sealed between the inner conductor 6 and the outer conductor 7 of the input section 2 of air-filled coaxial line.
  • the characteristic impedance of the abrupt transition water load having reduced section 4 is made substantially equal to the characteristic impedance of the 50-ohm coaxial linesection 2'by undercutting the center conductor 6 at 8 and by enlarging the inside diameter of the outer conductor 7 at 9 to compensate for the increased dielectric constant of the teflon-filled transition section 4 of the coaxial line.
  • an abrupt transition it is meant that the wave-permeable partition 5 has an axial length substantially less than one-quarter wavelength at the center frequency of the operating band of the load 1.
  • the loss section of coaxial line 3 includes an inner conductor 11 coaxially surrounded by a'h'ollow cylindrical outer con ductor 12.
  • a hollow cylindrical dielectric'sleeve structure 13, as of teflon, coaxially surrounds the inner conductor 11 and is interposed in the space between the inner conductor 11 and the outer conductor 12 for reducing the dielectric loading of the loss section of coaxial line 3.
  • the loss section 3 includes an input conduit 14 and an output conduit 15 communicating through a conductive end closing wall 16 which closes off the terminal end of the load 1 and provides a wave-reflective discontinuity at the terminal end for reflecting wave energy back into the loss section 3 for further attenuation.
  • a stream of wave energy attenuative liquid, as of water, is conducted through the coaxial loss section 3 in wave-energy-exchangingrelation with wave energy traveling therein for attenuating wave energy.
  • the dielectric constant of the water dielectric fill is approximately 81 such that the impedance of the water-filled loss section 3 would ordinarily be decreased by approximately a factor of 9 as compared to a similar air-filled section. Therefore,
  • a the teflon sleeve 13 is provided to reduce the dielectric loading of the loss section of coaxial line 3 by displacing some of the water between the inner and outer conductor 11 and 12, respectively.
  • the diameter of the inner conductor 11 can be maintained at a reasonable diameter consistent with the power-handling requirements of the inner conductor 11 while maintaining a 50.0 characteristic impedance to match the impedance of the transition 4 and the input line 2.
  • the inner conductor 11 is preferably made of a material which retains its strength at relatively high temperatures, such as stainless steel or Monel.
  • the loss section of coaxial line 3 also includes a delay-line section 18 and a delay-line transition section 19;
  • the delayline section 18 the inner conductor 11 is wound into a helix to form a helical delay-line, thereby substantially reducing the group velocity for wave energy traveling on the helix in the TEM mode.
  • the inner conductor 11 has an initial straight portion having a length sufficiently long to extend beyond the local electromagnetic fields of the discontinuity produced by the abrupt transition section 4.
  • the straight portion of the inner conductor 11 is followed, taken in the direction of power flow, indicated by the arrow p, by a helix having a conically tapered diameter d, which increases in the direction of power flow.
  • the diameter of the helix increases throughout the transition section 19 until it reaches the diameter of the helix in the delay section 18.
  • the transition section 19 performs two functions, first, it forms a velocity transformation for transforming the group velocity of wave energy on the coaxial'line from the velocity of light to a substantially slower group velocity in the delay line section 18, as of one-tenth the velocity of light.
  • transition section 19 provides an impedance transition section for transforming the impedance from the 509. characteristic impedance at the power input end of the loss section 3 to a relatively low characteristic impedance of approximately for the helix as immersed in water in the delay-line section 18.
  • the wave energy attenuative liquid passes into the loss section 3 via input conduit 14 and is passed through the annular chamber 21 between the teflon sleeve '13 and the outer conductor 12 to the power input end of the loss section 3 at which point the attenuative liquid flows to the center of the sleeve 13 via a plurality of inclined bores 22 passing through the wall of the sleeve 13.
  • the attenuative liquid within the center of the sleeve 13 immerses the helical delay-line and transition section in the wave energy attenuative liquid, thereby greatly attenuating the wave energy on the helical portion of the center conductor 11.
  • the inner conductor 11 has a diameter of three-sixteenths of an inch which tapers over a 6-inch length to a helix of an outside diameter of 1 inch with a pitch of five-sixteenths of an inch.
  • the attenuation for wave energy within the delay line section 18 is approximately 0.94 db. per inch.
  • a section 5.3 inches long yields db. for wave energy traveling in one direction.
  • the teflon sleeve has an outer diameter of 2.0 inches and an inside diameter of 1.285 inches and the outer conductor 12 has an inside diameter of 3 inches.
  • the inside diameter of the teflon sleeve 13 is bored to a larger diameter in the delay line section 18 since the dielectric sleeve structure 13 is not required in this region for impedance matching purposes.
  • the diameter of the helix in the loss section would then be increased to the inside diameter of the bored teflon sleeve to further decrease the group velocity for wave energy traveling in the delay-line section 18. If the helix is increased to 1.75 inches in diameter the axial length of the delay line section 18 can be reduced to 3 inches for 5 db. of attenuation for energy traveling in one direction.
  • the helix delay-line has been shown for the inner conductor 11, it is to be understood that other types of delay lines may be employed such as topological equivalents of the helix or helix derived circuits, namely, crosswound helices, bifilar helices, ring and bar, and double ring and bar slowwave circuits. It is also to be understood that other types of periodic loading for the center conductor may be employed such as a disc-loaded center conductor. Also, other types of delay-lines may be employed for the center conductor such as a meander line. As an alternative, the outer conductor 12 of the loss section 3 may include periodic loading members for decreasing the group velocity of wave energy traveling in the loss section 3.
  • a loss section of coaxial transmission line having a portion of the inner conductor thereof comprising a delay-line portion, and means for directing a stream of wave attenuative liquid through said loss section of line in wave-energy-exchanging relation with the wave energy on said delay-line for attenuating the wave energy, whereby the physical length of said loss section is reduced for a given amount of attenuation, and further including a dielectric structure interposed in said delay-line between said inner conductor and said outer conductor, said dielectric structure having a dielectric constant substantially less than the dielectric constant of the wave-attenuative liquid to be passed through said loss section of coaxial line for reducing the dielectric loading of the loss section of the coaxial line.
  • the apparatus of claim 1 including a conductive end closing wall disposed at the terminal end of said loss section and interconnecting said inner delay-line and said outer conductor to provide a wave reflective termination for said loss section.
  • said delay-line has a portion with tapered dimensions in the direction of power flow within said loss section for gradually decreasing the axial group velocity of wave energy traveling on said inner delayline in a direction of power flow therealon 5.
  • said inner delay-line is a helix and wherein the tapered dimension of said helix is the diameter, such diameter increasing in the direction of power flow on said helix.
  • said dielectric structure comprises a dielectric sleeve disposed coaxially of and surrounding said delay-line.
  • said means for directing a stream of wave attenuative liquid through said loss section includes means for immersing said delay-line in the stream of wave attenuative liquid.
  • the apparatus of claim 1 including a liquid-impervious dielectric wave-permeable structure sealed across said loss section of coaxial line between said inner conductor and said outer conductor at the wave energy input end of said loss section for partitioning an attenuative liquid-filled portion of said loss section from an input coaxial-line section to be connected to the input end of said loss section.
  • said dielectric partitioning structure is a disc, and including inductive reactive means disposed at said disc for impedance-matching said disc to said liquid-filled loss section.
  • liquid-filled loss section of coaxial line proximate said partitioning wavepermeable structure is dimensioned to have a characteristic impedance when filled with attenuative liquid which is substantially equal to the characteristic impedance of said coaxial line proximate the side of said partitioning wave-permeable structure opposite to said liquid-filled side to provide a broadband substantially wave-reflectionless transmission line transition to said liquid-filled loss section.

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  • Waveguides (AREA)
  • Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
US31710A 1970-04-24 1970-04-24 Water load Expired - Lifetime US3633131A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US3171070A 1970-04-24 1970-04-24

Publications (1)

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US3633131A true US3633131A (en) 1972-01-04

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Application Number Title Priority Date Filing Date
US31710A Expired - Lifetime US3633131A (en) 1970-04-24 1970-04-24 Water load

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US (1) US3633131A (cg-RX-API-DMAC10.html)
CA (1) CA998446A (cg-RX-API-DMAC10.html)
DE (1) DE2120024A1 (cg-RX-API-DMAC10.html)
FR (1) FR2086304B1 (cg-RX-API-DMAC10.html)
GB (1) GB1351297A (cg-RX-API-DMAC10.html)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4382239A (en) * 1981-04-30 1983-05-03 Lovelace Alan M Administrator Waveguide cooling system
US4593259A (en) * 1983-07-27 1986-06-03 Varian Associates, Inc. Waveguide load having reflecting structure for diverting microwaves into absorbing fluid
RU2101884C1 (ru) * 1995-01-26 1998-01-10 Таганрогский научно-исследовательский институт связи Свч нагреватель жидкости
RU170944U1 (ru) * 2016-12-29 2017-05-16 федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский ядерный университет МИФИ" (НИЯУ МИФИ) Волноводная нагрузка для обработки растворов, жидкостей и сыпучих материалов

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB598198A (en) * 1944-06-17 1948-02-12 Sperry Gyroscope Co Inc Improvements in and relating to micro-wave wattmeters
DE815501C (de) * 1948-10-02 1951-10-01 Siemens & Halske A G Kabelabschlusswiderstand
US2825874A (en) * 1954-03-03 1958-03-04 Itt Artificial load for broad frequency band
US3121204A (en) * 1960-12-23 1964-02-11 Giordano Salvatore Non-reflective liquid termination of a coaxial cable

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB598198A (en) * 1944-06-17 1948-02-12 Sperry Gyroscope Co Inc Improvements in and relating to micro-wave wattmeters
DE815501C (de) * 1948-10-02 1951-10-01 Siemens & Halske A G Kabelabschlusswiderstand
US2825874A (en) * 1954-03-03 1958-03-04 Itt Artificial load for broad frequency band
US3121204A (en) * 1960-12-23 1964-02-11 Giordano Salvatore Non-reflective liquid termination of a coaxial cable

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4382239A (en) * 1981-04-30 1983-05-03 Lovelace Alan M Administrator Waveguide cooling system
US4593259A (en) * 1983-07-27 1986-06-03 Varian Associates, Inc. Waveguide load having reflecting structure for diverting microwaves into absorbing fluid
RU2101884C1 (ru) * 1995-01-26 1998-01-10 Таганрогский научно-исследовательский институт связи Свч нагреватель жидкости
RU170944U1 (ru) * 2016-12-29 2017-05-16 федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский ядерный университет МИФИ" (НИЯУ МИФИ) Волноводная нагрузка для обработки растворов, жидкостей и сыпучих материалов

Also Published As

Publication number Publication date
CA998446A (en) 1976-10-12
DE2120024A1 (de) 1972-09-21
FR2086304B1 (cg-RX-API-DMAC10.html) 1977-01-07
FR2086304A1 (cg-RX-API-DMAC10.html) 1971-12-31
GB1351297A (en) 1974-04-24

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