US3810048A - Resistive power load - Google Patents

Resistive power load Download PDF

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Publication number
US3810048A
US3810048A US00334110A US33411073A US3810048A US 3810048 A US3810048 A US 3810048A US 00334110 A US00334110 A US 00334110A US 33411073 A US33411073 A US 33411073A US 3810048 A US3810048 A US 3810048A
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load
metal
waveguide
resistive
power load
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US00334110A
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English (en)
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M Baril
J Legendre
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Thales SA
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Thomson CSF SA
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01PWAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00Auxiliary devices
    • H01P1/24Terminating devices
    • H01P1/26Dissipative terminations

Definitions

  • a resistive power load for a microwave line of microstrip type is constituted by a dielectric arranged between a conductor strip made of a metal having good conductivity, and an earthing plane made of a resistive metal alloy having good thermal conductivity.
  • a load of this kind makes it possible to achieve substantial heat dissipation at the expense of only small volume and low weight.
  • the present invention relates to improvements in resistive power loads, employed in microwave circuits.
  • the invention applies more particularly to the design of a dissipative power load designed for transmission line matching applications, and of the type which produces progressive attenuation and dissipation of the power propagation through the load.
  • the load in the operating frequency band, should constitute a pure resistance whose value is equal to the characteristic impedance of the circuit.
  • power loads are generally manufactured using coaxial line or a waveguide, in which the whole of the power is dissipated in a loss-loaded dielectric.
  • these loads have a greater or lesser size and weight, plus a high cost and high thermal impedance.
  • a resistive power load designed more particularly to act as a matched load for a microwave transmission line, having a micro-strip structure comprising a dielectric substrate, a metal strip and a metal earthing plane laid on each side of said dielectric substrate, said metal strip being constituted by a metal having a good conductivity, and said earthing plane of the structure being constituted by a resistive metal alloy having good thermal conductivity.
  • a resistive power load as specified above overcomes the aforesaid drawback.
  • FIG. 2 is an example of the connection of the load to a coaxial point
  • FIG. 3 is an example of the matching of a microwave, line in the form of a rectangular-section waveguide and v FIG. 4 is an example of the matching of a-line in the form of a circular-section waveguide.
  • the object of the present invention is a resistive load of the microstrip type, illustrated in FIG. 1.
  • This structure comprises a dielectric plate 1 or substrate, arranged between a conductive metal strip 2 and a metal surface 3 known as the earthing plane.
  • the dielectric substrate provides the metal conductors, generally deposited upon it by known techniques such as photogravure, with the requisite mechanical stability.
  • Substrate l utilised is a low-loss dielectric material in order to limit the thermal dissipation there.
  • quartz and alumina ceramics exhibit 2 low losses.
  • Beryllium oxide is used preferentially because it offers goodthermal conductivity as well.
  • the strip conductor 2 is formed of a metal having good conductivity and the present invention is characterised in that the earthing plane is constituted by a resistive alloy having good thermal conductivity and presenting a resistance to the currents flowing there so that it attenuates the energy of the microwave signal propagating through the structure.
  • Nickel-chrome alloys or tita-- nium and vanadium alloys are used in particular.
  • the transmission line deposited upon the substrate has a length such that the power is sufficiently attenuated at the end of the said line, and a width such that the impedance presented by the load at its input is equal to the characteristic impedance of the preceding transmission line.
  • the earthing plane has a small thickness, in the order of only 6 to 10 microns, and is electrically at the earth potential of the preceding circuit, being connected to the earthing side of the latter at a single location 5 as close as possible to that end of the conductor strip constituting theload input.
  • a resistive load produced in accordance with the invention can be fixed flat, by its earthing plane, to a metal chassis or cast element, or thermal radiator. Because the earthing plane is constituted by a resistive metal, electric currents circulate at either side of said earthing plane.
  • loads in accordance with the invention which are integrated with the radiator and produced by integrated cicuit techniques, this using successive deposits upon a flat surface of an aluminium radiator, of a film of aluminium oxide, followed by the resistive earthing plane 3, the dielectric l and the conductor strip 2.
  • FIG. 1 illustrates a loadin accordance with the invention, the conductor of which is arranged in a spiral or serpentine form so that the first turns, which dissipate the major part of the load in order to achieve better heat distribution. It is generally necessary to arrange for a spacing between turns, in the order of three or four times the Width of the conductor strip, in order to prevent parasitic coupling.
  • connection of the load to the preceding circuit is generally effected by soldering on a coaxial connection such as that shown in FIG. 2.
  • the central conductor 40 of the connection is soldered in position.
  • the outer conductor 3 50 is connected to the opening plane by a solder ring 5.
  • the end 4 of the conductor strip is widened to im prove impedance matching.
  • FIG. 3 illustrates a method of utilising the load on a waveguide.
  • the load is attached to an external face of the waveguide, the energy being picked up by an antenna or probe 41 penetrating into the waveguide through an aperture formed in the wall thereof.
  • loads of this kind secure a substantial reduction in the transport powers required.
  • the matched load described can advantageously be employed for microwave circuits in particular ones comprising circulators or hybrid junctions. when associated with a circulator, it makes it possible to create a non-reciprocal device with a built-in load.
  • lts weight and size are around twenty times smaller than matched of conventional mached loads of the same power, and thus make it possible to use it with particular advantage in a small sized primary radar.
  • the problem of the shadow created by the primary source is a critical one. Sources which incorporate bulky elements, reduce the effective area of the antenna.
  • the use of the matched load in accordance with the invention makes it possible to reduce the size of the primary source in such radars and consequently to improve their efficiency.
  • these loads can be utilised in all areas of microwave work and can be mass-produced.
  • a resistive power load designed more particularly to act as a matched load for a microwave transmission line, having a micro-strip structure comprising a dielectric substrate, a metal strip and a metal earthing plane laid on each side of said dielectric substrate respectively, said metal strip being constituted by a metal having a good conductivity and said earthing plane of the structure being constituted by a resistive metal alloy having good thermal conductivity.
  • a resistive power load as claimed in claim 1, comprising further a chassis wherein a film of silicone grease is supplied between the earthing plane and the chassis being also called metal radiator, in order to electrically insulate said earthing plane from said chassis whilst achieving good thermal conductivity.
  • a resistive power load as claimed in claim '3 wherein a film of beryllium oxide grease is applied between the earthing plane and the chassis.
  • a resistive power load as claimed in claim 1 which is manufactured by the successive deposition upon a flat face of an aluminium thermal radiator, of an aluminium oxide film, a resistive metal film, a thick dielectric film, and finally, the conductive strip.
  • a resistive power load as claimed in claim 1 and a waveguide energy propagating in said waveguide and said energy being transmitted to said load for dissipation therein, said waveguide comprising at least a wall and said wall being in contact with said earthing plane of said load, a conductive probe being fixed to said load, an aperture in said wall of said waveguide for disposing said probe in said waveguide, whereby said energy propagating in said waveguide is picked up by said probe and transmitted to said dissipative load.

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  • Non-Reversible Transmitting Devices (AREA)
  • Waveguide Aerials (AREA)
US00334110A 1972-02-24 1973-02-20 Resistive power load Expired - Lifetime US3810048A (en)

Applications Claiming Priority (1)

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FR7206289A FR2172854B1 (enrdf_load_html_response) 1972-02-24 1972-02-24

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US3810048A true US3810048A (en) 1974-05-07

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US00334110A Expired - Lifetime US3810048A (en) 1972-02-24 1973-02-20 Resistive power load

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US (1) US3810048A (enrdf_load_html_response)
JP (1) JPS48100051A (enrdf_load_html_response)
DE (1) DE2309078C2 (enrdf_load_html_response)
FR (1) FR2172854B1 (enrdf_load_html_response)
GB (1) GB1418166A (enrdf_load_html_response)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317126U (enrdf_load_html_response) * 1976-06-22 1978-02-14
US5332981A (en) * 1992-07-31 1994-07-26 Emc Technology, Inc. Temperature variable attenuator
CN106169639A (zh) * 2016-08-26 2016-11-30 斯必能通讯器材(上海)有限公司 低互调功率负载
CN106410341A (zh) * 2016-11-18 2017-02-15 中国电子科技集团公司第四十研究所 一种基于平面螺旋形分布的宽带大功率负载
EP3912175A4 (en) * 2019-01-15 2022-10-12 Smiths Interconnect Americas, Inc. HIGH FREQUENCY SPIRAL TERMINATION

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7636449B2 (en) 2004-11-12 2009-12-22 Cognex Technology And Investment Corporation System and method for assigning analysis parameters to vision detector using a graphical interface

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3541474A (en) * 1969-07-31 1970-11-17 Bell Telephone Labor Inc Microwave transmission line termination
US3564464A (en) * 1967-08-21 1971-02-16 Marconi Co Canada Strip-line power dissipative device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3509495A (en) * 1966-12-01 1970-04-28 Raytheon Co Strip transmission line termination device
US3585533A (en) * 1970-02-26 1971-06-15 Sperry Rand Corp Microwave microcircuit element with resistive high grequency energy absorber

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3564464A (en) * 1967-08-21 1971-02-16 Marconi Co Canada Strip-line power dissipative device
US3541474A (en) * 1969-07-31 1970-11-17 Bell Telephone Labor Inc Microwave transmission line termination

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5317126U (enrdf_load_html_response) * 1976-06-22 1978-02-14
US5332981A (en) * 1992-07-31 1994-07-26 Emc Technology, Inc. Temperature variable attenuator
CN106169639A (zh) * 2016-08-26 2016-11-30 斯必能通讯器材(上海)有限公司 低互调功率负载
CN106410341A (zh) * 2016-11-18 2017-02-15 中国电子科技集团公司第四十研究所 一种基于平面螺旋形分布的宽带大功率负载
CN106410341B (zh) * 2016-11-18 2018-10-09 中国电子科技集团公司第四十一研究所 一种基于平面螺旋形分布的宽带大功率负载
EP3912175A4 (en) * 2019-01-15 2022-10-12 Smiths Interconnect Americas, Inc. HIGH FREQUENCY SPIRAL TERMINATION

Also Published As

Publication number Publication date
DE2309078C2 (de) 1987-01-29
FR2172854B1 (enrdf_load_html_response) 1980-02-15
DE2309078A1 (de) 1973-08-30
JPS48100051A (enrdf_load_html_response) 1973-12-18
GB1418166A (en) 1975-12-17
FR2172854A1 (enrdf_load_html_response) 1973-10-05

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