US2563613A - Translating means for ultra-short - Google Patents

Description

Aug. 7, 1951 R. s. OHL v 2,

TRANSLATING MEANS FOR ULTRA-SHORT WAVELENGTH ENERGY Filed March 20, 1948 2 Sheets-Sheet 1 I4 -20B ll lA/VEN TOR R. S. OHL

ATTORNEY Aug. 7, 1951 R. s. OHL 2,563,613

TRANSLATING MEANS FOR ULTRA-SHORT WAVELENGTH ENERGY Filed March 20, 1948 2 Sheets-Sheet 2 30 //v l EN TOR R. S. OHL

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A T TORM Patented Aug. 7, 1951 FICE TRANSLATING MEANS FOR ULTRA-SHORT WAVE LENGTH ENERGY Russell S. Ohl, Fair Haven, N. J assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application March 20, 1948, Serial No. 15,981

18 Claims. (Cl. 25031) This invention relates to translating devices and more particularly to devices especially suitable for use at ultra-short wavelengths.

Translating devices comprising a fine wire in point contact with the surface of a silicon or like crystal and generally known as crystal detectors or rectifiers have been used at relatively short wavelengths. These devices, in one form called a shielded detector, include an outer conductive shield or tube in which are fitted respectively an insulator supporting the, contact wire on a stud or inner conductor and a conductive body supporting the crystal. Thus the translating device is built into a short section of coaxial line. A device of this type is shown in Fig. 3 of Patent 2,415,841 toR. S. Ohl issued February 18, 1947. Such a device may be connected to a wave guide through a. suitable transformer. There is, however, a short wave limit at which such devices become ineiiicient. The need therefore arises for a detector or like device that will operate efficiently at or below this shortwave limit.

One way of meeting this need is to build the translator elements i. e., contact wire and crystal directly into a wave guide. This construction has the advantages of simple electrical circuits with a minimum of undesired losses from dielectrics and wave traps. It has, however, been found to be very difficult to obtain a good, stable translating device with this type of construction.

An object of this invention is to produce a translating device-having both the structural advantages of a coaxial unit and the electrical advantages of a translator built into a wave guide.

Another object of this invention is to achieve a translating device of the point contact type that will operate efiiciently at ultra-short wavelengths, for example, of the order of twelve and one-half millimeters (one-half inch) or less, more particularly in the range between 4.2 and 7 millimeters. A further object of this invention is to enable connection of a translator'to a wave guide with a minimum of disturbance as to physical and electrical continuity of the waveguide. f

One feature of thisinvention resides in a conductive shield or reflector overlying the face of the insulator adjacent the contact wire in a shielded type point contact translating device.

Another feature of this inventioninvolves the use, in a unitary translating device, of a window "or'opening in the outer conductor for the introduction of extraction of high frequency energy.

A further feature relates to a wav e. guide fix- "ture intowhich the unitary point contact trans- 2 lating means may be fitted without substantially destroying the continuity of the wave guide boundaries and which may include adjustable means for electrically matching the translating means to the wave guide.

Other objects and features of this invention will appear more fully and clearly from the following description of illustrative embodiments of the invention in connection with the appended drawings in which:

Fig. 1 shows a longitudinal section of a-translating device illustrative of one embodiment of this invention;

Fig. 2 is a view in elevation of another translating device in accordance with a different embodiment of the invention, with parts broken away to show details;

Fig. 3 is a cross-sectional view on lines 33 of Fig. 1;

Fig. 4 is a perspective view with parts broken away showing details of a wave guide fixture including a device such as is illustrated in: Figs. 1, 2 and 3;

Fig. 5 is a plan view with parts broken away of the device shown in Fig. 4; and

Fig. 6 is a sectional view taken on line 6-156 of Fig. 5.

As shown in Fig. 1, the translating device in one form may comprise a metallic tube or outer shield ID in which the other parts are mounted.

Onesuitable material for the tube is beryllium copper. Another is silver-plated brass. A metal body or cylinder l l, which may be of brass, plated on one face with silver, supports a crystal [2 in an orifice 13 in the plated face. Thecrystal [2 may be of suitably prepared silicon material. A body M of insulating material supports a stud or inner conductor [5 centrally. of thetubelfl. The body 14 may bemolded of a resin and silica dust and the stud 15 may be of silver-plated nickel. A contact wire 16 secured to one-end of stud 15 as by welding, makes point contact with the face of crystal l2. A suitable material iorthe wire I6 is tungsten.

A pair of oppositely located windows or orifices l1 and I8 (see also Fig. 3) through the wallof tubelll, allow for connection of wave guide means to the device.

Overlying the face of insulator I4 isa metal plate ISA which is connected to the stud l5 as by soldering and is spaced from the walls of tube ID. A suitable material for plate ISA is silver. The space between plate [9A and tube l0 may be filled with an insulating cement as shown adapted for use. as a detector.

means fitted to one window, say ll. wave guidemeans connected to window l8 pro- 3 at 20A or the cement may be omitted leaving the ambient atmosphere as the dielectric. I

The device shown in Fig. 2 is in all respects except one the same as that shown in Fig. l. The difference lies in the plate ISB which like ISA overlies insulator l4 but makes contact with the wall of tube In and is spaced from the stud l5. Insulating cement 203 may be used between the plate [913 and the stud IE or may be omitted as in the device of Fig; l. The plate [95, similarly to the plate [9A, may be of silver.

In the manufacture of these devices the as sembly consisting of insulator l4, stud l5, contact wire l6 and plate [9A o I913, is forced into the tube until the face of [9A or IBB is even with an edge of each of the opposite'windows l1 and I8. The cylinder H with crystal I2 mounted in the silver-plated face is then forced into the other end of tube I0 until contact is made between the point of wire l6 and the face of the crystal l2. Then member H is forced in enough further to deflect the contact spring a desired amount, say .001 inch. The dimensions of the parts should be so chosen that the inner, silverplated face of body II is even with the edges of windows I! and 18 respectively. By careful ad- ,iustment to make the window edges flush with the inner faces of body H and plate 19A or IQB undesirable discontinuities are avoided.

The crystal l2 may be secured in the orifice l3 by a suitabl solder. If the orifice I3 is drilled as shown, the conical bottom may be filled with the solder so that the face of the crystal I2 is flush with the face of body I l. The crystal is prepared for mounting by being coated on the bottom and edges with a'metal lic film, for example of nickel.

While the crystal I2 is shown as square with a diagonal corresponding to the diameter of. orifice l3, it may also be made cylindrical of a diameter to fit relatively closely into orifice l3. natively, the orifice l3 may be made square with a flat bottom to exactly fit the square'crystal sho n- I Point contact devices of the shielded type such as shown in the. previously noted Ohl Patent 2,415,841, and not having elements corresponding to the plate [9A or [9B of the present invention, when connected to a wave guide, develop undesirable resonances at very high frequencies.

Alter- These resonances, caused by the contact wire and the discontinuity due to. the insulator element make the wave guidecircuit associated with the device insensitive to tuning adjustments.

By substantially covering the face of the insulator l4 with the plate ISA or I9B, a conductive boundary that is practically continuous with that or the wave guide is obtained. The plate acts as a reflector that greatly inhibits loss of very high frequency energy through the coaxial line formed by the stud [5' and the wall of tube l0. Thus plate [9A or I9B- in connection with the inner surface of body- II and the wall of tube In form a wave guide section. The millimeter Waves are thus confined to the wave guide and the region around the contact wire I 6. As will be explained with respect to the illustrated embodiments of the translating device, the inhibiting effect of plate ISA is greater than that of I913.

The device shown in Fig. 1 with the plate [9A spaced from the conductor I 0 is particularly The high frequency energy is introduced from wave guide A suitable vides for matching of the incoming signal to the rectifier point. The capacity across the gap between plate ISA and the wall of tube l0 inhibits the escape of high frequency energy through the coaxial line including the stud 15. By making the gap small and at the outer periphery of plate 1 9A, a relatively large area capacitor is provided.

The device illustrated in Fig. 2, inwhich plate I93 is separated from the stud I5 by a gap, is adapted for the generation of harmonics at millimeter wavelengths. For example, 12% millimeter power canbe introduced along the coaxial portion of the device and the desired harmonics removed through a window by means of suitable wave guide elements. The lower capacity of the gap between plate I9B and stud I5 is here used in order to allow sufficient high frequency energy to enter the'device over the coaxial line.

The invention provides unitary point contact translating devices which may be conveniently fitted to wave guide. circuit elements for use at higher frequencies than unitary devices of this type have heretofore been capable of handling.

One way of adapting the point contact translator herein described to a wave guide system is by the fixture illustrated in Figs. 4, 5 and 6.. The translator, designated generally by 30, is clamped between two matchin portions or sections 3| and 32 of the wave guide fixture so that the windows or orifices I1 and I8 coincide withthe guide orifices in the sections 3| and 32. These sections may be made of coin silver. The slots 33 between mated sections 3| and 32 and the counterbores 34 of the opening in which the translator is clamped, assure that contacts of the sections 3| and 32 with the translating device 30 and with each other are in close proximity to the wave guide boundaries to insure good contact stability. There is thus provided a continuous guide through the translator. Since the. wave guide dimensions for the frequencies of interest are e; inch by inch, the Windows or orifices l1 and' [8 are of comparable size to fit these dimensions.

The terminating portion 3L of the waveguide is provided with an impedance matching element in the form of a tuning piston 35, which may be of any suitable configuration, for. example the U shape illustrated. The piston 35 may be adjusted by a screw 36 provided with a stop 31 and an operatin nut 38. The operating nut 38 is re-\ tained by the cap. 39 which is secured to the end of section 3| by screws in tapped orifices, one of which is, shown at,4 0 in Fig.4. These parts may also be of coin silver.

The wave guide section 32 may be provided with studs 4| and 42 which pass through suitably located borings. in section 3|. The parts 3| and 32 are clamped around the translator 30 by these studs and the nuts 43. and 44. The studs may be of steel and the nuts of brass.

A flange 45 on one end of; section comprises with suitable fastening means, such as bolts (not shown), a means for securing this section to a wave guide system.

Also provided in section 32 are impedance matching members comprising adjustable reactance screws 46 which may be employed in a suitable matching arrangement in the tapped holes 41. Since the effect of these reactance screws on the standing wave within the guide is a function of both their relative spacing and penetration of the guide, space, the provision of six holes and three screws allows for acertain amount of adjustment so that the desired matchaseae'ie 5 ing' may be obtained. Coin silver is a suitable niaterial for these screws.

By suitable adjustment of the piston 35 and the screws 46 the guided waves may be controlled so that in eiiect the translating means is located at a desired part of a wave.

Although this invention has been disclosed by means of particular illustrative embodiments thereof, it is not intended that it be limited thereby but by the scopeof the appended claims only.

What is claimed is:

1. A translating device for ultra-short wavelength electrical energy that comprises a hollow outer conductor, an insulator body having an inner conductor extending therethrough, and a conductive body, both fitted in the hollow outer conductor in spaced relation to form a cavity, a contact element and a crystal in point contact within the cavity, and secured respectively to the inner conductor and the conductive body, and a conductive member overlying the cavity face of conductive body, both fitted in the hollow outer conductor in spaced relation to form a cavity, a

contact element and a crystal in point contact within the cavity, and secured respectively to the inner conductor and the conductive body, and a conductive member overlying the cavity face of the insulator body, insulated from the outer conductor and connected to the inner con ductor, the wall of the hollow conductor being provided with an aperture opening into the cavity.

3. A translating device for ultra-short wavelength electrical energy that comprises a hollow outer conductor, an insulator body having an inner conductor extending therethrough, and a conductive body, both fitted in the hollow outer conductor in spaced relation to form a cavity, a contact element and a crystal in point contact within the cavity, and secured respectively to the inner conductor and the conductive body, and a conductive member overlying the cavity face of the insulator body, insulated from the inner conductor and in contact with the outer conductor, the wall of the hollow outer conductor being provided with an aperture opening into the cavity.

4. A translating device comprising a hollow elongated conductor, an insulating body having a central, metallic stud extending therethrough, and a conducting body, both fitted within the elongated conductor in spaced relation to form a cavity, a point contact element and a crystal, constituting a rectifier, secured respectively to the stud and conducting body within said cavity, and a metallic plate conductively secured to the stud but insulated from the hollow elongated conductor and overlying the cavity face of the insulating body, the wall of said hollow elongated conductor being provided with an aperture opening into the cavity.

5. A translating device comprising a hollow elongated conductor, an insulator body having a central, metallic stud extending therethrough, and a conducting body, both fitted within the elongated conductor in spaced relation to form a cavity, a point contact element and a crystal constituting translating means, secured respec tively to the stud and conducting body within said cavity, and a metallic plate insulated from the stud but in contact with the hollow elongated conductor and overlying the cavity face of the insulating body, the wall of said hollow elongated conductor being provided with an aperture opening into the cavity.

6. A shielded translating device comprising a hollow outer conductor, an inner conductor spaced from the outer conductor by an insulator body and a conductive body in contact with the outer conductor, the bodies cooperating with the outer conductor to define a cavity containing point contact and crystal translating elements, and a metallic shield overlying the cavity face of the insulator body and insulated from one of the outer and inner conductors whereby substantial conductor continuity of the cavity is provided.

7. A rectifier for ultra-short wave electrical energy comprisin a hollow outer conductor, an

insulator in the outer conductor, a conductive body fitted in the outer conductor in spaced relation to the insulator to form a cavity, an inner conductor supported in spaced relation to the outer conductor by the insulator, the inner and outer conductors constituting a coaxial line for the transmission of rectified electrical energy, a contact element secured to the inner conductor, a semiconductive element secured to the conductive body, the contact element being in point contact with the semiconductor element, and a metallic shield overlying the cavity face of the insulator, the shield being in contact with the inner conductor but insulated from the outer conductor, the outer conductor being provided with an aperture for introducing ultra-short wave energy into the cavity.

8; In a harmonic producer for ultra-short wave electrical energy a translating device comprising a hollow outer conductor, an insulator fitted in the outer conductor, a conductive body fitted in the outer conductor in spaced relation to the insulator to form a cavity, an inner conductor supported in spaced relation to the outer conductor by the insulator, the inner and outer conductors constituting a coaxial line for the introduction of ultra-short wave energy, a contact element secured to the inner conductor, a semiconductive element secured to the conductive body, the contact element being in point contact with the semiconductive element, and a metallic shield overlying the cavity face of the insulator, the shield being in contact with the outer conductor but insulated from the inner conductor, the outer conductor being provided with an aperture for extracting harmonics of the ultra-short wave energy from the cavity.

9. A translating device for ultra-short Wave electrical energy comprising an outer conductor, an inner conductor, an insulator supporting the inner conductor in spaced relation to the outer conductor, a contact element secured to wave energy.

-10. A'translatin device comprising a metallic tube constituting an outer conductor, an insulator block fitted in said tube, a metallic stud constituting an inner conductor, secured centrally of said tube through the insulator block and supported thereby, a metallic block fitted in said tube in spaced relation to the insulator'block and defining therewith a cavity within the tube, a semiconductive plate secured in a hollow of the metallic block with one face in a plane with the cavity face of said block, a metallic spring secured to the cavity end of said stud and in point contact with the face of the semiconductive plate, and a metallic plate on the cavityiace of the insulator block, said metallic plate being insulated from one of the inner and outerv conductors and in contact with the other, the part of said metallic tube bounding the cavity being provided with oppositely located apertures.

11. In a shielded type translating device including inner and outer coaxial conductors forming a coaxial line, an insulator for supporting the inner conductor within the outer conductor, a conductive member connected to the outer conductor and spaced from theinsulator to define a cavity within the outer conductor, and a translating means in said cavity, means for enhancing the cavity boundary discontinuity with respect to the coaxial line comprising a conductive covering on the cavity face of said insulator, said covering being in contact with one coaxial conductor and insulated from the other.

12. Translating means for ultra-short wavelength electrical energy comprising a unitary translating device and a fixture for adapting the device to a wave guide system, the translating device comprising a crystal and cooperating point contact means connected between coaxial conductors and housed Within the outer of said conductors, which is provided with oppositely located orifices, said fixture comprising two wave guide sections embracing the outer coaxial conductor to maintain the axis of the translating device in perpendicular relation to the wave guide with said orifices in register with the openings of the wave guide sections, said translating device including also conductive elements within the outer coaxial conductor cooperating therewith to form a continuation of the wave guide boundary, one surface of said crystal and said cooperating point contact being positioned within said continuation of said wave guide, and said fixture including tuning means for effectively locating the point contact means at a position of suitable impedance in the wave guide.

13. Translating means for ultra short wavelength electrical energy comprising a unitary translating device and a fixture comprising VCO" operating wave guide sections for adapting the device to a wave guide system, the translating device comprising a crystal and cooperating point contact means connected between coaxial conductors and housed within the outer of said conductors, which is provided with'orifices for communication with the wave guide, and located between spaced conductive elements that are electrically connected respectively to the outer coaxial conductor only and-to one of the coaxialconductors only, said conductive elements cooperating with theouter coaxial conductor to form a continuation of the wave guide, and said fixture including tuning means for effectively locating the point contact means at a position of suitable impedance in the wave guide.

14; Translating means for ultra-short WaVE- length electrical ,energy comprising a unitary translating device includin a crystal and cooperating point contact means connected between coaxial conductors and housed within the outer of said conductors, the outer conductor provided with orifices for effecting communication of said translating device with a wave-guide system through afixture, said fixture including two wave guide sections embracing the translating device and maintaining said device with its axis perpendicular to the wave guide, adjacent surfaces of said sections having relieved portions whereby the remaining contacting portions are limited to the region adjacent the guide boundary, thereby assuring good contact stability among the wave guide sections and the translating device,

15. A unitary translating device for connec tion to a wave guide system by means of a coopcrating fixture including mating wave guide sections between which the device is clamped, said device comprising a hollow conductive cylinder having oppositely located openings into respective wave guide sections, a crystal mounted on a conductive body fitted in said cylinder, a contact wire cooperating with the crystal and supported on a conductive stud. mounted coaxially within the cylinder by an insulating body and a conductive plate on the'surface of the insulating body and in contact with one only of the coaxial'c'on ductors', said body, plate and a portion of said cylinder providing a housing for the crystal and contact wire and a substantially continuous con} ductive wave guide boundary through the translating device.

16. A translating network for ultra-short wave energy that comprises a translating device and wave guide means for connecting and matching the translating device to a wave guide systennsaid translating device including an outer hollow con ductor having oppositely located orifices, a conductive body fitted in the hollow conductor and supporting a crystal, an insulating body fitted within the hollow conductor in spaced relation to the conductive body and supporting an inner conductor, a conductive plate onthe surface of the insulating body adjacent the conductive body, said plate being in contact with one andspaced from'the other or" the outer and inner conductors, a contact element secured to the inner confductor and cooperating with the crystal to form a translator, said conductive body, plate and the intervening portion of the outer conductor defining a cavity for the translator, said cavity having a substantially continuous conductive boundary through which the orifices allow communication with the wave guide means, said wave guide means comprising mating sections-embracing the translating device to include said cavity asa continuation of the wave guide, and tuning means for matchingthe translating device to the wave guide system.

17. Means for securing translating elements at suitable'locations in a wave-guide system that comprises a unitary translating device insert able into said system, said device comprising said elements and having an orificedconductive housing and conductive wave-guide sections in'phi ical contact with said housing, the openings of said wave-guide sections being in coincidence with the orificedportions of said housing, said device also comprising spaced conductive members defining a passage between' said orifices; said translating elements being positioned within said passage, said passage having a cross-sectional configuration substantially the" same as the cross-- 9 l0 sectional configuration of the openings of said UNITED STATES PATENTS Wave-guide sections. Number Name Date 18. Means as defined in claim 17 in which the 2 419 613 Webber Apr 29 1947 wave-guide sections comprise tuning means for 2427087 Carlson sepi; 1947 effectively locating the translating elements with 5 2427100 Kihn Sept 1947 respect to a guided Wave. 2:456:563

RUSSELL S. OHL.

REFERENCES CITED The following references are of record in the 1 0 file of this patent:

McCarthy Dec. 14, 1948

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