US2705307A - Double slug tuner - Google Patents

Description

March 29 1955 R NYSWANDER 2,705,307

DOUBLE SLUG TUNER Filed Feb. 1, 1946 FIG.|

FIG. 2

INVENTOR. R. EDSON NYSWANIDER ATTORNEY United States Patent DOUBLE SLUG TUNER R. Edson Nyswander, Denver, Colo., assignor, by mesne assignments, to the United States of America as represented by the Secretaryof the Navy Application February 1, 1946, Serial No. 644,980

4 Claims. (Cl. 333-98) This invention relates to the setting up of standing waves in a wave guide and more specifically to the use of a double slug tuner for the above purpose.

When taking megnatron performance tests, matching loads into a radio frequency line, or making cold resonance tests it is desirable that a tuning mechanism be available which is capable of making independent adjustments of the phase and magnitude of radio frequency standing waves. Heretofore the tuning devices to accomplish the foregoing purposes presented difficulties in construction and operation.

A primary object of the present invention is to provide an improved method of forming and varying the phase and magnitude of standing waves in a wave guide.

Another object of the present invention is to form standing waves in a wave guide by providing atuniug mechanism capable of making independent adjustments of the phase and magnitude of the radio frequency standing waves in the guide.

A further object is to provide a pair of dielectric slugs to be inserted in the wave guide to accomplish the above objects.

A still further object is to provide two slugs of material such as Mycalex inserted in a slot cut longitudinally in the broad dimension of the radio frequency wave guide for the purposes of the first two objects.

A still further object is to provide a mechanism for sliding the two dielectric slugs both with respect to each other and with respect to the guide.

These and other objects will be apparent from the following specification when taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of one form of the invention; and

Fig. 2 is an end view partially in section of Fig. 1 showing the construction thereof in some detail.

The invention broadly consists of a tuning assembly fitted to a longitudinal slot in a wave guide. The tuning assembly contains two dielectric slugs fitting in the .slots of the guide and extending down into the guide.

The tuning assembly also contains means for moving the slugs vertically and horizontally in the slots at the same time insuring that each slug extends the same distance into the guide.

The invention lies in the effect that the two dielectric slugs have on the phase and magnitude of standing waves in the guide. The depth to which the slugs extend into the guide determines the quantity of radio frequency energy that will be reflected by them, and thus determines the magnitude of the standing waves set up. The position of the two slugs with respect to the wave guide determines the phase of the standing waves to be formed and thus allows the maximum and minimum points of the standing wave pattern to be selected. The spacing between the two slugs determines whether the energy reflected by one will be in or out of phase with that reflected by the other and this in turn will determine the standing wave ratio.

It is well known in the art that when radio frequency energy strikes an object of a different dielectric constant than that of the medium through which it is traveling part of the energy will be reflected. It is the purpose of this invention to introduce into the wave guide two dielectric slugs 4 and of Fig. 1, in such a manner that radio frequency waves upon entering the guide will strike them and be reflected. These reflected waves will combine with the waves entering the guide to set up standing waves,

2,705,307 Patented Mar. 29, 1955 It has been determined experimentally that the conditions for maximum standing wave ratio occur when slugs 4 and 5 have a longitudinal dimension of and the spacing between the centers of slugs 4 and 5 is equal to an 4 where:

Ag is the wave length in the guide of the radio frequency energy;

K is the factor by which the wave length is shortened in the dielectric material used in the slug;

n is any integral number.

The longitudinal dimension of the slugs refers to the length of the slug in the direction of propagation of electromagnetic energy within the wave guide.

It is readily apparent that the deeper the slugs extend into the guide the greater will be the amount of energy reflected and the greater the magnitude of the standing waves.

Referring to Fig. 1 there is shown wave guide 1 with tuning assembly 2 mounted thereon. Tuning assembly 2 consists of movable slug carriage 3 with Mycalex slugs 4 and 5 mounted thereon held firmly in place by means of threadably mounted screws 6 and 7 which press firmly against slugs 4 and 5 and may be loosened to permit a vertical motion to slugs 4 and 5. Slugs 4 and 5 are held by blocks 8 and 9 with a rod 10 passing: through each block in such a manner that vertical motion of one slug is impossible without a corresponding vertical motion of the other. Block 8 is rigidly atfixed to rod 10 but block 9 holds rod 10 with a pressed fit in such a manner that block 9 is permitted to slide along rod 10. Slugs 4 and 5 are mounted on slug carriage 3 by means of blocks 11 and 12. Block 11 containing slug 4 is fixedly secured to slug carriage 3 but block 12 containing slug 5 is secured to slug carriage 3 by means of wing nut 13 which may be loosened to permit motion of block 12 and slug 5 along slot 14 of slot carriage 3. Wave guide 1 contains opening 15 through which slugs 4 and 5 enter the guide. Slug carriage 3 is connected by means of screws to blocks 16 and 17 slidably disposed on wave guide 1, being held firmly in place thereby. Slug carriage 3 is thus allowed to slide along longitudinal opening 15 of wave guide 1.

Referring to Fig. 2 the mechanism of both screw 7 for varying slug depth and wing nut 13 for varying slug spacing are shown. Slug depth screw 7 is threadably mounted on block 12 and extends therethrough pressing against slug 5. Screw 7 is capable of being rotated in such a manner as to hold slug 5 in place or if desirable to permit slug 5 freedom of motion in a vertical plane. Slug depth screw 6 operates in exactly the same manner as slug depth screw 7. Wing nut 13 is threadably mounted on screw 19 which in turn is threadably mounted on block 12 and passes through slot 14. It is readily apparent that by rotation of wing nut 13 a means is provided of either holding block 12 firmly in place or leaving it free to move along longitudinal slot 14..

In operation the invention operates to set up standing waves in guide 1. By means of screws 6 and 7, the depth of slugs 4 and 5 can be varied in the guide and this in turn will vary the magnitude of the standing waves set up. By means of wing nut 13 the distance between slugs 4 and 5 can be varied which in turn will vary the standing wave ratio. Slug carriage 3 maybe moved along slot 15 and this enables maxima and minima points of the standing waves to be positioned at any desirable point of wave guide 1.

The invention as disclosed and described applies to setting up standing waves in a wave guide but the same principle would apply to matching the impedance of a wave guide to that of a load. Also the use of dielectric or metallic sleeves in a coaxial conductor would in no way deviate from the basic principles of the present invention. Metallic rather than dielectric material might be used in the slugs allowing more critical tuning but having a lower breakdown point.

While a particular embodiment of the present invention has been disclosed and described it is to be understood that various changes and modifications may be made therein without departing from the spirit and scope thereof as set forth in the appended claims.

What is claimed is:

1. In combination with a wave guide, one broad wall of which has a longitudinal slot, means for developing standing waves in said wave guide comprising a movable carriage assembly mounted on said wave guide, a pair of dielectric slugs adjustably mounted on said carriage for insertion into said wave guide through said slot and means to adjust the relative spacing of said slugs along said slot. v

2. A device for forming standing waves in a wave guide, one broad wall of which has a longitudinal slot, comprising a carriage assembly mounted on said wave guide, a pair of rectangular dielectric slugs mounted on said carriage extending into said wave guide through said slot, said carriage including means for adjustably retaining said slugs in a predetermined spaced relationship with respect to each other and means for adjustably retaining said slugs at a predetermined depth of penetration in said wave guide.

3. A device for forming standing waves in a wave guide comprising a carriage assembly slidably mounted on said wave guide, a pair of rectangular dielectric slugs mounted on said carriage extending into said wave guide through said slot, said carriage including means for adjustably retaining said slugs in a predetermined spaced relationship with respect to each other, and means for adjustably retaining said slugs at a predetermined depth of penetration in said wave guide, the relative spacing and dimensions of said slugs being such as to form a maximum standing wave ratio in said wave guide.

4. Apparatus as in claim 3 wherein the dimension of said slugs in the direction of propagation of energy within said wave guide is equal to Khg 4 and the spacing between centers of said slugs is equal to where 1 is the wave length of said energy within said wave guide, K is the wave length modifying factor of the dielectric material of which said slug is composed, and n is any integral number.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,131 Webber June 28, 1949 2,238,438 Alford Apr. 15, 1941 2,376,785 Krasik May 22, 1945 2,407,267 Ginzton Sept. 10, 1946 2,408,745 Espley Oct. 8, 1946 2,419,208 Frantz Apr. 22, 1947 2,422,160 Woodward June 10, 1947 2,423,383 Hershberger July 1, 1947 2,427,100 Kihn Sept. 9, 1947 2,433,368 Johnson et al. Dec. 30, 1947 2,436,427 Ginzton Feb. 24, 1948 2,438,913 Hansen Apr. 6, 1948 2,465,719 Fernsler Mar. 29, 1949 2,514,678 Southworth July 11, 1950 2,544,842 Lawson Mar. 13, 1951

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