US2788497A

US2788497A - Ridged waveguide matching device

Info

Publication number: US2788497A
Application number: US229034A
Authority: US
Inventors: Thaddeus A Osial; Jr Clyde E Vogeley
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1951-05-31
Filing date: 1951-05-31
Publication date: 1957-04-09
Anticipated expiration: 1974-04-09

Description

April 1957 T.'A. OSIAL ET AL 2,788,497

RIDGED WAVEGUIDE MATCHING DEVICE Filed May 31, 1951 2 Shets-Sheet l WITNESSES: INVENTORS Thdddeus A. Osiol undl @Tm 1W Clyde E. Vogeley Jr.

April '9, 1957 T. A. OSIAL ET AL 2,788,497

RIDGED WAVEGUIDE MATCHING DEVICE Filed May 31, 1951 2 Shee't-Sheet 2 WITNESSES: INVENTORS Thaddeus A. Osial and Q4 Clyde E. Vogeley Jr.

ATTORNEY United States Patent RIDGED WAVEGUIDE MATCHING DEVICE Thaddeus A. Osial, Pittsburgh, and Clyde E. Vogeley, Jr., Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 31, 1951, Serial No. 229,034

9 Claims. (Cl. 333-83) Our invention relates to waveguides, and more particu larly to a ridged waveguide mixer, detector and modulating section. In accordance with the prior art, of which we are aware, several types of apparatus for conducting high-frequency, electromagnetic oscillations have been developed. The most common of these is the standard or rectangular waveguide which comprises, in essence, a hollow conductor having substantially a rectangular cross section. It has been found, however, that, the standard waveguide has several disadvantages, such as large space requirements, which may be overcome by the use of what is known in the art as a ridged waveguide. The ridged waveguide is substantially a rectangular waveguide with a substantially rectangular re'-entrant portion extending thereinto.

The ridged waveguide is substantially smaller for the same cut-off frequency than is the standard waveguide. it is, therefore, desirable in many microwave circuits to employ a ridged waveguide in preference to a standard waveguide. However, most of the waveguide circuit elements which have been developed are adaptable only for standard waveguides and not for ridged waveguides, due to the discontinuities produced when. a ridged. waveguide is attached to such elements. This necessitates the use of a transition section between the standard waveguides. and ridged waveguides.

It is, therefore, an object of our invention to provide an improved ridged waveguide matching device.

Another object of our invention is to provide a, matching device which can be utilized as a transition section between a standard waveguide and a ridged waveguide.

Still another object of our invention is to provide an improved modulator for microwave oscillations.

A further object of our invention is to provide a modulating and matching device which may be employed as a transition section, and

A still further object of our invention is to provide a simple detector for microwaves which also acts as a matching element and which may be connected to either standard waveguides or to ridged waveguides.

The novel features which we consider characteristic of our invention are set forth with more particularity in the appended claims. The invention, however, with respect to both the organization and the operation thereof, together with other objects and advantages may be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Figure 1 is a cross-sectional showing of a ridged waveguide as employed in one embodiment of our invention;

Fig. 2 is a plan view of apparatus embodying our in vention;

Fig. 3 is a showing, partly in section, of a matching section built in accordance with our invention;

Fig. 4 is a showing in perspective of a matching and detector section built in accordance with one embodiment of our invention; and

Fig. 5 is a showing in cross-section of a mixer detector 2,788,497 iatented. Apr. 9, 1957 and/ or modulating section built in accordance with one embodiment of our invention.

Inaccordance with our invention, we provide an outer cylinder 6 of electrically conducting material. Attached to the outer cylinder 6. and located inside the outer cylinder 6 is a stationary end piece 8 of conducting material which substantially fills the outer cylinder 6 at one part along its length and is fastened to the cylinder 6 so as to be stationary with respect thereto. A post 10 is provided which is electrically conducting material and which extends through the center of the outer cylinder. 6 parallel to the walls thereof. Connected to the post 10, so as to be movable with respect thereto, is a movable wall 12 filling one end of the outer cylinder, so as to form, in connection with the outer cylinder 6, the post 10, and the stationary wall 8, a cylindrical chamber 14. Extending into the chamber 1 through the stationary wall 8 is an inner cylinder 16 which surrounds the post 10 but which is separated by a substantial distance from the post 10 and from the inner wall of the outer cylinder 6.. The in: nor cylinder 16 is fastened to the post it), so that the distance which the inner cylinder extends into the cavity may be adjusted by rotating the inner cylinder 16 with respect to the post 10. The post it} is attached to the outer cylinder 6 so that it is stationary with respect thereto A region is thus formed between the inner cylinder 16, the outer cylinder 6, the stationary wall 8, the movable wall 12 and the post iii which is substantially a toroidal ridged waveguide, the dimensions of which may be varied as'desired. In the preferred embodiment of our invention the width of the toroidal ridged waveguide is substantially the sameas thewidth of a ridged waveguide designed to operate at the same frequencies as the toroidal ridged waveguide.

Connected through a portion. of the outer cylinder 6 is a ridged waveguide 18 providing a path into the chamber 14 through which electromagnetic oscillations may be either supplied to the chamber 14 or derived from the chamber 14. In the embodiment shown in Fig. 3 there is a standard waveguide 26 connected through the Wall of the chamber 14 at another point and connected to the chamber 14 so that it may either supply oscillations to the chamber 14 or derive oscillations from the chamber 14. We thus have a matching section for matching the impedances between a ridged waveguide 18 and a standard waveguide 20. While we have shown a standard waveguide and a ridged waveguide, it is, of course, in the embodiment shown in Fig. 3 within the scope of our invention to employ two ridged waveguides with such a matching device.

By the terms cylinder and cylindrical as used herein we do not mean to limit the apparatus to a circular cross section or to a constant dimension cross section since such variations are obvious to one skilled in the art.

In accordance with anot er embodiment of our inventien, as is shown in Fig. 5, the center post 19 extending through the matching cavity may include a section of a dielectric material 22, such as polystyrene, instead of being constructed entirely of an electrically conducting material as described previously. Inside the dielectric material 22 is a chamber 24 designed to enclose a crystal 26. The crystal 26 may be of several types which are well known in the art, such as a germanium diode. The primary requirement for the crystal 2.6 when it is employed to modulate the signal passing through the region 14 is that the impedance which it ofiers to electromagnetic oscillations must be a function of the potential impressed across it. One end of the crystal 26 is connected to the metallic part of the post 10 so as. to be effectively grounded thereto. The other end of; thecrystal 26, opposite to that end which is grounded, is insulated from the waveguide by a terminal support dielectric 28, but has attached thereto a terminal 30 for connecting a source of modulating signal if the apparatus is to be used as a modulator or for connecting apparatus for deriving energy from the crystal if it is to be used as a detector. A small doubly threaded cylinder 32 is provided for holding the terminal 30 in electrical contact with the crystal 26. The doubly threaded cylinder 32 engages a section of the polystyrene 22 and is thereby held in position. Between the modulating terminal 34 and the crystal 26 is shown a hemispherical resilient piece 34 of conducting material, such as a phosphor bronze. The hemispherical piece 34 is connected to one end of the crystal 26 and provides a contact between the crystal 26 and the modulating terminal 30 which serves to prevent undue stress on the crystal due to excessive tightening of the modulating terminal support assembly 36.

The movable wall 12 forming the modulating cavity 14 is threaded to engage the doubly threaded cylinder which in turn is engaged with the polystyrene 22. The movable wall 12 is thus held in place and is freely adjustable by rotation, such as by turning by an operator.

Surrounding the modulating terminal 30 is a halfwave choke 33 comprising a cylinder 36 and a dielectric 28 to prevent high frequency oscillations in the polystyrene 22 from being dissipated by escaping to the outside. The choke 38 comprising the cylinder 36 and the dielectric 28 is of a type which is well known to one skilled in the art.

We have thus shown an apparatus, the impedance of which may be varied so as to readily match its impedance to the impedance of waveguides connected thereto. In addition, by applying a modulating potential across the crystal 26, oscillations passing through the cavity 14 may be amplitude modulated. Also, by connecting means for deriving energy from the crystal, such as an amplifier, the apparatus may be used as a detector. We thus have a simple apparatus which is capable of performing the functions of a mixer, a detector, or a modulator.

While we have described the apparatus embodying our invention as having only one conductor for supplying high frequency oscillations thereto, nevertheless, it is understood that a plurality of input channels might be employed in accordance with the broader aspects of our invention.

Although we have shown and described specific embodiments of our invention, we are aware that other modifications thereof are possible. Our invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and the spirit of the invention.

We claim as our invention:

1. A ridged rectangular waveguide matching device constructed of electrical conducting material comprising: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, a post extending through said chamber; a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in conjunction with said post and said wall means of said chamber a toroidal ridged waveguide, connections for supplying electromagnetic oscillations to said chamber, and connections for deriving electromagnetic oscillations from said chamber.

2. In combination: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, said wall means being comprised of electrically conducting material; a post extending through said chamher; a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in conjunction with said post and said wall means of said chamber a toroidal ridged waveguide; and a ridged rectangular waveguide extending through said side wall means of said chamber for supplying energy to said toroidal ridged waveguide.

3. A microwave matching apparatus comprising end wall means and side wall means, said wall means comprising a hollow chamber, said wall means being comprised of electrically conducting material, a post extending through said chamber, a hollow non-apertnred cylinder extending through said chamber so as to surround a portion of said post, said cylinder being separated from said post and said side wall means of said chamber by a substantial distance over a portion of its length in said chamber, a ridged rectangular waveguide connected to said chamber through one part of said side wall means, and a standard waveguide connected to said chamber through another portion of said side wall means.

4. A ridged rectangular waveguide matching device constructed of electrical conducting material comprising: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, one of said Wall means being adjustable to vary the size of said chamber; a post extending through said chamber; a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in conjunction with said post and said wall means of said chamber a ridged rectangular waveguide, connections for supplying electromagnetic oscillations to said chamber and connections for deriving electromagnetic oscillations from said chamber.

5. In combination: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, said wall means being comprised of electrically conducting material; a post extending through said chamber; a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in conjunction with said post and said wall means of said chamber, a toroidal ridged waveguide; said ridge member being adjustable to vary the distance which said ridged member extends into said chamber; and a ridged rectangular Waveguide extending through said side wall means of said chamber for supplying energy to said toroidal ridged waveguide.

6. A ridged rectangular waveguide matching device constructed of electrical conducting material comprising: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, a post extending through said chamber; a portion of the post Within the cavity comprising a hollow dielectric member having therein a crystal diode, opposite ends of said diode being electrically connected to said end wall means at the frequency of electromagnetic oscillations, a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post so as to form in conjunction with said post and said wall means of said chamber a toroidal ridged waveguide, connections for supplying electromagnetic oscillations to said chamber and connections for deriving electromagnetic oscillations from said chamber.

7. A ridged rectangular waveguide matching device constructed of electrical conducting material comprising: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, a post extending through said chamber; a portion of the post within the cavity comprising a hollow dielectric member having therein a crystal diode, opposite ends of said diode being electrically connected to said end wall means at the frequency of electromagnetic oscillations, a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in conjunction with said post and said wall means of said chamber a toroidal ridged waveguide, connections for supplying electromagnetic oscillations to said chamber and connections for deriving electromagnetic oscillations from said chamber.

8. A ridged rectangular waveguide matching device constructed of electrical conducting material comprising: end wall means and side wall means, said wall means defining a hollow cylindrical chamber, a post extending through said chamber, a ridge member extending into said chamber and surrounding said post a substantial distance from said post and from said side wall means of said chamber opposite said post, so as to form in con junction with said post and said wall means of said chambet a toroidal ridged waveguide, means for adjusting the distance which said ridge member extends into chamber, means for moving at least a portion of said end wall means of said chamber where-by to vary the size of said chamber, connections for supplying electromagnetic oscillations to said chamber, connections for deriving electromagnetic oscillations from said chamber, a portion of the post Within the cavity comprising a hollow dielectric member having therein a crystal diode, opposite ends of said diode being electrically connected to said end Wall means at the frequency of said electromagnetic oscillations.

9. Apparatus substantially as claimed in claim 8 wherein a resilient conductor is electrically connected to one of said ends of said crystal diode.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES 'lyrrell: Hybrid Circuits for Microwaves, Proceeding of the I. R. E., November 1947, pp. l2941306.

Regan: Microwave Transmission Circuits, vol. 9, M. I. T. Rad. Lab. Series, McGraw-Hill, 1948, pages 358-61.