waveguide

Abstract

The present invention relates to a waveguide (1) consisting of two waveguide components (11, 12). Each waveguide component (11, 12) has a waveguide body (111, 121) and at least one waveguide channel (10) portion (110, 120), which are arranged to form at least one waveguide channel (10) when the two waveguide components (11, 12) are joined. The opposing surfaces (112, 122) of the two waveguide components (11, 12) are formed parallel to each other. A pin (2) is formed in the waveguide body (111) of the first waveguide component (11), and the pin (2) protrudes toward the second waveguide component (12). A recess (3) for accommodating the pin (2) is formed in the waveguide body (121) of the second waveguide component (12). The pin (2) and the recess (3) are arranged coaxially with each other, and the pin (2) and the recess (3) do not come into contact with each other when the waveguide (1) is joined.

Description

[Technical Field]

[0001] The present invention relates to a waveguide consisting of two joined waveguide parts. Each waveguide part has at least one portion of a waveguide channel (i.e., a portion of one waveguide channel or portions of multiple waveguide channels), in particular the upper or lower half of at least one waveguide channel. The waveguide parts are joined by, for example, welding, gluing, screwing, etc. After the waveguide parts are joined, they form at least one waveguide channel. The facing surfaces of the two waveguide parts are formed parallel to each other. [Background technology]

[0002] For example, a waveguide can be produced by forming two waveguide parts and then joining them together. Each waveguide part has a waveguide body, and at least one waveguide channel section is machined into the waveguide body by a method known per se, for example, milling or injection molding. The two waveguide parts are then joined together at their waveguide bodies to create a strong connection. During joining, the at least one waveguide channel section is aligned one above the other and combined into at least one waveguide channel. The joining can be performed by a method such as screwing, gluing, press-fitting, or welding.

[0003] At the joints, leakage of electromagnetic waves transmitted through the waveguide can occur. This is due to the interruption of the current path at the surface due to imperfect galvanic contact. From Montgomery et al., "Principles of Microwave Circuits," Stevenage: IET, 1987, it is known to divide a waveguide at a region where little, ideally no, current flows. In a rectangular waveguide, for example, this region is located in the middle of the longer side with respect to the fundamental mode. When the waveguide is divided at this region, symmetry is nearly maintained, and ideally no leakage occurs, even if there is imperfect galvanic contact between the two waveguide parts, for example, due to bonding or press-fitting.

[0004] However, this does not completely prevent leakage. Even if the waveguide design were perfectly symmetrical (which is usually not the case due to components such as bends and transistors), small imperfections and manufacturing tolerances will result in a slightly asymmetric waveguide, which will result in at least a small amount of energy leaking between the waveguide parts. However, the smaller the asymmetry, the smaller the leakage, so when the asymmetry is small enough, the leakage can be neglected in some applications.

[0005] Typically, gaps remain between the waveguide bodies. The aligned surfaces of the waveguide bodies run parallel to each other and can be considered parallel plates of a parallel-plate capacitor. Even a small amount of leakage can cause excitation of a parallel-plate mode between the parallel surfaces of the waveguide bodies of a waveguide component. As long as the amount of energy is small enough, the leakage can be ignored. However, excitation can cause resonance within the gap between two waveguide bodies of a waveguide component or between adjacent waveguide channels. Resonance can significantly increase the amount of energy in the parallel-plate mode, resulting in a reduction in the mode propagating within the waveguide. This results in increased leakage and degraded performance of the waveguide (or a waveguide antenna using a waveguide). The occurrence of resonance depends on the frequency used, as well as the geometric boundary conditions of the waveguide and the gap between the waveguide components. This can prevent the use of waveguide-related designs or require welding for joining. Summary of the Invention

[0006] The waveguide according to the present invention has a pin formed in the waveguide body of a first waveguide component. The pin protrudes toward the second waveguide component, preferably perpendicular to the surface of the first waveguide component. The pin can have various shapes, such as a cylindrical or columnar shape for a bolt, a conical shape for a conical pin, a truncated cone, a pyramidal or truncated pyramidal shape, and can have a circular, elliptical, square, rectangular, trapezoidal, or other polygonal cross section. The second waveguide component has a recess, which accommodates the pin and is preferably formed in the second waveguide component perpendicular to the surface of the second waveguide component. The recess is adapted to the pin and is preferably formed in the shape of a counter part to the pin, but can also have any other shape. The pin and recess are arranged coaxially with each other. Furthermore, the pin and recess are formed so that the pin can enter the recess without touching the recess wall when the waveguide components are joined. Therefore, a gap remains between the pin and the recess, and no galvanic contact occurs.

[0007] The pin, recess, and gap between them can be interpreted as a short coaxial line when joined. Here, the pin acts as the inner conductor, the waveguide body surrounding the recess acts as the outer conductor, and the air-filled gap between them acts as the dielectric medium. This consequently changes the geometric boundary conditions of the parallel-plate mode between the parallel surfaces of the waveguide body. The pin and recess act as a coaxial choke. By positioning and number of the pins and recesses, the resonant frequency of the waveguide body can be controlled and eliminated within the relevant frequency band. As a result, energy leakage from the waveguide is reduced.

[0008] Advantageously, the length of the pin corresponds to one-quarter of the wavelength (λ0 / 4) of the signal for which the at least one waveguide channel is designed, so that the coaxial choke consisting of the pin and recess acts as a short circuit in the first waveguide component, thereby significantly reducing the propagation of parallel plate modes.

[0009] The coaxial choke works particularly advantageously in the waveguide channel configuration described below, but can be applied in any configuration. In one embodiment, the waveguide has a bent or meandered waveguide channel surrounding a region where a resonant cavity can occur within the gap between two waveguide components. Resonance occurs when one dimension of the resonant cavity corresponds to approximately half (or a multiple of) the free-space wavelength of the signal propagating through the waveguide channel (I≈λ0 / 2). The pin is preferably located in this region of the waveguide body of the first waveguide component surrounded by the bent or meandered waveguide channel. Accordingly, the recess is similarly located in the region of the waveguide body of the second waveguide component surrounded by the bent or meandered waveguide channel. This destroys the resonant cavity and significantly reduces parallel-plate modes within the gap between the waveguide bodies. In general, any shape of waveguide surrounding such a region where a resonant cavity can occur is relevant here. Of particular interest are U-shaped waveguide channels, in which the two legs of the waveguide channel run parallel, V-shaped waveguide channels, or L-shaped waveguide channels, in which the legs are at an angle to one another.

[0010] A plurality of pins may be formed in the waveguide body of the first waveguide component, and a plurality of recesses corresponding to the pins may be formed in the waveguide body of the second waveguide component, thereby enabling selective and particularly effective suppression of parallel plate modes. Similarly, one or more pins and one or more recesses may be formed in the waveguide body of the first waveguide component, and correspondingly, one or more recesses and one or more pins may be formed in the second waveguide component.

[0011] In particular, the pins and recesses are arranged along a straight line, where the coaxial choke forms a "fence" that effectively suppresses the parallel plate mode over a certain range. When the line along which the pins and recesses are arranged runs parallel to the waveguide channel, the parallel plate mode generated perpendicular to the parallel plate mode is suppressed over the length of the waveguide channel.

[0012] In a further embodiment, the waveguide has two parallel waveguide channels. In the region of the waveguide body between the two parallel waveguide channels, a resonant cavity may form in the gap between the two waveguide components. Furthermore, unwanted energy coupling may occur between the two waveguide channels. Resonance occurs when the distance between the two parallel waveguide channels corresponds to approximately half (or a multiple of) the free-space wavelength of the signal propagating through the waveguide channels (I ≈ λ0 / 2). With this configuration, the aforementioned arrangement of pins and recesses along a straight line to form a "fence" is particularly advantageous. The straight line extends parallel to the waveguide channels and is positioned between them. Thus, a "fence" consisting of a coaxial choke is formed along the parallel waveguide channels between them. This destroys the resonant cavity and significantly reduces parallel-plate modes in the gap between the waveguide bodies. Furthermore, this prevents energy coupling between the waveguide channels through the gap.

[0013] To form an impenetrable boundary, the pins are spaced from one another by at most half a wavelength (d≦λ 0 / 2) of the signal for which the waveguide channel is designed. Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view of a waveguide joined from two waveguide sections comprising a waveguide channel. [Figure 2] 1 is a cross-sectional view of a pin and recess in a waveguide according to one embodiment of the present invention. [Figure 3] 1 is a partially transparent perspective view of an exemplary embodiment of a waveguide according to the present invention comprising a waveguide channel of a first configuration; [Figure 4] 2 is a partially transparent perspective view of a further exemplary embodiment of a waveguide according to the present invention, comprising a waveguide channel of a second configuration; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1 shows a waveguide 1 made up of two waveguide components 11, 12. The first waveguide component 11 has a waveguide body 111 in which a cutout 110 is formed, which in this example has a rectangular cross section and extends in a direction perpendicular to a cross section through the waveguide body 111. Similarly, the second waveguide component 12 has a waveguide body 121 in which a cutout 120 is formed, which in this example has the same shape as the cutout 110 of the first waveguide component 11. The waveguide bodies 111, 121 have opposing surfaces 112 and 122 outside the cutout, which surfaces 112 and 122 extend parallel to each other. To assemble the waveguide 1, the two waveguide parts 11, 12 are joined at their surfaces 112, 122. In addition to welding, adhesive bonding or screwing can also be used as joining methods. By joining, the two recesses 110, 120 come together to form the waveguide channel 10, which is formed as a rectangular hollow tube, through which an electromagnetic signal (not shown) can be transmitted. That is, the recesses 110, 120 are part of the waveguide channel 10, and can be easily formed separately in the waveguide bodies 111, 121, for example by milling or injection molding, to form the waveguide channel 10 when joined. By appropriately forming the recesses 110, 120, waveguide channels of different shapes and also multiple waveguide channels can be formed within the same waveguide 1. For this, see FIGS. 3 and 4. Upon joining, a gap 13 may occur between surfaces 112 and 122, which gap 13 is shown larger than actual scale in the drawings. Because the two surfaces 112 and 122 are parallel to each other, a parallel plate mode may form within gap 13. This results in leakage of electromagnetic energy (indicated by arrow 131) of the signal being transmitted in waveguide channel 10, thereby reducing the energy of the signal within waveguide channel 10.

[0016] In the further figures, identical components are characterized by identical reference symbols, for the description of which reference is made to the above description. 2 shows a cross section of a waveguide 1 according to the invention, configured as shown in FIG. 1. The waveguide 1 according to the invention has a pin 2, which extends perpendicularly from the surface 112 of the waveguide body 111 of the first waveguide part 11 towards the second waveguide part 12, passing through the gap 13. In the example shown here, the pin 2 has a cylindrical shape. Furthermore, the pin 2 may have a conical portion at its tip (not shown in FIG. 2, see FIG. 3). In other embodiments (not shown here), the pin 2 may have other shapes, for example with a rectangular base or another circular or polygonal base. A recess 3 is formed in the waveguide body 121 of the second waveguide 12 coaxially with the pin 2, and protrudes into the waveguide body 121 perpendicular to the surface 122 of the waveguide body 121 of the second waveguide component 12 (since the surface 122 is parallel to the surface 112 of the first waveguide component 11, it is also perpendicular to the surface 112). In this example, the recess 3 also has a cylindrical shape, with a diameter greater than the diameter of the pin 2 and a depth greater than the height h of the pin 2 (the distance of the gap 13 can typically be ignored). Therefore, after bonding, a gap remains between the pin 2 and the recess 3, and this gap does not create galvanic contact between them. The pin 2 is positioned as centrally as possible within the recess 3. The recess 3 can also have other shapes that may differ from the shape of the pin 2, as long as there is a gap between the pin 2 and the recess 3. The height h of pin 2 is one-quarter of the wavelength of the signal in the waveguide channel 10 (h=λ 0 / 4), so that a short circuit occurs at the base of pin 2 .

[0017] 3 and 4 show exemplary embodiments of a waveguide 1 according to the invention, each having a different form of waveguide channel 10. In FIG. 3, waveguide channel 10 is formed in a U-shape, with a base portion 101 and two leg portions 102, 103 extending parallel to one another. Base portion 101 and leg portions 102, 103 surround a region of waveguide body 111 on three sides. If the length I of this region of waveguide body 111 between leg portions 102, 103, i.e., the distance between leg portions 102, 103, is close to half the wavelength of the signal in waveguide channel 10 (I≈λ0 / 2), a resonant cavity may form in the enclosed region at gap 13 between parallel waveguide bodies 111 and 121, amplifying the leakage of electromagnetic energy. In other exemplary embodiments (not shown), the waveguide channel may be formed in a V- or L-shape and may similarly surround a region within which a resonant cavity may form. According to the invention, within the enclosed region, as shown with respect to Figure 2, the waveguide body 111 of the first waveguide part 11 is provided with a pin 2 and the waveguide body 121 of the second waveguide part 12 is provided with a recess 3, which are separated by a gap 4 (not shown here). The pin 2 and the recess 3 change the geometric boundary conditions, which suppress the parallel plate mode and result in no or only little leakage.

[0018] 4 shows two waveguide channels 10 and 100 extending parallel to each other. The waveguide channels surround a region of a waveguide body 111 from two opposing sides. If the length I of this region of the waveguide body 111 between the waveguide channels 10, 100, i.e., the distance between the waveguide channels 10, 100, is close to half the wavelength of the signal in one of the waveguide channels 10, 100 (I≈λ0 / 2), a resonant cavity may develop in the surrounded region in the gap 13 between the parallel waveguide bodies 111 and 121, which amplifies the leakage of electromagnetic energy. According to the present invention, within the enclosed region, as shown in FIG. 2, a plurality of pins 21-25 (here, five) are provided on the waveguide body 111 of the first waveguide component 11, and a corresponding plurality of recesses 31-35 (here, five) are provided on the waveguide body 121 of the second waveguide component 12. The pins 21-25 are arranged along a straight line G that extends parallel to the waveguide channels 10, 100 within the enclosed region. The pins 21-25 are spaced apart at equal intervals d, which corresponds to half the wavelength of the signal in the waveguide channels 10, 100 (d=λ0 / 2). Accordingly, the recesses 31-35 are also similarly arranged along this straight line G, spaced apart at equal intervals d. Thus, the pins 21-25 and the recesses 31-35 form a "fence" along the waveguide channels 10, 100, which suppresses parallel plate modes and therefore causes little or no leakage.

Claims

1. A waveguide (1) consisting of two waveguide parts (11, 12), each of which has a waveguide body (111, 121) and a portion (110, 120) of at least one waveguide channel (10), said portions (110, 120) being arranged to form said at least one waveguide channel (10) when said two waveguide parts (11, 12) are joined, and opposing surfaces (112, 122) of said two waveguide parts (11, 12) are formed parallel to one another. Pins (2, 21 to 25) are formed in the waveguide body (111) of the first waveguide part (11), the pins (2, 21 to 25) protrude toward the second waveguide part (12), recesses (3, 31 to 35) for accommodating the pins (2, 21 to 25) are formed in the waveguide body (121) of the second waveguide part (12), the pins (2, 21 to 25) and the recesses (3, 31 to 35) are arranged coaxially with each other, and the pins (2, 21 to 25) and the recesses (3, 31 to 35) do not come into contact with each other in the joined state of the waveguide (1). A waveguide (1) characterized in that

2. 2. The waveguide (1) according to claim 1, characterized in that the pins (2, 21-25) protrude from the first waveguide body (111) perpendicular to the surface (112) of the first waveguide body (111), and the recesses (3, 31-35) are formed in the second waveguide body (121) perpendicular to the surface (122) of the second waveguide body (121).

3. 3. A waveguide (1) according to claim 1 or 2, characterized in that the length of the pins (2, 21-25) corresponds to a quarter of the wavelength of the signal for which the at least one waveguide channel (10) is designed.

4. 4. The waveguide (1) according to claim 1, characterized in that in a waveguide (1) having a bent or meandered waveguide channel (101, 102, 103) surrounding a region, the pin (2) is arranged within the region of the waveguide body (111) surrounded by the bent or meandered waveguide channel (101, 102, 103).

5. The waveguide (1) according to any one of claims 1 to 4, characterized in that a plurality of pins (21 to 25) are formed in the waveguide body (111) of the first waveguide part (11), and a plurality of recesses (31 to 35) corresponding to the pins (21 to 25) are formed in the waveguide body (121) of the second waveguide part (12).

6. The waveguide (1) according to claim 5, characterized in that the plurality of pins (21-25) and the plurality of recesses (31-35) are arranged along a straight line (G).

7. The waveguide (1) according to claim 6, characterized in that the straight line (G) along which the plurality of pins (21-25) and the plurality of recesses (31-35) are arranged extends parallel to the waveguide channel (10).

8. 8. The waveguide (1) according to any one of claims 5 to 7, characterized in that in the waveguide (1) having two parallel waveguide channels (10, 100), the plurality of pins (21-25) and the plurality of recesses (31-35) are arranged along a straight line (G) extending between the waveguide channels (10, 100) and parallel to the waveguide channels (10, 100).

9. 9. A waveguide (1) according to any one of claims 5 to 8, characterized in that the pins are spaced from each other by a distance (d) of at most half a wavelength of the signal for which the waveguide channel (10) is designed.

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