Waveguide

Abstract

The invention relates to a waveguide (1) consisting of two waveguide parts (11, 12). Each waveguide part (11, 12) has a wave guide body (111, 121) and a part (110, 120) of at least one waveguide channel (10), which are arranged such that they form the at least one waveguide channel (10) when the two waveguide parts (11, 12) are joined together. The opposing surfaces (112, 122) of the two waveguide parts (11, 12) are designed in parallel. A pin (2) is formed in the waveguide body (111) of the first waveguide part (11), which projects in the direction of the second waveguide part (12). A recess (3) receiving the pin (2) is formed in the waveguide body (121) of the second waveguide part (12). The pin (2) and the recess (3) are arranged coaxially relative to one another and the pin (3) and the recess (3) do not come into contact in the assembled state of the waveguide (1).

Description

[0001] Description

[0002] title

[0003] Waveguide

[0004] The present invention relates to a waveguide consisting of two waveguide parts that are joined together. Each waveguide part comprises a part of at least one waveguide channel (i.e., a part of a waveguide channel or a part of several waveguide channels), in particular an upper or lower half of the at least one waveguide channel. The waveguide parts are, for example, welded, glued, screwed, or similarly connected. After the waveguide parts are joined together, they form the at least one waveguide channel. Opposing surfaces of the two waveguide parts are parallel.

[0005] State of the art

[0006] Waveguides are manufactured, for example, by forming two waveguide parts and then joining them together. Each waveguide part has a waveguide body into which a part of at least one waveguide channel is machined using conventional methods, such as milling or injection molding. The two waveguide parts are then joined together at their waveguide bodies, thus creating a firm connection. During joining, the parts of the at least one waveguide channel are aligned one above the other and combined to form at least one waveguide channel. Joining is achieved, for example, by screwing, gluing, press-fitting, welding, or similar methods.

[0007] Leakage of electromagnetic waves carried in the waveguide can occur at the joint. This results from the interruption of current paths at the surface due to imperfect galvanic contacts. From the publication Montgomery et al.: Principles of Microwave Circuits. Stevenage: I ET, 1987, it is known that the waveguide can be split in a region where only small or ideally no currents flow. For example, in a rectangular waveguide, this region for the fundamental mode is in the middle of the longer side. If the waveguide is split in this region, the symmetry is largely maintained and ideally no leakage occurs, even if there is imperfect galvanic contact between the two waveguide sections, for example due to gluing or press-fitting.

[0008] However, even this approach cannot completely eliminate leakage. Even if the waveguide design were perfectly symmetrical, which is usually not the case due to bends and components such as transistors, small defects and manufacturing tolerances will result in a slightly asymmetric waveguide, resulting in at least a small amount of energy leaking between the waveguide sections. However, small asymmetries also lead to smaller leakages, so that if the asymmetry is small enough, depending on the application, the leakage is negligible.

[0009] A gap typically remains between the waveguide bodies. The aligned surfaces of the waveguide bodies run parallel to each other, so they can be viewed as the plates of a parallel plate capacitor. Even the smallest leakage can generate excitation of a parallel plate mode between the parallel surfaces of the waveguide bodies of the waveguide sections. As long as the amount of energy is small enough, the leakage can be neglected. However, the excitation can cause resonance within the gap between the two waveguide bodies of the waveguide sections or between adjacent waveguide channels. Resonance can drastically increase the energy amount of the parallel plate mode, which leads to a reduction in the mode propagating in the waveguide. As a result, the leakage increases and the performance of the waveguide (or of a waveguide antenna using the waveguide) is reduced.The occurrence of resonances depends on the frequency used and the geometric boundary conditions of the waveguide and the gap between the waveguide sections. This can lead to waveguide designs being unusable or requiring welding during assembly. Disclosure of the invention.

[0010] The waveguide has a pin formed in the waveguide body of a first waveguide part. The pin protrudes in the direction of the second waveguide part, preferably perpendicular to the surface of the first waveguide part. The pin can have various shapes, e.g., cylindrical or columnar as a bolt, conical as a cone, truncated cone, pyramid or truncated pyramid, and with a circular, elliptical, square, rectangular, trapezoidal, or other polygonal cross-section. A recess is provided in the second waveguide part, which receives the pin and is preferably formed therein perpendicular to the surface of the second waveguide part. The recess is adapted to the pin and is preferably designed in the form of the counterpart to the pin, but can also have any other shape. The pin and the recess are arranged coaxially to one another.In addition, the pin and the recess are shaped so that when the waveguide parts are joined, the pin can penetrate into the recess without touching its walls. Thus, a gap remains between the pin and the recess, preventing galvanic contact.

[0011] The pin, the groove, and the gap between them can be interpreted as a short coaxial line when assembled. The pin serves as the inner conductor, the waveguide body around the groove serves as the outer conductor, and the air-filled gap between them serves as the dielectric medium. As a result, the geometric boundary conditions of the parallel plate mode between the parallel surfaces of the waveguide bodies are changed. The pin and groove act as a coaxial choke. By positioning and numbering the pins and grooves, the resonant frequencies of the waveguide bodies can be controlled and removed within the relevant frequency band. As a result, energy leakage from the waveguide is reduced.

[0012] Advantageously, the length of the pin corresponds to a quarter of the wavelength (Ao / 4) of a signal for which the at least one waveguide channel is designed. As a result, the coaxial choke consisting of the pin and recess acts as a short circuit on the first waveguide section, significantly reducing the propagation of the parallel plate mode. The coaxial choke is particularly advantageous in the waveguide channel configurations described below, but can be applied to any configuration.

[0013] In one embodiment, the waveguide has a bent or kinked waveguide channel surrounding a region in which a resonant cavity can form in the gap between the two waveguide parts. Resonance forms when one dimension of the resonant cavity corresponds approximately to half the free-space wavelength (or a multiple thereof) of the signal propagating through the waveguide channel (I » Ao / 2). The pin is preferably arranged in this region of the waveguide body of the first waveguide part surrounded by the bent or kinked waveguide channel. Accordingly, the recess is also arranged in the region of the waveguide body of the second waveguide part surrounded by the bent or kinked waveguide channel. This destroys the resonant cavity and significantly reduces the parallel-plate mode in the gap between the waveguide bodies.In general, any waveguide shape surrounding such an area in which a resonant cavity can form can be relevant. The following shapes are particularly relevant: a U-shaped waveguide channel, in which the waveguide channel runs parallel along its two limbs, a V-shaped waveguide channel, or an L-shaped waveguide channel, in which the limbs are angled to each other.

[0014] It is also possible to form a plurality of pins in the waveguide body of the first waveguide part, and a plurality of recesses corresponding to the pins in the waveguide body of the second waveguide part. This allows the parallel plate modes to be selectively and particularly effectively suppressed. Similarly, one or more pins and one or more recesses can be formed in the waveguide body of the first waveguide part, and correspondingly, one or more recesses and one or more pins can be formed in the second waveguide part.

[0015] In particular, the multiple pins and multiple recesses are arranged along a straight line. The coaxial chokes then form a "fence" that effectively suppresses the parallel plate mode over a certain area. If the straight line along which the multiple pins and multiple recesses are arranged runs parallel to a waveguide channel, the parallel plate mode perpendicular to the parallel plate mode is suppressed over the length of the waveguide channel.

[0016] 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 can form in the gap between the two waveguide parts. In addition, unwanted energy coupling can occur between the two waveguide channels. Resonance forms when the distance between the two parallel waveguide channels corresponds approximately to half the free-space wavelength (or a multiple thereof) of the signal propagating through the waveguide channel (I » Ao / 2). For this embodiment, the above-described arrangement of the pins and recesses along a straight line, so that they form a "fence," is particularly advantageous. The straight line runs parallel to the waveguide channels and is arranged between the waveguide channels.The "fence" of coaxial chokes is thus formed along the parallel waveguide channels between them. This destroys the resonant cavity and significantly reduces the parallel plate mode in the gap between the waveguide bodies. Furthermore, this prevents energy coupling between the waveguide channels across the gap.

[0017] In order to form an impenetrable boundary, the plurality of pins are spaced apart from each other by at most half the wavelength (d < Ao / 2) of a signal for which the waveguide channel is designed.

[0018] Short description of the drawings

[0019] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

[0020] Figure 1 shows a sectional view of a waveguide assembled from two waveguide parts with a waveguide channel.

[0021] Figure 2 shows a sectional view of a pin and a recess in the waveguide according to one embodiment of the invention. Figure 3 shows a partially transparent isometric view of an embodiment of the waveguide according to the invention with a first configuration of a waveguide channel.

[0022] Figure 4 shows a partially transparent isometric view of another embodiment of the waveguide according to the invention with a second configuration of a waveguide channel.

[0023] Embodiments of the invention

[0024] Figure 1 shows a waveguide 1 consisting of two waveguide parts 11, 12. The first waveguide part 11 has a waveguide body 111 in which a recess 110 is formed, which in this example has a rectangular cross-section and extends in the direction perpendicular to the cross-section through the waveguide body 111. Similarly, the second waveguide part 12 has a waveguide body 121 in which a recess 120 is formed, which in this example has the same shape as the aforementioned recess 110 of the first waveguide part 11. Outside the recesses, the waveguide bodies 111, 121 have opposing surfaces 112 and 122 that run parallel to each other. For assembly of the waveguide 1, the two waveguide parts

[0025] II, 12 are joined together at these surfaces 112 and 122. In addition to welding, gluing or screwing can be used as joining methods. By joining, the two recesses 110 and 120 together form a waveguide channel 10 designed as a rectangular waveguide, in which electromagnetic signals (not shown here) can be guided. This means that the recesses 110, 120 are parts of the waveguide channel 10, which, when separated, can be easily integrated into the waveguide bodies, for example, by milling or injection molding.

[0026] III, 121 can be formed and, when joined together, form the waveguide channel 10. By means of appropriately designed recesses 110, 120, different shapes of waveguide channels and also multiple waveguide channels can be formed in the same waveguide 1. Reference is made to Figures 3 and 4 for this purpose. During joining, a gap 13 can arise between the surfaces 112 and 122, which is shown disproportionately large in the present figures. Since the two surfaces 112 and 122 are parallel to one another, a parallel plate mode can form in the gap 13. This leads to a leakage, represented by the arrows 131, of electromagnetic energy of the signals guided in the waveguide channel 10, whereby the energy of the signal in the waveguide channel 10 decreases.

[0027] In the other figures, identical components are identified by identical reference numerals and reference is made to the above description for an explanation thereof.

[0028] Figure 2 shows a section of the waveguide 1 according to the invention, which is constructed as shown in Figure 1. The waveguide 1 according to the invention has a pin 2 that extends perpendicularly from the surface 112 of the waveguide body 111 of the first waveguide part 11 in the direction of the second waveguide part 12 and penetrates the gap 13. In the examples shown here, the pin 2 has a cylindrical shape. In addition, the pin

[0029] 2 have a cone at its tip (not shown in Figure 2; see Figure 3). In other embodiments not shown here, the pin 2 can also take on other shapes, for example with a rectangular base or another round or polygonal base. Coaxial with this pin 2, a recess 3 is formed in the waveguide body 121 of the second waveguide 12, which recess projects into the waveguide body 121 perpendicular to the surface 122 of the waveguide body 121 of the second waveguide part 12 (and, since this surface 122 is parallel to the surface 112 of the first waveguide part 11, also perpendicular to this). In this example, the recess 3 also has a cylindrical shape, the diameter of which is larger than the diameter of the pin 2 and the depth of which is greater than the height h of the pin 2 (the distance of the gap 13 can typically be neglected).Thus, after assembly, a gap remains between pin 2 and recess 3, and no galvanic contact is formed between the two. Pin 2 is positioned as centrally as possible within recess 3. Recess 3 can also take on other shapes, which may also differ from the shape of pin 2, as long as a gap remains between pin 2 and the recess.

[0030] 3. The height h of the pin 2 is one-quarter of the wavelength (h = Ao / 4) of the signal in the waveguide channel 10, so that a short circuit occurs at the base of the pin 2. Figures 3 and 4 each show exemplary embodiments of the waveguide 1 according to the invention with different configurations of the waveguide channel 10.

[0031] In Figure 3, the waveguide channel 10 is U-shaped and has a base section 101 and two parallel leg sections 102, 103. The base section 101 and the leg sections 102 and 103 surround a region of the waveguide body 111 on three sides. If the length I of this region of the waveguide body 111 between the leg sections 102, 103, i.e. the distance between the leg sections 102, 103, is close to half the wavelength of the signal in the waveguide channel 10 (I » Ao / 2), a resonant cavity can form in the gap 13 between the parallel waveguide bodies 111 and 121 in the surrounding region, which amplifies the leakage of the electromagnetic energy. In other embodiments not shown, the waveguide channel may be V-shaped or L-shaped and may also surround an area in which a resonant cavity may form.According to the invention, a pin 2 in the waveguide body 111 of the first waveguide part 11 and a recess 3 in the waveguide body 121 of the second waveguide part 12 are provided in the surrounding area, which are separated by a gap 4 (not shown here), as shown with reference to Figure 2. The pin 2 and the recess 3 change the geometric boundary conditions so that the parallel plate mode is suppressed and no or only minimal leakage occurs.

[0032] Figure 4 shows two waveguide channels 10 and 100 that run parallel to each other. The waveguide channels enclose a region of the waveguide body 111 from two opposite 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 » Ao / 2), a resonant cavity can form in the gap 13 between the parallel waveguide bodies 111 and 121 in the surrounding area, which amplifies the leakage of electromagnetic energy. According to the invention, a plurality of pins (here five) 21 to 25 are provided in the waveguide body 111 of the first waveguide part 11 and correspondingly a plurality of recesses (here five) 31 to 35 are provided in the waveguide body 121 of the second waveguide part 12 in the surrounding area, as shown with reference to Figure 2.The plurality of pins 21 to 25 are arranged along a straight line G that runs parallel to the waveguide channels 10, 100 in the surrounding area. The plurality of pins 21 to 25 are each arranged at the same distance d, which corresponds to half the wavelength of the signal in the.

[0033] Waveguide channels 10, 100 (d = Ao / 2). Accordingly, the recesses 31 to 35 are also arranged along this straight line G and at the same distance d. The pins 21 to 25 and the recesses 31 to 35 thus form a "fence" along the waveguide channels 10, 100, which suppresses the parallel plate mode and thus results in little or no leakage.

Claims

Claims 1. Waveguide (1) consisting of two waveguide parts (11, 12), each waveguide part (11, 12) having a waveguide body (111, 121) and a part (110, 120) of at least one waveguide channel (10), which are arranged to form the at least one waveguide channel (10) when the two waveguide parts (11, 12) are joined together, the opposing surfaces (112, 122) of the two waveguide parts (11, 12) being parallel, characterized in that a pin (2, 21-25) is formed in the waveguide body (111) of the first waveguide part (11), which protrudes in the direction of the second waveguide part (12), and in that a recess (3, 31-35) receiving the pin (2, 21-25) is formed in the waveguide body (121) of the second waveguide part (12). wherein the pin (2, 21-25) and the recess (3, 31-35) are arranged coaxially to each other and the pin (2, 21-25) and the recess (3,31-35) when the waveguide (1) is assembled.

2. Waveguide (1) according to claim 1, characterized in that the pin (2, 21-25) protrudes from the first waveguide body (111) perpendicular to the surface (112) of the latter and in that the recess (3, 31-35) is formed in the second waveguide body (121) perpendicular to the surface (122) of the latter.

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

4. Waveguide (1) according to one of the preceding claims, wherein the waveguide has a bent or kinked waveguide channel (101, 102, 103) surrounding a region, characterized in that the pin (2) is arranged in the region of the waveguide body (111) surrounded by the bent or kinked waveguide channel (101, 102, 103). Waveguide (1) according to one of the preceding claims, characterized in that a plurality of pins (21-25) are formed in the waveguide body (111) of the first waveguide part (11), and a plurality of depressions (31-35) corresponding to the pins (21-25) are formed in the waveguide body (121) of the second waveguide part (12). Waveguide (1) according to claim 5, characterized in that the plurality of pins (21-25) and the plurality of depressions (31-35) are arranged along a straight line (G). 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 depressions (31-35) are arranged runs parallel to a waveguide channel (10).Waveguide (1) according to one of claims 5 to 7, wherein the waveguide (1) has two parallel waveguide channels (10, 100), characterized in that the plurality of pins (21-25) and the plurality of recesses (31-35) are arranged along a straight line (G) that runs parallel to the waveguide channels (10, 100) between the waveguide channels (10, 100). Waveguide (1) according to one of claims 5 to 8, characterized in that the plurality of pins are spaced apart by a distance (d) of at most half the wavelength of a signal for which the waveguide channel (10) is designed.

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