Emission element, waveguide antenna and method for producing an emission element
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2024-06-17
- Publication Date
- 2026-06-17
Smart Images
Figure EP2024066804_13022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] title
[0003] From radiating element, waveguide antenna and method for producing a radiating element
[0004] The present invention relates to a radiating element for a waveguide antenna, a waveguide antenna and a method for producing a radiating element.
[0005] State of the art
[0006] In a waveguide, electromagnetic energy is transported within a metallic cavity. The waveguide can be part of a waveguide antenna. In the simplest case, a slot is formed in the waveguide, forming an interface between the inner region of the waveguide and free space, i.e., serving as a radiating element. This slot does not have to run completely parallel to the currents of the electromagnetic wave traveling through the waveguide.
[0007] Since a single slot has only a low directivity, waveguide antennas typically comprise multiple slots forming an antenna array. The simplest way to create a waveguide antenna array is to place the slots along the long side of a rectangular cross-section of the waveguide, maintaining a spacing of half a wavelength, creating a zigzag pattern relative to the center of the waveguide. This zigzag pattern ensures that all slots radiate with the same phase.
[0008] In the mass production of such waveguide antenna arrays using cost-effective processes, two metal parts can be manufactured and then joined together. The waveguide channels can be arranged vertically, leaving the narrow side free for radiation. The two parts are connected parallel to the narrow side of the waveguide, thus ensuring that the currents flowing through the waveguide are not disturbed. The two metal parts do not even need to be galvanically connected, so the conduction performance of the waveguide is barely affected.
[0009] To enable the required distance between the radiating elements, US 2020 / 203841 A1 proposes a center-fed open waveguide antenna array, wherein the feeding waveguide is connected to elements formed by two openings.
[0010] Disclosure of the invention
[0011] The invention provides a radiating element for a waveguide antenna, a waveguide antenna and a method for producing a radiating element for a waveguide antenna having the features of the independent claims.
[0012] Preferred embodiments are the subject of the respective subclaims.
[0013] According to a first aspect, the invention relates
[0014] According to a first aspect, the invention accordingly relates to a radiating element for a waveguide antenna having a first waveguide section into which an electromagnetic wave can be coupled. The first waveguide section has a first rectangular cross-section, wherein a narrow side of the first rectangular cross-section runs parallel to a first axis, wherein a wide side of the first rectangular cross-section runs parallel to a second axis, wherein the first waveguide section extends along a third axis, and wherein the first to third axes are orthogonal to one another in pairs.The radiating element comprises a second waveguide section, wherein the second waveguide section has a second rectangular cross-section, wherein a narrow side of the second rectangular cross-section runs parallel to the third axis, wherein a wide side of the second rectangular cross-section runs parallel to the first axis, and wherein the second waveguide section extends along the second axis. The radiating element further comprises a third waveguide section which extends along the second axis and adjoins the second waveguide section at a first end and has at least two rectangular openings separated by webs at a second end, wherein a dimension of the third waveguide section at the second end is larger than a dimension of the second waveguide section along the third axis.The electromagnetic wave can be fed from the first waveguide section into the second waveguide section via a slot in the second waveguide section and emitted via the openings of the third waveguide section.
[0015] According to a second aspect, the invention relates to a waveguide antenna having a plurality of radiating elements according to the first aspect and having a power splitting device which is designed to feed an electromagnetic wave into the respective first waveguide sections of the radiating elements.
[0016] According to a third aspect, the invention relates to a method for producing a radiating element for a waveguide antenna. A first waveguide section is formed into which an electromagnetic wave can be coupled, wherein the first waveguide section has a first rectangular cross-section, wherein a narrow side of the first rectangular cross-section runs parallel to a first axis, wherein a wide side of the first rectangular cross-section runs parallel to a second axis, wherein the first waveguide section extends along a third axis, and wherein the first to third axes are orthogonal to one another in pairs.A second waveguide section is formed, the second waveguide section having a second rectangular cross-section, a narrow side of the second rectangular cross-section running parallel to the third axis, a wide side of the second rectangular cross-section running parallel to the first axis, and the second waveguide section extending along the second axis. A third waveguide section is formed which extends along the second axis and adjoins the second waveguide section at a first end and has at least two rectangular openings separated by webs at a second end, a dimension of the third waveguide section at the second end being larger than a dimension of the second waveguide section along the third axis.The electromagnetic wave can be fed from the first waveguide section into the second waveguide section via a slot in the second waveguide section and can be emitted through the openings of the third waveguide section. Advantages of the invention.
[0017] By widening the third waveguide section compared to the second waveguide section and by creating a bridge between the openings, channels are formed through which the electromagnetic wave can be guided and then exit through the openings. The bridge ensures that the electromagnetic radiation does not exit predominantly at the center of the aperture, but rather through the preferably slit-shaped openings. This increases the aperture efficiency. Due to the increased aperture efficiency, the electromagnetic radiation is better focused. Thus, more radiation occurs in the central angular range and less radiation at larger angles.
[0018] , meaning the emission occurs with a larger aperture, since the radiation energy is not limited to the central region but also significantly radiates at larger angles. Thus, a larger aperture is achieved in the direction of the third axis.
[0019] The invention provides independent radiating elements which can be fed by a power splitting device and then emit electromagnetic radiation.
[0020] The emitting element comprises a first waveguide section, which serves to feed the electromagnetic radiation into a second waveguide section. The feed is made laterally into the slot in the second waveguide section, i.e., perpendicular to the emitting aperture formed by the opening of the second waveguide section. This enables a compact design of the waveguide antenna, since multiple emitting elements can be arranged adjacent to one another at a short distance.
[0021] According to one embodiment of the radiating element, a dimension of the third waveguide section with respect to the third axis increases in a funnel-shaped or horn-shaped manner along the second axis. In particular, the dimension of the third waveguide section with respect to the third axis can increase linearly, but the dimension can also increase parabolically or hyperbolically. The widening increases the aperture. Dimensions here refer to the respective lengths.
[0022] According to one embodiment of the radiating element, the third waveguide section has a cuboid structure, wherein the cross section is larger than the cross section of the second waveguide section.
[0023] According to one embodiment of the radiating element, a dimension of the second waveguide section with respect to the first axis is greater than or equal to half a wavelength of the electromagnetic wave and less than or equal to three-quarters of a wavelength of the electromagnetic wave, for a given application area, ie a given wavelength (which may be given, for example, by a radar application).
[0024] According to one embodiment of the radiating element, a dimension of the second waveguide section relative to the third axis is less than half a wavelength of the electromagnetic wave. This allows the occurrence of cross-polarization to be avoided.
[0025] According to one embodiment of the radiating element, a dimension of the webs with respect to the third axis is smaller than a dimension of the second waveguide section with respect to the third axis.
[0026] According to one embodiment of the radiating element, all side surfaces of the first waveguide section and / or the second waveguide section are planar. This enables good waveguiding.
[0027] According to one embodiment of the radiating element, the slot in the second waveguide section is offset along the third axis with respect to a center of the second waveguide section.
[0028] According to one embodiment of the method for producing a radiating element, the radiating element is composed of two parts that are connected to one another in a plane perpendicular to the second axis (i.e., parallel to a plane spanned by the first axis and the third axis). Further advantages, features, and details of the invention will become apparent from the following description, in which various exemplary embodiments are described in detail with reference to the drawings.
[0029] Short description of the drawings
[0030] They show:
[0031] Figure 1 is a schematic cross-sectional view of a waveguide antenna with radiating elements according to an embodiment of the invention;
[0032] Figure 2 is a schematic oblique top view of a radiating element according to an embodiment of the invention;
[0033] Figure 3 is a further schematic view obliquely from above of the radiating element shown in Figure 2;
[0034] Figure 4 is a diagram illustrating the dimensions of the radiating element shown in Figures 2 and 3;
[0035] Figure 5 is a schematic oblique view from below of the radiating element shown in Figures 2 to 4;
[0036] Figure 6 is a schematic exploded view of the radiating element shown in Figures 1 to 5; and
[0037] Figure 7 is a schematic plan view obliquely from above of the waveguide antenna shown in Figure 1; and
[0038] Figure 8 shows a flowchart of a method for manufacturing a radiating element for a waveguide antenna according to one embodiment of the invention. In all figures, identical or functionally identical elements and devices are provided with the same reference numerals. The numbering of method steps serves the purpose of clarity and is generally not intended to imply a specific chronological order. In particular, multiple method steps can also be performed simultaneously.
[0039] Description of the embodiments
[0040] Figure 1 shows a schematic cross-sectional view of a waveguide antenna 10 with a power splitter 8 and four radiating elements 1a-1d. The power splitter 8 includes an input 81, which is fed with an electromagnetic signal. The power of the electromagnetic signal is divided by the power splitter 8, and the four radiating elements 1a-1d are fed with respective electromagnetic signals. The amplitudes and phase relationships for the individual radiating elements 1a-1d can be adjusted by the design and dimensions of the power splitter 8.
[0041] The invention is not limited to a specific number of radiating elements la-ld.
[0042] Figure 2 shows a schematic view of a radiating element 1 obliquely from above, illustrating the housing. Figure 3 shows a further schematic view of the radiating element 1 shown in Figure 2, illustrating the waveguides. Figure 4 shows a schematic representation to explain the dimensions of the radiating element shown in Figures 2 and 3, again illustrating the waveguides. Figure 5 shows a schematic view obliquely from below of the radiating element 1 shown in Figures 2 to 4.
[0043] The emitting element 1 comprises a first waveguide section 2, into which an electromagnetic wave can be coupled. The first waveguide section 2 is cuboid-shaped and thus has a constant first rectangular cross-section, with a narrow side of the first rectangular cross-section running parallel to a first axis X, and a wide side of the first rectangular cross-section running parallel to a second axis Z. The first waveguide section extends along a third axis Y. The first to third axes X, Y, Z are orthogonal to each other in pairs.
[0044] The radiating element 1 further comprises a second waveguide section 3, wherein the second waveguide section 3 has a second rectangular cross-section. A narrow side of the second rectangular cross-section is parallel to the third axis Y. A wide side of the second rectangular cross-section is parallel to the first axis X. The second waveguide section 3 extends along the second axis Z.
[0045] The side surfaces of the first waveguide section 2 and the second waveguide section 3 are planar. The first waveguide section 2 and the second waveguide section 3 can thus be constructed in a cuboid shape.
[0046] The emitting element 1 further comprises a third waveguide section 4, which extends along the second axis Z and connects to the second waveguide section 3 at a first end. The third waveguide section 4 has two rectangular openings 41, 42 at a second end. The two openings 41, 42 are separated by a web 5. The web 5 can be cuboid-shaped.
[0047] A dimension of the third waveguide section 4 along the third axis Y is larger at the second end than a dimension of the second waveguide section 3 along the third axis Y. In the embodiment shown, the third waveguide section 4 widens from the first end to the second end. In the embodiment shown in Figures 1 to 4, a dimension of the third waveguide section 4 along the first axis X is constant. A dimension along the third axis Y widens towards the openings 41, 42 in a hom-shaped manner, e.g., parabolically.
[0048] Channels are created by the widening of the third waveguide section 4 from the first end to the second end and by the web 5. The second waveguide section 3 has a slot extending along the second axis Z and corresponding to the first rectangular cross-section. The electromagnetic wave can be fed from the first waveguide section 2 via the slot into the second waveguide section 3. The electromagnetic wave is further fed into the described channels and can finally be emitted via the openings 41, 42 of the third waveguide section 4.
[0049] The slot in the second waveguide section 3 is offset along the third axis X relative to a center of the second waveguide section 3. The slot can, for example, terminate at the edge of the second waveguide section 3.
[0050] The wide side of the first rectangular cross-section of the first waveguide section 2 has a length Hinp.
[0051] The wide side of the second rectangular cross-section of the second waveguide section 3 has a length La. The narrow side of the second rectangular cross-section of the second waveguide section 3 has a length Wa.
[0052] The cross-section of the third waveguide section 4 has a length Lap at the second end (at the openings 41, 42) along the first axis X. The cross-section of the third waveguide section 4 has a length Wap at the second end along the third axis Y. The web 5 has a width Wbrg along the third axis Y and a height Hbrg along the second axis Z. The first waveguide section 3 and the second waveguide section 4 have a total height Htotal along the second axis Z.
[0053] The dimensions mentioned as well as the shape of the waveguide sections 2, 3, 4 can be selected to suit the impedance matching.
[0054] Preferably, the dimension La of the wide side of the second rectangular cross-section of the second waveguide section 3 is greater than or equal to half a wavelength Xo of the electromagnetic wave and less than or equal to three-quarters of a wavelength Xo of the electromagnetic wave:
[0055] Xo / 2 < La < 3Xo / 4.
[0056] Preferably, the length Wa of the narrow side of the second rectangular cross-section of the second waveguide section 3 is less than half the wavelength Xo of the electromagnetic wave: Wa < Xo / 2.
[0057] Preferably, the width Wbrg of the web 5 is smaller than the length Wa of the narrow side of the second rectangular cross-section of the second waveguide section 3:
[0058] Wbrg < Wa.
[0059] Figure 6 shows a schematic exploded view of the radiating element 1. A housing of the radiating element 1 comprises a first part 6 and a second part 7, which are connected to each other centrally parallel to the first axis X and the third axis Y. The connection may not be galvanically formed.
[0060] Figure 7 shows a schematic top view of the waveguide antenna 10 shown in Figure 1.
[0061] Figure 8 shows a flow chart of a method for producing a radiating element for a waveguide antenna, in particular one of the radiating elements 1, 1a-1d described above.
[0062] In a first method step S1, a first waveguide section 2 is formed into which an electromagnetic wave can be coupled, wherein the first waveguide section 2 has a first rectangular cross-section, wherein a narrow side of the first rectangular cross-section runs parallel to a first axis X, wherein a wide side of the first rectangular cross-section runs parallel to a second axis Z, wherein the first waveguide section extends along a third axis Y, and wherein the first to third axes X, Y, Z are orthogonal to one another in pairs.
[0063] In a method step S2, a second waveguide section 3 is formed, wherein the second waveguide section 3 has a second rectangular cross-section, wherein a narrow side of the second rectangular cross-section runs parallel to the third axis Y, wherein a wide side of the second rectangular cross-section runs parallel to the first axis X, and wherein the second waveguide section 3 extends along the second axis Z. A third waveguide section 4 is formed in a method step S3, which extends along the second axis Z and adjoins the second waveguide section 3 at a first end and has at least two rectangular openings 41, 42 separated by webs 5 at a second end, wherein along the third axis Y, a dimension of the third waveguide section 4 at the second end is larger than a dimension of the second waveguide section 3.
[0064] The electromagnetic wave can be fed from the first waveguide section 2 into the second waveguide section 3 via a slot in the second waveguide section 3 and can be emitted via the openings 41, 42 of the third waveguide section 4.
Claims
Claims 1. Radiating element (1a-1d; 1) for a waveguide antenna (10), comprising: a first waveguide section (2) into which an electromagnetic wave can be coupled, wherein the first waveguide section (2) has a first rectangular cross-section, wherein a narrow side of the first rectangular cross-section runs parallel to a first axis (X), wherein a wide side of the first rectangular cross-section runs parallel to a second axis (Z), wherein the first waveguide section (2) extends along a third axis (Y), and wherein the first to third axes (X, Y, Z) are orthogonal to one another in pairs;a second waveguide section (3), wherein the second waveguide section (3) has a second rectangular cross-section, wherein a narrow side of the second rectangular cross-section runs parallel to the third axis (Y), wherein a wide side of the second rectangular cross-section runs parallel to the first axis (X), and wherein the second waveguide section (3) extends along the second axis (Z); and a third waveguide section (4) which extends along the second axis (Z) and adjoins the second waveguide section (3) at a first end and has at least two rectangular openings (41, 42) separated by webs (5) at a second end, wherein along the third axis (Y), a dimension of the third waveguide section (4) at the second end is larger than a dimension of the second waveguide section (3);wherein the electromagnetic wave can be fed from the first waveguide section (2) into the second waveguide section (3) via a slot in the second waveguide section (3) and via the openings (41, 42); of the third waveguide section (4).
2. Radiating element (1a-1d; 1) according to claim 1, wherein a dimension of the third waveguide section (4) with respect to the third axis (Y) increases in a funnel-shaped or horn-shaped manner along the second axis (Z).
3. Radiating element (la-ld; 1) according to claim 1 or 2, wherein a dimension (La) of the second waveguide section (3) with respect to the first axis (X) is greater than or equal to half a wavelength of the electromagnetic wave and less than or equal to three-quarters of a wavelength of the electromagnetic wave.
4. Radiating element (la-ld; 1) according to one of the preceding claims, wherein a dimension (Wa) of the second waveguide section (3) with respect to the third axis (Y) is less than half a wavelength of the electromagnetic wave.
5. Radiating element (la-ld; 1) according to one of the preceding claims, wherein a dimension (Wbrg) of the webs (5) with respect to the third axis (Y) is smaller than a dimension (Wa) of the second waveguide section (3) with respect to the third axis (Y).
6. Radiating element (la-ld; 1) according to one of the preceding claims, wherein all side surfaces of the first waveguide section (2) and / or the second waveguide section (3) are planar.
7. Radiating element (1a-1d; 1) according to one of the preceding claims, wherein the slot in the second waveguide section (3) is offset along the third axis (X) with respect to a center of the second waveguide section (3).
8. Waveguide antenna (10) comprising: a plurality of radiating elements (1a-1d) according to one of the preceding claims; and a power splitting device (8) which is designed to split an electromagnetic wave into the respective first waveguide sections (2) of the Radiating elements (la-ld) to be fed.
9. A method for producing a radiating element (la-ld; 1) for a waveguide antenna (10), comprising the steps: Forming (S1) a first waveguide section (2) into which an electromagnetic wave can be coupled, wherein the first waveguide section (2) has a first rectangular cross-section, wherein a narrow side of the first rectangular cross-section runs parallel to a first axis (X), wherein a wide side of the first rectangular cross-section runs parallel to a second axis (Z), wherein the first waveguide section (2) extends along a third axis (Y), and wherein the first to third axes (X, Y, Z) are orthogonal to one another in pairs; Forming (S2) a second waveguide section (3), wherein the second waveguide section (3) has a second rectangular cross-section, wherein a narrow side of the second rectangular cross-section runs parallel to the third axis (Y), wherein a wide side of the second rectangular cross-section runs parallel to the first axis (X), and wherein the second waveguide section (3) extends along the second axis (Z); and Forming (S3) a third waveguide section (4) which extends along the second axis (Z) and adjoins the second waveguide section (3) at a first end and has at least two rectangular openings (41, 42) separated by webs (5) at a second end, wherein a dimension of the third waveguide section (4) at the second end along the third axis (Y) is greater than a dimension of the second waveguide section (3); wherein the electromagnetic wave can be fed from the first waveguide section (2) into the second waveguide section (3) via a slot in the second waveguide section (3) and can be emitted via the openings (41, 42) of the third waveguide section (4).
10. The method according to claim 9, wherein the radiating element (la-ld; 1) is composed of two parts which are connected to one another in a plane perpendicular to the second axis (Z).