Waveguide antenna, radar device and method for manufacturing a waveguide antenna

Abstract

A waveguide antenna comprises a multitude of waveguide channels. Each waveguide channel is formed by lateral wall structures and is designed to couple an electromagnetic wave from an open output region of the waveguide channel. A surrounding air groove is formed in an outer area of ​​the lateral wall structures for each waveguide channel. Air grooves of adjacent waveguide channels share a common air groove section.

Description

[0001] The present invention relates to a waveguide antenna, a radar device and a method for manufacturing a waveguide antenna. State of the art

[0002] Radar systems generate and transmit electromagnetic radar radiation, and the radar radiation reflected from objects is then detected. Waveguide technology is increasingly replacing printed circuit board technology with microstrip lines in the automotive industry. Waveguide technology is characterized by advantageous antenna properties and lower costs.

[0003] An exemplary high-frequency element arrangement with a waveguide is known from DE 10 2009 009317 A1. In this high-frequency element arrangement, an air structure is arranged near the waveguide in a mounting area between two high-frequency elements attached to one another.

[0004] Waveguide antennas can be implemented as a separate component and connected to the radar signal generation unit via an interface. Particular attention must be paid to the high-frequency power and placement tolerances. Disclosure of the invention

[0005] The invention provides a waveguide antenna, a radar device and a method for manufacturing a waveguide antenna with the features of the independent patent claims.

[0006] Preferred embodiments are the subject of the respective dependent claims.

[0007] According to a first aspect, the invention relates to a waveguide antenna with a plurality of waveguide channels. Each waveguide channel is formed by lateral wall structures and is designed to couple an electromagnetic wave from an open output region of the waveguide channel. For each waveguide channel, a surrounding air groove is formed in an exterior area of ​​the lateral wall structures. Air grooves of adjacent waveguide channels share a common air groove section.

[0008] According to a second aspect, the invention relates to a radar device with a waveguide antenna according to the first aspect and with a radar signal generation device which generates a radar signal and couples it into the waveguide channels of the waveguide antenna.

[0009] According to a third aspect, the invention relates to a method for manufacturing a waveguide antenna. A plurality of waveguide channels are formed, each waveguide channel being formed by lateral wall structures and configured to couple an electromagnetic wave out of an open output region of the waveguide channel. Air grooves are formed, with a surrounding air groove being formed for each waveguide channel in an exterior area of ​​the lateral wall structures. Air grooves of adjacent waveguide channels share a common air groove section. Advantages of the invention

[0010] The invention provides a waveguide antenna that is very compact because adjacent waveguide channels share a common air groove section. The waveguide antenna is multi-channel, meaning it can process multiple high-frequency channels.

[0011] According to one embodiment of the waveguide antenna, a plurality of notches are provided in the lateral wall structures of each waveguide channel in the region of the waveguide channel's exit area. These notches form stubs, which reduce resonances that can occur between interconnected parallel plates. This reduces such resonances in the interface between the waveguide antenna and the radar signal generation unit. A corresponding radar device thus exhibits good electrical characteristics with respect to return loss, insertion loss, and crosstalk between channels. Furthermore, it is robust because the positioning tolerances are relatively large without any degradation of the electrical properties.

[0012] According to one embodiment of the waveguide antenna, the air groove has a depth of approximately one-quarter of a wavelength λ of the coupled electromagnetic wave. Preferably, the depth lies between 0.2 · λ and 0.3 · λ. This prevents crosstalk, since the high impedance of the air groove prevents it from propagating the electromagnetic wave to adjacent waveguide channels.

[0013] According to one embodiment of the waveguide antenna, the notches of adjacent waveguide channels are arranged parallel to each other.

[0014] According to one embodiment of the waveguide antenna, each waveguide channel has a substantially rectangular cross-section. The waveguide channel is formed by four lateral wall structures, each of which has a notch. The notches can, for example, be located centrally in each lateral wall structure.

[0015] According to one embodiment of the waveguide antenna, the air groove has a double-ridge structure. This allows unwanted modes to be suppressed more effectively.

[0016] According to one embodiment of the waveguide antenna, each waveguide channel has a substantially circular cross-section. The waveguide channel can also have other cross-sections.

[0017] According to one embodiment, the radar device has a printed circuit board, wherein the waveguide antenna is arranged on a first surface of the printed circuit board, and wherein the radar signal generation device is arranged on a second surface of the printed circuit board.

[0018] According to one embodiment of the radar device, the radar signal generation unit is designed as a system-on-chip.

[0019] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawings. Brief description of the drawings

[0020] They show: Fig. 1 a schematic cross-sectional view of a radar device according to an embodiment of the invention; Fig. 2 a schematic oblique view of a waveguide antenna according to an embodiment of the invention; Fig. 3 a schematic top view of the waveguide antenna according to Fig. 2; Fig. 4 a schematic top view of a waveguide antenna according to a further embodiment of the invention; and Fig. 5 a flowchart of a method for manufacturing a waveguide antenna according to an embodiment of the invention.

[0021] In all figures, identical or functionally equivalent elements and devices are designated with the same reference numerals. The numbering of process steps serves for clarity and generally does not imply a specific chronological order. In particular, several process steps can be performed simultaneously. Description of the embodiments

[0022] Fig. Figure 1 shows a schematic cross-sectional view of a radar device 10 comprising a waveguide antenna 1, a printed circuit board 2, and a radar signal generation unit 3. The waveguide antenna 1 is arranged on a first surface of the printed circuit board 2. The radar signal generation unit 3 is arranged on a second surface of the printed circuit board 2. The printed circuit board 2 thus serves as an interface element between the waveguide antenna 1 and the radar signal generation unit 3.

[0023] The radar signal generation unit 3 generates a radar signal and couples the radar signal into the waveguide channels 11-13 of the waveguide antenna 1. The radar signal generation unit 3 comprises launcher pads 31-33, each of which couples a radar signal into a corresponding waveguide channel 11-13.

[0024] The radar signal generation unit 3 can be designed as a system-on-chip. The launcher pads 31-33 can be integrated into the system-on-chip (launcher-in-package, LiP).

[0025] The waveguide antenna 1 is arranged in an interface area 4 on the circuit board 2. Slight misalignment in the vertical and / or horizontal direction can cause parallel plate modes, i.e., waves that propagate parallel between the circuit board 2 and the waveguide antenna 1. Furthermore, crosstalk can occur between adjacent waveguide channels 11-13. Finally, reflections can occur if the electromagnetic wave is reflected in the interface area 4.

[0026] The waveguide antenna 1 can in particular correspond to one of the embodiments described in the following Fig. Figures 2 to 4 illustrate the effects mentioned above, which are reduced by the appropriately chosen design described below.

[0027] Fig. Figure 2 shows a schematic oblique view of a waveguide antenna 1a. Fig. Figure 3 shows a schematic top view of the in Fig. 2 illustrated waveguide antenna 1a.

[0028] The waveguide antenna 1a has a plurality of waveguide channels 11-14, the invention being not limited to the illustrated number of four waveguide channels 11-14. Each waveguide channel 11-14 is formed by lateral wall structures and is designed to couple an electromagnetic wave out of an open output region of the waveguide channel 11-14. The wave can be coupled in through the launcher pads 31-33 described above.

[0029] In the embodiment shown, each waveguide channel 11-14 has a rectangular cross-section and is formed by four lateral wall structures which are connected to each other in rounded corner areas.

[0030] According to other embodiments, the waveguide channel 11-14 can also have other cross-sections.

[0031] In the Fig. 2 and in Fig. In the 3 shown embodiments, the rectangular cross-sections of adjacent waveguide channels 11-14 are each rotated by 90 degrees relative to each other and thereby emit orthogonal modes.

[0032] For each waveguide channel 11-14, a surrounding air groove 15a is formed in an exterior area of ​​the lateral wall structures, i.e., a surrounding exposed channel. The air grooves 15a of adjacent waveguide channels 11-14 share a common air groove section 151a-153a.

[0033] Thus, a first common air groove section 151a is provided between the first waveguide channel 11 and the second waveguide channel 12, a second common air groove section 152a is provided between the second waveguide channel 12 and the third waveguide channel 13, and a third common air groove section 153a is provided between the third waveguide channel 13 and the fourth waveguide channel 14.

[0034] The common air groove section 151a-153a can have the same thickness as the remaining sections of the air groove 15a. According to other embodiments, the thickness of the common air groove sections 151a-153a can also be chosen to be larger or smaller.

[0035] Due to the common air groove section 151a-153a, the air groove 15 can therefore be continuously fluidically connected.

[0036] The air groove 15a has a depth of approximately one quarter of a wavelength λ of the coupled electromagnetic wave (i.e., the radar radiation of the radar device 10). Preferably, the depth of the air groove 15a is between 0.2 · λ and 0.3 · λ.

[0037] The width of the air groove 15a can, for example, correspond to one eighth of the wavelength λ.

[0038] Furthermore, for each waveguide channel 11-14, in the area of ​​the exit region of the waveguide channel 11-14, a notch 111-114, 121-124, 131-134, 141-144 is provided in each of the four lateral wall structures. The notches 111-114, 121-124, 131-134, 141-144 of adjacent waveguide channels 11-14 are arranged parallel to each other.

[0039] The notches 111-114, 121-124, 131-134, 141-144 can be designed as arc-shaped recesses. They prevent resonances between the waveguide antenna 1a and the radar signal generation unit 3. The depth of the notches 111-114, 121-124, 131-134, 141-144 is relatively small, approximately less than one-eighth or less than one-tenth of the wavelength λ of the coupled electromagnetic wave.

[0040] Fig. Figure 4 shows a schematic top view of a waveguide antenna 1b. For each waveguide channel 11-14, the air slot 15b has a double-beam structure, which may be interrupted in the area of ​​the common air slot sections 151b-153b. Furthermore, the cross-section of the waveguide channels 11-14 is thinned in the center, thus enabling a more compact design.

[0041] Fig. Figure 5 shows a flowchart of a process for manufacturing a waveguide antenna 1. In particular, one of the waveguide antennas 1a, 1b described above can be manufactured.

[0042] In a first step S1, a plurality of waveguide channels 11-14 are formed in a substrate, wherein each waveguide channel 11-14 is formed by lateral wall structures and is designed to couple out an electromagnetic wave from an open output region of the waveguide channel 11-14.

[0043] In a second step S2, air grooves 15a; 15b are formed, wherein for each waveguide channel 11-14 in an outer area of ​​the lateral wall structures, a surrounding air groove 15a; 15b is formed. Air grooves 15a; 15b of adjacent waveguide channels 11-14 share a common air groove section 151a-153a; 151b-153b.

[0044] The common air groove section 151a-153a; 151b-153b can have the same thickness as the remaining sections of the air groove 15a; 15b.

[0045] The depth of the air groove 15a can be chosen to be equal to a quarter of the wavelength λ of the coupled electromagnetic wave.

[0046] Furthermore, it can be provided that for each waveguide channel 11-14, in the area of ​​the exit region of the waveguide channel 11-14, a notch 111-114, 121-124, 131-134, 141-144 is formed in each of the four lateral wall structures. The notches 111-114, 121-124, 131-134, 141-144 of adjacent waveguide channels 11-14 are arranged parallel to each other.

[0047] According to some embodiments, the air groove 15b has a double bead structure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2009 009317 A1

[0003]

Claims

[1] Waveguide antenna (1; 1a; 1b), with: a plurality of waveguide channels (11-14), each waveguide channel (11-14) being formed by lateral wall structures and being designed to couple out an electromagnetic wave from an open output region of the waveguide channel (11-14); wherein for each waveguide channel (11-14) a surrounding air groove (15a; 15b) is formed in an outer region of the lateral wall structures; and wherein air grooves (15a; 15b) of adjacent waveguide channels (11-14) share a common air groove section (151a-153a; 151b-153b). [2] Waveguide antenna (1; 1a; 1b) according to claim 1, wherein a plurality of notches are provided in the lateral wall structures for each waveguide channel (11-14) in the region of the exit region of the waveguide channel (11-14). [3] Waveguide antenna (1; 1a; 1b) according to claim 2, wherein the notches of adjacent waveguide channels (11-14) are arranged parallel to each other. [4] Waveguide antenna (1; 1a; 1b) according to claim 2 or 3, wherein each waveguide channel (11-14) has a substantially rectangular cross-section and the waveguide channel (11-14) is formed by four lateral wall structures, wherein a notch is formed in each of the lateral wall structures. [5] Waveguide antenna (1; 1a; 1b) according to one of the preceding claims, wherein for each waveguide channel (11-14) the air groove (15a; 15b) has a double bead structure. [6] Waveguide antenna (1; 1a; 1b) according to one of the preceding claims, wherein each waveguide channel (11-14) has a substantially circular cross-section. [7] Radar device (10), comprising: a waveguide antenna (1; 1a; 1b) according to one of the preceding claims, and a radar signal generating device (3) which is designed to generate a radar signal and to couple it into the waveguide channels (11-14) of the waveguide antenna (1; 1a; 1b). [8] Radar device according to claim 7, further comprising a circuit board (2), wherein the waveguide antenna (1; 1a; 1b) is arranged on a first surface of the circuit board (2), and wherein the radar signal generating device (3) is arranged on a second surface of the circuit board (2). [9] Radar device according to claim 7 or 8, wherein the radar signal generating device (3) is designed as a system-on-chip. [10] Method for producing a waveguide antenna (1; 1a; 1b), comprising the steps: Forming (S1) a plurality of waveguide channels (11-14), wherein each waveguide channel (11-14) is formed by lateral wall structures and is designed to couple out an electromagnetic wave from an open output region of the waveguide channel (11-14); Forming (S2) air grooves (15a; 15b), wherein a surrounding air groove (15a; 15b) is formed for each waveguide channel (11-14) in an outer region of the lateral wall structures; and wherein air grooves (15a; 15b) of adjacent waveguide channels (11-14) share a common air groove section (151a-153a; 151b-153b).

Images