Millimeterwellenantenne

Abstract

A millimeter wave antenna comprises a first printed circuit board (PCB1) and a second printed circuit board (PCB2), wherein the second printed circuit board (PCB2) is substantially parallel to the first printed circuit board (PCB1) and is spaced apart from the first printed circuit board (PCB1) by a distance (155), wherein the first printed circuit board (PCB1) comprises a propagation structure (160), in particular a waveguide, in which an electromagnetic wave can propagate with low loss and which is configured to radiate the electromagnetic wave towards the second printed circuit board and / or to receive the electromagnetic wave from the second printed circuit board, wherein the propagation structure (160) is defined by a magnetic wall (130, 170) in the first printed circuit board (PCB1) which has at least one artificial magnetic conductor, AMC, (170), wherein the millimeter wave antenna further comprises a coupling structure (WG),which is configured to establish electromagnetic coupling of the propagation structure (160) to or from outside, wherein the second circuit board comprises an antenna structure (270-1, 270-2, 270-3, 270-4) for radiating and / or receiving the electromagnetic wave to / from outside.

Description

TECHNICAL AREA

[0001] Embodiments of the present disclosure generally relate to a millimeter wave antenna. BACKGROUND

[0002] The automotive industry has a need for the development of extremely cost-effective and efficient millimeter-wave antennas, particularly in the 77 GHz frequency range. Analysis of the final product reveals two key cost factors: the manufacturing materials and the manufacturing process. There is a demand for a cost-effective millimeter-wave antenna. SUMMARY OF THE INVENTION

[0003] According to one aspect of the present disclosure, a millimeter-wave antenna is specified. The millimeter-wave antenna comprises a first printed circuit board and a second printed circuit board, the second printed circuit board being substantially parallel to the first printed circuit board and spaced apart from the first printed circuit board. The first printed circuit board comprises a propagation structure, in particular one or more waveguides. The propagation structure is configured such that an electromagnetic wave can propagate therein with low loss. The propagation structure is further configured to radiate the electromagnetic wave towards the second printed circuit board and / or to receive the electromagnetic wave from the second printed circuit board. The propagation structure is defined by a magnetic wall in the first printed circuit board. The magnetic wall comprises at least one artificial magnetic conductor (AMC).The millimeter-wave antenna also includes a coupling structure. This coupling structure is configured to establish electromagnetic coupling between the propagation structure and the outside. The second circuit board includes an antenna structure for radiating and / or receiving the electromagnetic wave to / from the outside.

[0004] Low loss, as used herein, includes in particular a property whereby, when an electromagnetic wave with a wavelength λ is fed in or coupled out, an insertion loss of less than approximately 0.2 dB with respect to the wavelength λ is achieved. For example, if the propagation structure includes a waveguide, then this also includes a structure (so-called non-classical waveguide) that behaves in its electromagnetic behavior like a waveguide or at least similarly to a waveguide. For example, a waveguide, as used herein, can be formed by two electric walls and two magnetic walls. In particular, the magnetic walls need only fulfill their property to a degree that permits waveguide-like electromagnetic behavior.For example, the amplitude at such a non-ideal magnetic wall does not need to become zero; rather, it is sufficient if a sufficient amplitude drop is observed. In general, a waveguide, as used here, comprises a reflection structure configured to confine an internally propagating electromagnetic wave between the (electrical, magnetic, and possibly non-ideal) walls.

[0005] In embodiments, the AMC comprises a plurality of structured patches. The patches are connected vias. In some embodiments, the patches are arranged in a single row around the propagation structure. In others, the patches are arranged in two rows around the propagation structure. In a two-row arrangement, the patches of the second row may be offset from the patches of the first row. A via is typically a conductive passage, for example, a metallized through-hole, through the corresponding printed circuit board. "Single-row arrangement," as used herein, refers to a structure in which the patches form a sequence along a respective boundary edge of the propagation structure, for example, a substantially linear sequence along the respective boundary edge of the propagation structure. "Double-row arrangement," as used herein, refers to a structure in which the patches form a sequence along a respective boundary edge of the propagation structure, for example, a substantially linear sequence along the respective boundary edge of the propagation structure.Arranged in two rows, as used herein, denotes a structure in which the patches of a first row form a sequence along a respective boundary edge of the propagation structure, for example, an substantially spatially linear sequence along the respective boundary edge of the propagation structure, and in which the patches of a second row form a sequence along the patches of the first row, typically on the respective side opposite the boundary edge of the propagation structure.

[0006] For example, the spreading structure has a longitudinal extent and a transverse extent with respective boundary edges, and the longitudinal extent is greater than the transverse extent; for example, the longitudinal extent is at least twice or at least three times the transverse extent.

[0007] In embodiments, the distance between the first printed circuit board and the second printed circuit board is defined by a gap that is at least partially filled with a material. The material may be an organic surface protectant (OSP) or a solder resist, such as a solder mask (LSL). For example, the gap may be greater than 0.5 µm and less than 1 / 100 of the wavelength, or less than 1 / 50 of the wavelength, or less than 1 / 20 of the wavelength. In other examples, the gap may be greater than 0.5 µm and less than 20 µm, or less than 50 µm, or less than 80 µm, which may also be referred to herein as the gap size. For example, the gap size may be substantially the same everywhere. For example, the gap size may be substantially determined by the thickness of the LSL and / or OSP.

[0008] In embodiments, the second printed circuit board comprises at least one choke. A choke, as used herein, is configured to block surface waves. For example, the choke comprises a surface wave blocking structure. The choke can be implemented using a material of the second printed circuit board. The choke can be formed at least partially from a material of the second printed circuit board. The choke can be formed at least partially integrally with the second printed circuit board. The choke can comprise a metallic structure.

[0009] In embodiments, the second printed circuit board comprises at least one absorber. The absorber is configured, for example, to absorb surface waves. The absorber can be implemented using a printed circuit board material of the second printed circuit board, for example, using a printed circuit board material on the top surface of the second printed circuit board. The absorber can, for example, be implemented using the printed circuit board material of the second printed circuit board beyond one or more chokes.

[0010] In embodiments, the antenna structure comprises a linear sequence of slots. For example, the antenna structure comprises a linear sequence of at least three slots. For example, the slots are arranged at substantially equal intervals. For example, the slots are arranged substantially equidistantly at a distance of half a wavelength (0.5λ) of the electromagnetic wave. The half wavelength here refers to the electromagnetic wave in the waveguide. A linear sequence, as used herein, refers to a spatial arrangement substantially along a line with respect to a reference plane. The reference plane may, for example, be defined by a surface of the respective printed circuit board. For example, an upper surface of the second printed circuit board lies substantially in the reference plane for the linear sequence of slots. The arrangement substantially along a line (the linear sequence) may, for example,to the centers of the respective slots. For example, the slots are substantially uniform and / or have substantially the same dimensions relative to each other. A slot, as used herein, is, for example, a recess, typically a cutout extending through the second printed circuit board substantially perpendicular to the reference plane, such as a through-hole. The recess may, for example, have a longitudinal extent in the reference plane and a transverse extent in the reference plane, the longitudinal extent being substantially along the line defining the linear sequence of slots, and the transverse extent being substantially orthogonal to the longitudinal extent. The longitudinal extent is typically larger than the transverse extent, for example, at least 1.5 times or at least twice the transverse extent. The recess may have a rounded rectangular shape in the reference plane and / or perpendicular to the reference plane.

[0011] In various embodiments, the slots form one or more slot groups. A slot group, as used herein, is configured to form a radiation lobe of the electromagnetic wave to be radiated or received. A radiation lobe, as used herein, is a portion of the antenna pattern belonging to the millimeter-wave antenna, bounded by relative minima. For example, a radiation lobe is a main lobe.

[0012] In embodiments in which the slots form one or more slot groups, the slots of each slot group are arranged at a substantially equidistant distance from one another. In particular, the slots are arranged substantially at a distance of half a wavelength (0.5λ) in the waveguide of the electromagnetic wave to be transmitted or received. Optionally, the slots can also be spaced further apart than half a wavelength in the waveguide, for example, more than two wavelengths (2λ) and preferably more than five wavelengths (5λ).

[0013] In some embodiments, the propagation structure has a curved path. A curved path can also be described as a serpentine path. A curved path can be defined, for example, by a curvature, particularly a multiple reciprocating curvature, of two opposing boundary edges of the propagation structure in the corresponding printed circuit board plane. Typically, the long boundary edges of the propagation structure (those boundary edges that define the longitudinal extent) are curved. The curved path can be designed such that constructive interference occurs when the electromagnetic wave is emitted or received through the slots.

[0014] In embodiments, the antenna structure comprises a sequence of slots that run linearly in a first direction along a surface of the second circuit board, as well as a metal structure.

[0015] The linear sequence refers to the spatial arrangement essentially along a line with respect to the surface of the second printed circuit board as the reference plane. The metal structure is arranged on the surface of the second printed circuit board. The metal structure is essentially continuous and surrounds the slots. In embodiments, the metal structure has an extension in a second direction along the surface of the second printed circuit board, the second direction being orthogonal to the first direction. The extension is greater than one-tenth the wavelength of the electromagnetic wave to be emitted or received. The extension is smaller than the wavelength of the electromagnetic wave to be emitted or received.

[0016] In embodiments, the millimeter-wave antenna further comprises a system circuit board. The system circuit board is arranged adjacent to the first circuit board and is separated by a system plate gap, which is at least partially filled with a material. The material may be an organic surface protectant (OSP) or a solder mask material, e.g., a solder resist (LSL). For example, the system plate gap is larger than 0.5 µm and less than 1 / 100 of the wavelength, or less than 1 / 50 of the wavelength, or less than 1 / 20 of the wavelength, which may also be referred to herein as the system plate gap dimension. A coupling structure is arranged in the system circuit board. The coupling structure comprises a waveguide. In embodiments, the waveguide of the coupling structure is configured such that the electromagnetic wave to be radiated or received is capable of propagation in one layering direction.The layering direction is defined by the layering of the system circuit board, the first circuit board, and the second circuit board. The waveguide is configured such that the electromagnetic wave couples into or out of the propagation structure. In embodiments, the propagation structure is defined by a magnetic wall with at least one artificial magnetic conductor (AMC) in the first circuit board, and the propagation structure is narrower than half a wavelength of the emitted or received electromagnetic wave in an input coupling region of the coupling structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Fig. 1 Figure 1 is a side sectional view (a) and a top view (b) of parts of a millimeter wave antenna according to one embodiment. Fig. 2 Figure 1 is a side sectional view (a) and a top view (b) of parts of a millimeter wave antenna according to one embodiment. Fig. 3 Figure 1 is a side sectional view (a) and a top view (b) of a millimeter wave antenna according to an embodiment, as well as a side sectional view (c) and a side sectional view (d) to define a technological implementation of a millimeter wave antenna according to an embodiment. Fig. 4 is a top view (a) of a first printed circuit board, a top view (b) of a second printed circuit board, a side section view (c) and a top view (d) of a combination of the first and second printed circuit boards of a millimeter wave antenna according to one embodiment. Fig. 5 is a top view of a second circuit board of a millimeter wave antenna according to one embodiment. Fig. 6 Figure 1 is a side sectional view (a) and a top view (b) of a millimeter wave antenna according to one embodiment. Fig. 7 is a top view of a first printed circuit board of a millimeter wave antenna according to one embodiment. Fig. 8 is a top view of a second circuit board of a millimeter wave antenna according to one embodiment. Fig. 9 is a top view of a first printed circuit board of a millimeter wave antenna according to one embodiment. Fig. 10 bis 12 These are perspective views of a section of a millimeter wave antenna according to one embodiment. DESCRIPTION OF EXECUTION FORMS

[0018] Embodiments of the present disclosure are explained in more detail below with reference to the drawings. Identical reference numerals in the various drawings denote identical, equivalent, or comparably similar elements.

[0019] Radar systems, such as those used in the automotive sector, utilize millimeter-wave antennas, which can be at least partially integrated onto one or more printed circuit boards (PCBs). PCBs designed for high-frequency (HF) applications exhibit good HF loss performance but are expensive. A widely used and cost-effective material for non-HF applications is, without limitations, FR4, which, however, exhibits high losses in the HF range, for example, in striplines. Printed radiating elements and transmission lines on PCBs, such as microstrip lines, are subject to dielectric losses. When waveguides (air waveguides) are used in conjunction with PCBs, very tight mechanical manufacturing tolerances and alignment tolerances during assembly must often be observed.

[0020] Typically, the proportions of a propagation structure 160 define a maximum wavelength of the electromagnetic wave that can propagate within the propagation structure 160. The propagation structure 160 is designed such that the electromagnetic wave is radiated towards the second printed circuit board PCB2. In the case where the electromagnetic wave originates from the direction of the second printed circuit board, the propagation structure enables the reception of the electromagnetic wave.

[0021] The artificial magnetic conductor, AMC, is occasionally also referred to as an electromagnetic bandgap structure (EBG). The EBG structure (AMC structure) is configured to suppress the propagation of the electromagnetic wave in an undesired direction (in particular, surface waves). Through the AMC structure, the electromagnetic wave propagates essentially within the propagation structure 160 and essentially without dielectric losses. The AMC structure can be a structure that essentially fulfills the properties mentioned in patent document DE 10 2006 012 452 B4, which is hereby incorporated by reference in its entirety.

[0022] "Spaced apart," as used herein, means that the parts in question are arranged at a distance from each other greater than zero. In particular, "spaced apart" means a distance greater than 0.5 µm.

[0023] The printed circuit boards (PCBs) are essentially designed as planar bodies. They comprise a planar material that lies essentially in one plane and typically has only a very small extent in one direction orthogonal to the plane. The PCBs are typically two-layer PCBs. The PCBs are typically made of a non-RF material. A non-RF material particularly includes a PCB material that typically exhibits very high losses in the RF range. RF range, as used herein, is in particular the range corresponding to a frequency of 10 GHz or more, for example, a frequency of 50 GHz or more, typically a frequency in the range of automotive radar, e.g., approximately 76–81 GHz. Examples of the non-RF material include FR2, FR3, CEM1, CEM3, FR4, and FR5. FR2 and FR4 are particularly preferred.An RF material is not necessary, since the electromagnetic wave mainly propagates in air.

[0024] The electromagnetic wave to be transmitted or received has a maximum wavelength corresponding to a frequency above 10 GHz. For example, the maximum wavelength corresponds to a frequency above 50 GHz or between 60 GHz and 90 GHz. The maximum wavelength corresponds to a frequency below 200 GHz. For example, the center frequency of the electromagnetic wave to be transmitted or received lies in the 77 GHz band, which is between approximately 76 GHz and approximately 81 GHz, and the center frequency is, for example, approximately 79 GHz, but is not limited to this.

[0025] Fig. 1 Figure 1 shows the first printed circuit board, PCB1, according to one embodiment. The propagation structure 160 is designed as a waveguide. In this example, PCB1 is made of FR4. The waveguide walls 130 represent a variant of the magnetic walls, which are manufactured using PCB technology with an FR4 substrate. The specific properties of the walls prevent wave propagation in the substrate and facilitate the assembly of the waveguide, since no electrical contact is required between the PCB and the metal layers 110, 120 (metal sheets) or metallized surfaces of the waveguide. Fig. 2 Figure 130 shows the magnetic walls consisting of so-called AMC unit cells, which can also be referred to as AMC structures 170 (Artificial Magnetic Conductor). These are the structured patches connected by vias. Structured patches, as used here, denote a structural arrangement of the patches with respect to the propagation structure. For example, the structured patches are arranged close to each other. For example, the distance between two adjacent structured patches is less than one wavelength of the electromagnetic wave that can propagate in the propagation structure. Fig. 2(b) An exemplary training is shown with a first row 171 of the AMC structures 170 and a second row 172 of the AMC structures. In other words: In the example according to Fig. 2(b) The AMC structures forming the structured patches are arranged in two rows around the spreading structure 160. However, this is merely an example, and the structured patches can also be arranged in a single row around the spreading structure 160, or they can be arranged in multiple rows around the spreading structure 160. The AMC structures 170 of the first row 171 are arranged along a boundary edge 161 of the spreading structure 160. The AMC structures 170 of the second row 172 are arranged along the AMC structures 170 of the first row 171. As in Fig. 2(b) As shown, the AMC structures 170 of the second row 172 can be arranged offset from each other in the xy-plane compared to the AMC structures 170 of the first row 170, but this is only an example.

[0026] PCB1 is bordered by an upper metal layer 110 and a lower metal layer 120. The waveguide 160 is filled with air. The arrow labeled K in Fig. 3(a) indicates that there is no electrical (galvanic) contact between PCB 1 and the metal layers 110 and 120, respectively.

[0027] Fig. 3 Figures (a) and (b) show the first printed circuit board PCB1 in conjunction with a second printed circuit board PCB2. The second printed circuit board PCB2 replaces the upper metal layer 110 made of Fig. 1 and 2 The first printed circuit board, PCB1, is arranged adjacent to the second printed circuit board, PCB2, in a stacking direction z. The second printed circuit board, PCB2, has slots 270-1, 270-2, 270-3, and 270-4. Instead of the metal sheet of the waveguide, a PCB with an FR4 substrate and milled slots is also used here. Fig. 3 The slots are offset from each other along the y-direction in the x-direction (alternating slots). Typically, adjacent slots are separated by half a wavelength (λ / 2). For example, the centers of adjacent slots are separated by half a wavelength (λ / 2). The half wavelength here refers to the electromagnetic wave in the waveguide. They would normally radiate with destructive interference (out of phase). The offset arrangement causes a reflection towards the center of the waveguide. This corresponds to a phase shift of 180° (a multiplication by -1). As a result, the slots radiate with constructive interference (in phase).

[0028] In other words, the current state of the art for alternating slots in a waveguide stipulates that the slots are spaced λ / 2 apart. Half a wavelength refers to the electromagnetic wave in the waveguide. Without alternating, this would result in destructive, i.e., out-of-phase, radiation. However, the reflection towards the center of the waveguide (alternating) creates a 180° phase shift, which in turn leads to constructive (in-phase) radiation. In this case, they radiate constructively, i.e., in phase, with each other. Due to the serpentine alternating waveguide design (alternating relative to the slots), the slots can still be positioned as close together as in the prior art. The relative alternating is thus implemented in a different way.

[0029] Fig. 3 Figures (c) and (d) show the first printed circuit board PCB1 in conjunction with the second printed circuit board PCB2 and a system printed circuit board "PCB-S". The system printed circuit board can also be referred to as PCB-S here. Fig. 3(c) A solder mask (LSL) is applied between the first circuit board (PCB1) and the second circuit board (PCB2). A solder mask may also be applied between PCB1 and PCB-S. Fig. 3(d) An organic surface protection (OSP) is applied between the first printed circuit board (PCB1) and the second printed circuit board (PCB2). An OSP may also be applied between PCB1 and PCB-S. Fig. 3(c) und Fig. 3(d) show alternatives. However, it is also conceivable to go into Fig. 3(c) und Fig. 3(d) to exchange one of the OSP and the LSL for the other, or to combine the methods. LSL and / or OSP are a specific technological implementation for defining the distances or gap dimensions 155, 156. LSL and / or OSP are applied with a thickness of less than 1 / 20 of the wavelength, preferably less than 1 / 50 of the wavelength, particularly preferably less than 1 / 100 of the wavelength and greater than or equal to 0.5 µm. For example, LSL and / or OSP are applied with a thickness of less than 80 µm, preferably less than 50 µm, particularly preferably less than 20 µm and greater than or equal to 0.5 µm. Accordingly, they define the gap dimensions or distances 155, 156 within the specified range of values. It should be noted that LSL and / or OSP can be applied partially, partially, or completely. In particular, the waveguide cutout 160 is preferably not covered with LSL and / or OSP.

[0030] Fig. 4 The first circuit board, PCB1, is shown in conjunction with a second circuit board, PCB2. The second circuit board, PCB2, replaces the upper metal layer 110. Fig. 1 and 2 The first printed circuit board, PCB1, is arranged adjacent to the second printed circuit board, PCB2, in a stacking direction z. The second printed circuit board, PCB2, has slots 270-1, 270-2, 270-3, and 270-4. Instead of the metal sheet of the waveguide, a PCB with an FR4 substrate and milled slots is also used here. Fig. 4 are the slots arranged linearly in the y-direction, i.e., they are arranged in the opposite direction to... Fig. 3 The PCBs are not offset from each other in the x-direction. The arrow labeled K indicates that there is no electrical (galvanic) contact between PCB1 and PCB2. PCB1 and PCB2 are arranged at a distance of 155° from each other. To ensure a uniformly low side-lobe and grating-lobe behavior for the 3D radiation pattern, PCB1 is designed with a specific, curved shape for the waveguide section. The waveguide 160° is curved. The slots arranged in series exhibit less interaction with each other. This low interaction and the geometric arrangement result in a reduction of the side-lobe level throughout the entire space. Typically, adjacent slots are separated by half a wavelength in the waveguide (λ / 2). For example, the centers of the slots of adjacent slots are separated by half a wavelength in the waveguide (λ / 2).They therefore radiate with constructive interference (in phase). The curved shape of the waveguide section 160 causes a detour in the feeding of the slots. Due to the detour of the serpentine path, the slots are nevertheless as close together as the slots of the alternating version.

[0031] The decoupling of the adjacent antennas is achieved by using a Choke 280 (see...). Fig. 5 ) and by utilizing the lossy properties of the FR4 substrate. A Choke 280 is typically a via / copper structure, for example, in the form of rounded rectangular strips with central vias. A choke is typically a barrier structure.

[0032] Furthermore, the metallization 275 surrounding the slots contributes to increasing the antenna's efficiency. The metallization 275 is continuous and interrupted only by the slots. The metallization extends from the slot center in the x-direction with a dimension of d / 2. The following inequality is satisfied: (λ / 10) < d < λ.

[0033] The waveguide-like antenna is fed via a waveguide (WG ("waveguide") ( Fig. 6 This is, on the one hand, the common way of powering the chip, and on the other hand, it aims to achieve a higher efficiency by reducing potential transition losses.

[0034] The gaps 150, 151 and the resulting distances 155, 156 are galvanically contactless. This is achieved through surface finishing, etc., i.e., standard printed circuit board processes, preferably OSP or solder mask. This results in a very small gap distance 155 or 156 in the range of, for example, 0.5 µm to 1 / 20 of the wavelength, for example, 0.5 µm to approximately 80 µm. This, in turn, results in a very cost-effective mechanical definition of the gaps 150 or 151.

[0035] An absorber 290 for surface waves is implemented via the RF-lossy (preferably FR2 or FR4) printed circuit board material on the top side of PCB 2. The absorber 290 is, for example, the PCB material of PCB2 beyond the chokes 280.

[0036] Surface waves can occur, for example, when the millimeter-wave antenna disclosed herein is used in a radar for automotive applications that is integrated into or located behind a vehicle's plastic shock absorber. When a radar signal encounters the plastic shock absorber, it does not penetrate it completely, and a portion is reflected. This reflection of the radar signal back and forth between the radar and the shock absorber can reduce its detection accuracy. The phenomenon that arises in this context is known as surface waves. The absorber 290 can effectively suppress or reduce such surface waves.

[0037] The absorber 290 can be formed using a process such as etching. For example, the absorber 290 is arranged hexagonally, rectangularly, or circularly, or a combination thereof. Typically, a plurality of absorbers 290 are formed. For example, the plurality of absorbers 290 can be arranged in a grid with a certain density. The density can be defined, for example, by the wavelength of the electromagnetic wave to be absorbed. The absorber 290 is, for example, a surface area of ​​copper obtained through etching. The absorber 290 is formed, in particular, only in or on the surface of the printed circuit board. The absorber 290 is implemented, in particular, without vias. This effect can be enhanced by metallic structures (geometric arrangement). The chokes 280 lead to improved decoupling of the individual antennas and shaping of the antenna radiation patterns.

[0038] PCB1 and PCB2 can each be two-layered. This makes the PCBs very cost-effective to manufacture, while the vias still allow for AMC (Artificial Magnetic Conductor) walls, offering the advantages of a metal-to-metal contactless design. Preferably, a second row of AMC vias is arranged offset from the first. However, a single row of AMC vias is also conceivable.

[0039] The metallic rim 275 around the radiating slots ensures that there is no connection (except for the slots) to the ground of the PCB (underside of PCB2). This has the advantage of improving efficiency and allowing for advantageous shaping of the antenna radiation patterns.

[0040] By feeding the slots in a curved pattern, alternating slots can be avoided. Alternating slots, compared to a straight-line arrangement, always exhibit grating lobes in some spatial directions, which is highly detrimental in conventional radar systems. In the millimeter-wave antenna described here, the radiators (slots) are aligned in a straight line, resulting in very good radiation patterns and low side-lobe and grating lobe levels throughout the entire space.

[0041] Fig. 6 Figure 300 shows a monolithic microwave integrated circuit (MMIC) feeding the vertical waveguide WG in the system PCB PCB-S. It should be noted that the MMIC 300 can feed multiple vertical waveguides WG. The vertical waveguide WG transmits the electromagnetic wave to the horizontal waveguide 160 in PCB 1. The distance between a vertical waveguide and the horizontal waveguide it feeds is determined by the gap 155, ranging from 0.5 µm to 1 / 20 of the wavelength, for example, from 0.5 µm to 80 µm. The distance between two vertical waveguides is determined by the footprint of the MMIC interface. For a typical MMIC, the distance between two vertical waveguides is, for example, 1.4 mm. For reasons of cost and space, it is desirable to place the outputs very close together. This is only possible if the transition from waveguide to antenna feed line functions with such small distances.With the solution proposed here, it is possible to reduce the antenna feed line in the MMIC area to < λ / 2 in air (see . Fig. 11 ). Fig. 6 shows a shared apartment E-bend. Fig. 7 This shows a WG-H bend. Due to space constraints (because the chip outputs are so close together), it is not possible to use only E-bends. The closely spaced chip outputs are alternately oriented horizontally and vertically to minimize coupling. Fig. 8 PCB2 shows Chokes 280 and Metallization 275. Fig. 9 This shows Fig. 8 Associated PCB1. It can be seen that several microwave antennas, as described herein, are configured. In other words, the first printed circuit board PCB1 comprises several propagation structures 160-1, 160-2, 160-3, 160-4, 160-5, 160-6, 160-7, 160-8, each configured as an air-filled waveguide in which an electromagnetic wave can propagate, and each configured to radiate the electromagnetic wave towards the second printed circuit board and / or to receive the electromagnetic wave from the second printed circuit board. The millimeter-wave antenna comprises a coupling structure (WG-H, WG-E) for each of the propagation structures. Each coupling structure is configured to establish electromagnetic coupling of the associated propagation structure (160) to or from outside, in particular to / from the MMIC 300.The second circuit board, PCB2, includes an associated antenna structure (270-1, 270-2, 270-3, 270-4) for each propagation structure, used to radiate and / or receive the electromagnetic wave to / from the outside. Each antenna structure comprises a slot group consisting of linearly (not offset or alternating) arranged slots. Each propagation structure feeds the slot group with a curved waveform.

[0042] Figs. 10 bis 12 The diagram shows WG-E bends and WG-H bends, respectively, in a perspective view. The dimensions b are each narrower than half the wavelength (narrower than λ / 2). . The AMC interface thus enables geometric dimensions below the cutoff frequency of the TE-01 mode of a conventional waveguide, thereby allowing for high integration density. Waveguides are characterized by low interface transmission losses.

[0043] The millimeter wave antenna disclosed herein can also be described as a 2.5D combined waveguide antenna. The electromagnetic wave is guided in air, resulting in very good overall efficiency, despite the use of FR2 or FR4 PCBs, as well as very good radiation patterns and phase response, e.g., for multiple-input multiple-output radar systems (MIMO radar systems).

[0044] The millimeter-wave antenna disclosed herein can be advantageously used where a high integration density is desired, for example in imaging radars (e.g., at a frequency of approximately 80 GHz). However, significantly higher frequencies are also possible, e.g., approximately 140 GHz.

[0045] Specific embodiments have been shown and described. However, the disclosure is not limited to these, and it is immediately apparent to a person skilled in the art that various modifications can be devised and / or the features, aspects, and embodiments can be appropriately combined without deviating from the scope of the disclosure. The description and the drawings are clear and illustrative. The claims are intended to cover alternatives, modifications, and equivalents.

[0046] The following aspects are also part of the present revelation.

[0047] Aspect 1. Millimeter wave antenna, comprehensive: a first printed circuit board (PCB1) and a second printed circuit board (PCB2), wherein the second printed circuit board (PCB2) is substantially parallel to the first printed circuit board (PCB1) and is spaced apart from the first printed circuit board (PCB1) by a distance (155), wherein the first printed circuit board (PCB1) comprises a propagation structure (160), in particular a waveguide, in which an electromagnetic wave can propagate, and which is configured to radiate the electromagnetic wave towards the second printed circuit board and / or to receive the electromagnetic wave from the second printed circuit board, wherein the millimeter wave antenna further comprises a coupling structure (WG) configured to establish electromagnetic coupling of the propagation structure (160) to or from outside, and wherein the second printed circuit board comprises an antenna structure (270-1, 270-2, 270-3, 270-4) for radiating and / or receiving the electromagnetic wave to / from outside..

[0048] Aspect 2. Millimeter wave antenna according to aspect 1, wherein the spacing (155) is less than 80 µm, preferably less than 50 µm, particularly preferably less than 20 µm.

[0049] Aspect 3. Millimeter wave antenna according to aspect 1 or 2, where the distance is greater than 0.5 µm.

[0050] Aspect 4. Millimeter wave antenna according to one of aspects 1 to 3, wherein the distance (155) is defined by a gap (150) at least partially filled with a material.

[0051] Aspect 5. Millimeter wave antenna according to aspect 4, wherein the material of the gap (150) has an organic surface protection, OSP - Organic Solderability Preservative.

[0052] Aspect 6. Millimeter wave antenna according to aspect 4, wherein the material of the gap comprises a solder mask material, in particular solder mask lacquer.

[0053] Aspect 7. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the first printed circuit board (PCB1) and / or the material of the second printed circuit board (PCB2) comprises a non-RF material, in particular a material selected from the group consisting of: FR2, FR3, CEM1, CEM3, FR4, FR5.

[0054] Aspect 8. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the first printed circuit board (PCB1) and the material of the second printed circuit board (PCB2) is FR2 or FR4.

[0055] Aspect 9. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the first printed circuit board (PCB1) is FR2.

[0056] Aspect 10. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the first printed circuit board (PCB1) is FR4.

[0057] Aspect 11. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the second printed circuit board (PCB2) is FR2.

[0058] Aspect 12. Millimeter wave antenna according to one of aspects 1-6, wherein the material of the second circuit board (PCB2) is FR4.

[0059] Aspect 13. Millimeter wave antenna according to one of aspects 1-12, wherein the second printed circuit board (PCB2) comprises at least one choke (280) and / or at least one absorber (290).

[0060] Aspect 14. Millimeter wave antenna according to aspect 13, wherein the at least one choke (280) is realized by means of the material of the second circuit board (PCB2), in particular FR2 or FR4.

[0061] Aspect 15. Millimeter wave antenna according to aspect 14, wherein the at least one choke (280) comprises a metallic structure.

[0062] Aspect 16. Millimeter wave antenna according to one of aspects 1-15, wherein the antenna structure comprises a linear sequence of slots (270-1, 270-2, 270-3, 270-4).

[0063] Aspect 17. Millimeter wave antenna according to aspect 16, wherein the slots (270-1, 270-2, 270-3, 270-4) are arranged at an essentially equidistant distance, in particular half a wavelength in the waveguide (0.5λ) of the electromagnetic wave, from each other.

[0064] Aspect 18. Millimeter wave antenna according to aspect 16 or 17, comprising at least three slots (270-1, 270-2, 270-3, 270-4).

[0065] Aspect 19. Millimeter wave antenna according to aspect 16, wherein the slots (270-1, 270-2, 270-3, 270-4) form a slot group to form a radiation lobe.

[0066] Aspect 20. Millimeter wave antenna according to aspect 19, which has a plurality of slot groups, each forming a slot group to form a radiation lobe.

[0067] Aspect 21. Millimeter wave antenna according to aspect 20, wherein each slot group comprises at least three slots.

[0068] Aspect 22. Millimeter wave antenna according to aspect 21, wherein the slots of each slot group are arranged at a substantially equidistant distance, in particular half a wavelength in the hollow conductor (0.5λ) of the electromagnetic wave.

[0069] Aspect 23. Millimeter wave antenna according to one of aspects 20 to 22, wherein the slot groups are spaced apart from each other by more than half a wavelength in the waveguide (0.5λ), in particular more than two wavelengths (2λ) and preferably more than five wavelengths (5λ) of the electromagnetic wave.

[0070] Aspect 24. Millimeter wave antenna according to one of aspects 1 to 23, wherein the propagation structure (160) has a curved or wavy profile.

[0071] Aspect 25. Millimeter wave antenna according to aspect 24, wherein the curved course of the propagation structure (160) is configured such that a constructively interfering radiation of the slots (270-1, 270-2, 270-3, 270-4) takes place.

[0072] Aspect 26. Millimeter wave antenna according to one of aspects 1 to 25, wherein the first circuit board (PCB1) and / or the second circuit board (PCB2) is each designed in two layers.

[0073] Aspect 27. Millimeter wave antenna according to one of aspects 1 to 26, wherein the propagation structure (160) is defined by a magnetic wall (130, 170) in the first printed circuit board (PCB1).

[0074] Aspect 28. Millimeter wave antenna according to aspect 27, wherein the magnetic wall comprises at least two unit cells of an artificial magnetic conductor (170), AMC - artificial magnetic conductor.

[0075] Aspect 29. Millimeter wave antenna according to aspect 28, wherein the AMC (170) has a plurality of structured patches connected by vias.

[0076] Aspect 30. Millimeter wave antenna according to aspect 29, wherein the majority of structured patches are arranged in a single row around the propagation structure (160).

[0077] Aspect 31. Millimeter wave antenna according to aspect 29, wherein the majority of structured patches are arranged in two rows around the propagation structure (160).

[0078] Aspect 32. Millimeter wave antenna according to aspect 31, wherein the second row of structured patches is offset from the first row of structured patches.

[0079] Aspect 33. Millimeter wave antenna according to one of aspects 1 to 32, wherein the antenna structure comprises a linear sequence of slots (270-1, 270-2, 270-3, 270-4) in a first direction (y) of a surface of the second printed circuit board (PCB2) and a metal structure (275), wherein the metal structure (275) is arranged on the surface of the second printed circuit board (PCB2).

[0080] Aspect 34. Millimeter wave antenna according to aspect 33, wherein the metal structure (275) is essentially continuous and surrounds the slots.

[0081] Aspect 35. Millimeter wave antenna according to aspect 33 or 34, wherein the metal structure (275) has an extent (d) in a second direction (x) of the surface of the second printed circuit board (PCB2), wherein the extent satisfies the inequality (λ / 10) < d < λ, where λ is the wavelength of the electromagnetic wave, wherein the second direction (x) is orthogonal to the first direction (y).

[0082] Aspect 36. Millimeter wave antenna according to one of aspects 33 to 35, wherein the metal structure (275) is galvanically contactless with respect to an opposite side of the second circuit board (PCB2).

[0083] Aspect 37. Millimeter wave antenna according to aspect 36, wherein the metal structure (275) comprises a surface metallization.

[0084] Aspect 38. Millimeter wave antenna according to one of aspects 33 to 37, if dependent on one of aspects 13 to 15, wherein the choke (280) is spaced from the metal structure (275).

[0085] Aspect 39. Millimeter wave antenna according to one of aspects 1 to 38, which further comprises a system circuit board (PCB-S) that is located adjacent to the first circuit board (PCB1).

[0086] Aspect 40. Millimeter wave antenna according to aspect 39, wherein the coupling structure (WG) is arranged in the system circuit board (PCB-S).

[0087] Aspect 41. Millimeter wave antenna according to aspect 40, wherein the coupling structure (WG) includes a waveguide.

[0088] Aspect 42. Millimeter wave antenna according to aspect 41, wherein the waveguide of the coupling structure (WG) is configured such that the electromagnetic wave (E1) is capable of propagation in a layering direction (z) of system circuit board (PCB-S), first circuit board (PCB1) and second circuit board (PCB2), and wherein the propagation structure (160) is configured such that the electromagnetic wave (E1) is capable of propagation in a principal propagation direction (y) orthogonal to the layering direction (z).

[0089] Aspect 43. Millimeter wave antenna according to aspect 42, wherein the waveguide of the coupling structure (WG) is configured such that the electromagnetic wave (E) couples into or from the propagation structure (160).

[0090] Aspect 44. Millimeter wave antenna according to one of aspects 41 to 43, wherein the propagation structure (160) is defined by a magnetic wall with at least one AMC (170) in the first printed circuit board (PCB1), and wherein the propagation structure (160) is formed in a coupling region of the coupling structure (WG) narrower than half the wavelength (λ / 2) of the electromagnetic wave (E).

[0091] Aspect 45. Millimeter wave antenna according to one of aspects 40 to 44, wherein a monolithic microwave integrated circuit (MMIC) is arranged on the system circuit board (PCB-S) which is configured to couple the electromagnetic wave (E) into / out of the coupling structure (WG).

[0092] Aspect 46. Millimeter wave antenna according to one of aspects 1 to 45, wherein the electromagnetic wave has a maximum wavelength corresponding to a frequency above 10 GHz, in particular above 50 GHz and preferably between 60 GHz and 90 GHz.

[0093] Aspect 47. Millimeter wave antenna according to one of aspects 1 to 46, wherein the electromagnetic wave has a maximum wavelength corresponding to a frequency below 200 GHz.

Claims

1. Millimeter wave antenna comprising: a first printed circuit board (PCB1) and a second printed circuit board (PCB2), wherein the second printed circuit board (PCB2) is substantially parallel to the first printed circuit board (PCB1) and is spaced apart from the first printed circuit board (PCB1) by a distance (155), wherein the first printed circuit board (PCB1) comprises a propagation structure (160), in particular a waveguide, in which an electromagnetic wave can propagate with low loss and which is configured to radiate the electromagnetic wave towards the second printed circuit board and / or to receive the electromagnetic wave from the second printed circuit board, wherein the propagation structure (160) is defined by a magnetic wall (130, 170) in the first printed circuit board (PCB1) which has at least one artificial magnetic conductor, AMC, (170), wherein the millimeter wave antenna further comprises a coupling structure (WG),which is configured to establish electromagnetic coupling of the propagation structure (160) to or from outside, wherein the second circuit board comprises an antenna structure (270-1, 270-2, 270-3, 270-4) for radiating and / or receiving the electromagnetic wave to / from outside.

2. Millimeter wave antenna according to claim 1, wherein the AMC (170) has a plurality of structured patches connected by vias.

3. Millimeter wave antenna according to claim 2, wherein the plurality of structured patches are arranged in one or two rows around the propagation structure (160), wherein in the case of a two-row arrangement the second row of structured patches is preferably arranged offset from the first row of structured patches.

4. Millimeter wave antenna according to one of the preceding claims, wherein the distance (155) is defined by a gap (150) that is at least partially filled with a material.

5. Millimeter wave antenna according to claim 4, wherein the material of the gap (150) comprises an organic surface protection, OSP, or a solder mask material, in particular solder mask lacquer.

6. Millimeter wave antenna according to one of the preceding claims, wherein the second printed circuit board (PCB2) comprises at least one choke (280) and / or at least one absorber (290), wherein preferably the at least one choke (280) is realized by means of the material of the second printed circuit board (PCB2), in particular FR2 or FR4, wherein more preferably the at least one choke (280) comprises a metallic structure.

7. Millimeter wave antenna according to one of the preceding claims, wherein the antenna structure comprises a linear sequence of slots (270-1, 270-2, 270-3, 270-4), in particular at least three slots, wherein preferably the slots (270-1, 270-2, 270-3, 270-4) are arranged at a substantially equidistant distance, in particular half a wavelength, 0.5λ in the waveguide of the electromagnetic wave, from each other.

8. Millimeter wave antenna according to claim 7, wherein the slots (270-1, 270-2, 270-3, 270-4) form at least one slot group for forming a radiation lobe.

9. Millimeter wave antenna according to claim 8, wherein the slots of each slot group are arranged substantially at a substantially equidistant distance from each other of the electromagnetic wave, wherein optionally the slot groups are spaced apart from each other by half a wavelength, 0.5λ, or by more than half a wavelength, 0.5λ, in the waveguide, in particular more than two wavelengths, 2λ, and preferably more than five wavelengths, 5λ, of the electromagnetic wave.

10. Millimeter wave antenna according to one of the preceding claims, wherein the propagation structure (160) has a curved or curved profile, wherein in particular the curved profile of the propagation structure (160) is configured such that constructively interfering radiation of the slots (270-1, 270-2, 270-3, 270-4) takes place.

11. Millimeter wave antenna according to one of the preceding claims, wherein the antenna structure comprises a linear sequence of slots (270-1, 270-2, 270-3, 270-4) in a first direction (y) of a surface of the second printed circuit board (PCB2) and a metal structure (275), wherein the metal structure (275) is arranged on the surface of the second printed circuit board (PCB2), wherein the metal structure (275) is substantially continuous and surrounds the slots.

12. Millimeter wave antenna according to claim 11, wherein the metal structure (275) has an extension (d) in a second direction (x) of the surface of the second printed circuit board (PCB2), wherein the extension satisfies the inequality (λ / 10) < d < λ, where λ is the wavelength of the electromagnetic wave, wherein the second direction (x) is orthogonal to the first direction (y).

13. Millimeter wave antenna according to one of the preceding claims, further comprising a system circuit board (PCB-S) arranged adjacent to the first circuit board (PCB1), wherein the coupling structure (WG, WG-E, WG-H) is arranged in the system circuit board (PCB-S), wherein the coupling structure (WG, WG-E, WG-H) comprises a waveguide.

14. Millimeter wave antenna according to claim 13, wherein the waveguide of the coupling structure (WG, WG-E, WG-H) is configured such that the electromagnetic wave (E1) is capable of propagating in a layering direction (z) of system circuit board (PCB-S), first circuit board (PCB1) and second circuit board (PCB2), and wherein the propagation structure (160) is configured such that the electromagnetic wave (E1) is capable of propagating in a principal propagation direction (y) orthogonal to the layering direction (z), wherein the waveguide of the coupling structure is configured such that the electromagnetic wave (E1) couples into or from the propagation structure (160).

15. Millimeter wave antenna according to claim 13 or 14, wherein the propagation structure (160) is defined by a magnetic wall with at least one AMC (170) in the first printed circuit board (PCB1), and wherein the propagation structure (160) is formed in a coupling region of the coupling structure (WG, WG-E, WG-H) narrower than half a wavelength, λ / 2, of the electromagnetic wave (E1).

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