Device for connecting monolithic integrated circuits to antenna elements of an antenna array

Abstract

Optimize the performance of the antenna array, which depends on the antenna position. [Solution] A device (1) for connecting a monolithic integrated circuit (2) to an antenna element (3) of an antenna array (4), comprising a decoupling unit for decoupling a signal emitted in the microwave region by the monolithic integrated circuit (2) to one dielectric waveguide (5) of a distribution network (6) consisting of dielectric waveguides, wherein the distribution network (6) is designed to supply the decoupled signal to the antenna element (3) of the antenna array (4), and a metal shield between adjacent dielectric waveguides (5) of the distribution network (6) shields the dielectric waveguides (5) of the distribution network (6) from each other.

Description

Technical Field

[0001] The present invention relates to an apparatus for connecting a monolithic integrated circuit to an antenna element of an antenna array and, in particular, to a combination of a dielectric component and a metal component in an antenna array for a radar sensor.

Background Art

[0002] Conventional approaches for connecting a MMIC (Microwave Monolithic Integrated Circuit) to an antenna element are based only on metal components with high line losses. In particular, in the case of a large antenna array with a large number of antenna elements, strong constraints are caused by the high line losses based on long conductors.

[0003] DE102015221803A1 describes a radar sensor with a monolithic microwave integrated circuit (MMIC). Conventionally, only metal components are used to connect a MMIC to an antenna element of an antenna array. In this case, the distribution network for the individual antenna elements is realized by a waveguide. A metal structure is used for the antenna elements. As an alternative possibility, a dielectric antenna element with a dielectric waveguide is provided. Thereby, an antenna array with a large antenna spacing and a small number of antenna elements can be realized.

[0004] Traditionally, especially in antenna arrays with a large number of antenna elements, only metal components have been used to connect the MMIC to the antenna elements. A common approach in this regard, particularly in the field of automotive radar, is the use of high-loss microstrip patch antenna arrays. However, this high loss negatively impacts the performance of radar equipment. To avoid the dielectric loss of microstrip patch antennas, waveguide slot antennas may be used instead. The conventional approach of using metal components to connect MMICs to antenna elements results in high losses, particularly in the millimeter-wave region, leading to reduced radiation efficiency. This is thought to be due to the dielectric loss of the patch array and distribution network in the case of currently used microstrip patch arrays.

[0005] When using metal waveguides, in addition to the dielectric loss of the filler material, ohmic losses due to surface currents also occur. The costly and precise fabrication required for metal waveguides is a further limitation of this line-type design. With the trend towards better angular resolution, two-dimensional radar systems with large apertures are increasingly being used. In this regard, the line losses of long conductors restrict the positioning of antenna elements.

[0006] Using only dielectric components for distribution networks and antenna elements is not suitable for realizing antenna arrays with a large number of antenna elements and small spacing between them. Strong coupling occurs when adjacent waveguides or antenna elements are spaced close together, based on electromagnetic field induction outside the dielectric waveguide. In addition, dielectric components alone have low mechanical stability, thus requiring additional support structures. Furthermore, the low mechanical stability of antenna arrays using only dielectric components severely limits their scalability to antenna arrays with a large number of antenna elements. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] DE102015221803A1 [Overview of the project]

[0008] According to a first aspect of the present invention, the present invention provides an apparatus for connecting a monolithic integrated circuit to an antenna element of an antenna array, comprising a decoupling unit for decoupling a signal emitted in the microwave region by the monolithic integrated circuit to one dielectric waveguide of a distribution network consisting of dielectric waveguides, wherein the distribution network is designed to supply the decoupled signal to the antenna element of the antenna array, and a metal shield between adjacent dielectric waveguides of the distribution network shields the dielectric waveguides of the distribution network from each other.

[0009] The apparatus according to the present invention enables, in particular, low-loss connection of an MMIC (Microwave Monolithic Integrated Circuit) to the antenna elements of an antenna array. The transition section required for this is realized by a combination of dielectric and metallic components.

[0010] The apparatus according to the present invention enables the realization of a distribution network for antenna arrays with low loss, a simple configuration, and low cost. By combining dielectric and metallic components, the line loss of the antenna array distribution network can be reduced compared to the conventional use of metallic components alone.

[0011] A Monolithic Microwave Integrated Circuit (MMIC) is a specialized class of integrated components, circuits, or systems in high-frequency technology and microelectronics. In this context, active and passive components are realized on a single semiconductor substrate (typically 100 μm thick). This miniaturization allows circuits to be measured in millimeters. MMICs are a specialized type of integrated circuit for use in high-frequency and microwave applications.

[0012] A dielectric waveguide is a waveguide that guides electromagnetic waves through a dielectric medium. Unlike metallic waveguides, which rely on reflection at metal walls, dielectric waveguides utilize total internal reflection at the interface between different dielectric materials. Dielectric waveguides preferably consist of a core material with a high refractive index surrounded by a cladding material with a lower refractive index. This structure allows electromagnetic waves to be guided within the core by total internal reflection.

[0013] In one possible embodiment of the apparatus according to the present invention for connecting monolithic integrated circuits to antenna elements of an antenna array, a distribution network consisting of dielectric waveguides is provided on a metal surface. This increases mechanical stability.

[0014] In addition, the use of dielectric waveguides on metal surfaces is a preferred and low-loss option for the simple configuration of dielectric waveguides with large relative bandwidths. In a possible embodiment of the apparatus according to the present invention for connecting a monolithic integrated circuit to an antenna element of an antenna array, decoupling of the signal emitted in the microwave region by the monolithic integrated circuit to a dielectric waveguide of a distribution network is performed by a first mode converter designed to supply the signal emitted in the microwave region to the waveguide, and by a second mode converter designed to supply the signal supplied to the waveguide to a dielectric waveguide of a distribution network.

[0015] In a possible embodiment of the apparatus according to the present invention for connecting a monolithic integrated circuit to an antenna element of an antenna array, decoupling of the signal emitted in the microwave region by the monolithic integrated circuit to the dielectric waveguide of the distribution network is performed by an on-chip antenna of the monolithic integrated circuit, the on-chip antenna is designed for excitation of fundamental modes in the dielectric waveguide of the distribution network.

[0016] This allows for direct coupling without the use of intermediate waveguides. An on-chip antenna may be used for the transition from the MMIC circuit to the dielectric waveguide of the distribution network. This ensures efficient mode excitation within the dielectric waveguide.

[0017] In one possible embodiment of the apparatus according to the present invention for connecting a monolithic integrated circuit to the antenna elements of an antenna array, coupling from a dielectric waveguide to each antenna element of the antenna array is performed by a mode converter.

[0018] In a possible embodiment of the apparatus according to the present invention for connecting monolithic integrated circuits to antenna elements of an antenna array, the dielectric waveguides of the distribution network are fixed by overlaying onto a metal surface and / or by clamping between metal shields. This can facilitate assembly and further save space.

[0019] The present invention further provides a radar sensor comprising a device for connecting a monolithic integrated circuit according to a first aspect of the present invention to an antenna element of an antenna array. The present invention further provides a vehicle equipped with at least one radar sensor, which includes a device for connecting a monolithic integrated circuit according to a first aspect of the present invention to an antenna element of an antenna array. [Brief explanation of the drawing]

[0020] [Figure 1]Schematic diagram of an apparatus according to the present invention for connecting a monolithic integrated circuit to an antenna element of an antenna array. [Figure 2] FIG. showing a possible embodiment of an apparatus according to the present invention for connecting a monolithic integrated circuit to an antenna element of an antenna array.

Embodiments for Carrying Out the Invention

[0021] According to a first aspect, the present invention provides an apparatus 1 for connecting a monolithic integrated circuit 2 to an antenna element 3 of an antenna array 4, the apparatus comprising a decoupling unit for decoupling a signal emitted in the microwave region by the monolithic integrated circuit 2 into one dielectric waveguide 5 of a distribution network 6 formed by dielectric waveguides, the distribution network 6 being designed to supply the decoupled signal to the antenna element 3 of the antenna array 4, and a metal shield between adjacent dielectric waveguides 5 of the distribution network 6 shielding the dielectric waveguides 5 of the distribution network 6 from each other.

[0022] Preferably, the monolithic integrated circuit 2 connected by the apparatus 1 has a MMIC circuit (Microwave Monolithic Integrated Circuit). An MMIC circuit is a class of integrated components, circuits, or systems in high-frequency technology and microelectronics, in which active and passive components can typically be realized on a single semiconductor substrate having a thickness of about 100 μm.

[0023] The MMIC circuit 2 connected by the device 1 is an integrated circuit designed for frequencies in the microwave region (typically above 1 GHz to over 100 GHz). Regarding this, "Monolithic" means that the entire circuit 2 is manufactured on a single semiconductor substrate, which brings high reliability and compact installation dimensions. The MMIC circuit 2 can be manufactured from semiconductor materials such as gallium arsenide (GaAs), silicon (Si), or silicon germanium (SiGe). Among them, the use of GaAs provides excellent characteristics for high-frequency applications. The MMIC circuit 2 has various components such as transistors (FET - field effect transistors), resistors, capacitors, and inductors, and all of these are integrated on a single chip.

[0024] The MMIC circuit 2 utilizes microwave circuit technologies such as stripline design or microstrip design for transmitting high-frequency signals. Regarding this, the circuit elements are formed to be optimized for microwave frequencies. Since all components are integrated on a single chip, the MMIC circuit 2 is configured compactly and provides a high power density. Monolithic integration minimizes the number of connections and connection errors, which enhances the reliability of the MMIC circuit 2. The MMIC circuit 2 is particularly optimized for the microwave region and provides higher performance than discrete components in this frequency range.

[0025] In a possible embodiment of the device 1 according to the present invention for connecting the monolithic integrated circuit 2 to the antenna elements 3 of the antenna array 4, a distribution network 6 consisting of a dielectric waveguide 5 is provided on a metal surface for mechanical stability. The use of the dielectric waveguide 5 on the metal surface is a suitable possibility with low losses due to the simple configuration of the dielectric waveguide 5 having a large frequency bandwidth.

[0026] As shown in Figure 2, in one possible embodiment of the apparatus 1 according to the present invention, the decoupling of the signal emitted in the microwave region by the monolithic integrated circuit 2 to the dielectric waveguide 5 of the distribution network 6 is performed by a first mode converter 7 designed to supply the signal emitted in the microwave region to the waveguide 8, and by a second mode converter 9 designed to supply the signal supplied to the waveguide 8 to the dielectric waveguide 5 of the distribution network 6.

[0027] The monolithic integrated circuit 2 generates a microwave signal. This is a signal in the microwave region that is generated and emitted within the circuit. Waveguide 8 serves as a transport medium for the microwave signal between the first mode converter 7 and the second mode converter 9. Waveguide 8 transmits the microwave signal through its waveguide, which holds and transmits the signal within the waveguide 8. The second mode converter 9 receives the microwave signal from waveguide 8 and converts it from the waveguide transmission mode to a transmission mode suitable for the dielectric waveguide 5. The second mode converter 9 ensures that the signal is supplied from waveguide 8 to the dielectric waveguide 5 of the distribution network 6. Dielectric waveguide 5 is a medium optimized for the transmission of microwave signals by dielectric material. Therefore, the signal is transported by the dielectric waveguide 5, which is part of the distribution network 6.

[0028] In one possible alternative embodiment of the apparatus 1 according to the present invention for connecting a monolithic integrated circuit 2 to the antenna elements 3 of an antenna array 4, the decoupling of the signal emitted in the microwave region by the monolithic integrated circuit 2 to the dielectric waveguide 5 of the distribution network 6 is performed by an on-chip antenna of the monolithic integrated circuit 2, which is designed for the excitation of fundamental modes within the dielectric waveguide 5 of the distribution network 6. The on-chip antenna circuit 2 may be used for the transition from the MMIC circuit 2 to the dielectric waveguide 5. This ensures efficient mode excitation within the dielectric waveguide 5 of the distribution network 6.

[0029] As shown in Figure 2, coupling from the dielectric waveguide 5 to each antenna element 3 of the antenna array 4 can be performed by a third mode converter 10. The mode converters 7, 9, and 10 in the embodiment shown in Figure 2 of the apparatus 1 according to the present invention are essential for matching transmission modes between different transmission media. The function of the mode converters 7, 9, and 10 is to ensure that signals are transmitted from one medium to another without significant loss or reflection.

[0030] In one possible embodiment of the apparatus 1 according to the present invention for connecting a monolithic integrated circuit 2 to an antenna element 3 of an antenna array 4, the dielectric waveguide 5 of the distribution network 6 is mechanically fixed by overlaying onto a metal surface and / or by clamping between metal shields.

[0031] In addition, according to one further aspect of the present invention, the present invention provides a radar sensor or radar device comprising a device 1 for connecting a monolithic integrated circuit 2 according to a first aspect of the present invention to an antenna element 3 of an antenna array 4. The radar device includes a monolithic integrated circuit 2, which is connected to the antenna array 4 of the radar device via the device 1. The radar device has a two-dimensional radar device in one possible embodiment.

[0032] In addition, according to one further aspect, the present invention provides a vehicle equipped with at least one radar sensor or radar device, which includes a device 1 for connecting a monolithic integrated circuit 2 to the antenna elements of an antenna array 4 of a radar device. The vehicle may be a road vehicle, in particular a passenger car or a truck. The vehicle may also be an aerial vehicle or a water vehicle.

[0033] The concept according to the present invention, based on a combination of dielectric and metallic components, enables the realization of a distribution network 6 for an antenna array 4 with relatively low loss. The dielectric waveguide 5 of the distribution network 6 can alleviate the constraints on the positioning of the antenna elements 3 during the array design of the antenna array 4.

[0034] A significant technical difference between the apparatus 1 according to the present invention and conventional approaches for antenna arrays lies in the combination of dielectric and metallic components. In apparatus 1 according to the present invention, the additional metallic structure allows adjacent dielectric components to shield from each other. In addition, when the distribution network 6 is realized on a metallic surface based on dielectric waveguides 5, a mechanically stable antenna array 4 can be scaled for a large number of antenna elements 3. The concept according to the present invention, based on the combination of dielectric and metallic components, enables a low-loss connection of the MMIC circuit 2 to the antenna elements 3 of the antenna array 4.

[0035] For this purpose, in one possible embodiment of the apparatus 1 according to the present invention, the signal is supplied from the MMIC circuit 2 to the waveguide 8 by a first mode converter 7, and then from the waveguide 8 to the dielectric waveguide 5 of the distribution network 6 by a further mode converter 9.

[0036] Alternatively, in a further possible embodiment of the apparatus 1 according to the present invention, the signal may be supplied directly from the MMIC circuit 2 to the dielectric waveguide 5 of the distribution network 6 by a metal supply structure in order to transition from the MMIC circuit 2 to the dielectric waveguide 5 of the distribution network 6. An on-chip antenna is used to excite the fundamental modes in the dielectric waveguide 5 in order to decouple the signal from the MMIC 2.

[0037] The fundamental mode within the dielectric waveguide 5 is the basic mode of the electromagnetic wave guided by the dielectric waveguide 5. This mode is of the lowest order and has the simplest electromagnetic field distribution and the least loss. The fundamental mode is the simplest solution to the wave equation for the dielectric waveguide 5 and has no nodes (zeros) of electric field strength in the cross-section of the dielectric waveguide 5. The electric field of the fundamental mode is distributed symmetrically around the axis of the waveguide 5. Within a cylindrical waveguide 5, the fundamental mode has a Gaussian intensity distribution in the cross-section.

[0038] The distribution network 6 consists of dielectric waveguides 5, which are suitable for supplying decoupled signals from the MMIC circuit 2 to the corresponding antenna elements 3 of the antenna array 4 with low loss. In addition, by fixing the dielectric waveguides 5 on a metal surface, the mechanical stability of the antenna array 4 is ensured, especially in the case of a large number of antenna elements 3 with long conductors. Moreover, mutual coupling of signals within the distribution network 6 is prevented based on metal shielding between adjacent dielectric waveguides 5. In this regard, fixing the dielectric waveguides 5 of the distribution network 6 can be done by overlaying them onto a metal surface and by clamping them between metal shields.

[0039] In one possible embodiment of the apparatus 1 according to the present invention, the supply of signals to the antenna elements 3 of the antenna array 4 is performed by a third mode converter 10 from the dielectric waveguide 5 to each antenna element 3. In this case, the isolation of individual antenna elements 3 is ensured by a metal shield between adjacent antenna elements 3.

[0040] The apparatus 1 according to the present invention enables the realization of a distribution network 6 for an antenna array 4 with low loss, a simple configuration, and low cost. The combination of dielectric and metallic components can reduce the line loss of the distribution network 6 of the antenna array 4 compared to the conventional use of metallic components alone. In this case, the metallic components allow shielding of adjacent dielectric waveguides or antenna elements from each other. Therefore, coupling of adjacent dielectric waveguides or antenna elements can be reduced, which allows for smaller antenna spacing compared to the use of dielectric components alone.

[0041] The apparatus 1 according to the present invention enables scaling to an antenna array 4 with a large number of antenna elements 3 by using a low-loss distribution network 6. The low loss of the dielectric waveguide 5 reduces the constraints on the positioning of the antenna elements 3, thereby increasing the design flexibility during array design. In other words, instead of minimizing line loss in the distribution network with as few conductors as possible, the performance of the antenna array, which depends on the antenna position, can be optimized. [Explanation of symbols]

[0042] 1 device 2 Monolithic Integrated Circuits 3 Antenna Tension 4 Antenna Array 5 Dielectric Waveguides 6 Distribution Network 7. First mode converter 8 Waveguide 9. Second mode converter 10. Third mode converter

Claims

1. A device (1) for connecting a monolithic integrated circuit (2) to an antenna element (3) of an antenna array (4), comprising a decoupling unit for decoupling a signal emitted in the microwave region by the monolithic integrated circuit (2) to one dielectric waveguide (5) of a distribution network (6) consisting of dielectric waveguides (5), wherein the distribution network (6) is designed to supply the decoupled signal to the antenna element (3) of the antenna array (4), and a metal shield between adjacent dielectric waveguides (5) of the distribution network (6) shields the dielectric waveguides (5) of the distribution network (6) from each other.

2. An apparatus for connecting a monolithic integrated circuit according to claim 1 to an antenna element of an antenna array, wherein the distribution network (6), which consists of dielectric waveguides (5), is provided on a metal surface for mechanical stabilization.

3. Apparatus for connecting a monolithic integrated circuit according to claim 1 or 2 to an antenna element of an antenna array, wherein the decoupling of the signal emitted in the microwave region by the monolithic integrated circuit (2) to the dielectric waveguide (5) of the distribution network (6) is performed by a first mode converter (7) designed to supply the signal emitted in the microwave region to a waveguide (8), and by a second mode converter (9) designed to supply the signal supplied to the waveguide (8) to the dielectric waveguide (5) of the distribution network (6).

4. An apparatus for connecting a monolithic integrated circuit according to claim 1 or 2 to an antenna element of an antenna array, wherein the decoupling of the signal emitted in the microwave region by the monolithic integrated circuit (2) to the dielectric waveguide (5) of the distribution network (6) is performed by an on-chip antenna of the monolithic integrated circuit (2), and the on-chip antenna is designed for exciting the fundamental modes in the dielectric waveguide (5) of the distribution network (6).

5. An apparatus for connecting a monolithic integrated circuit to an antenna element of an antenna array according to any one of claims 1 to 4, wherein the coupling from the dielectric waveguide (5) to each of the antenna elements (3) of the antenna array (4) is performed by a third mode converter (10).

6. An apparatus for connecting a monolithic integrated circuit according to any one of claims 1 to 5 to an antenna element of an antenna array, wherein the dielectric waveguide (5) of the distribution network (6) is fixed by covering it with a metal surface and / or by clamping it between the metal shields.

7. An antenna array (4) comprising an antenna element (3) and a device (1) for connecting a monolithic integrated circuit (2) according to any one of claims 1 to 6 to the antenna element (3) of the antenna array (4).

8. A radar device comprising a device (1) for connecting a monolithic integrated circuit (2) according to any one of claims 1 to 6 to an antenna element of an antenna array (4) of a radar device.

9. The radar device according to claim 8, wherein the radar device includes a two-dimensional radar device.

10. A vehicle equipped with at least one radar device according to claim 8 or 9.

11. The vehicle according to claim 10, wherein the vehicle has a road-traveling vehicle.

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