Radar system, integrated radar circuit and method for a radar system

Abstract

Radar system (100), comprising: a first integrated radar circuit (110) with several first transmission paths (111) and a local oscillator (113) configured to generate a local oscillator signal (114), wherein the first integrated radar circuit (110) also has a first connection (112) configured to output an oscillation signal based on the local oscillator signal (114); a second integrated radar circuit (120) with at least one second transmission path (121) and a second connection (122); and a partially reflective element (130) which is coupled to the first terminal (112) via a first line section (140) and to the second terminal (122) via a second line section (150), wherein the partially reflective element (130) is configured to reflect a first component of the oscillation signal back to the first terminal (112) as a reflected signal via the first line section (140) and to transmit a second component of the oscillation signal as a forward signal via the second line section (150) to the second terminal (122), wherein the first integrated radar circuit (110) comprises a directional coupler (115) which is coupled to the first terminal (112) via a first port and is configured to output the reflected signal via a second port to a signal node (116) of the first integrated radar circuit (110), wherein the first transmission paths (111) are coupled to the signal node (116) and at least part of the first transmission paths (111) is set up to generate radar transmission signals (117) based on the reflected signal.

Description

Technical field

[0001] Exemplary embodiments relate to a radar system, an integrated radar circuit, and a method for a radar system. background

[0002] High-resolution radar systems typically use a large number of transmit and receive channels. However, the number of possible transmit and receive channels for a single monolithic microwave integrated circuit (MMIC) is limited. Therefore, multiple MMICs are often cascaded, meaning several radar transmit-receiver MMICs are coupled, with one MMIC acting as the master and providing the system clock, trigger line, high-frequency transmit signal, etc. (see, for example, publication EP 3 339 899 A1). For the radar system to operate correctly, the high-frequency transmit signals of the channels distributed across the individual MMICs must be synchronized. Summary

[0003] There is therefore a need to provide improved technology for the synchronization of integrated radar circuits.

[0004] The need can be met by the subject matter of the patent claims.

[0005] One embodiment relates to a radar system. The radar system comprises a first integrated radar circuit with several first transmission paths and a local oscillator configured to generate a local oscillator signal. The first integrated radar circuit also has a first terminal configured to output an oscillation signal based on the local oscillator signal. The radar system further comprises a second integrated radar circuit with at least one second transmission path and a second terminal. The radar system also includes a partially reflective element coupled to the first terminal via a first transmission line and to the second terminal via a second transmission line.The partially reflective element is configured to reflect a first component of the oscillation signal back to the first terminal via the first transmission line segment and to transmit a second component of the oscillation signal as a forward signal to the second terminal via the second transmission line segment. The first integrated radar circuit further comprises a directional coupler connected to the first terminal via a first port and configured to output the reflected signal to a signal node of the first integrated radar circuit via a second port. The first transmission paths are coupled to the signal node, and at least a portion of the first transmission paths are configured to generate radar transmission signals based on the reflected signal.

[0006] Another embodiment relates to an integrated radar circuit. The integrated radar circuit comprises several transmission paths and a local oscillator configured to generate a local oscillator signal. Furthermore, the integrated radar circuit includes a connection for linking an external element via a cable segment. The connection is configured to output an oscillation signal based on the local oscillator signal to the cable segment and to receive a portion of the oscillation signal reflected by the external element as a reflected signal via the cable segment. The integrated radar circuit also includes a directional coupler, which is coupled to the connection via a first port and configured to output the reflected signal via a second port to a signal node of the integrated radar circuit.The transmission paths are coupled to the signal node and at least some of the transmission paths are set up to generate radar transmission signals based on the reflected signal.

[0007] Furthermore, an embodiment relates to a method for a radar system comprising a first integrated radar circuit, which includes at least several first transmission paths, a local oscillator, and a first terminal, and a second integrated radar circuit, which includes at least a second transmission path and a second terminal. The method comprises outputting an oscillation signal based on a local oscillator signal from the local oscillator via the first terminal to a partially reflective element, which is coupled to the first terminal via a first transmission line segment and to the second terminal via a second transmission line segment. The method further comprises reflecting a first component of the oscillation signal back as a reflected signal via the first transmission line segment to the first terminal through the partially reflective element.The method further comprises forwarding a second component of the oscillation signal as a forward signal via the second transmission line segment to the second terminal through the partially reflective element. The method further comprises outputting the reflected signal via a second port of a directional coupler of the first integrated radar circuit to a signal node of the first integrated radar circuit. A first port of the directional coupler is coupled to the first transmission line segment. The method further comprises generating radar transmit signals based on the reflected signal through at least some of the first transmit paths coupled to the signal node. Character description

[0008] Some examples of devices and / or methods are explained in more detail below with reference to the accompanying figures. These show: Fig. Figure 1 shows a first embodiment of a radar system; Fig. Figure 2 shows a second embodiment of a radar system; Fig. Figure 3 shows a first embodiment of a directional coupler; Fig. Figure 4 shows a second embodiment of a directional coupler; Fig. Figure 5 shows a third embodiment of a directional coupler; Fig. Figure 6 shows an embodiment of a partially reflective element; Fig. Figure 7 shows a third embodiment of a radar system; and Fig. Figure 8 shows a flowchart of an exemplary embodiment of a method for a radar system. Description

[0009] Several examples will now be described in more detail with reference to the accompanying figures, which illustrate some of these examples. The thickness of lines, layers, and / or areas may be exaggerated in the figures for clarity.

[0010] While further examples of various modifications and alternative forms are suitable, some specific examples are accordingly shown in the figures and are described in detail below. However, this detailed description does not limit further examples to the specific forms described. Further examples may encompass all modifications, correspondences, and alternatives that fall within the scope of revelation. Equal or similar reference signs throughout the description of the figures refer to identical or similar elements that, upon comparison, may be implemented identically or in a modified form while providing the same or a similar function.

[0011] It is understood that when an element is described as "connected" or "coupled" to another element, the elements may be connected or coupled directly or via one or more intermediate elements. When two elements A and B are combined using "or," this is to be understood as revealing all possible combinations, i.e., only A, only B, and A and B, unless explicitly or implicitly defined otherwise. An alternative formulation for the same combinations is "at least one of A and B" or "A and / or B." The same applies, mutatis mutandis, to combinations of more than two elements.

[0012] The terminology used here to describe certain examples is not intended to be limiting for other examples. Where a singular form, e.g., "a" and "the," "a," "a," is used, and the use of only a single element is neither explicitly nor implicitly defined as mandatory, further examples may also use plural elements to implement the same function. Similarly, where a function is subsequently described as being implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity.It is further understood that the terms “include”, “comprehensive”, “exhibit” and / or “exhibit” when used specify the presence of the indicated features, integers, steps, operations, processes, elements, components and / or a group thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and / or a group thereof.

[0013] Unless otherwise defined, all terms (including technical and scientific terms) are used herein in their usual meaning within the field to which examples belong.

[0014] Fig. Figure 1 shows a radar system 100 comprising a first integrated radar circuit 110 and a second integrated radar circuit 120. For example, the integrated radar circuits 110 and 120 can be implemented as MMICs. The first integrated radar circuit 110 serves as the master, while the second integrated radar circuit 120 serves as the slave. The two integrated radar circuits 110 and 120 are implemented on different semiconductor chips.

[0015] The first integrated radar circuit 110 comprises several primary transmission paths 111 to generate radar transmission signals 117 (e.g., with a carrier frequency of approximately 77 GHz). The second integrated radar circuit 120 also comprises at least one secondary transmission path 121 to generate a radar transmission signal 123. Thus, a multiple of radar transmission signals can be generated by means of the integrated radar circuits 110 and 120 to enable high-resolution radar scanning of the area surrounding the radar system 100.

[0016] Furthermore, the first integrated radar circuit 110 includes a local oscillator 113 configured to generate a local oscillator signal 114. The local oscillator signal 114 can, for example, be frequency-modulated (e.g., to transmit chirp signals in the 77 GHz range). The local oscillator signal 114 serves as the basis for the synchronous generation of the radar transmission signals in the two integrated radar circuits 110 and 120.

[0017] To synchronize the two integrated radar circuits 110 and 120 based on the local oscillator signal 114, the first integrated radar circuit 110 also includes a first connection 112, which is configured to output an oscillation signal based on the local oscillator signal 114. The oscillation signal based on the local oscillator signal 114 can be, for example, the local oscillator signal 114 itself or a signal derived from the local oscillator signal 114. For example, the oscillation signal can have a lower frequency than the local oscillator signal 114 and be a down-rate local oscillator signal (e.g., a high-frequency signal with half or a quarter of the frequency of the local oscillator signal 114). Likewise, the oscillation signal can be, for example, a power-amplified (and optionally filtered) copy of the local oscillator signal 114.The oscillation signal can be applied to terminal 112, for example, by the local oscillator 113 or by a circuit component of the first integrated radar circuit 110, which generates the oscillation signal based on the local oscillator signal 114.

[0018] To couple the second integrated radar circuit 120 to the first integrated radar circuit 110, the second integrated radar circuit 120 includes a second connection 122.

[0019] A partially reflective element 130 is coupled between the first integrated radar circuit 110 and the second integrated radar circuit 120. The partially reflective element 130 is coupled to the first terminal 112 via a first conductor section 140 and to the second terminal 122 via a second conductor section 150. Accordingly, the partially reflective element 130 receives the oscillation signal present at the first terminal 112 via the first conductor section 140. The partially reflective element 130 is thus connected between terminals 112 and 122. The conductor sections 140 and 150 can be, for example, striplines, waveguides, or dielectric waveguides. The conductor sections 140 and 150 can, for example, extend on a circuit board or other substrate on which the radar circuits 110 and 120 are mounted.

[0020] The partially reflective element 130 is configured to reflect a first portion of the oscillation signal back as a reflected signal via the first line section 140 to the first terminal 112, and to forward a second portion of the oscillation signal as a forward signal via the second line section 150 to the second terminal 122. In other words, part of the oscillation signal is reflected back to the first integrated radar circuit 110 by the partially reflective element 130, while another portion passes through the partially reflective element 130 and reaches the second integrated radar circuit 120 via the second line section 150.

[0021] The first integrated radar circuit 110 comprises a directional coupler 115, which is coupled via a first port to the first terminal 112 (or the first line section 140) and configured to output the reflected signal via a second port to a signal node 116 of the first integrated radar circuit 110. Due to the directional characteristics of the directional coupler 115, the reflected signal can be output to the signal node 116 essentially without components of other signal elements present at the first terminal 112. In other words, the directional coupler 115 enables the reflected signal to be extracted from the totality of all signals present at the first terminal 112.

[0022] The first transmission paths 111 are coupled to the signal node and can therefore receive the reflected signal. At least some of the first transmission paths 111 are configured to generate radar transmission signals 117 based on the reflected signal. For example, in some embodiments, only some of the first transmission paths 111 may be configured (or controlled) to generate radar transmission signals 117 based on the reflected signal. Alternatively, all transmission paths 111 may be configured to generate radar transmission signals 117 based on the reflected signal. Thus, the portion of the first transmission paths 111 that generates the radar transmission signals 117 can generate the radar transmission signals 117 in a time-correlated manner with respect to the reflected signal.

[0023] The second transmission path 121 of the second integrated radar circuit 120 is coupled to the second connection 122 and can thus receive the forward signal. The second transmission path 121 is configured to generate the radar signal 123 based on the forward signal. For example, the received forward signal can be fed to one or more power amplifiers to generate the transmission signal 123. If the received forward signal is based on a down-split local oscillator signal, a frequency multiplier can be provided in the radar circuit 120 to recover the frequency of the local oscillator signal. Thus, the second transmission path 121 can generate the radar transmission signal 123 in time correlated with the forward signal.

[0024] The two integrated radar circuits 110 and 120 can be synchronized by means of partial reflection of the oscillation signal in the high-frequency range, since each integrated radar circuit 110 and 120 is thus provided with a portion of the oscillation signal. Only a single connection is required in the integrated radar circuit 110 to output the oscillation signal used for synchronization and to receive its reflected portion.

[0025] In addition to synchronizing the transmit paths 111 and 121, the reflected signal and the forward signal can also be used to synchronize receive paths of the two integrated radar circuits 110 and 120.

[0026] For example, the first integrated radar circuit 110 can have at least one first receive path 118 coupled to the signal node 115, and the second integrated radar circuit 120 can further have at least one second receive path 124 coupled to the second port 122 for receiving and processing radar receive signals. Accordingly, the at least one first receive path 118 is configured to downmix a received radar receive signal 119 using the reflected signal (i.e., to downmix the radar receive signal 119 in a time-correlated manner to the reflected signal), while the at least one second receive path 124 is configured to downmix a received radar receive signal 125 using the forward signal (i.e., the radar receive signal 125 is downmixed in a time-correlated manner to the forward signal).

[0027] The partially reflective element 130 is configured to generate the reflected signal and the forward signal with a constant phase relative to each other. When φ 11 (f) the phase of the reflected signal and φ 21 (f) to denote the phase of the forward signal, the following relationship applies: φ11(f)φ21(f)=const.

[0028] For example, the partially reflective element 130 can be configured to generate the reflected signal and the forward signal in phase, such that φ 11 (f) = φ 21 (f). Alternatively, the partially reflecting element 130 can be configured to generate the reflected signal with a fixed phase shift c relative to the forward signal, such that φ 11 (f) = φ 21 (f) + c.

[0029] To ensure synchronization of the two integrated radar circuits 110 and 120, the phases of the reflected signal and the forward signal should be (as close as possible to) identical when they reach terminals 112 and 122, respectively. The phases of the reflected signal and the forward signal upon reception at terminals 112 and 122 are determined not only by the partially reflective element 130, but also by the lengths of the two cable sections 140 and 150. Accordingly, the lengths of the first cable section 140 and the second cable section 150 can be selected such that the phase of the reflected signal upon reception at the first terminal 112 is equal to the phase of the forward signal upon reception at the second terminal 122.

[0030] For example, the first conductor section 140 and the second conductor section 150 can have the same electrical length and the same properties if the partially reflective element 130 generates the reflected signal and the forward signal in phase. In other words, the partially reflective element 130 can be located centrally within the two terminals 112 and 122.

[0031] If the partially reflective element 130 generates the reflected signal with a phase shift relative to the forward signal, one of the two line sections 140 and 150 can, for example, be longer than the other to compensate for the phase shift generated by the partially reflective element 130. In other words, the partially reflective element 130 can be positioned offset from the center of the line connecting the two terminals 112 and 122.

[0032] Likewise, the partially reflective element 130 can be configured such that the reflected signal and the forward signal have similar signal strengths. For example, the partially reflective element 130 can be configured to partially reflect the oscillation signal such that the respective signal strengths of the reflected signal and the forward signal differ from each other by less than 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10%. In some embodiments, the partially reflective element 130 can be configured to partially reflect the oscillation signal such that the respective signal strengths of the reflected signal and the forward signal are (essentially) the same. 11 the scattering parameter of the reflected signal, i.e. the input reflection factor of the partially reflecting element 130, and S 21To describe the scattering parameter of the forward signal, i.e., the forward transmission factor of the partially reflecting element 130, the following relationship can therefore apply: S11=S21

[0033] For example, the reflected signal and the forward signal can each have a signal strength of -3dBm if a power of 0dBm is applied to the first line section 140 (i.e., S 11 = S 21 = -3dB).

[0034] In some embodiments, the reflected signal can thus be (essentially) identical to the forward signal, so that the first integrated radar circuit 110 effectively receives the same signal as the second integrated radar circuit 120. The two integrated radar circuits 110 and 120 can therefore be synchronized to the same signal. In other words, the master MMIC 110 and the slave MMIC 120 can be phase-synchronized using the oscillation signal in the high-frequency range. The proposed synchronization architecture uses the reflected component of the oscillation signal as feedback for the master MMIC 110, so that the master MMIC 110 can be kept synchronized with the slave MMIC 120. This also makes it possible, for example, for the channels of the master MMIC 110 and the slave MMIC 120 to be operated in a MIMO (Multiple In-Multiple Out) system.In contrast to existing concepts for self-sufficiency with local oscillation signals, the proposed synchronization architecture requires only a single connection to the master MMIC 110.

[0035] The oscillation signal can, for example, be applied to the first terminal 112 via the directional coupler 115. The directional coupler can, for example, be configured to receive the oscillation signal via a third port from the local oscillator 115 or another circuit element of the first integrated radar circuit 110 and output it via the first port to the first line section 140 or the first terminal 112. Alternatively, the oscillation signal can also be coupled in or applied to the first terminal 112 via a coupling element (not shown) arranged between the directional coupler 115 and the first terminal 112.

[0036] According to some embodiments, the two integrated radar circuits 110 and 120 can exchange their roles as master and slave (temporarily or permanently). For example, if the local oscillator 113 fails, the first integrated radar circuit 110 can become a slave, and conversely, the second integrated radar circuit 120 can become a master. More generally, in another operating mode of the radar circuit 100, the local oscillator 113 of the first integrated radar circuit 110 can be inactive. The second integrated radar circuit 120 can have another local oscillator 126, which in this other operating mode is configured to generate another local oscillator signal 127. The second terminal 122 is configured in this other operating mode to output another oscillation signal based on the other local oscillator signal.The synchronization of the two integrated radar circuits 110 and 120 can also be carried out in the further operating mode analogously to the concept described above. Thus, the partially reflective element 130 can be configured in the further operating mode to reflect a first component of the further oscillation signal back as a further reflected signal via the second line section 150 to the second terminal 122, and to forward a second component of the further oscillation signal as a further forward signal via the first line section 140 to the first terminal 112.

[0037] Part of the first transmission paths 111 can be configured in the further operating mode to generate the radar transmission signals 117 in a time-correlated manner with the further forward signal, and at least one second transmission path 121 can be configured in the further operating mode to generate the radar transmission signal 123 in a time-correlated manner with the further reflected signal. Thus, for example, the radar system 100 can continue to operate even if the local oscillator 113 fails.

[0038] At the in Fig. In the embodiment shown in Figure 1, a slave MMIC is coupled to the master MMIC. According to this embodiment, multiple slave MMICs can also be coupled to the master MMIC (e.g., two, three, four, or more slave MMICs). This is illustrated by example in Figure 1. Fig. 2 shown. Compared to the one in Fig. The radar system 100 shown in 1 indicates that in Fig. The radar system 200 shown in Figure 2 includes an additional third integrated radar circuit 270. The third integrated radar circuit 270 comprises a third connection 272 and at least one third transmission path 271 to generate a radar transmission signal 273.

[0039] The partially reflective element 230 is coupled to the third terminal 272 via a third line section 260. To synchronize the third integrated radar circuit 270 with the two other integrated radar circuits 110 and 120, the partially reflective element 230 is further configured to transmit a third component of the oscillation signal as an additional forward signal via the third line section 260 to the third terminal 272. The at least one third transmission path 271 is coupled to the third terminal 272 and configured to generate the radar transmission signal 273 in time correlated with the additional forward signal.

[0040] In addition to synchronizing the transmit paths 111, 121, and 271, the reflected signal and the forward signal can also be used to synchronize receive paths of the integrated radar circuits 110, 120, and 270. For example, the third integrated radar circuit 270 can further comprise at least one third receive path 274 coupled to the third terminal 272, which is configured to downmix a radar receive signal 275 using the further forward signal (i.e., downmix the radar receive signal 275 in a time-correlated manner with the further forward signal).

[0041] To enable reliable synchronization of all three integrated radar circuits 110, 120, and 270, the partially reflective element 230 is configured to generate the reflected signal, the forward signal, and the subsequent forward signal with a constant phase relative to each other. For example, in some embodiments, the partially reflective element 230 can be configured to generate the reflected signal, the forward signal, and the subsequent forward signal in phase, such that φ 11 (f) = φ 21 (f) = φ 31 (f), where φ 31 (f) denotes the phase of the further forward signal. Alternatively, the partially reflecting element 230 can be configured to generate the reflected signal, the forward signal and the further forward signal with fixed phase offsets c and d relative to each other, such that φ 11 (f) = φ 11 (f) + c = φ 31 (f) + d.

[0042] The phases of the reflected signal, the forward signal, and the subsequent forward signal can also be determined by the lengths of the line segments 140, 150, and 260. Accordingly, the lengths of the first line segment 140, the second line segment 150, and the third line segment 260 can be selected such that the phase of the reflected signal upon reception at the first terminal 112 is equal to the phase of the forward signal upon reception at the second terminal 122, and to the phase of the subsequent forward signal upon reception at the third terminal 272. For example, the line segments 140, 150, and 260 can be of the same length. Alternatively, one or more of the line segments 140, 150, and 260 can be longer than the others.

[0043] Regarding the signal strengths of the reflected signal, the forward signal, and the subsequent forward signal, essentially the same principles apply as previously discussed in connection with Fig. 1. For example, the partially reflective element 230 can be configured to partially reflect the oscillation signal such that the respective signal strengths of the reflected signal, the forward signal, and the subsequent forward signal differ from each other by less than 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10%. In some embodiments, the partially reflective element 230 can be configured to partially reflect the oscillation signal such that the respective signal strengths of the reflected signal, the forward signal, and the subsequent forward signal are (essentially) equal. For example, the following relationship may hold: S11=S21=S31=−3dB where S 31the scattering parameter of the further forward signal, i.e. the forward transmission factor of the partially reflecting element 230 towards the third terminal 272.

[0044] As already mentioned in connection with Fig. As described in section 2 for the second integrated radar circuit 120, the third integrated radar circuit 270 can also be operated as a master in some embodiments instead of as a slave, i.e., it can generate a local oscillation signal and output an oscillation signal based on this signal to the partially reflective element 230 for synchronizing the integrated radar circuits 110, 120, and 270. To avoid unnecessary repetition, reference is therefore made to the above descriptions of the second integrated radar circuit 120, which also apply accordingly to the third integrated radar circuit 270.

[0045] The in the Fig. 1 and Fig. The integrated radar circuits 110, 120, and 270 shown in Figure 2 can, according to some embodiments, be identically constructed (e.g., using identical MMICs) and differ only in their operating mode (master or slave). However, in other embodiments, different MMICs can be used.

[0046] The following are related to the Fig. 3, Fig. 4 to Fig. 5 Some exemplary directional couplers are described that can be used for the proposed synchronization architecture.

[0047] Fig. Figure 3 shows a rat-race coupler 300 with a ring conductor 310 and four ports P1, P2, P3, and P4. The oscillation signal is present at port P1 (i.e., port P1 is coupled to the source of the oscillation signal), while port P2 is coupled to the first terminal of the first integrated radar circuit, i.e., the partially reflecting element. Port P3 is coupled to the signal node of the first integrated radar circuit, and port P4 is isolated. The distances between ports P1 and P4, P4 and P3, and P4 and P2 are each 1 / 4 of the wavelength λ used (i.e., the wavelength of the oscillation signal). The distance between ports P1 and P2 is 3 / 4 of the wavelength λ. Accordingly, good isolation is achieved between ports P1 and P3, so that the scattering parameters S 13 = S 31 are very low. Therefore, essentially only the reflected signal received via gate P2 is present at gate P3.

[0048] Fig. Figure 4 shows a branch-line coupler 400 with four ports P1, P2, P3, and P4. The oscillation signal is present at port P1 (i.e., port P1 is coupled to the source of the oscillation signal), while port P2 is coupled to the first terminal of the first integrated radar circuit, or the partially reflecting element. Port P3 is isolated, and port P4 is coupled to the signal node of the first integrated radar circuit. The spacing between the ports is 1 / 4 of the wavelength λ used. Accordingly, good isolation is achieved between ports P1 and P4, so that the scattering parameters S 14 = S 41 are very low. Therefore, at gate P4, essentially only the reflected signal received via gate P2 is present.

[0049] The in the Fig. 3 and Fig. The four directional couplers shown thus both exhibit good isolation between the ports for the input of the oscillation signal and the branching point for the reflected signal. Another directional coupler, which exhibits lower signal losses compared to those shown in the Fig. 3 and Fig. The 4 directional couplers shown can enable this, is in Fig. 5 shown. Fig. Figure 5 shows another ring coupler 500, in which, compared to the ring coupler 300, a biasable PIN diode 520 (Positive Intrinsic Negative Diode) is arranged between the third port P3, which is coupled to the signal node, and the ring conductor 510. A bias voltage can be applied to the PIN diode 520 via a bias circuit (not shown), allowing the PIN diode 520 to operate as a controllable resistor. Appropriate control logic for adjustment can be connected to the PIN diode 520. The PIN diode 520 can thus be used as an amplitude controller for the reflected signal at port P3. The PIN diode 520 can also be used as a high-frequency switch, thereby disconnecting channels P3 and P4 from the circuit via control logic. This reduces power loss through the structure itself and makes it possible to use the channel as a transmit channel.Other embodiments may also include other active elements.

[0050] Likewise, a biasable PIN diode 530 is arranged between the insulated fourth port P4 of the ring coupler 500 and the ring conductor 510.

[0051] However, the directional coupler used for the proposed synchronization architecture is not compatible with the ones mentioned above in connection with the Fig. 3, Fig. 4 to Fig. The directional coupler described in section 5 is limited. However, any other suitable directional coupler can also be used.

[0052] In Fig. Figure 6 shows an exemplary implementation of the partially reflective element. For example, the partially reflective element can be configured as a butterfly stub 600. By adjusting the radius R0 and the angle of the circular segment-shaped stubs 610 and 620, a desired impedance mismatch can be created in the lines connecting the integrated radar circuits. This allows a portion of the incoming oscillation signal from the first connection to be reflected back with the desired phase and / or signal strength characteristics, while another portion of the incoming oscillation signal with the desired phase and / or signal strength characteristics is allowed to pass to the second connection.

[0053] However, the partially reflective element used for the proposed synchronization architecture is not limited to the butterfly-shaped 600 mm² branch line. Rather, any other suitable element can also be used (e.g., a coupler or power divider).

[0054] In some embodiments, the partially reflective element can be formed exclusively by passive components. The reflection can then result from a geometric structure that is adapted to the wavelengths of the oscillation signal. For example, a ring structure or an impedance mismatch structure, distinct from the transmission line segments, can be used to achieve both partial reflection and forward propagation by appropriately selecting the geometric dimensions. Compared to partially reflective elements with active components, this approach can achieve greater robustness and reduce the failure probability of the partially reflective element.

[0055] Fig. Figure 7 shows another embodiment of a radar system. The radar system 700 comprises a first integrated radar circuit 710 and a second integrated radar circuit 720. The first integrated radar circuit 710 serves as the master, while the second integrated radar circuit 720 serves as the slave.

[0056] The first integrated radar circuit 710 comprises several first transmit paths 711-1, 711-2 and 711-3 as well as several first receive paths 714-1, 714-2, 714-3 and 714-4. Likewise, the second integrated radar circuit 720 comprises several second transmit paths 721-1 and 721-2 as well as several second receive paths 724-1, 724-2, 724-3 and 724-4.

[0057] Furthermore, the first integrated radar circuit 710 includes a local oscillator 713 which is configured to generate a local oscillator signal 714.

[0058] To synchronize the two integrated radar circuits 710 and 720 based on the local oscillator signal 714, the first integrated radar circuit 710 also includes a first terminal 712-1, which is configured to output an oscillation signal based on the local oscillator signal 714. The first terminal 712-1 is coupled to the local oscillator 713 via the first transmit path 711-1. In other words, one of the first transmit paths 711-1, 711-2, and 711-3 is coupled to the first terminal 712-1 and configured to apply the oscillation signal based on the local oscillator signal 714 to the first terminal 712-1. For example, the first transmit path 711-1 can filter and amplify the local oscillator signal 714 and apply the processed local oscillator signal as an oscillation signal to the first terminal 712-1.The oscillation signal is applied to the first terminal 712-1 via a directional coupler 715, which is coupled to the first terminal 712-1 via a first port and to the first transmit path 711-1 via a third port.

[0059] To couple the second integrated radar circuit 720 to the first integrated radar circuit 710, the second integrated radar circuit 720 includes a second connection 722-1.

[0060] A partially reflective element 730 is coupled between the first integrated radar circuit 710 and the second integrated radar circuit 720. The partially reflective element 730 is coupled to the first terminal 712 via a first line section 740 and to the second terminal 722-1 via a second line section 750. Accordingly, the partially reflective element 730 receives the oscillation signal present at the first terminal 712 via the first line section 740.

[0061] The partially reflective element 730 is configured to reflect a first portion of the oscillation signal back as a reflected signal via the first line section 740 to the first terminal 712, and to forward a second portion of the oscillation signal as a forward signal via the second line section 750 to the second terminal 722. In other words, part of the oscillation signal is reflected back to the first integrated radar circuit 710 by the partially reflective element 730, while another portion passes through the partially reflective element 730 and reaches the second integrated radar circuit 720 via the second line section 750.

[0062] Although the first section of the line is 740 in Fig. The first line section 740, represented by two lines in Figure 7, is a single signal line. The representation of the first line section 740 by two lines was chosen to illustrate that between the first terminal 712-1 and the partially reflective element 730, both a forward component (namely the oscillation signal) and a backward component (namely the reflected portion of the oscillation signal) are transmitted simultaneously via the first line section 740.

[0063] The reflected signal is output via a second port of the directional coupler 115 to a signal node 716 of the first integrated radar circuit 710. The directional coupler 115 thus couples the reflected signal from the totality of all signals present at the first port 112.

[0064] The remaining first transmit paths 711-2 and 711-3 are also coupled to signal node 716 and receive the reflected signal via this node. Thus, the first transmit paths 711-2 and 711-3 can generate radar transmit signals in time correlation with the reflected signal and output them to transmit antennas for broadcast into the environment via connections 712-2 and 712-3, respectively. The first receive paths 714-1, 714-2, 714-3, and 714-4 are also coupled to signal node 716 and thus receive the reflected signal. Thus, the first reception paths 714-1, 714-2, 711-3 and 714-4 can downmix radar reception signals received from receiving antennas via connections 717-1, 717-2, 717-3 and 717-4 using the reflected signal, or downmix the radar reception signals in a time-correlated manner to the reflected signal.

[0065] The second transmit paths 721-1 and 721-2 of the second integrated radar circuit 720 are coupled to the second terminal 722-1 and thus receive the forward signal. Therefore, the second transmit paths 721-1 and 721-2 can generate radar transmit signals in time correlation with the forward signal and output them to the transmitting antenna via terminals 722-2 and 722-3, respectively, for transmission into the environment. Furthermore, the second receive paths 724-1, 724-2, 724-3, and 724-4 are coupled to the second terminal 722-1 and receive the forward signal via this connection. Thus, the second reception paths 724-1, 724-2, 724-3 and 724-4 can downmix radar reception signals received from receiving antennas via connections 723-1, 723-2, 723-3 and 723-4 using the forward signal, or downmix the radar reception signals in a time-correlated manner to the forward signal.

[0066] As already mentioned above in connection with Fig. If the process is carried out as described in point 1, the reflected signal can be (essentially) identical to the forward signal, so that the first integrated radar circuit 710 effectively receives the same signal as the second integrated radar circuit 720. The two integrated radar circuits 710 and 720 can thus be synchronized or phase-synchronized to (essentially) the same signal in the high-frequency range. In contrast to existing concepts for self-supply with local oscillation signals, the proposed synchronization architecture requires only a single connection on the integrated radar circuit 710.

[0067] In addition to the oscillation signal for phase synchronization in the high-frequency range, the two integrated radar circuits 710 and 720 can also exchange one or more other signals for synchronization. For example, the first integrated radar circuit 710 can output a system clock via additional pins 712-5 and 712-6, which is received by the second integrated radar circuit 720 via pins 722-5 and 722-6, which are coupled to pins 712-5 and 712-6. Accordingly, both integrated radar circuits 710 and 720 can operate with the same system clock. Likewise, the first integrated radar circuit 710 can output a trigger signal for ramping up the radar transmission signals in the frequency domain via an additional pin 712-4, which is received via pin 722-4 of the second integrated radar circuit 720, which is coupled to pin 712-4.Accordingly, the ramp-up of the radar transmission signals in both integrated radar circuits 710 and 720 can be performed synchronously.

[0068] The two integrated radar circuits 710 and 720 can also have additional connections, such as a (high-speed) interface 719-1 or 729-1 for outputting the downmixed radar reception signals or serial buses (e.g. a Serial Peripheral Interface) for exchanging other data.

[0069] Likewise, in some embodiments, the integrated radar circuits 710 and 720 can also be operated independently. For example, the first integrated radar circuit 710 can be used alone (i.e., without the integrated radar circuit 720). In this operating mode, synchronization of the first integrated radar circuit 710 with the second integrated radar circuit is not necessary. Accordingly, the first transmit path 711-1 can also be used to generate a radar transmit signal in this operating mode.

[0070] For example, the first integrated radar circuit 720 can further include a switch (not shown) configured to couple the local oscillator 713 with the signal node 716 in the advanced operating mode, so that all first transmit paths 711-1, 711-2, and 711-3 now receive the local oscillator signal 714. Similarly, the first transmit path 711-1 can be configured in the advanced operating mode to generate a radar transmit signal based on the local oscillator signal 714 and output it to the first terminal 712-1. In the advanced operating mode, the first terminal 712-1 is coupled to a transmit antenna instead of the partially reflective element 730. The other transmit paths 711-2 and 711-3 are configured in the advanced operating mode to generate the radar transmit signals based on the local oscillator signal 714.Accordingly, in single operation of the first integrated radar circuit 710, all transmission paths can be used for the generation of radar transmission signals.

[0071] The integrated radar circuits 710 and 720 can, according to some embodiments, have an identical construction (e.g., be identical MMICs) and differ only in the operating mode used (master or slave). For example, the second integrated radar circuit 720 can also have a local oscillator and / or an additional transmit path which is (or are) coupled to the second terminal 722-1 via a directional coupler, so that, analogous to the above descriptions for the first integrated radar circuit 710, the second terminal 722-1 can be used both for receiving the forward signal in cascaded operation and for outputting a radar transmit signal in standalone operation of the second integrated radar circuit 720.

[0072] To summarize the aspects described above regarding the synchronization of integrated radar circuits, it is necessary to... Fig. Figure 8 shows a flowchart of a method 800 for a radar system. The radar system comprises a first integrated radar circuit, which includes at least several first transmission paths, a local oscillator and a first terminal, and a second integrated radar circuit, which includes at least a second transmission path and a second terminal.

[0073] Method 800 comprises outputting 802 an oscillation signal based on a local oscillator signal of the local oscillator via the first terminal to a partially reflective element, which is coupled to the first terminal via a first line segment and to the second terminal via a second line segment. Method 800 further comprises reflecting back 804 a first component of the oscillation signal as a reflected signal via the first line segment to the first terminal through the partially reflective element. Method 800 further comprises forwarding 806 a second component of the oscillation signal as a forward signal via the second line segment to the second terminal through the partially reflective element.Method 800 further comprises outputting 808 the reflected signal via a second port of a directional coupler of the first integrated radar circuit to a signal node of the first integrated radar circuit. A first port of the directional coupler is coupled to the first terminal. Method 800 further comprises generating 810 radar transmit signals based on the reflected signal by at least some of the first transmit paths coupled to the signal node.

[0074] Further details and aspects of the procedure are described above in connection with further examples of implementation (e.g. Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7) described. The method may include one or more optional features as described in the further embodiments.

[0075] The examples of implementation described herein can be summarized as follows: Some embodiments relate to a radar system. The radar system comprises a first integrated radar circuit with several first transmission paths and a local oscillator configured to generate a local oscillator signal. The first integrated radar circuit also has a first terminal configured to output an oscillation signal based on the local oscillator signal. The radar system further comprises a second integrated radar circuit with at least one second transmission path and a second terminal. The radar system also includes a partially reflective element coupled to the first terminal via a first transmission line and to the second terminal via a second transmission line.The partially reflective element is configured to reflect a first component of the oscillation signal back to the first terminal via the first transmission line segment and to transmit a second component of the oscillation signal as a forward signal to the second terminal via the second transmission line segment. The first integrated radar circuit further comprises a directional coupler connected to the first terminal via a first port and configured to output the reflected signal to a signal node of the first integrated radar circuit via a second port. The first transmission paths are coupled to the signal node, and at least a portion of the first transmission paths are configured to generate radar transmission signals based on the reflected signal.

[0076] According to some embodiments, the part of the first transmission paths is configured to generate radar transmission signals temporally correlated to the reflected signal, wherein the at least one second transmission path is coupled to the second connection and configured to generate a radar transmission signal temporally correlated to the forward signal.

[0077] In some embodiments, the first integrated radar circuit further comprises at least a first receive path which is coupled to the signal node and configured to downmix a radar receive signal using the reflected signal.

[0078] According to some embodiments, the second integrated radar circuit further comprises at least a second receive path which is coupled to the second terminal and configured to downmix a radar receive signal using the forward signal.

[0079] In some embodiments, the partially reflective element is configured to generate the reflected signal and the forward signal with a constant phase relative to each other.

[0080] According to some embodiments, the partially reflective element is configured to generate the reflected signal and the forward signal in phase.

[0081] In some embodiments, the lengths of the first line section and the second line section are chosen such that a phase of the reflected signal upon reception at the first terminal is equal to a phase of the forward signal upon reception at the second terminal.

[0082] For example, according to some embodiments, the first line section and the second line section have the same length.

[0083] In some embodiments, the respective signal strengths of the reflected signal and the forward signal differ from each other by less than 50%.

[0084] For example, according to some embodiments, the respective signal strengths of the reflected signal and the forward signal are the same.

[0085] In some embodiments, the partially reflective element comprises exclusively passive components.

[0086] According to some embodiments, the directional coupler is a ring coupler, wherein a biasable PIN diode is arranged between the second port of the ring coupler and the ring conductor of the ring coupler.

[0087] In some embodiments, one of the first transmit paths is coupled to the first terminal via the directional coupler and configured to apply the oscillation signal based on the local oscillator signal to the first terminal.

[0088] According to some embodiments, the directional coupler is configured to receive the oscillation signal from the local oscillator via a third port and output it to the first line via the first port.

[0089] In some embodiments, the radar system further comprises a third integrated radar circuit with at least one third transmission path and a third connection, wherein the partially reflective element is coupled to the third connection via a third line segment. The partially reflective element is further configured to transmit a third component of the oscillation signal as a further forward signal via the third line segment to the third connection. The at least one third transmission path is coupled to the third connection and configured to generate a radar transmission signal temporally correlated with the further forward signal.

[0090] According to some embodiments, the partially reflective element is configured to generate the reflected signal, the forward signal and the further forward signal with a constant phase relative to each other.

[0091] For example, in some embodiments, the partially reflective element is configured to generate the reflected signal, the forward signal, and the subsequent forward signal in phase.

[0092] In some embodiments, the third integrated radar circuit further comprises at least a third receive path which is coupled to the third terminal and configured to downmix a radar receive signal using the further forward signal.

[0093] According to some embodiments, the local oscillator of the first integrated radar circuit is inactive in a further operating mode, wherein the second integrated radar circuit has a further local oscillator which, in the further operating mode, is configured to generate a further local oscillator signal. The second terminal is configured in the further operating mode to output a further oscillation signal based on the further local oscillator signal. The partially reflective element is configured in the further operating mode to reflect a first component of the further oscillation signal back to the second terminal as a further reflected signal via the second line segment and to forward a second component of the further oscillation signal as a further forward signal via the first line segment to the first terminal.

[0094] In some embodiments, the part of the first transmission paths is configured in the further operating mode to generate the radar transmission signals in a time-correlated manner to the further forward signal, wherein the at least one second transmission path is configured in the further operating mode to generate the radar transmission signal in a time-correlated manner to the further reflected signal.

[0095] Further embodiments relate to an integrated radar circuit. The integrated radar circuit comprises several transmission paths and a local oscillator configured to generate a local oscillator signal. The integrated radar circuit also includes a connection for linking an external element via a cable segment. This connection is configured to output an oscillation signal based on the local oscillator signal to the cable segment and to receive a portion of the oscillation signal reflected by the external element as a reflected signal via the cable segment. Furthermore, the integrated radar circuit includes a directional coupler, which is coupled to the connection via a first port and configured to output the reflected signal via a second port to a signal node of the integrated radar circuit.The transmission paths are coupled to the signal node and at least some of the transmission paths are set up to generate radar transmission signals based on the reflected signal.

[0096] According to some embodiments, one of the transmission paths is coupled to the connection via the directional coupler and configured to apply the oscillation signal to the connection based on the local oscillator signal.

[0097] In some embodiments, the integrated radar circuit further includes a switch configured to couple the local oscillator to the signal node in an additional operating mode. In this additional operating mode, one of the transmit paths is configured to generate a radar transmit signal based on the local oscillator signal and output it to the terminal. The other transmit paths are configured in this additional operating mode to generate radar transmit signals based on the local oscillator signal.

[0098] According to some embodiments, the integrated radar circuit further comprises at least one receive path coupled to the signal node and configured to downmix a radar receive signal using the reflected signal.

[0099] Furthermore, exemplary embodiments relate to a method for a radar system comprising a first integrated radar circuit, which includes at least several first transmission paths, a local oscillator, and a first terminal, and a second integrated radar circuit, which includes at least a second transmission path and a second terminal. The method comprises outputting an oscillation signal based on a local oscillator signal from the local oscillator via the first terminal to a partially reflective element, which is coupled to the first terminal via a first transmission line and to the second terminal via a second transmission line. The method further comprises reflecting a first component of the oscillation signal back as a reflected signal via the first transmission line to the first terminal through the partially reflective element.The method further comprises forwarding a second component of the oscillation signal as a forward signal via the second transmission line segment to the second terminal through the partially reflective element. The method further comprises outputting the reflected signal via a second port of a directional coupler of the first integrated radar circuit to a signal node of the first integrated radar circuit. A first port of the directional coupler is coupled to the first terminal. The method further comprises generating radar transmit signals based on the reflected signal through at least some of the first transmit paths coupled to the signal node.

[0100] Cascading multiple MMICs allows the use of more receive and transmit antennas for radar scanning. This can, for example, improve the radar image in terms of azimuth angle resolution and / or elevation angle resolution. Implementations of the proposed synchronization architecture can allow the use of the maximum number of available transmit paths for antenna coupling instead of synchronization. This can be particularly advantageous in smaller systems with only two or three cascaded MMICs. As mentioned above, phase synchronization in the high-frequency range is important for cascaded MMICs. The proposed synchronization architecture can enable synchronization by means of feedback of reflected signals to the master MMIC.Unlike existing approaches, connecting the master MMIC is sufficient for synchronization, so that additional antennas or transmission paths can be used for the actual radar scanning.

[0101] The aspects and features described together with one or more of the previously detailed examples and figures can also be combined with one or more of the other examples to replace an identical feature of the other example or to additionally introduce the feature into the other example.

[0102] The descriptions and drawings only illustrate the principles of revelation. Furthermore, all examples presented here are expressly intended for illustrative purposes only, to assist the reader in understanding the principles of revelation and the concepts contributed by the inventor(s) to the advancement of technology. All statements made here regarding principles, aspects, and examples of revelation, as well as specific examples thereof, include their corresponding references.

[0103] A block diagram, for example, can represent a rough circuit diagram that implements the principles of the disclosure. Similarly, a flowchart, a process flowchart, a state transition diagram, pseudocode, and the like can represent various processes, operations, or steps that are, for example, substantially depicted in a computer-readable medium and thus executed by a computer or processor, regardless of whether such a computer or processor is explicitly shown. Methods disclosed in the description or in the claims can be implemented by a component that includes means for performing each of the respective steps of these methods.

[0104] It is understood that the disclosure of multiple steps, processes, operations, or functions in the description or claims should not be interpreted as being in a specific order unless explicitly or implicitly stated otherwise, for example, for technical reasons. Therefore, the disclosure of multiple steps or functions does not restrict them to a specific order unless these steps or functions are not interchangeable for technical reasons. Furthermore, in some examples, a single step, function, process, or operation may include and / or be broken down into multiple sub-steps, sub-functions, sub-processes, or sub-operations. Such sub-steps may be included and form part of the disclosure of that single step unless explicitly excluded.

[0105] Furthermore, the following claims are hereby included in the detailed description, where each claim can stand alone as a separate example. While each claim can stand alone as a separate example, it should be noted that—although a dependent claim may refer in the claims to a specific combination with one or more other claims—other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are explicitly suggested here unless it is stated that a particular combination is not intended. Furthermore, features of a claim for any other independent claim are also to be included, even if that claim is not directly dependent on the independent claim.

Claims

[1] Radar system (100), comprising: a first integrated radar circuit (110) with several first transmission paths (111) and a local oscillator (113) configured to generate a local oscillator signal (114), wherein the first integrated radar circuit (110) also has a first connection (112) configured to output an oscillation signal based on the local oscillator signal (114); a second integrated radar circuit (120) with at least one second transmission path (121) and a second connection (122); and a partially reflective element (130) which is coupled to the first terminal (112) via a first line section (140) and to the second terminal (122) via a second line section (150), wherein the partially reflective element (130) is configured to reflect a first component of the oscillation signal back to the first terminal (112) as a reflected signal via the first line section (140) and to transmit a second component of the oscillation signal as a forward signal via the second line section (150) to the second terminal (122), wherein the first integrated radar circuit (110) comprises a directional coupler (115) which is coupled to the first terminal (112) via a first port and is configured to output the reflected signal via a second port to a signal node (116) of the first integrated radar circuit (110), wherein the first transmission paths (111) are coupled to the signal node (116) and at least part of the first transmission paths (111) is set up to generate radar transmission signals (117) based on the reflected signal. [2] Radar system according to claim 1, wherein the part of the first transmission paths (111) is configured to generate the radar transmission signals (117) in a time-correlated manner to the reflected signal, and wherein the at least one second transmission path (121) is coupled to the second connection (122) and configured to generate a radar transmission signal (123) in a time-correlated manner to the forward signal. [3] Radar system according to claim 1 or claim 2, wherein the first integrated radar circuit (110) further comprises at least a first receive path (118) coupled to the signal node (116) and configured to downmix a radar receive signal (119) using the reflected signal. [4] Radar system according to one of claims 1 to 3, wherein the second integrated radar circuit (120) further comprises at least a second receiving path (124) which is coupled to the second connection (122) and configured to downmix a radar receiving signal (125) using the forward signal. [5] Radar system according to any one of claims 1 to 4, wherein the partially reflective element (130) is configured to generate the reflected signal and the forward signal with a constant phase relative to each other. [6] Radar system according to any one of claims 1 to 5, wherein the partially reflective element (130) is configured to generate the reflected signal and the forward signal in phase. [7] Radar system according to claim 6, wherein the first line section (140) and the second line section (150) have the same length, and / or wherein the lengths of the first line section (140) and the second line section (150) are selected such that a phase of the reflected signal upon reception at the first terminal (112) is equal to a phase of the forward signal upon reception at the second terminal (122). [8] Radar system according to any one of claims 1 to 7, wherein the respective signal strengths of the reflected signal and the forward signal differ from each other by less than 50%, and / or wherein the respective signal strengths of the reflected signal and the forward signal are equal. [9] Radar system according to any one of claims 1 to 8, wherein the partially reflective element (130) comprises exclusively passive components. [10] Radar system according to any one of claims 1 to 9, wherein the directional coupler (115) is a ring coupler (500), and wherein a biasable PIN diode (520) is arranged between the second port of the ring coupler and the ring conductor (510) of the ring coupler. [11] Radar system according to one of claims 1 to 10, wherein one of the first transmit paths (111) is coupled to the first terminal (112) via the directional coupler (115) and is configured to apply the oscillation signal based on the local oscillator signal (114) to the first terminal (112). [12] Radar system according to any one of claims 1 to 11, further comprising a third integrated radar circuit (270) with at least one third transmission path (271) and a third connection (272), wherein the partially reflective element (230) is coupled to the third connection (272) via a third line section (260), wherein the partially reflective element (230) is configured to transmit a third component of the oscillation signal as a further forward signal via the third line section (260) to the third connection (270), and wherein the at least one third transmission path (271) is coupled to the third connection (272) and configured to generate a radar transmission signal (273) temporally correlated with the further forward signal. [13] Radar system according to claim 12, wherein the partially reflective element (230) is configured to generate the reflected signal, the forward signal and the further forward signal with a constant phase relative to each other, and / or wherein the partially reflective element (230) is configured to generate the reflected signal, the forward signal and the further forward signal in phase. [14] Radar system according to one of claims 1 to 13, wherein in a further operating mode the local oscillator (113) of the first integrated radar circuit (110) is inactive, wherein the second integrated radar circuit (120) has a further local oscillator (126) which in the further operating mode is configured to generate a further local oscillator signal (127), wherein the second terminal (122) in the further operating mode is configured to output a further oscillation signal based on the further local oscillator signal (127), wherein the partially reflective element (130) in the further operating mode is configuredto reflect a first part of the further oscillation signal back as a further reflected signal via the second line section (150) to the second terminal (122) and to forward a second part of the further oscillation signal as a further forward signal via the first line section (140) to the first terminal (112). [15] Radar system according to claim 14, wherein the part of the first transmission paths (111) is configured in the further operating mode to generate the radar transmission signals (117) in a time-correlated manner to the further forward signal, and wherein the at least one second transmission path (121) is configured in the further operating mode to generate the radar transmission signal (123) in a time-correlated manner to the further reflected signal. [16] Integrated radar circuit (110), comprising: multiple transmission paths (111); a local oscillator (113) configured to generate a local oscillator signal (114); a connection (112) for connecting an external element (130) via a line section (140), wherein the connection (112) is configured to output an oscillation signal based on the local oscillator signal (114) to the line section (140) and to receive a portion of the oscillation signal reflected by the external element (130) as a reflected signal via the line section (140); and a directional coupler (115) which is coupled to the connection (112) via a first port and configured to output the reflected signal via a second port to a signal node (116) of the integrated radar circuit (110), wherein the transmission paths (111) are coupled to the signal node (116) and at least part of the transmission paths (111) is set up to generate radar transmission signals (117) based on the reflected signal. [17] Integrated radar circuit according to claim 16, wherein one of the transmit paths (111) is coupled to the terminal via the directional coupler (115) and is configured to apply the oscillation signal based on the local oscillator signal (114) to the terminal. [18] Integrated radar circuit according to claim 17, further comprising a switch which is configured to couple the local oscillator (113) to the signal node (116) in a further operating mode, wherein one of the transmit paths (111) is configured in the further operating mode to generate a radar transmit signal based on the local oscillator signal (114) and output it to the terminal, and wherein the other transmit paths (111) are configured in the further operating mode to generate the radar transmit signals (117) based on the local oscillator signal (114). [19] Integrated radar circuit according to one of claims 16 to 18, further comprising at least one receiving path (118) coupled to the signal node (116) and configured to downmix a radar receiving signal (119) using the reflected signal. [20] Method (800) for a radar system comprising a first integrated radar circuit comprising at least several first transmission paths, a local oscillator and a first terminal, and a second integrated radar circuit comprising at least a second transmission path and a second terminal, comprising the method: Output (802) of an oscillation signal based on a local oscillator signal of the local oscillator via the first terminal to a partially reflective element which is coupled to the first terminal via a first line section and to the second terminal via a second line section; Reflecting back (804) a first part of the oscillation signal as a reflected signal via the first line section to the first terminal through the partially reflecting element; Forwarding (806) a second component of the oscillation signal as a forward signal via the second line section to the second terminal through the partially reflecting element; Output (808) of the reflected signal via a second port of a directional coupler of the first integrated radar circuit to a signal node of the first integrated radar circuit, wherein a first port of the directional coupler is coupled to the first terminal; and Generating (810) radar transmit signals based on the reflected signal through at least some of the first transmit paths coupled to the signal node.

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