Test equipment for sensors

Abstract

A test device (10) for a sensor (DUT), the sensor (DUT) being configured to perform object detection by transmitting a first electromagnetic signal (S1) and receiving a second electromagnetic signal (S2), the test device (10) having a chamber (K) with a housing (AUF) for the sensor (DUT), the chamber (K) further having at least two transceivers (SE, SE1, SE2), the at least two transceivers (SE, SE1, SE2) being configured to receive the first signal (S1) transmitted from the sensor (DUT) into the chamber (K) and transmit a second signal (S2) to be received by the sensor (DUT), the at least two transceivers (SE, SE1, SE2) each having one radiating element for radiating the second signal (S2), and a spacing device (BA) being provided, the spacing device (BA) being capable of changing the mutual spacing of the at least two radiating elements in exactly one spatial direction.

Description

[Technical Field]

[0001] The present application relates to a test device for sensors that operate with electromagnetic waves and involve the evaluation of transmitted and received electromagnetic signals. [Background technology]

[0002] WO 2020 / 127984 discloses a test bench for testing distance sensors operating with electromagnetic waves, in which the distance sensor under test has a sensor emitting element for emitting at least one transmission signal and a sensor receiving element for receiving a reflected signal. The test bench includes a housing for holding the distance sensor under test and a connecting member that is at least partially movable in the emission area of ​​the distance sensor held in the housing. At least one test bench receiving element held on the connecting member is provided to receive the transmission signal radiated by the sensor emitting element. At least one test bench radiating element held on the connecting member is provided to radiate the test bench transmission signal as a simulated reflected signal. Reliable ambient simulation, particularly for testing multi-input, multi-output distance sensors, is achieved by arranging at least one test bench receiving element and the test bench radiating element together on the movable part of the connecting member.

[0003] WO 2017 / 198613 discloses an antenna measuring chamber for measuring the antenna characteristics of RF antennas, which is provided with a complete lining with absorbers at the boundary surfaces located inside the chamber, separate supports for the antenna under test and for the transmitting antenna, a double bottom for guiding the cables of the antenna's feed and control lines invisibly, and a support configured as a movable carriage for one of the two antennas, which support is movable on the lower of the two bottoms of the double bottom and passes through the upper bottom on which the lining rests.

[0004] German Patent Application No. DE 10 2019 123 155 A1 discloses a test bench for testing ambient sensors operating with electromagnetic waves, in which the ambient sensor to be tested has a sensor emitting element for emitting at least one transmission signal and a sensor receiving element for receiving a reflected signal, the test bench having a receiving part for holding the ambient sensor to be tested and at least one pivoting arm with a rotation axis, in which a first test bench emitting element and / or a first test bench receiving element is held, the first test bench emitting element and / or the first test bench receiving element being movable about the pivoting axis within the visibility range of the ambient sensor held in the receiving part by the pivoting arm, independent of the orientation of the pivoting arm, the test bench receiving element being configured to receive the transmission signal emitted by the sensor emitting element, and the test bench emitting element being configured to emit the test bench transmission signal as a simulated reflected signal, the pivoting arm having a supporting device supported for sliding movement. Summary of the Invention [Means for solving the problem]

[0005] A test device for a sensor is proposed. The sensor is configured to perform object detection by transmitting a first electromagnetic signal and receiving a second electromagnetic signal. The test device includes a chamber with a housing for the sensor. The chamber further includes at least two transceivers configured to receive a first signal transmitted from the sensor into the chamber and transmit a second signal for reception by the sensor, each of the at least two transceivers having a radiating element for radiating the second signal. A spacing device is provided, which can be used to change the mutual spacing of the at least two radiating elements in exactly one spatial direction.

[0006] The test device for the sensor has the advantage that the spacing device, which allows the mutual spacing of at least two radiating elements to be varied in exactly one spatial direction, allows the test device to perform low-cost and simple angular separation measurements, in which it is determined at what angle the sensor can still separately perceive a second signal received after reflection from two adjacent objects.

[0007] The ability to vary the spacing of at least two radiating elements in only one linear spatial direction allows targeted testing of this very parameter.

[0008] The sensor for object detection may be an ambient sensor, particularly for use in a vehicle. Such ambient sensors operate with electromagnetic waves and are used, for example, as distance sensors. For this purpose, radar sensors with wavelengths in the microwave range are used, for example. However, the test device is also suitable for sensors, particularly ambient sensors, that operate with electromagnetic waves in other frequency ranges, for example in the visible light range, or that operate with electromagnetic radiation sources that emit electromagnetic waves with long coherence lengths, such as in laser applications (e.g., lidar).

[0009] The sensor, in particular the ambient sensor, can then transmit a first signal and receive its reflection as a second signal. By evaluating the first and second signals, information about the presence of an object, the distance to the object, the relative speed, and / or further properties of the object, such as its size and / or surface properties, can be obtained.

[0010] A test device is understood to be a device configured to test a sensor for object detection, for example, before it is installed in a vehicle. For this purpose, the test device has a receiving portion as a holder for receiving the sensor as a so-called device under test. Thus, the sensor can emit a first electromagnetic signal into a chamber of the test device and receive a second electromagnetic signal from the chamber. This allows the functionality of the sensor to be reliably tested by the test device.

[0011] For this purpose, the test device has a transceiver device that can receive a first signal from the sensor and transmit a second signal to the sensor, thereby simulating an object, which in this case offers the advantage that by varying the spacing between two radiating elements, i.e. two simulated objects, it is possible to find out what the spacing between these radiating elements should be, at which point such a sensor can still just barely distinguish between these two objects.

[0012] Thus, the test device not only provides a mechanical structure for holding the sensor in the housing, but also a unique transmitter / receiver for receiving a first signal emitted by the sensor and transmitting a second signal to the sensor. For this purpose, a corresponding drive and evaluation device is also provided, for example in a computing unit, to complete such a test device. Such a test device allows the sensor to be tested in many situations, for example before being installed in a vehicle.

[0013] The sensor according to the present application may be, for example, a radar or lidar sensor. The radar sensor may emit a first signal, for example, at 24 GHz, 60 GHz, or 77 GHz. The lidar signal is emitted, for example, in the near infrared. For this purpose, the sensor therefore comprises a transmitter, for example a radar or lidar transmitter, and a receiver, i.e., a corresponding radar or lidar receiver.

[0014] Radar or lidar sensors may be used for object detection. That is, such sensors may be configured to identify, classify, and / or track objects. An important criterion is that the sensor must be able to distinguish between two objects, even if they are close to each other. This is a requirement that such sensors must reliably fulfill, especially at relatively long distances.

[0015] The spacing device in this case makes it possible to vary the distance between the radiating elements linearly in exactly one spatial direction, thereby varying the distance between the simulated objects and thereby ascertaining at what distance the two objects are no longer distinguishable by the sensor or are still just distinguishable. The spacing device in this case is configured to make it possible to vary the mutual position and thus the distance between the at least two radiating elements in one spatial direction, while in this case the position and thus the distance between the at least two radiating elements is fixed in the other spatial direction.

[0016] The test device herein has a chamber into which the sensor can transmit a first signal and from which the sensor can receive a second signal, thus providing a defined environment for testing the sensor. In particular, to avoid unwanted reflections, such a chamber can be lined with a corresponding absorber, so that only the second signals emitted from the at least two transmitting / receiving devices are visible to the sensor and are received accordingly, while interfering radiation is substantially eliminated.

[0017] That is, the at least two transceivers are configured to transmit and receive radar or lidar radiation, just like the sensor itself. However, the at least two transceivers may be configured more simply, similarly, or more complexly. The at least two transceivers must be capable of receiving a first signal and, depending on the first signal, transmitting a second signal that simulates an object for the sensor. This allows for controlled simulation within the chamber. Therefore, each of the two transceivers has a radiating element for radiating the second signal. The radar sensor may be a radiating element, such as a transmitting antenna. The lidar sensor may be a radiating element, such as an optical emitter.

[0018] The test device offers the advantage, among other things, of being able to vary the position of the radiating elements relative to one another. This is important, since it is desired to test the resolution of the radiating points. In other words, in order to test with the finest possible resolution, it is desirable that the points from which the second signal is transmitted to the sensor are as close to one another as possible.

[0019] The spacing device, the possible embodiments of which are described in the dependent claims, allows the mutual spacing of at least two radiating elements to be varied linearly in exactly one spatial direction. This may be, for example, the horizontal direction, but may also be the vertical direction. When varying horizontally, a so-called azimuth angle is found at which the two objects are still distinguishable. When spacing the two radiating elements vertically, the smallest elevation angle is found at which the two radiating elements are barely distinguishable from one another.

[0020] The test device therefore offers the advantage that the radiating element of the transmitting / receiving device can be varied in space in only one direction and fixed in space in the other direction.

[0021] The test device therefore offers the advantage that the radiating elements of the transmitting and receiving devices can be constructed, for example, at the same height, i.e. at the same elevation angle, and only the lateral spacing, i.e. the azimuth angle, can be varied during testing.

[0022] Alternatively, the radiating elements of the transmitter and receiver may be constructed on the same vertical line, i.e., at the same azimuth angle, and only the height, i.e., elevation angle, may be varied during testing.

[0023] In one embodiment, if a separate receiving element per transceiver is used in addition to the radiating element, the position of the receiving element can be changed together with the radiating element to avoid introducing a phase shift between the receiving element and the radiating element. To avoid this, it is advantageous to keep the radiating element and the receiving element of the transceiver as close to each other as possible. The sensor waits for a response from the same direction as it transmitted. Therefore, it is preferably envisaged that the radiating element and the receiving element slide together.

[0024] In one embodiment, the spacing device has at least one rail, by means of which the mutual spacing of at least two radiating elements can be changed in exactly one spatial direction. The rail allows the spacing change to be achieved particularly accurately and reliably. This can then be done, for example, manually or automatically. To change the spacing in a linear spatial direction, the rail is configured as a linear rail, in particular allowing the radiating elements to move along a linear trajectory in space.

[0025] It is further proposed that the spacing device can be used to change the mutual spacing of the at least two transmitting and receiving devices in exactly one spatial direction, the spacing device having, inter alia, at least one rail, by means of which the mutual spacing of the at least two transmitting and receiving devices can be changed in exactly one spatial direction, i.e., the positions of the at least two transmitting and receiving devices with their respective radiating elements can be changed together on the rail, while the spacing in other spatial directions remains unchanged. In this embodiment, the rail is also configured linearly, so that the spacing change is performed in one linear direction.

[0026] In each embodiment, the spacing device has a first operating device for manually changing the spacing and / or a second operating device for automatically changing the spacing. Manually changing the spacing then allows the spacing to be individually adapted to the situation at hand, without the need to input additional data. Automatically changing the spacing allows for the use of a predefined inspection program and / or for dynamically adapting to the sensor's response. For example, this allows the spacing to be set depending on the second signal and / or on the evaluation performed by the sensor. This then allows for very precise specification of the spacing at which two objects are still barely distinguishable, or at which the two objects are no longer distinguishable.

[0027] Furthermore, the chamber can have multiple modules that extend the chamber in at least one direction, particularly from the sensor to the radiating element or transceiver. This modular design therefore allows the spacing between the sensor and the radiating element or transceiver to be adapted depending on the test requirements or the specific characteristics of the sensor, thereby enabling testing to be extended to larger distances.

[0028] It is further conceivable that the housing is configured to change the position and / or orientation of the sensor. This allows the sensor to be not only attached in a fixed position but also to be changed with respect to its position, thus allowing the geometrical position of the sensor and the at least two transmitting and receiving devices to be changed in addition to the spacing device. This also allows the orientation of the sensor, i.e., the direction in which the sensor emits the first signal, to be changed. This then allows a very precise evaluation of the quality of object detection for the sensor.

[0029] As already mentioned above, it is proposed that the chamber is substantially lined with an absorbent material that absorbs electromagnetic signals within the interior space of the chamber.

[0030] Furthermore, it is proposed that the at least two transmitting / receiving devices each have a receiving element for receiving the first signal, the transmitting element and the receiving element of each transmitting / receiving device are arranged in the wall area of ​​the interior space of the chamber, and the spacing device is arranged outside the chamber. This has the advantage that the spacing device does not need to be specially lined to avoid undesired reflections from the spacing device. Furthermore, the spacing device can be more easily maintained or operated outside the chamber.

[0031] Furthermore, it is assumed that the at least two transceiver units each have one transmitting transducer and one receiving transducer, and that the transmitting and receiving transducers of each transceiver unit are arranged outside the chamber. This also has the advantage that the test device can be more easily operated, for example, when a transmitting or receiving transducer must be replaced, and that lining the inside of the chamber to avoid reflections is not necessary. Each radiating element of each transceiver unit is connected to the transmitting transducer via a waveguide. The transmitting transducer converts, among other things, an electrical baseband signal, which can be extracted as a working signal via the transmitting element / receiving element interface, into a modulated high-frequency signal that can be radiated from the radiating unit. Each receiving element of each transceiver unit is connected to the receiving transducer via a waveguide. The receiving transducer converts, among other things, the modulated high-frequency signal output from the receiving element into a baseband signal, which can then be output as a working signal via the transmitting element / receiving element interface.

[0032] It is further proposed that the chamber wall has a region with a slit through which each radiating element is connected to its respective transmitting transducer via a waveguide, and each receiving element is connected to its respective receiving transducer via a waveguide. Terminals can be guided through the slit, i.e., through elongated openings in the chamber wall. To avoid reflections at these feedthroughs, the slits can also be lined accordingly. Preferably, a waveguide is provided for connection to the transducer to ensure reliable transmission of high-frequency signals. Furthermore, the slits, particularly inside the chamber, can be substantially covered with an absorbent material.

[0033] In one embodiment, the region is configured as a wall insert for a wall opening, the wall insert being insertable into the wall of the chamber in at least two different orientations, which allows the insert to be used, for example, at 90° different angles, to test azimuth or elevation angles.

[0034] Furthermore, it can be assumed that the radiating element and the receiving element of each transceiver device are configured as a combined radiating / receiving element, where, in particular for radar sensors, the radiating element can be configured as a transmitting antenna and the receiving element can be configured as a receiving antenna.

[0035] Optionally, the transmitting and receiving antennas may be configured as a single antenna, which may in particular be configured as a horn or curved antenna, as this allows for savings in material or horn or curved antennas are particularly suitable for the purposes of the present invention, as they allow for particularly small spacing between the radiating elements of the respective transmitting and receiving devices.

[0036] Furthermore, such combined antennas of each transceiver are connected via respective waveguides to a transceiver, which may include a transmitting transducer and a receiving transducer of each transceiver.

[0037] As mentioned above, the sensor may also be configured as a radar sensor, or alternatively as a lidar sensor.

[0038] In a method for testing a sensor configured to perform object detection by transmitting a first electromagnetic signal and receiving a second electromagnetic signal, the sensor is first positioned in a housing at a predetermined orientation relative to a transceiver. Then, the spacing between the radiating elements of the transceiver is linearly varied in one spatial direction. The varying spacing can be automated, for example, in an automated test flow.

[0039] Several embodiments are shown in the drawings and are explained in more detail in the following description. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram of a test setup. [Figure 2] FIG. 1 is a schematic diagram of a transmitting and receiving device. [Figure 3] Schematic diagram of two transmitter / receiver devices on a rail. [Figure 4] FIG. 1 is a schematic diagram of a rail. [Figure 5] FIG. 1 is a schematic overall view of a test apparatus. [Figure 6] FIG. 2 is a further schematic diagram of a test apparatus with multiple modules.

[0041] In the drawings, the same reference numbers are used for the same or similar elements. The illustrations in the drawings may not be to scale. DETAILED DESCRIPTION OF THE INVENTION

[0042] 1 shows a schematic diagram of a test setup 10 in which a sensor DUT is installed in a housing AUF together with its antenna A3. In the illustrated embodiment, the sensor DUT is a sensor, e.g., a radar sensor, having an antenna for emitting and receiving signals S1, S2.

[0043] The sensor DUT radiates a first signal S1 into the chamber K using its antenna A3, in which two transceiver devices SE1 and SE2 are arranged, with the respective antennas A1 and A2 of both of these two transceiver devices SE1 and SE2 being located inside the chamber K. Outside the chamber K, both transceiver devices SE1 and SE2 each have one transmitting transducer TX1, TX2 and one receiving transducer RX1 or RX2. Between the two transceiver devices SE1 and SE2, a spacing device BA is arranged, which changes the distance between the two transceiver devices SE1 and SE2 in exactly one spatial direction, which is in particular a linear direction in space.

[0044] The sensor DUT is further configured to receive and evaluate a second signal S2 via its antenna A3, i.e., antenna A3 is one combined transmit and receive antenna.

[0045] The distance between the transceiver units SE1 and SE2 can be changed automatically or manually via the spacing device BA. The antennas A1 and A2 are used both to emit the second signal S2 and to receive the first signal S1. That is, the antennas A1 and A2 are combined transmitting and receiving antennas into one antenna A1 and A2. The antennas A1 and A2 are connected via waveguides to the transmitting converters TX1 and TX2 or the receiving converters RX1 and RX2 of the transceiver units SE1 and SE2, respectively.

[0046] 2 shows a further schematic diagram of the transceiver SE. The antenna A is connected to a receiving converter RX or a transmitting converter TX via a waveguide WL. The transmitting converter TX and the receiving converter RX are themselves connected on the other side to a computing device RE. The receiving converter RX converts a first signal S1 into a working signal so that the first signal S1 can be transmitted to the computing device RE for further processing. The computing device RE drives the transmitting converter TX via a further working signal to emit a second signal S2 via the waveguide WL and the antenna A.

[0047] The waveguide WL is guided through a slit SL in the wall W of the chamber K. Inside the chamber K, the wall W is covered with an absorbent material AB to prevent unwanted reflections of the first signal S1. Therefore, the absorbent material AB is arranged on the wall W of the chamber K. In the illustrated example, the spacing device BA is configured as a rail SI. The rail SI is located behind the wall W and allows the distance from the antenna A to the further antenna A to be varied. In this case, further components of the transceiver SE, in particular the transmitting transducer TX and / or the receiving transducer RX, can remain in their respective locations outside the chamber K. In addition to the antenna A of the transceiver SE, the mutual distance between the transceivers SE, together with their respective transmitting and receiving transducers TX and RX, can also be varied via the rail SI. The distance between the antennas A is technically important, since the antennas A emulate the reflection of the first signal S1 by the second signal S2 transmitted by them.

[0048] 3 shows a schematic representation of a wall insert WE for an opening 40 (FIG. 4) of a chamber K, which wall insert WE comprises a rail SI and the receiving transducers RX1, RX2 and the transmitting transducers TX1 and TX2 of two transmitting / receiving devices SE1 and SE2. The rail SI with the receiving transducers RX1, RX2 and the transmitting transducers TX1 and TX2 is located outside the chamber K. The wall insert WE is thus shown, i.e. how it looks when viewed from outside the chamber K.

[0049] 4 shows a view of the other side of the wall element WE, as it may appear when viewed from inside the chamber K in its installed state. Both antennas A1 and A2 are positioned inside the chamber K in front of the slit SL.

[0050] Both antennas A1 and A2 are connected to their respective transmitting transducers TX1, TX2 / receiving transducers RX1, RX2 via a waveguide WL through a slit SL. This allows the transceivers SE1, SE2 to slide together with their respective antennas A1, A2 via the rail SI. This allows the spacing between the transceivers SE1 and SE2, and therefore also the spacing between the antennas A1 and A2, to be changed in the direction of the rail SI.

[0051] The slits SL can be covered by an absorbent material AB, which can also substantially cover the rails SI mounted on the outside of the chamber K. In that case, the absorbent material AB can be provided with, for example, slits, and can be extended by the waveguides WL and / or antennas A1, A2 only where the waveguides or antennas are guided through the slits SL and the slits provided in the absorbent material AB.

[0052] 5 shows a schematic diagram of the test fixture 10 on a frame with a chamber K and an opening 40 into which the wall insert WE described above can be inserted, with the sensor DUT then being located on the opposite side of the chamber K. This illustration is schematic, and the wall insert WE may be configured larger or smaller relative to the wall of the chamber K than the wall insert shown in the drawing.

[0053] 6 shows the entire test fixture 10 with a horizontal length L and a vertical height H, where a chamber K is made up of multiple modules M1-M4, in which a sensor DUT is arranged in a receiving portion AUF and a door DO is provided on the module M4 for arranging the sensor DUT. The modules M1-M4 extend the length L of the chamber K. Additional modules can further extend the chamber K in the direction L of the chamber K.

[0054] The wall insert WE is arranged in the wall W of the chamber K together with the antennas A1 and A2, which are connected to the respective transmitting and receiving transducers TX1, TX2 and RX1, RX2 via a waveguide WL. The distance between the antennas A1 and A2 can thus be varied until the sensor DUT can no longer detect both antennas A1 and A2 as separate objects. The receiving and transmitting transducers RX1, RX2 are connected to a computing device RE, which controls the transmitting and receiving devices SE1 and SE2 or evaluates the received signals and transmits corresponding transmitted signals. This is an exemplary illustration. In practice, it is entirely possible and common to provide one computing unit per transmitting and receiving device, i.e., one computing unit per transmitting and receiving transducer pair TX1 / RX1, TX2 / RX2. [Explanation of symbols]

[0055] 10 Test Equipment 40 Opening A, A1, A2, A3 antennas BA spacing device DUT Sensor AUF storage unit S1 First signal S2 Second signal SE, SE1, SE2 transceiver K Chamber WL Waveguide M1, M2, M3, M4 chamber modules TX,TX1,TX2 Transmitting converter RX,RX1,RX2 receiving converter SI Rail W wall AB absorbent material RE Computation Unit WE Wall Insert SL Slit DO Door H Chamber height L Chamber length

Claims

1. A test apparatus (10) for a sensor (DUT), comprising: The sensor (DUT) is configured to perform object detection by transmitting a first electromagnetic signal (S1) and receiving a second electromagnetic signal (S2); The test device (10) has a chamber (K) having a receiving portion (AUF) for the sensor (DUT), The test device (10) further comprises at least two transceiver devices (SE, SE1, SE2), the at least two transceivers (SE, SE1, SE2) are configured to receive a first signal (S1) transmitted from the sensor (DUT) into the chamber (K) and to transmit a second signal (S2) for reception by the sensor (DUT); said at least two transceiver units (SE, SE1, SE2) each having one radiating element for radiating said second signal (S2); a spacing device (BA) is provided, by means of which the mutual spacing of at least two of said radiating elements can be varied in exactly one spatial direction; Test device (10).

2. The spacing device has at least one rail (SI), said rail (SI) being capable of varying the mutual spacing of at least two of said radiating elements in exactly one spatial direction; 2. The test device of claim 1.

3. the spacing device is capable of varying the mutual spacing of the at least two transmitting / receiving devices (SE, SE1, SE2) in exactly one spatial direction, The spacing device comprises, inter alia, at least one rail (SI), said at least one rail (SI) being capable of varying the mutual spacing of said at least two transmitting / receiving devices (SE, SE1, SE2) in exactly one spatial direction; 3. A test device according to claim 1 or 2.

4. The spacing device is a first operating device for manually varying said spacing; and / or a second operating device for automatically varying the interval; 4. A test device according to any one of claims 1 to 3.

5. The chamber has a plurality of modules (M1, M2, M3, M4), said modules (M1, M2, M3, M4) enlarge said chamber (K) in at least one direction; the direction extends in particular from the sensor to at least two of the radiating elements of the test device; 5. A test device according to any one of claims 1 to 4.

6. The accommodation unit (AUF) is configured to change the position and / or orientation of the sensor (DUT).

6. A test device according to any one of claims 1 to 5.

7. the chamber (K) is substantially lined with an absorbent material (AB) that absorbs the electromagnetic signals within the interior space of the chamber (K); 7. A test device according to any one of claims 1 to 6.

8. said at least two transceiver devices (SE, SE1, SE2) each having a receiving element for receiving said first signal (S1); the radiating element and the receiving element of each transmitting / receiving device are arranged in the interior space of the chamber (K) in the region of the wall of the chamber (K), the spacing device is located outside the chamber; Test device according to any one of claims 1 to 7.

9. said at least two transceiver devices (SE, SE1, SE2) each having one transmitting transducer (TX, TX1, TX2) and one receiving transducer (RX, RX1, RX2); the transmitting transducers (TX, TX1, TX2) and the receiving transducers (RX, RX1, RX2) of each transmitting / receiving device (SE, SE1, SE2) are arranged outside the chamber; 9. The test device of claim 8.

10. the region has a slit; Through the slits, each of the radiating elements is connected to a respective one of the transmitting transducers (TX, TX1, TX2) via a waveguide (WL), and each of the receiving elements is connected to a respective one of the receiving transducers (RX, RX1, RX2) via a waveguide.

10. The test device of claim 9.

11. The slit is substantially covered by the absorbent material (AB) inside the chamber.

11. The test device of claim 10.

12. said area being configured as a wall insert (WE) for said wall opening (40); the wall insert (WE) is insertable into the wall (W) of the chamber (K) in particular in at least two different orientations, Test device according to any one of claims 8 to 11.

13. the radiating element and the receiving element of each transceiver (SE, SE1, SE2) are configured as a combined radiating / receiving element, Test device according to any one of claims 8 to 12.

14. The sensor (DUT) is a radar sensor, the radiating element is configured as a transmitting antenna; the receiving element is configured as a receiving antenna; Test device according to any one of claims 1 to 13.

15. The transmitting antenna and the receiving antenna of each transmitting / receiving device (SE, SE1, SE2) are configured as one antenna (A, A1, A2), The antennas (A, A1, A2) are configured in particular as horn antennas or curved antennas, 15. The test device of claim 14.

16. the region has a slit; Through the slits, the antennas (A, A1, A2) of the respective transmitting / receiving devices (SE, SE1, SE2) are connected to a transceiver via respective waveguides (WL), the transceiver comprises the transmitting transducers (TX, TX1, TX2) and the receiving transducers (RX, RX1, RX2) of the respective transmitting / receiving devices (SE, SE1, SE2), 16. The test device of claim 15.

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