Microwave Imaging Radar Sensor

Abstract

The present invention relates to a microwave imaging radar sensor (10) for creating an image of at least a portion of a surrounding space, the sensor (10) comprising at least one transmitting unit (12), a receiving unit (14), and an evaluation unit (15) having an output port (38) for outputting the image and connected to the transmitting unit (12) and the receiving unit (14), the image comprising a field, the field being associated with a pair of a transmitting channel (TX.X) and a receiving channel (RX.X), and at least two transmitting channels The at least two receive channels (TX.X) each correspond to a sector-shaped beam (BT.X, BR.X) having a first dimension (D1) significantly greater than a second dimension (D2), the first dimension (D1) being perpendicular to the second dimension (D2), and the field is assigned to a radar result characteristic (RC) provided by the receive channel (RX.X), and the sector-shaped receive beam (BR.X) of the receive channel overlaps with the sector-shaped transmit beam (BT.X) of the transmit channel (TX.X) to define an overlap region (OA, OA.X). The present invention relates to a transmission channel (TX.X) associated with a transmission unit (12), the transmission unit (12) including a refractive beamformer (20) including a transmission reference plane (RP-T) along which a sector-shaped transmission beam (BT.X) of the transmission channel (TX.X) is perpendicular to a first dimension (D1) thereof, the transmission unit (12) including a plurality of transmission transition structures (TTS.X) associated with the refractive beamformer (20) at different transition locations (27), each transmission channel (TX.X) being associated with at least one transmission transition structure (TTS.X). The receive channel (RX.X) is associated with a receive unit (14), the receive unit (14) having a refractive beamformer (21) including a receive reference plane (RP-R) to which a fan-shaped receive beam (BR.X) of the receive channel (RX.X) is perpendicular to its first dimension (D1), and the receive unit (14) has a plurality of receive transition structures (RTS.X) associated with the refractive beamformer (21) at different transition positions (27), and each receive channel (RX.X) is associated with at least one receive transition structure (RTS.X).

Description

[Technical Field]

[0001] The present invention relates to a microwave imaging radar sensor for producing an image of at least a part of the surrounding space close to the sensor, according to the preamble of claim 1 . [Background technology]

[0002] Document US 2010 0141 527 A1 discloses a radar sensor with an orthogonal antenna system in which at least one transmit aperture generates a transmit beam and at least one receive aperture is associated with a receive beam. The transmit aperture is substantially orthogonal to the corresponding receive aperture, thereby generating a cross product of the two orthogonal apertures. The transmit beam is narrow in a first dimension and wide in a second dimension, while the receive beam is wide perpendicular to the first dimension and narrow perpendicular to the second dimension. As the transmit signal is reflected from an object and received by the orthogonal array, a two-way transfer function generates a cross product of two antenna patterns in the vertical and horizontal directions. The intersection of the transmit and receive beams generates a composite narrow beam cross product.

[0003] Document US 2014 0176 377 A1 shows an antenna system comprising a cylindrical electromagnetic lens configured to direct at least one electromagnetic signal to a launch region by at least a change in dielectric constant and to generate a beam output from the launch region, the antenna system comprising a dielectric member configured to receive the beam output from the launch region and to focus the beam in an elevation plane perpendicular to the plane of the cylindrical electromagnetic lens, the cylindrical electromagnetic lens being housed in a conductive mount, which mount supports the dielectric member.

[0004] WO 2018 035 148 A1 discloses a radar application that uses a 3D-printed spherical Luneberg lens for beam steering. The receiver is mounted around the lens, maintaining the antenna radiation pattern at all angles without beam distortion. The radar adaptively adjusts the spatial detection pattern, sweep frequency band, pulse repetition frequency, and coherent processing interval according to the environment. This is achieved by first performing a coarse scan and then updating the detection results via narrowband waveforms and wideband beam scans. Once a target of interest is identified, a high-resolution detailed scan is performed on the specific region of interest. Methods for mitigating interference in 3D-printed Luneberg lens-based radar and improving angular resolution using a lens-based MIMO approach are also disclosed.

[0005] Document US 2008 0055 175 A1 shows a multi-beam antenna comprising at least one electromagnetic lens on a dielectric substrate and a plurality of transition structures with antenna feed elements, the transition structures being configured to transmit and receive electromagnetic waves in a direction substantially away from a convex or concave edge of the dielectric substrate, at least two antenna elements operating in different directions. Summary of the Invention

[0006] SUMMARY OF THE INVENTION It is an object of the present invention to provide a microwave imaging radar sensor that can provide an image of at least a portion of the surrounding space at high speed and with low analysis effort.

[0007] The above object is solved by a microwave radar sensor according to claim 1.

[0008] The dependent claims are advantageous embodiments of the invention.

[0009] The present invention relates to a microwave imaging radar sensor for producing an image of at least a portion of a surrounding space, which can be used to detect objects within a range of less than 200 m, particularly about 20 m, from the sensor.

[0010] The microwave imaging radar sensor includes at least one transmitting unit, a receiving unit, and an evaluation unit, the evaluation unit being connected to both the transmitting unit and the receiving unit for generating a plurality of transmitting beams and a plurality of receiving beams, respectively.

[0011] The evaluation unit has an output port for outputting an image of at least a portion of the space surrounding the microwave imaging radar sensor, the image including multiple fields, each field associated with a pair of transmit and receive channels.

[0012] Each of the at least two transmit channels and the at least two receive channels corresponds to a fan beam, which represents a region of a fan-shaped radiation pattern associated with the microwave signal.

[0013] Each fan beam has a first dimension and a second dimension perpendicular to the first dimension. The first dimension is significantly larger than the second dimension, at least three times larger than the second dimension. The first dimension is related to the elevation angle, and the second dimension is related to the azimuth angle. Thus, the electromagnetic energy associated with the fan beams is not spread evenly in all directions. The electromagnetic energy is directed primarily in the desired direction and is attenuated in other directions.

[0014] A fan beam corresponding to a receive channel (a fan receive beam) overlaps with a fan beam corresponding to a transmit channel (a fan transmit beam), thereby forming an overlap region. A transmit channel is associated with a fan transmit beam having specific signal characteristics. Transmit microwaves associated with the fan transmit beam are reflected by objects in the space surrounding the sensor, thereby forming echo waves that overlap with the fan receive beam.

[0015] The echo waves have signal characteristics that change with respect to the transmitted microwaves. The evaluation unit processes the received signals based on the transmitted signals to provide a result signal having radar result characteristics. The radar result characteristics include the amplitude, frequency, phase, etc. of the microwave signal. The radar result characteristics are assigned to corresponding receive channels, and each field of the image is assigned result information based on the radar result characteristics provided by the receive channels.

[0016] The radar result characteristics assigned to a receive channel depend on the particular pair of overlapping transmit and receive beams that form the overlap region. Thus, each field of the image is associated with an overlap region of a transmit beam and a receive beam.

[0017] The present invention is characterized in that the transmit channels are associated with a transmit unit including a refractive beamformer. The refractive beamformer is an analog passive beamformer and has a transmit reference plane to which the first dimension of the fan beams of the transmit channels is orthogonal. The transmit unit includes a refractive beamformer and multiple transmit transition structures associated with each refractive beamformer at different transition positions. The transmit transition structures are preferably located on the surface of the refractive beamformer or at a distance therefrom. The transmit transition structures convert electrical signals into electromagnetic signals, which are sent to the refractive beamformer of the transmit unit. The microwaves are refracted by the refractive beamformer to generate the transmit beam. Thus, each transmit channel is associated with at least one transmit transition structure.

[0018] A refractive beamformer achieves spatial selectivity in the transmission of microwave signals by changing the directionality of the electromagnetic waves passing through it. Thus, with a refractive beamformer, the radiated energy is not spread evenly in all directions, but rather is directed in a desired direction and attenuated in other directions. Specifically, the electromagnetic waves are associated with a fan beam of the fan-shaped radiation pattern associated with the microwave signal. The fan beam represents an angular region of the radiation pattern that is comprised of gain values ​​close to the maximum gain, typically below a certain threshold below the maximum gain. The threshold is proportional to the maximum gain amplitude of the radiation pattern, e.g., between 3 dB and 10 dB.

[0019] The first dimension of the fan-shaped transmit beam is perpendicular to the transmit reference plane. The first dimension of the transmit beam spans a transmit angle in a transmit angle plane perpendicular to the transmit reference plane. The second dimension spans a transmit azimuth angle in the transmit reference plane. Specifically, the first dimension corresponds to the beam height and the second dimension corresponds to the beam width.

[0020] Furthermore, like the transmit channels, the receive channels are correlated with a receive unit. The receive unit includes a refractive beamformer, i.e., an analog passive beamformer, and a receive reference plane to which the first dimensions of the receive channel fan beams are orthogonal. The receive unit includes multiple receive transition structures associated with the refractive beamformer at different transition positions relative to the refractive beamformer, and each receive channel is associated with at least one receive transition structure.

[0021] Preferably, multiple receive transition structures at different transition positions are associated with the refractive beamformer of the receive unit and are located on or a short distance from the surface of the refractive beamformer. Each receive transition structure is associated with a separate transition position relative to the refractive beamformer of the receive unit. The receive transition structures receive corresponding echoes of transmitted electromagnetic signals as they pass through the refractive beamformer of the receive unit. The echo waves enter the refractive beamformer, and echo waves with wave directions correlated with a particular receive beam are efficiently captured by the corresponding receive transition structure. In other words, spatial selectivity in receiving the echo waves is achieved, with a first dimension of the receive beam perpendicular to the reference plane of the receive unit and a second dimension within the receive reference plane.

[0022] Similarly, for a receiving unit, the definitions of elevation plane, elevation angle, and azimuth angle are the same. The first dimension of the receive beam spans the receive angle in the receive angle plane perpendicular to the receive reference plane. The second dimension spans the receive azimuth angle in the receive reference plane.

[0023] According to the present invention, to generate an image of at least a portion of the space surrounding the microwave imaging radar sensor, an image region can be associated with a plurality of fields. Each field corresponds to a pair of transmit and receive channels where the respective fan beams of the transmit and receive channels overlap, thereby providing an overlap region that correlates with result information based on radar result characteristics. The result information is assigned to each field of the image. Depending on the embodiment of the transmit and receive units, the overlap region has a fixed relationship with the position of each pair of transmit transition structures of the transmit unit and receive transition structures of the receive unit. Therefore, the image formed by the accumulation of the overlap region can be obtained simply by evaluating the relationship between the transmit and receive channels.

[0024] In accordance with an embodiment of the transmit and receive units, each refractive beamformer, which is an analog passive beamformer, is associated with a plurality of transition structures, which can be sequentially and individually addressed to transmit microwaves. In other words, the plurality of transmit transition structures associated with individual transition positions for each refractive beamformer can be sequentially and individually triggered, thereby achieving beam switching in the transmit unit. The addressed transmit transition structures are assigned to specific transmit channels. For each individual transmit channel, multiple receive transition structures can provide receive signals from the echo waves. The receive signals are evaluated based on the corresponding transmit signals, thereby providing result signals having radar result characteristics assigned to the corresponding receive channel. In other words, the output of one transition channel, preferably corresponding to a single transmit transition structure, is correlated with the input of multiple receive transition structures corresponding to each receive channel.

[0025] The transmit and receive channels are evaluated in sets. Thus, in a single evaluation cycle, correlations can be established between individually addressed transmit transition structures and multiple receive transition structures that are evaluated for radar result characteristics to obtain result information. Thus, by evaluating a single transmit-receive channel relationship, multiple fields of an image are assigned result information provided by the radar result characteristics. This means a quick and easy analysis to generate an image of at least a portion of the space surrounding the sensor.

[0026] In a preferred embodiment, the evaluation unit includes a radar control unit and an imaging unit connected to each other. The radar control unit is connected to the transmitting unit and the receiving unit via transmission lines, and the imaging unit includes an output port. The radar control unit is connected to the transmitting transition structure of the transmitting unit and the receiving transition structure of the receiving unit via transmission lines. These transmission lines are adapted for connection to the radar control unit and transmit electrical signals between the radar control unit and the transition structures of the transmitting unit and the receiving unit, respectively.

[0027] The radar control unit is further connected to an imaging unit, which assigns result information relating to radar result characteristics obtained by the overlapping beams to each region of the image to create an image of at least a portion of the space surrounding the sensor. Each result information based on the respective radar result characteristics, and therefore each region of the image, is correlated with a predefined pair of receive and transmit channels. The correlation between the receive and transmit channels and each overlap region is preferably defined in a table stored in a data memory of the imaging unit.

[0028] The image may be output from the imaging unit via an output port, for example to an image processing unit for further analysis, which may be part of the microwave imaging radar sensor or part of a sensor system that includes the microwave imaging radar sensor.

[0029] The transmit and / or receive transition structures relay signals between the transmission line and the waveguide. The waveguide propagates electromagnetic energy associated with microwaves between the transmit and / or receive transition structures and the respective refractive beamformers. Specifically, the transmit transition structures receive electrical energy from the transmission line connecting to the radar control unit. The transmit transition structures convert this electrical energy into electromagnetic energy, which is transmitted to the refractive beamformer of the transmit unit by the waveguide associated with the transmit transition structure. Thus, the refractive beamformer of the transmit unit is supplied with microwaves from the waveguide at a transition location associated with the respective transmit transition structure.

[0030] Meanwhile, electromagnetic energy received by the refractive beamformer of the receiving unit enters the waveguide at the transition locations and is directed from the refractive beamformer to a receiving transition structure associated with each transition location, which converts the received electromagnetic energy into electrical energy and relays it to the radar control unit via a connecting transmission line.

[0031] The transmit and / or receive transition structures may be, for example, tapered microstrip transitions.

[0032] In a preferred embodiment, the radar control unit transmits a signal to a transmit transition structure, or a combination of transmit transition structures, associated with a particular transmit channel. The radar control unit addresses a particular transmit transition structure and triggers it to transmit microwaves, i.e., a particular transmit signal exhibiting particular transmission characteristics. The transmit transition structures may be addressed individually in sequence, or adjacent transmit transition structures may be addressed simultaneously to generate a mixed microwave signal that produces a beam having a main direction intermediate the main directions of the beams of the two adjacent transmit transition structures. A transmit channel corresponds to an individually addressed transmit transition structure or a set of addressed transmit transition structures.

[0033] Furthermore, the radar control unit receives a receive signal associated with a corresponding echo wave using a receive transition structure, preferably multiple receive transition structures. The radar control unit determines a radar result characteristic of the receive signal based on the corresponding transmit signal. In other words, the multiple receive-transmit structures pick up receive signals associated with echo waves having signal characteristics different from microwaves. The radar control unit evaluates the receive signal, that is, the echo, based on the corresponding transmit signal and provides a result signal having a radar result characteristic different from the transmit characteristic.

[0034] The radar control unit includes an interface having an input port and an output port, the input port receiving a specification of an addressed transmit transition structure and the transmit characteristics provided by the addressed transmit transition structure of a transmit unit associated with the transmit channel.

[0035] Reciprocally, the output port of the interface outputs a set of radar result characteristics associated with the evaluated receive transition structures of the receive unit associated with the receive channels, where the radar result characteristics for each receive transition structure are associated with a particular receive channel and can be input in digital form to the imaging unit.

[0036] According to a preferred embodiment, the sensor has a field of view direction in which the field of view plane is vertical, the sensor has a sensor reference plane perpendicular to the field of view plane, the transmitting reference plane and the receiving reference plane are perpendicular to the field of view plane, the field of view plane allowing projection of at least a part of the space around the sensor by the imaging unit.

[0037] The sensor reference plane is perpendicular to the field of view plane, and the sensor has a sensor elevation plane that is perpendicular to both the field of view plane and the sensor reference plane, and the sensor reference plane and sensor elevation plane contain the field of view direction. Thus, the sensor reference plane contains the sensor azimuth angle, and the sensor elevation plane contains the sensor elevation angle.

[0038] To provide an image in a preferred manner, the sensor reference plane, transmit reference plane, and receive reference plane can be assumed to intersect at a common line of intersection. This allows for easy conversion of transmit azimuth and elevation angles and receive azimuth and elevation angles to correlated sensor azimuth and elevation angles. This assumption is possible because the transmit and receive units each include a refractive beamformer, preferably approximately 5 cm in diameter, and are spaced a short distance apart relative to the intended measurement distance. More specifically, the transmit reference plane may lie within the sensor reference plane.

[0039] In a preferred embodiment, the fan beam has a principal direction that is the direction of peak gain, and this principal direction depends on the placement of the transition structure relative to each refractive beamformer. The placement and / or orientation of the transition structure relative to each refractive beamformer determines the principal direction in which the electromagnetic signal associated with the fan beam propagates. The principal direction is the direction of peak gain in the second dimension, which lies in each reference plane. In other words, the energy associated with the beam is radiated primarily in one direction, which is the principal direction, which lies in each reference plane, while electromagnetic energy is radiated to a lesser extent in other directions.

[0040] The at least two fan beams of the transmitting unit and the receiving unit are configured such that their main directions are generally oriented in the line-of-sight direction, so that the at least two fan beams of the transmitting unit and the receiving unit at least partially overlap each other in an overlap region, and the fan beams may exhibit an angular deviation between their main directions and the line-of-sight direction in their respective reference planes ranging from 90° to −90°.

[0041] Furthermore, the at least two fan beams of both the transmitting and receiving units at least partially overlap each other over a distance of more than 10 wavelengths, or alternatively, preferably over a distance of about twice the major extension of the refractive beamformer in the line of sight direction for each transmitting structure, thereby enabling accurate monitoring of an area near the sensor.

[0042] The overlap region is defined by the azimuth and elevation range of the sensor. At least two corresponding beams overlap each other, ensuring at least two overlap regions, which advantageously allows a single evaluation of the paired transmit and receive channels to provide a 2D image of at least a portion of the space around the sensor.

[0043] The overlap region is correlated with the field of view of the image, so that the set of overlap regions defines the image region. The set of overlap regions may preferably include all overlap regions. Thus, the sensor provides a 2D raster-based image based on the full range or spectrum of sensor azimuth and elevation angles.

[0044] In a preferred embodiment, the imaging unit is connected to an interface of the radar control unit. The imaging unit configures the inputs of the radar control unit to correspond to specific transmit channel combinations. The imaging unit specifies the individual transmit transition structures to which the radar control unit is to associate, as well as the signal characteristics transmitted by the transmit transition structures. This information is relayed to the radar control unit via the input port.

[0045] The imaging unit, in turn, receives a set of radar result characteristics associated with each receive transition structure associated with the evaluated receive channel. The radar control unit evaluates the receive signals of the echo waves against the corresponding transmit signals and provides a result signal having radar result characteristics associated with a particular receive transition structure. The receive transition structures are assigned to each corresponding receive channel. This information, i.e., the radar result characteristics associated with the associated receive transition structure, is relayed to the imaging unit via an interface output port of the radar control unit.

[0046] The imaging unit receives radar result characteristics associated with the receive transition structure and processes the radar result characteristics to determine result information. The imaging unit then creates an image based on the acquired radar result characteristics by associating the result information with fields corresponding to pairs of transmit and receive channels. Since the fields have a fixed relationship with the pairs of transmit and receive channels, they are also associated with the corresponding pairs of transmit and receive transition structures.

[0047] The image field may be correlated with at least a subzone of the sensor's surrounding space, the overlap region having associated therewith result information based on radar result characteristics and derived solely from knowledge of the evaluated relationship between the transmit and receive channels, thereby enabling at least a portion of the sensor's surrounding space to be quickly and easily analyzed to generate an image of the detection zone, which is a subzone of the sensor's surrounding space.

[0048] According to one embodiment of the present invention, the refractive beamformer is a dielectric lens. A dielectric lens includes a solid dielectric material, particularly one with a variable dielectric constant. The physical properties of the solid dielectric material affect the refraction of microwaves, i.e., their direction or propagation as they pass through the lens. The dielectric lens is designed to refract the waves into a fan-shaped radiation pattern, which includes a fan beam, a region of the radiation pattern. Refraction narrows the beam width and controls the emitted energy, thereby improving directivity in the second dimension, which corresponds to the beam's azimuth angle relative to each reference plane. Meanwhile, the transmitted beam exhibits an enhanced fan shape, and the directivity ensures that most of the energy is sent in the main direction. Since the receiving unit also has a fan beam, this combination prevents unwanted energy from being scattered and provides high spatial selectivity. This improves the efficiency of the sensor.

[0049] The echo waves reflected from the target object and traveling in a specific direction are focused by the dielectric lens of the receiving unit. The echo waves are refracted by the dielectric lens and intersect at the focal points of the lens. In particular, the echo waves are focused at the focal points at the respective antipodal points of the lens. Here, the received signal may be input to the receiving transition structure depending on the exact position and / or orientation of the receiving transition structure. Preferably, the receiving transition structure coincident with the focal point can absorb energy from the reflected microwaves.

[0050] The change in the dielectric constant of the lens can be achieved, for example, by radially adjoining multiple dielectric layers with different dielectric constants, e.g., different dielectric materials. It is also conceivable that the change in dielectric constant can be achieved by different arrangements of air holes in the lens material. The hole distribution can vary depending on the hole density, hole spacing, hole diameter, etc., within the lens.

[0051] According to a preferred embodiment, the dielectric lens is a gradient index lens. A gradient index (GRIN) lens has a gradient in the refractive index of the lens material. That is, for non-magnetic materials, the dielectric constant varies in a gradient across the lens material. A GRIN lens preferably has a maximum refractive index at the center and a minimum refractive index at the periphery. To produce a fan-shaped radiation pattern, the GRIN lens is cylindrical, with the refractive index preferably decreasing radially. A cylindrical gradient index lens preferably has a dielectric constant at the edge of 1.5 or greater, preferably 2.5 or greater, and more preferably 3.0 or greater.

[0052] In one embodiment, the cylindrical lens is a generalized Luneberg lens. A classical Luneberg lens is a well-known approach to beam shaping, where the lens has a variable refractive index, one focus point is at the lens surface or periphery, and the other focus point is at infinity. The focusing properties of the lens are achieved by a myriad of different relationships between the distribution of dielectric constants inside the lens and the lens radius.

[0053] A cylindrical generalized Luneberg lens is a symmetric gradient index lens with focal points distributed on a focal cylinder. The radius of the focal cylinder preferably coincides with the radius of the lens, i.e., the focal points are located at the periphery of the lens. However, the radius of the focal cylinder may be smaller than that of the cylindrical lens, and the focal points may be located inside the lens.

[0054] A cylindrical generalized Luneberg lens can convert a wave emitted from one of its foci into a quasi-plane wave, i.e., a wave with a fan-shaped pattern, at the other side of the lens, thereby transmitting a beam with a small angular width from the exit area on the outer surface of the cylindrical lens.

[0055] The rotational symmetry of the cylindrical generalized Luneburg lens allows its associated transition structures to be oriented in various directions, providing the microwave radar sensor with a wide angular range for steering the beam and analyzing at least a portion of the space surrounding the sensor. This type of lens is suitable for applications requiring wide beam switching and high antenna gain.

[0056] The reference plane of a cylindrical generalized Luneberg lens is perpendicular to the central axis of the lens. This lens collimates electromagnetic radiation entering the lens at the transmit transition. The lens focuses the electromagnetic signal into a narrow beam with a second dimension that is in the reference plane and perpendicular to the central axis of the lens. Refraction by the cylindrical Luneberg lens causes the beam to fan out, resulting in a highly directional radiation pattern and increased gain. This minimizes unwanted energy dispersion and improves the efficiency of the sensor.

[0057] Objects in the space surrounding the sensor reflect the transmitted microwaves. The microwaves have a maximum signal, which is primarily concentrated in one dimension and attenuated in other dimensions, enhancing reception of the echo waves by the receiving unit and improving the resolution of the sensor. This embodiment of the generalized Luneberg lens focuses echo microwaves in a specific direction to the focal point of the lens. Multiple receiving transition structures are arranged around the lens near such a focal point. If the position of the receiving transition structure coincides with the peripheral focal point where the echo waves are focused, the receiving transition structure will pick up a signal. Specifically, the focal point is the peripheral focal point, and the receiving transition structure is arranged to cover the peripheral focal point.

[0058] In a preferred embodiment, the cylindrical generalized Luneberg lens has a dielectric constant gradient that varies according to a square law of radial position. In particular, the relative dielectric constant ε at the lens center is r is the relative permittivity ε at the lens periphery r Preferably, the relative dielectric constant at the center, ε r can be calculated using the following relation, taking into account a tolerance of 0.2:

[0059]

number

[0060] Relative permittivity ε r may satisfy the following conditions: |ε r (Center)-ε r (periphery)|>0.1

[0061] The distribution of the dielectric constant is determined by the relative dielectric constant ε of the external medium into which the lens radiates. r It is normalized by the relative permittivity ε r If is 1, the external medium is air. The relative permittivity ε at the periphery r is not necessarily equal to 1. According to the above relationship, the relative permittivity ε r The distribution of ensures optimal gain for the lens.

[0062] Preferably, the reference plane of the receiving unit and the reference plane of the transmitting unit intersect with each other at an intersection angle of 0° to 90°, i.e., 0°≦intersection angle≦90°. The receiving unit and the transmitting unit each include a refractive beamformer. The refractive beamformer of the receiving unit is disposed at an angle to the refractive beamformer of the transmitting unit, and the intersection angle is 0° to 90°.

[0063] Specifically, each transition structure correlates with a fan-shaped radiation pattern having a first beam dimension in a field of view perpendicular to the respective reference plane. Microwaves emitted from the transmitting transition structure are reflected by objects in the space surrounding the sensor, causing the corresponding radiation patterns of the transmitting and receiving units to overlap with each other, thereby forming an intersection angle between them. The overlap regions are associated with subzones of the surrounding space. These overlap regions have a fixed relationship to the positions of the respective pairs of transition structures of the transmitting and receiving units. The position of the overlap region is determined relative to the reference plane of the sensor according to the angle between the reference plane of the transmitting unit and the reference plane of the receiving unit.

[0064] In a preferred embodiment, the angle between the transmitting and receiving reference planes is between 15° and 90°, forming a surveillance grid. The receiving units are set so that the receiving reference plane is tilted at an angle between 15° and 90° relative to the transmitting reference plane of the transmitting unit. As a result, the respective radiation patterns are tilted at the same angle relative to each other. This allows at least a portion of the space around the sensor to be represented by a kind of grid resolution of the overlapping areas of the corresponding fan beams.

[0065] In one embodiment, the radar control unit includes a receive chain connected to the receive unit, whereby the radar control unit determines signal characteristics received via the plurality of receive transition structures and derives radar result characteristics in response to the transmitted signals. The radar result characteristics for each receive transition structure can be provided to the imaging unit in a digital manner. Specifically, the interface of the radar control unit includes an output port that provides a set of radar result characteristics each associated with a corresponding receive transition structure associated with a receive channel.

[0066] Additionally, the radar control unit includes a transmission chain connected to the transmitting unit. The radar control unit relays information from the imaging unit to the transmitting unit. This information includes a set of output signal characteristics associated with the transmit transition structures, i.e., this information determines which of multiple transmit transition structures is addressed to provide a particular transmit characteristic. Thus, a transmit channel may be associated with a single transmit transition structure or multiple transmit transition structures that are simultaneously addressed, thereby generating a mixed signal.

[0067] In a preferred embodiment, the radar control unit performs at least one evaluation cycle to establish a relationship between a set of transmit channels and a set of receive channels, and in each evaluation cycle, the radar control unit addresses a single transmit transition structure or a combination of multiple transmit transition structures and transmits a signal having specific signal characteristics to the single transmit transition structure or combination of multiple transmit transition structures.

[0068] The radar control unit can perform multiple evaluation cycles, each of which addresses a predefined transmission channel, triggered by the imaging unit, with the number of evaluation cycles depending on the number of relationships defined in the data memory required to generate the desired image.

[0069] The imaging unit receives radar result characteristics of a set of receive transition structures and associates them with respective receive channels in each evaluation cycle. The imaging unit processes the radar result characteristics to determine result information. Because the result information is associated with a particular receive transition structure, the imaging unit can assign the result information to the corresponding receive channel. The imaging unit then assigns the result information to overlap regions corresponding to the transmit and receive channels in each evaluation cycle.

[0070] This allows multiple relationships between one transmit channel and multiple receive channels to be analyzed and correlated in a single evaluation cycle. This allows simultaneous analysis of the receive transition structure, resulting in low analysis effort and fast scanning of at least a portion of the space around the sensor. This low effort is related to the fact that overlapping regions can be identified simply by using predefined relationships between transmit and receive channels.

[0071] During each iteration of the evaluation cycle, the transmit channels corresponding to the individually addressed transmit transition structures or sets thereof are analyzed successively. That is, each transmit channel is preferably associated with multiple receive transition structures, each of which is assigned to a receive channel. The radar control unit may be capable of parallel processing of the received signals obtained by the receive transition structures. Therefore, in such a case, to ensure fast analysis, it is preferable that the receive unit has more transition structures than the transmit unit. This reduces the number of sets of transmit channels analyzed per cycle, significantly reducing the evaluation time per cycle.

[0072] By repeating the evaluation cycle, the imaging unit can generate an image from a data set including addressed transmit transition structures corresponding to the receive transition structures and result information based on radar result characteristics obtained therefrom, where the result information is assigned to each field of the image. The image can be a collection of raw data. In particular, the image can be an array of values ​​associated with the result information, from which, for example, a graphic image can be created.

[0073] The imaging unit may then output the image.

[0074] Preferably, the imaging unit includes a data memory for storing mapping information consisting of a plurality of relationships between the transmit and receive channels and the overlap regions, in particular overlap region coordinates.

[0075] More preferably, the data memory may contain a plurality of mapping information each associated with a particular angle between the transmitting and receiving reference planes, thereby allowing the resolution of at least a portion of the space around the sensor to be flexibly adjusted to particular conditions during operation.

[0076] The imaging unit uses the mapping information in the data memory to assign the result information generated by the radar control unit in each evaluation cycle to a corresponding overlap region.

[0077] The imaging unit analyzes the radar result characteristics and determines result information, such as evaluating the signal based on Doppler effect, amplitude, or distance. For example, if the result information includes "distance," the image processing unit may be able to provide a 3D image by understanding the overlapping area.

[0078] In a preferred embodiment, the imaging unit outputs a raw data image, e.g., an image that is an array having multiple entries associated with result information for each single overlap region, to the image processing unit, which maps an image of at least a portion of the sensor's surrounding space as a grid of multiple pixels stored in a data memory. Each pixel is assigned a relationship between a transmit transition structure and a receive transmission structure. Each image field is gridded into multiple pixels. Each pixel is associated with at least a section and / or location of the surrounding space. Each pixel is assigned a value associated with result information. Thus, the processed image can be a graphic image. Values ​​and / or value changes associated with result information can be coded, for example, by color coding, allowing a pixel image to be created using graphic image processing and / or filter algorithms. In this way, the image processing unit can create a visually processed image of at least a portion of the sensor's surrounding space from the grid.

[0079] In a preferred embodiment, the transmit signal and radar result characteristics are generated by FMCW. The radar control unit operates in FMCW mode. Frequency modulated continuous wave radar emits a continuous transmit signal whose frequency is continuously varied at a known rate. That is, the operating frequency varies during the measurement. Typically, this may involve a linear change in frequency over time. Modulation of the transmit frequency allows for additional measurements such as object range and radial velocity. Using this technique, the result information "distance" can be obtained.

[0080] Alternatively, the transmit and receive signals may be transmitted and received in a pulsed mode, respectively, to measure the distance to the object.

[0081] Radar result characteristics can also be analyzed by evaluating the received signal relative to the transmitted signal using the Doppler effect in continuous wave (CW) mode. The Doppler effect approach is a powerful tool for analyzing the motion, or velocity, of objects in a microwave field.

[0082] The microwave signal reflects off an object, and the frequency of the received signal, or reflected wave, is analyzed to see how it has changed from the original microwave transmission. By observing the frequency change of the scattered wave, data can be generated about the object's speed, without revealing its distance or position.

[0083] In a preferred embodiment, beam switching is achieved by switching the transmit transition structures, with the transmit signal being applied to one transmit transition structure at a time per evaluation cycle. For each evaluation cycle, a separate transmit transition structure is designated to emit the transmit signal. That is, a single separate transmit transition structure is opened, and the transmit signal is emitted from the transmit transition structure to the refractive beamformer, while the remaining transmit transition structures remain closed. Beam steering is achieved by switching between the transmit transition structures. In other words, by controlling the transmit transition structures, the angular deviation between the main direction of the emitted electromagnetic radiation and the line of sight direction is changed, with the azimuthal deviation being within the reference plane. For each successive evaluation cycle, a different separate transmit transition structure is opened and transmits the transmit signal. The transmit transition structures are triggered one after another in successive evaluation cycles, sweeping the signal within an azimuthal range or spectrum perpendicular to the first dimension. Beam switching results in multiple overlap regions. The overlap regions can be projected onto a field of view, which is a projection of at least a portion of the space surrounding the sensor. The overlapping regions of corresponding beams can be considered to represent corridors in a Cartesian coordinate system of at least a part of the space around the sensor, so that a 3D spatial assignment can be made to the overlapping regions, for example by an image processing unit.

[0084] In another embodiment, two adjacent transmit transition structures can be provided simultaneously in a transmit channel within a single evaluation cycle, in which case the radar control unit may perform phase evaluation of the transmit transition structures to correct for phase differences between the adjacent transmit transition structures.

[0085] According to a preferred embodiment, the receiving unit, the transmitting unit, and the transmission lines connecting the radar control unit to both the transmitting unit and the receiving unit are implemented as a single circuit board, preferably a PCB body. Thus, the receiving unit and the transmitting unit are mounted on the same PCB board, which also includes the transmission lines connecting the radar control unit to the transmitting unit and the receiving unit, respectively. A transmission line refers to a pair of electrical wires or conductors that transfer energy from one point to another.

[0086] These are typically made of copper wiring and are structures that transmit electrical signals through the body of the PCB.

[0087] Preferably, a single circuit board, particularly a PCB body, includes one core layer with at least one metallization layer on top and one on bottom. Alternatively, the PCB body may include multiple core layers, with top and bottom metallization layers surrounding the PCB body and providing the lens properties.

[0088] In particular, the PCB body includes at least two cores, which are attached to each other by at least one prepreg layer.

[0089] The PCB body is designed in such a way that the transmitter unit can be tilted relative to the receiver unit, in particular by using at least one flexible PCB core layer, as is known for example from SEMI FLEX multilayer PCB bodies, which allow the transmitter and receiver units to be tilted relative to each other.

[0090] Furthermore, a rigid core layer can be used in addition or alternatively, and the connection region between two rigid regions, each having multiple layers, may, for example, include only a single core layer resulting in a thinner region, thereby providing a flexible bend.

[0091] By using at least two cores on a single circuit board, the transmit and / or receive transition structures can be realized as blind vias.

[0092] According to a preferred embodiment, at least one core layer is formed from a dielectric substrate, and the core layers of the transmitting unit and the receiving unit each form a refractive beamformer with a curved profile. Because dielectrics have poor electrical conductivity, a non-conductive substrate layer is provided between conductive metal layers. The dielectric constant of the PCB substrate material has a significant impact on signal quality and power quality. Therefore, the relative dielectric constant is preferably greater than 2.5, more preferably greater than 3.0. A particularly preferred relative dielectric constant is approximately 3.5.

[0093] Each refractive beamformer may, for example, form at least a portion of a cylinder, or may have a circular or elliptical profile to focus or diverge the signal into a line, i.e., a fan beam, rather than a point or circle. Thus, the dielectric core substrate and any prepreg layers that may be present act as a lens, in particular a graded index lens, with the dielectric constant affected by holes through the dielectric layers of the core and any prepreg layers that may be present, and the metallization layers surrounding the core.

[0094] Preferably, the waveguide is integrated into a single circuit board and is surrounded by top and bottom metallization layers of the PCB body and metallized vias that connect the metallization layers and act as the sidewalls of the waveguide. The waveguide is made from the same substrate as the PCB body and is surrounded by top and bottom metallization layers. These layers are connected to each other by metallized vias that traverse the PCB body, forming walls on either side of the waveguide. In this way, the waveguide contains a geometry that acts as a physical constraint, allowing waves to be guided in a specific direction by internal reflection. This reduces energy loss associated with the wave.

[0095] In a preferred embodiment, the radar control unit is mounted on a single circuit board and connected to the transmitting and receiving transition structures. The radar control unit may be implemented as one or more microchips mounted on the PCB body. The radar control unit is connected to the transmitting transition structure of the transmitting unit and the receiving transition structure of the receiving unit by transmission lines adapted for connection to the radar control unit, transmitting electrical signals between the radar control unit and the respective transmission lines.

[0096] Preferably, the radar control unit includes a radar control receiving unit and a radar control transmitting unit, each implemented as a microchip that can be placed near a corresponding refractive beamformer, and both microchips are interconnected to communicate synchronization signals, thereby enabling radar evaluation in the high frequency range while minimizing or reducing the length of the transition structure and the associated losses.

[0097] The radar control unit is also connected to an imaging unit which may be mounted on a separate PCB board, or the imaging unit may be mounted on the same PCB body as the radar control unit.

[0098] In a preferred embodiment, the refractive beamformer is enclosed in a lens housing, providing circularly polarized radiation. Due to the dielectric constant change according to Luneberg's law, spherical electromagnetic waves emitted from the transition structures located around the circumference of the cylindrical lens are converted into nearly plane waves at the lens output. This results in a collimated beam that spreads primarily in the primary direction as the energy propagates, with minimal spread in other directions. A beam with a small angular width is emitted from the exit region on the outer surface of the cylindrical lens. The housing converts the linearly polarized electromagnetic radiation output from the lens into circular polarization. Circular polarization is preferred when analyzing RF waves reflected from irregular objects, as it allows for the collection of more reflected energy. This can improve the detection sensitivity of microwave radar sensors, particularly because the human body does not necessarily maintain linear polarization when reflecting echo waves.

[0099] Preferably, the refractive beamformer is a cylindrical lens having a first dielectric property and housed within a toroidal lens housing around a central axis of rotation with apertures or different dielectric materials at opposite poles. The housing has a toroidal shape with the central hyperboloid removed, with the apertures at opposite poles of the housing. Thus, the cylindrical lens is radially surrounded by the toroidal housing, while both flat circular surfaces of the cylindrical lens are only partially surrounded by the housing around their edges. Due to its curvature and dielectric properties, the toroidal housing effectively enhances the projection of the beam in one dimension, thereby further suppressing unwanted diffusion of the beam's energy and improving the efficiency of the sensor.

[0100] In one embodiment, the lens housing is integrated into the sensor housing. The entire microwave radar sensor, particularly its electronic components, are contained and protected within the housing. The lens housing can be integrated into the sensor housing, facilitating assembly of the sensor. It is also conceivable that the integrated housing, including the lens housing and a portion of the remaining housing, could be manufactured as a single piece from the same material, ensuring uniform dielectric properties throughout the housing. Alternatively, the components interconnecting the sensor housing and the lens housing could be configured to have different dielectric properties than the lens housing, further improving beam directionality.

[0101] In a preferred embodiment, the microwave sensor includes multiple transmitting units and multiple receiving units, which increases the resolution of the sensor. Alternatively, some of the transmitting and / or receiving units may function as backup components to provide redundancy in case of failure of a primary component.

[0102] Further advantages, features and potential applications of the present invention can be understood by reference to the following description in conjunction with the embodiments illustrated in the drawings.

[0103] Throughout the specification, claims and drawings, these terms and associated reference numbers are used as set forth in the accompanying reference number list. [Brief explanation of the drawings]

[0104] [Figure 1] FIG. 1 is a perspective view of a first embodiment of a microwave imaging radar sensor. [Figure 2] FIG. 2 shows a microwave imaging radar sensor with transmit and receive beams according to FIG. [Figure 3] FIG. 3 is a perspective view of a second embodiment of a microwave imaging radar sensor. [Figure 4] FIG. 4 is a far-field depiction of the microwave imaging radar sensor according to FIG. [Figure 5] FIG. 5 is a plan view of the microwave imaging radar sensor according to the second embodiment of FIG. [Figure 6] FIG. 6 is a grid of overlapping areas provided by corresponding fan-shaped transmit and receive beams. [Figure 7] FIG. 7 shows a fan radiation pattern including a fan beam. [Figure 8] FIG. 8 is a schematic of a microwave imaging radar sensor that generates an image of at least a portion of the surrounding space. [Figure 9] Figure 9 is a microwave imaging radar sensor with a housing for a refractive beamformer. DETAILED DESCRIPTION OF THE INVENTION

[0105] Figure 1 is a perspective view of a first embodiment of a microwave imaging radar sensor 10 according to the present invention. The microwave imaging radar sensor 10 comprises a transmitting unit 12 and a receiving unit 14, which are connected to an evaluation unit 15. The evaluation unit is not shown in Figure 1 for clarity. The sensor 10, the transmitting unit 12, and the receiving unit 14 are assigned coordinate systems X, Y, and Z, respectively.

[0106] Sensor 10 includes a line-of-sight direction VD directed toward the surrounding space and a line-of-sight plane VP perpendicular to line-of-sight direction VD. Sensor 10 has a sensor reference plane RP-S in plane XZ and a sensor elevation plane EP-S in plane YZ. Thus, sensor reference plane RP-S is perpendicular to sensor elevation plane EP-S.

[0107] The transmitting unit 12 includes a refractive beamformer 20 having a central axis MT. The transmitting unit 12 also includes a transmit reference plane RP-T. The center of the X, Y, and Z coordinates of the transmitting unit 12 is located at the intersection of the central axis MT, the transmit reference plane RP-T, and the field of view plane VP. The transmit reference plane RP-T is located in the XZ plane of the transmitting unit 12 and is perpendicular to the field of view plane VP, which is located in the XY plane. The transmitting unit 12 has a transmit angle plane EP-T, which is located in the YZ plane and is perpendicular to both the transmit reference plane RP-T and the field of view plane VP.

[0108] The receiving unit 14 includes a refractive beamformer 21 having a central axis MR. The receiving unit 14 also includes a receiving reference plane RP-R. The coordinate center of the receiving unit 14 is located at the intersection of the central axis MR, the receiving reference plane RP-R, and the field of view plane VP. The receiving unit 14 includes a receiving reference plane RP-R that is located in the XZ plane of the sensor and perpendicular to the field of view plane VP that is located in the XY plane. The receiving unit 14 includes a receiving angle plane EP-R that is located in the YZ plane and perpendicular to both the receiving reference plane RP-R and the field of view plane VP.

[0109] In this embodiment, the transmitting unit 12 and the receiving unit 14 are arranged in the same plane XZ, so the transmitting reference plane RP-T and the receiving reference plane RP-R intersect at an angle of 0°. Both the transmitting reference plane RP-T and the receiving reference plane RP-R are parallel to the sensor reference plane RP-S, and may particularly coincide with the sensor reference plane RP-S. The sensor elevation plane EP-S is parallel to the transmitting elevation plane EP-T and the receiving elevation plane EP-R, and is located at half the distance between the transmitting central axis MT and the receiving central axis MR.

[0110] The transmitting unit 12 and the receiving unit 14 each include a refractive beamformer 20, 21 made of a dielectric material and which changes the directionality of microwaves passing through it.

[0111] A plurality of transmit transition structures TTS.X, in particular two transmit transition structures TTS.1, TTS.2, are associated with the refractive beamformer 20 of the transmitting unit 12, and a plurality of receive transition structures RTS.X, in particular three receive transition structures RTS.1, RTS.2, RTS.3, are associated with the refractive beamformer 21 of the receiving unit 14. Each transition structure TTS.1, TTS.2, RTS.1, RTS.2, RTS.3 is located at a different transition position 27 on the circumference of each of the transmitting unit 12 and the receiving unit 14.

[0112] In the first embodiment shown in Figure 1, the refractive beamformer 20 has two transmit transition structures TTS.1, TTS.2 arranged around it. These structures convert electrical energy into electromagnetic energy, which is transmitted to the refractive beamformer 20. Meanwhile, three receive transition structures RTS.1, RTS.2, RTS.3 are associated with the refractive beamformer 21 of the receiving unit 14 and receive the echo waves.

[0113] According to the illustrated embodiment, the refractive beamformers 20, 21 are cylindrical and therefore provide a fan-shaped radiation pattern, as shown in FIG.

[0114] Microwaves with specific signal characteristics transmitted from the transmitting unit 12 are reflected by objects in the space surrounding the sensor. Addressed transmitting transition structures TTS.1, TTS.2 that transmit the microwave signals are assigned to transmission channels.

[0115] The receiving unit 14 can receive echo waves with varying characteristics in multiple receive transition structures RTS.1, RTS.2, RTS.3. The echo wave signals are compared to the transmitted signals to provide result signals having radar result characteristics. Each echo or received signal is also evaluated with respect to the set of receive transition structures that received the signal. Each result signal having a particular radar result characteristic is assigned to a receive channel depending on the receive transition structure RTS.1, RTS.2, RTS.3, or combination of receive transition structures RTS.1, RTS.2, RTS.3, from which the respective echo or received signal was received. Result information related to the radar result characteristic is assigned to the particular receive channel associated with the corresponding transmit channel.

[0116] The receive beam BR.X overlaps with the transmit beam BT.X, creating an overlap area OA, which corresponds to the sensor azimuth range αS and the sensor elevation range βS. The overlap area OA is correlated with the spatial coordinates of a portion of the sensor's surrounding space and the paired transmit and receive channels, resulting in radar result characteristics assigned to the receive channels.

[0117] Therefore, the overlap area OA corresponds to a pair of transmit and receive channels, to which radar result characteristics are assigned. The image can be created by assigning the result information obtained from the radar result characteristics assigned to the pair of transmit and receive channels to the overlap area. Thus, the spatial relationship can be obtained simply by knowing the addressed paired sets of transmit transition structures and receive transition structures and the radar result characteristics.

[0118] The set of overlapping areas OA.X preferably includes all overlapping areas OA.X. Thus, the sensor 10 provides an image based on a 2D raster based on the sensor azimuth range αS and the sensor elevation range βS and radar result characteristics.

[0119] Figure 2 shows the microwave imaging radar sensor 10 according to the first embodiment shown in Figure 1. The sensor 10 has a line of sight direction VD.

[0120] The evaluation unit 15 of the sensor 10 comprises a radar control unit 16 and an imaging unit 18 connected to each other. The radar control unit 16 is connected to the transmitting unit 12 and the receiving unit 14 via a power line 24 adapted for connection to the radar control unit 16.

[0121] In this embodiment, the transmitting unit 12, the receiving unit 14, and the power transmission line 24 are implemented as a single circuit board 25, or PCB body 26. The radar control unit 16 can be implemented as one or more microchips mounted on the PCB body 26. The radar control unit 16 and the imaging unit 18 are mounted on the same PCB body 26. Alternatively, the radar control unit 16 and the imaging unit 18 may be mounted on separate PCB bodies.

[0122] The circuit board 25 includes a core layer 22 with top and bottom metallization layers 23 surrounding the substrate of the core layer 22. In particular, the circuit board 25 includes a PCB body 26 with a flexible core 22, and the connection region 28 may include a thinner region that provides flexible bending and allows the transmitter unit 12 and receiver unit 14 to tilt relative to one another, as shown in the embodiments of Figures 3 and 5. For example, the PCB body 26 may include two core layers 22 attached to one another by a prepreg layer, and the connection region 28 may include only a single core layer 22, thereby forming a thinner region that allows bending.

[0123] In FIG. 2, at least one core layer 22 of the transmitting unit 12 and the receiving unit 14 forms a refractive beamformer 20, 21, respectively. The core layer 22, surrounded by a metallization layer 23, is preferably formed from a dielectric substrate and has a curved profile, thereby functioning as a lens, particularly a gradient index lens. The dielectric constant is affected by holes 29 that penetrate the dielectric layer of the core 22. Thus, in this embodiment, the refractive beamformers 20, 21 comprise cylindrical dielectric bodies; that is, they have a circular profile, with the top and bottom surfaces of each circle surrounded by a metal layer. The refractive beamformers 20, 21 may also have an elliptical profile.

[0124] Each refractive beamformer 20, 21 has a plurality of transmit transition structures TTS.1, TTS.2 and associated receive transition structures RTS.1, RTS.2, RTS.3. The transmit and / or transition structures TTS.1, TTS.2, RTS.1, RTS.2, RTS.3 may be, for example, tapered microstrip transition structures, and are disposed around the respective refractive beamformer 20, 21, on or at a distance from the surface of the respective refractive beamformer 20, 21. Each transition structure TTS.1, TTS.2, RTS.1, RTS.2, RTS.3 is associated with a respective transition location 27 for the respective refractive beamformer 20, 21.

[0125] The transition structures TTS.1, TTS.2, RTS.1, RTS.2, and RTS.3 convert one form of energy to another, thereby transmitting electrical energy, and transmit signals between the associated transmission lines 24 and respective waveguides 48, which direct the electromagnetic energy in a specific direction. The waveguides 48 are made from the same core substrate as the PCB body 26, with the core layer 22 surrounded by top and bottom metallization layers 23. The top and bottom metallization layers 23 are connected to each other by metallized vias that penetrate the core layer 22 and serve as walls on either side of the waveguides 48. Thus, the waveguides 48 direct microwaves in a specific direction by internal reflection, i.e., between the refractive beamformers 20 and 21 and the respective transition structures TTS.1, TTS.2, RTS.1, RTS.2, and RTS.3.

[0126] Specifically, the radar control unit 16 supplies electrical energy and signals to the transmit transition structures TTS.1, TTS.2 via the connecting power lines 24. The transmit transition structures TTS.1, TTS.2 convert the electrical energy into electromagnetic energy, i.e., microwaves, which are guided by waveguides 48 to the refractive beamformers 20 at the respective transition locations 27.

[0127] Due to reciprocity, electromagnetic energy received by the refractive beamformer 21 of the receiving unit 14 enters the waveguide 48 at the transition location 27 associated with each receiving transition structure RTS.1, RTS.2, RTS.3. The waveguide 48 guides the electromagnetic energy to each receiving transition structure RTS.1, RTS.2, RTS.3, where these structures convert the electromagnetic energy to electrical energy. The converted electrical energy and associated signals are transmitted over the transmission line 24 to the radar control unit 16.

[0128] Depending on the transition positions 27 associated with the transmit transition structures TTS.1, TTS.2, the refractive beamformer 20 refracts the transmitted microwaves to generate fan beams BT.1, BT.2, as shown schematically in FIG. 2. The transmit beams BT.1, BT.2 are defined by a transmit azimuth angle range αT and a transmit angle range βT. The transmit azimuth angles αT1, αT2 lie in the transmit reference plane RP-T, and the transmit angle angles βT1, βT2 lie in the transmit angle plane EP-T, as shown in FIG. 1.

[0129] The transmit beams BT.1, BT.2 have a first dimension D1 over a transmit elevation angle range βT (specifically 60°). The first dimension D1 is perpendicular to the transmit reference plane RP-T. The transmit beams BT.1, BT.2 have a second dimension D2 perpendicular to the first dimension D1 over a transmit azimuth angle range αT (specifically 10°). Thus, the second dimension D2 is significantly smaller than the first dimension D1, and the first dimension D1 is at least three times larger than the second dimension D2. The first dimension D1 is related to the elevation angles βT1, βT2, and the second dimension is related to the azimuth angles αT1, αT2.

[0130] Depending on the transition positions 27 with which the transmit transition structures TTS.1, TTS.2 are associated, the beams BT.1, BT.2 have main directions MDT.1, MDT.2. In the example shown, the main directions MDT.1, MDT.2 of the transmit beams BT.1, BT.2 are separated by an azimuth angle φT of approximately 120°.

[0131] The same is true for the receiving unit 14, but the refractive beamformer 21 of the receiving unit 14 is associated with receiving transition structures RTS.1, RTS.2, RTS.3, so that the receiving unit 14 can provide three fan beams BR.1, BR.2, BR.3.

[0132] In the particular example shown in Figure 2, the main directions MDR.1, MDT.2 of the corresponding beams BR.1, BT.2 intersect, resulting in an overlap area OA of the second transmitting beam BT.2 and the first receiving beam BR.1. The transmitted microwaves are therefore reflected by an object at this position, and a received signal related to the echo wave is received by the receiving transition structure RTS.1.

[0133] The overlap region OA corresponds to the elevation range βS of the sensor and the azimuth range αS of the sensor, as shown in FIG. 2 and also described in FIG.

[0134] 3 shows a perspective view of a second embodiment of the microwave imaging radar sensor 10. Unlike the first embodiment, the circuit board 25 is bent at the central connection region 28, so that the transmitting unit 12 and the receiving unit 14 are arranged perpendicular to each other. The transmitting reference plane RP-T defined by the transmitting unit 12 and the receiving reference plane RP-R defined by the receiving unit 14 preferably have an intersection angle ranging from 15° to 90°. In the second embodiment, this intersection angle is 90°.

[0135] The field plane VP is orthogonal to both the receiving reference plane RP-R and the transmitting reference plane RP-T. The line of sight direction VD is orthogonal to the field plane VP and lies in the receiving reference plane RP-R and the transmitting reference plane RP-T.

[0136] The center of coordinates X, Y, Z (not shown) of the transmitting unit 12 is located at the intersection of the central axis MT, the transmitting reference plane RP-T, and the field of view plane VP. The transmitting unit 12 has a transmitting angle plane EP-T that is perpendicular to the transmitting reference plane RP-T and the field of view plane VP.

[0137] Similarly, the center of coordinates X, Y, Z (not shown) of the receiving unit 14 is located at the intersection of the central axis MR, the receiving reference plane RP-T, and the field of view plane VP. The receiving unit 14 has a receiving angle plane EP-R that is perpendicular to the receiving reference plane RP-R and the field of view plane VP.

[0138] Thus, in the illustrated example, the transmit reference plane EP-T correlates with the receive reference plane RP-R, and the receive reference plane EP-R correlates with the transmit reference plane RP-T.

[0139] The sensor 10 has a sensor reference plane RP-S parallel to the transmission reference plane RP-T, and a sensor elevation plane EP-S perpendicular to the sensor reference plane RP-S and the field of view plane VP.

[0140] Depending on the transition positions 27 associated with the transmit transition structures TTS.1, TTS.2, the refractive beamformer 20 shapes the electromagnetic energy into fan-shaped beams BT.1, BT.2. These beams are shown schematically in FIG. 3. Each transmit beam BT.1, BT.2 is defined by a transmit azimuth angle αT and a transmit angle βT. Each transmit beam BT.1, BT.2 includes transmit azimuth angles αT1, αT2, which lie within a transmit reference plane RP-T. Meanwhile, the transmit angles βT1, βT2 lie within a transmit angle plane EP-T. A central axis MT is the intersection of the transmit angle plane EP-T and the field plane VP. Each transmit beam BT.1, BT.2 has a first dimension D1 across a transmit angle range βT1, βT2 (specifically, 60°). The first dimension D1 is perpendicular to the transmit reference plane RP-T. The transmit beams BT.1 and BT.2 have a second dimension D2 perpendicular to the first dimension D1 over the transmit azimuth angle range αT1 and αT2 (specifically 10°). Therefore, the second dimension D2 is significantly smaller than the first dimension D1.

[0141] The same is true for the receiving unit 14, except that the refractive beamformer 21 of the receiving unit 14 is associated with multiple receiving transition structures RTS.1, RTS.2, and RTS.3. This allows the receiving unit 14 to provide three fan beams BR.1, BR.2, and BR.3. FIG. 3 shows two receiving beams BR.1 and BR.2, defined by receiving azimuth angles αR1 and αR2 and receiving angle angles βR1 and βR2, respectively. The receiving beams BR.1 and BR.2 have main directions MDR.1 and MDR.2. In this example, these beams are separated by an azimuth angle φR of approximately 120°.

[0142] Each fan-shaped receive beam BR.1, BR.2 is associated with a receive channel RX-1, RX-2, respectively, and each fan-shaped transmit beam BT.1, BT.2 is associated with a transmit channel TX-Ch1, TX-Ch2, respectively. For example, transmit beams BT.1, BT.2 and their corresponding receive beams BR.1, BR.2 overlap to provide overlap regions OA.1, OA.2, OA.3, OA.4.

[0143] Each overlap area OA.1, OA.2, OA.3, and OA.4 corresponds to a sensor azimuth range αS and a sensor elevation angle range βS. Overlap area OA.1 has a sensor azimuth range αS1 corresponding to the transmission azimuth angle αT1 and a sensor elevation angle range βS1 corresponding to the reception azimuth angle αR1. Overlap area OA.2 has a sensor azimuth range αS1 corresponding to the transmission azimuth angle αT1 and a sensor elevation angle range βS2 corresponding to the reception azimuth angle αR2. Overlap area OA.3 has a sensor azimuth range αS2 corresponding to the transmission azimuth angle αT2 and a sensor elevation angle range βS1 corresponding to the reception azimuth angle αR1. Overlap area OA.4 has a sensor azimuth range αS2 corresponding to the transmission azimuth angle αT2, and the sensor elevation angle range βS2 corresponds to the reception azimuth angle αR2.

[0144] Similar to the first embodiment, multiple transition structures TTS.1, TTS.2, RTS.1, RTS.2, RTS.3 at different transition positions 27 are associated with the refractive beamformers 20, 21 of the transmitting unit 12 and the receiving unit 14, respectively. In contrast to the first embodiment shown in FIG. 2, a kind of grid is obtained from the overlapping areas OA.1, OA.2, OA.3, OA.4 based on the sensor azimuth ranges α, α and sensor elevation ranges β, β of the corresponding overlapping beams BT.1, BT.2, BR.1, BR.2. Resulting information on radar result characteristics obtained from the corresponding overlapping areas OA.1, OA.2, OA.3, OA.4 is assigned to pixels of the image field to provide an image of at least a part of the space around the sensor, as shown in detail in FIG. 6.

[0145] Similar to the discussion above, it should be understood that the third receive beam BR.3 creates two additional overlap regions, although for clarity, these overlap regions are not shown or explicitly described in this example.

[0146] Preferably, the transmit transition structures TTS.1, TTS.2 are switched, i.e., individually addressed one after the other, to achieve beam switching. In other words, a transmit signal is applied to one transmit transition structure TTS.1, TTS.2 at a time in successive evaluation cycles. Thus, by controlling the transmit transition structures TTS.1, TTS.2, the angular deflection of the main directions MDT.1, MDT.2 of the transmit beams BT.1, BT.2 is changed relative to the line of sight. This angular deflection lies within the transmit reference plane RP-T. In each successive evaluation cycle, a different individual transmit transition structure is opened and a signal is transmitted, sweeping within the transmit azimuth angle range in successive evaluation cycles. Beam switching results in multiple overlapping regions OA.X.

[0147] Alternatively or additionally, two adjacent transmit transition structures TTS.1, TTS.2 may be input simultaneously in one evaluation cycle, in which case the radar control unit 16 may perform a phase evaluation of the transmit transition structures TTS.1, TTS.2 to potentially correct for a phase difference between the adjacent transmit transition structures TTS.1, TTS.2.

[0148] Thus, for example, there can be a sequence of evaluation cycles that triggers the individual transition structures TTS.1, TTS.2 and a sequence of evaluation cycles that triggers the combined transition structure TTS.1, TTS.2.

[0149] 4 illustrates the sensor 10 according to the second embodiment shown in FIG. 3 in a far-field representation showing the angular extents of the overlap regions OA.1, OA.2, OA.3, and OA.4. The sensor 10 includes a sensor reference plane RP-S that is normal to the field of view plane VP. The sensor elevation plane EP-S is normal to both the sensor reference plane RP-S and the field of view plane VP.

[0150] The coordinate systems assigned to the transmitting unit 12 and the receiving unit 14 intersect the sensor's coordinate system X, Y, Z at their origins, i.e., they can be superimposed to correspond to the sensor's coordinate system X, Y, Z.

[0151] In the second embodiment, the transmitting unit 12 and the receiving unit 14 are orthogonal to each other, and the transmitting reference plane RP-T and the receiving reference plane RP-R intersect at a 90° angle. Accordingly, corresponding beams BT.1, BR.1 and corresponding beams BT.2, BR.2 are also orthogonal to each other. The transmitting beams BT.1, BT.2 and the receiving beams BR.1, BR.2 overlap as shown in FIG. 3 , thereby forming a kind of grid of overlapping regions OA.1, OA.2, OA.3, OA.4 having sensor azimuth ranges α, α and sensor elevation ranges β, β, as described in FIG. 3 . In other words, the overlapping region OA.1 corresponding to the overlapping beams BT.1, BR.1 has a sensor azimuth range α and a sensor elevation range β. The overlapping region OA.2 corresponding to the overlapping beams BT.1, BR.2 has a sensor azimuth range α and a sensor elevation range β. The overlap area OA.3 corresponding to the overlapping beams BT.2 and BR.1 has a sensor azimuth range αS2 and a sensor elevation range βS1. The overlap area OA.4 corresponding to the overlapping beams BT.2 and BR.2 has a sensor azimuth range αS2 and a sensor elevation range βS2.

[0152] 5 shows a plan view of a second embodiment of the sensor 10 according to FIG. 3. The transmitting unit 12 and the receiving unit 14 are separated by a distance D. In order for the sensor 10 to accurately detect an object in a portion of the surrounding space, the overlap area OA.X must be within the coverage zone of the sensor 10. The coverage zone starts at the manifold of the distance D. For example, the distance D is the shortest distance between the transmitting unit 12 and the receiving unit 14, and the coverage zone starts at 10 times the distance D.

[0153] In particular, the transmit reference plane RP-T corresponds to the sensor reference plane RP-S, which covers the entire sensor azimuth range or spectrum, including the sensor azimuth range αS. The sensor elevation plane EP-S, which is perpendicular to both the line of sight direction VD and the sensor reference plane RP-S, covers the entire sensor elevation range or spectrum, including the sensor elevation range βS, but is not shown.

[0154] The radar control unit 16 controls two transmit transition structures TTS.1 and TTS.2 that transmit electromagnetic signals, generating transmit beams BT.1 and BT.2 via a refractive beamformer 20. The refractive beamformer 20 is designed to collimate electromagnetic energy based on its physical properties. Therefore, each transition structure TTS.1 and TTS.2 is associated with a fan-shaped beam BT.1 and BT.2, respectively. Here, the beams BT.1 and BT.2 represent the angular extent of the fan-shaped radiation pattern, as shown in FIG. 7.

[0155] The position and / or orientation of the transmit transition structures TTS.1, TTS.2 relative to the refractive beamformer 20 determines the main directions MDT.1, MDT.2 in which the electromagnetic signals propagate. The main directions of energy propagation MDT.1, MDT.2 lie in a transmit reference plane RP-T which is relative to the sensor reference plane RP-S.

[0156] Transmit beams BT.1 and BT.2 have transmit azimuth angles αT1 and αT2, respectively, which are associated with sensor azimuth angle ranges αS1 and αS2. Transmit beams BT.1 and BT.2 span transmit elevation angles βT1 and βT2, respectively, which correlate with sensor elevation angle ranges βS1 and βS2, ​​not shown in this figure.

[0157] FIG. 5 shows how the echo waves of the transmit beam BT.1, which correlates with the receive beam BR.1, are received by the receive unit 14. The receive transition structure RTS.1 (not shown) associated with the refractive beamformer 21 receives the electromagnetic signals arriving from a specific direction correlated with the receive beam BR.1. In the second embodiment, the transmit unit 12 and the receive unit 14 are orthogonal to each other. Therefore, the corresponding beams BT.1 and BR.1 are also inclined perpendicularly to each other. The receive beam BR.1 is perpendicular to the receive reference plane RP-R and has a receive angle βR1 of approximately 60° and a receive azimuth angle αR1 of approximately 10° (not shown in this figure). Because the receive unit 14 is perpendicular to the transmit unit 12, the receive angle βR1 corresponds to the sensor azimuth range αS, and the receive azimuth angle αR1 corresponds to the sensor elevation angle range βS.

[0158] FIG. 5 illustrates an overlap area OA.1 formed by the overlap of transmit beam BT.1 and receive beam BR.1. Due to the perspective of the figure, the overlap area OA.1 is shown by an intersection line. The overlap area OA.1 is related to the sensor azimuth angle range αS and the sensor elevation angle range βS of beams BT.1 and BR.1, respectively. As described in FIG. 3, the overlap area OA.1 includes the sensor azimuth angle range αS1 and the sensor elevation angle range βS1. The sensor azimuth angle range αS1 corresponds to the transmit azimuth angle αT1, and is shown by an intersection line in FIG. 5. Additionally, the sensor elevation angle range βS1 corresponds to the receive azimuth angle αR1, but is not shown in this perspective view.

[0159] 5 has a first dimension D1 perpendicular to the reference plane RP-T, RP-R of the respective refractive beamformer 20, 21. The first dimension D1 corresponds to the height of the beam associated with the respective refractive beamformer 20, 21. In the example shown, the first dimension D1 of the receive beam BR.1 is perpendicular to the receive reference plane RP-R and extends over a receive angle range βR1 that includes approximately 60° and corresponds to the sensor orientation range αS.

[0160] Similarly, transmit beams BT.1, BT.2 have a first dimension D1 that is perpendicular to the reference plane RP-T of the respective refractive beamformer 20 and corresponds to a beam height related to the transmit angle range of the refractive beamformer 20. Thus, the first dimension D1 of transmit beams BT.1, BT.2 is related to the transmit angle βT1, βT2 (not shown) of the refractive beamformer 20 and therefore also to the sensor elevation angle range βS (not shown).

[0161] Each beam BT.1, BT.2, BR.1 also has a second dimension D2 perpendicular to the first dimension D1 and corresponding to a beamwidth associated with the azimuth angle of the respective refractive beamformer 20, 21. The second dimension D2 of the transmit beams BT.1, BT.2 corresponds to approximately 10°, respectively, and extends across transmit azimuth angles αT1, αT2 associated with a sensor elevation angle range αS1, αS2. Similarly, the second dimension D2 of the receive beam BR.1 (not shown) extends across a receive azimuth angle αR1 (not shown) associated with a sensor elevation angle range βS (not shown).

[0162] Figure 6 shows multiple overlapping areas OA.X that are created when corresponding fan beams BT.1 to BT.4, BR.1 to BR.6 overlap to form a kind of grid, and by assigning information to each overlapping area OA.X, an image of at least a part of the space surrounding the sensor can be generated.

[0163] 6 specifically illustrates the embodiment shown in FIG. 3, where transmit beams BT.1 and BT.2 overlap with corresponding receive beams BR.1 and BR.2, providing overlap regions OA.1, OA.2, OA.3, and OA.4. Additional transmit and receive beams BT.3, BT.4, BR.3, BR.4, BR.5, and BR.6 are also shown to illustrate the high resolution that can be achieved. Similarly, the description of transmit beams BT.1 and BT.2 overlapping with corresponding receive beams BR.1 and BR.2 also applies to all corresponding beams BT.1, BT.2, BT.3, BT.4, BR.1, BR.2, BR.3, BR.4, BR.5, and BR.6 shown in the grid, each with an overlap region OA.X.

[0164] The grid includes transmit beams BT.1, BT.2 having a first dimension D1 perpendicular to the respective transmit reference plane RP-T, which spans a transmit angular range βT (specifically, 120°).

[0165] Each of the fan beams BT.1, BT.2 has a second dimension D2 perpendicular to the first dimension and extends over a transmit azimuth angle range αT1, αT2 of 10° relative to the sensor azimuth angle range αS. In particular, each of the transmit beams BT.1, BT.2 corresponds to a sensor azimuth angle range αS1, αS2 of approximately 10°. Thus, the second dimension D2 is significantly smaller than the first dimension D1.

[0166] The same is true for receive beams BR.1 and BR.2, which have a first dimension D1 perpendicular to their respective reference planes RP-R and extending over receive angle ranges βR1 and βR2 of approximately 120° relative to the receive reference plane RP-R. Receive beams BR.1 and BR.2 have a second dimension D2 perpendicular to the first dimension D1 and extending over respective receive azimuth angle ranges αR1 and αR2 (each approximately 10°). The receive reference plane RP-R is perpendicular to the transmit reference plane RP-T, which corresponds to the sensor reference plane RP-S. Thus, receive beams BR.1 and BR.2 exhibit receive angle ranges βR1 and βR2 that fall within the sensor azimuth range, and receive beams BR.1 and BR.2 have receive azimuth angle ranges αR1 and αR2 that fall within the sensor elevation angle range and correspond to the sensor elevation angle ranges βS1 and βS2.

[0167] As described in detail above in FIG. 3, overlap areas OA.1, OA.2, OA.3, and OA.4 are defined by the sensor azimuth ranges α, α and sensor elevation ranges β, β associated with corresponding beams BT.1, BT.2, BR.1, and BR.2, respectively, as shown in the table of FIG. 6. In other words, corresponding beams BT.1 and BR.1 are associated with a sensor azimuth range α and a sensor elevation range β, thereby defining overlap area OA.1. Transmit beam BT.1 overlaps with receive beam BR.2, generating overlap area OA.2, defined by the sensor azimuth range α and the sensor elevation range β. Corresponding beams BT.2 and BR.1 generate overlap area OA.3, defined by the sensor azimuth range α and the sensor elevation range β. Corresponding beams BT.2 and BR.2 are associated with a sensor azimuth range α and a sensor elevation range β, thereby defining overlap area OA.4.

[0168] Corresponding beams BT.1, BT.2, BR.1, and BR.2 are associated with transmit and receive transition structures TTS.1, TTS.2, RTS.1, and RTS.2, respectively, and these transition structures are associated with transmit and receive channels TX.1, TX.2, RX.1, and RX.2, respectively. In other words, the set of corresponding beams BT.1, BR.1; BT.1, BR.2; BT.2; BR.1; BT.2, and BR.2 is associated with transmit and receive channels TX.1, RX.1; TX.1, RX.2; TX.2, RX.1; TX.2, and RX.2. Thus, referring to the table of FIG. 6 , the sensor azimuth range α of the transmit beams BT.1 and BT.2 and the sensor elevation range β of the receive beams BR1 and BR.2, which define overlap regions OA.1, OA.2, OA.3, and OA.4, can be associated with the respective receive channels RX.1 and RX.2 paired with the corresponding transmit channels TX.1 and TX.2. In other words, during each evaluation cycle, the radar control unit establishes a relationship between the individually addressed transmit channels TX.1, TX.2 and the set of receive channels RX.1, RX.2 that received the signals from the echo waves.

[0169] Further, each overlap area OA.1, OA.2, OA.3, OA.4 is associated with radar result characteristics provided by receive channels RX.1, RX.2 where receive beams BR.1, BR.2 overlap with transmit beams BT.1, BT.2 of transmit channels TX.1, TX.2. The radar result characteristics, which may include amplitude, frequency, phase, etc., are processed to determine result information I-1, I-2, I-3, I-4, which is then assigned to the corresponding receive channel RX.1, RX.2 and therefore to the overlap areas OA.1, OA.2, OA.3, OA.4 corresponding to the respective pairs of transmit and receive channels TX.1, RX.1; TX.1, RX.2; TX.2, RX.1; TX.2, RX.2.

[0170] In summary, the resulting information I-1, I-2, I-3, and I-4 are generated by a particular pair of overlapping transmit and receive beams BT.1, BT.2, BR.1, and BR.2, which generate particular overlap regions OA.1, OA.2, OA.3, and OA.4 associated with respective sensor azimuth and elevation ranges α, β. These relationships are mapped in a predefined manner in the data memory 32, and the imaging unit 18 uses this mapping information to assign the resulting information I-1, I-2, I-3, and I-4 to overlap regions OA.1, OA.2, OA.3, and OA.4 corresponding to the predefined relationships between the transmit and receive channels TX.1, TX.2, RX.1, and RX.2. In this manner, an image of at least a portion of the space surrounding the sensor can be created from the grid of overlap regions OA.1, OA.2, OA.3, and OA.4 and the resulting information I-1, I-2, I-3, and I-4. The values ​​and / or value changes associated with the result information can be coded, for example color coded, to allow the creation of pixel images using graphic image processing and / or filter algorithms.

[0171] 7 shows an example of a fan-shaped transmit beam BT.1, which is a region of a fan-shaped radiation pattern 44 associated with a transmit transition structure TTS.X of a transmitting unit 12 by a cylindrical refractive beamformer 20. For ease of reference, the fan-shaped radiation pattern 44 is preferably shown in the coordinate system X, Y, Z of the transmitting unit 12, where X denotes the axis of rotation for the transmit angle range βT and Y denotes the axis of rotation for the transmit azimuthal angle range αT. The reference plane RP-T lies in the XZ plane, and the transmit angle plane EP-T lies in the YZ plane and is perpendicular to the reference plane RP-T.

[0172] The sector-shaped radiation pattern 44 radiates energy mainly in one direction, the main direction MDT.1, and to a lesser extent in other directions. The main direction MDT.1 of the signal depends on the position of the respective transmitting transition structure TTS.1, not shown.

[0173] The angular area of ​​the fan-shaped radiation pattern 44 representing the fan-shaped transmit beam BT.1 is less than a threshold below the maximum gain amplitude of the radiation pattern 44. The threshold may be, for example, in the range of 3 dB to 10 dB. In the illustrated example, the threshold corresponds to 3 dB. Thus, the transmit azimuth range αT of beam BT.1 is narrow, for example 10°, while the transmit angle range βT is wide, for example 60°.

[0174] Therefore, beam BT.1 in this case has a first dimension D1 that is six times larger than its second dimension D2. The first dimension D1 is perpendicular to the reference plane RP-T and to the second dimension D2, which contains the direction of peak gain. The main direction of energy propagation MDT.1 lies in the reference plane RP-T.

[0175] 8 shows in detail how a microwave imaging radar sensor 10 functions to provide an image of at least a portion of its surrounding space. The sensor 10 comprises at least one transmitting unit 12 coupled to a receiving unit 14, and an evaluation unit 15 including a radar control unit 16 and an imaging unit 18.

[0176] The radar control unit 16 comprises a transmission chain that relays information from the imaging unit 18 to the transmission unit 12. The radar control unit 16 comprises an interface 30 to which the imaging unit 18 is connected.

[0177] The imaging unit 18 includes a calculation unit 31 that sets information signals to be transmitted to the radar control unit 16 via the interface 30. These signals are assigned to respective transmit channels TX.X. In other words, the imaging unit 18 provides a signal set that determines which of a plurality of transmit transition structures TTS.X the radar control unit 16 will address in a single evaluation cycle to emit a transmit beam BT.X, and which transmit characteristics TC will be transmitted by the addressed transmit transition structure TTS.X. The information, i.e., the transmit transition structures TTS.X and the associated transmit characteristics TC, is stored, for example, in a transmit information map 35a and is accessible to the calculation unit 31. This allows the interface 30 to relay the transmit specifications TTS.X.-TC to the radar control unit 16.

[0178] The computing unit 31 may include a CPU and / or an FPGA and / or an ASIC and / or a microprocessor.

[0179] The imaging unit 18 includes a data memory 32 that stores mapping information consisting of a plurality of predetermined relationships between the transmit channel TX.X and the receive channel RX.X and their respective overlap areas OA.X, in particular, overlap area coordinates with respect to the sensor azimuth range αS and the sensor elevation angle range βS as shown in Figure 6. The data memory 32 preferably includes a plurality of pieces of mapping information, each of which is associated with a specific angle between the transmit reference plane RP-T and the receive reference plane RP-R, so as to flexibly adjust the resolution of the sensor 10.

[0180] The imaging unit 18 communicates the transmit specifications TTS.X-TC to the radar control unit 16. The radar control unit 16 has an input port 34 that receives these signals from the imaging unit 18 via the interface 30. The imaging unit 18 can instruct the radar control unit 16 to perform multiple evaluation cycles, in which an addressed transmit transition structure TTS.X and its corresponding transmit characteristics TC are assigned to a particular transmit channel TX.X. The calculation unit 31 of the imaging unit 18 performs a cycle for each transmit channel TX.X present in the mapping information stored in the data memory 32. For each transmit channel TX.X, the associated transmit characteristics TC are applied to the associated transmit transition structure TTS.X using information from the transmit information map 35a of the corresponding transmit channel TX.X.

[0181] In each evaluation cycle, the radar control unit 16 addresses a particular transmit transition structure TTS.X to output a transmit signal to transmit microwaves having transmit characteristics TC. The transition structure TTS.X directs the microwaves to the refractive beamformer 20 of the transmitter unit 12, generating a fan-shaped radiation pattern 44 including a fan beam BT.X.

[0182] The multiple transmit transition structures TTS.X are preferably individually addressable one after the other in successive evaluation cycles, so that microwaves are individually supplied to the refractive beamformer 20 at multiple transition locations 27. By operating the transmit transition structures TTS.X one after the other, multiple beams are individually generated, each with a main direction pointing broadly in the line of sight direction, thereby sweeping the azimuthal range or spectrum of the refractive beamformer 20 of the transmitting unit 12 in successive evaluation cycles.

[0183] Each transmitted microwave contains electromagnetic energy primarily directed in a desired direction, which is the primary direction. The microwave provides a particular transmission characteristic TC. A target object that reflects the transmitted microwave generates an echo wave associated with a receive beam BR.X, which may be received by the refractive beamformer 21 of the receiving unit 14. The echo wave has different characteristics compared to the transmitted microwave.

[0184] Reciprocally, the radar control unit 16 includes a receive chain that relays information from the receiving unit 14 to the imaging unit 18. The echo waves are preferably received by a plurality of receive transition structures RTS.X, each associated with a receive channel RX.X. The radar control unit 16 evaluates the received signals based on the corresponding transmit signals and generates a result signal having a radar result characteristic RC. The radar result characteristic RC is associated with a particular receive transition structure RTS.X. This information, i.e., the receive evaluation RTS.X-RC, including the evaluated receive transition structure RTS.X associated with the particular radar result characteristic RC, is output by the radar control unit 16 via the output port 36 and relayed to the imaging unit 18 via the interface 30.

[0185] Preferably, the radar control unit 16 uses analog processing to transmit electromagnetic energy by activating an addressed transmit transition structure TTS.X and evaluates the set of receive transition structures RTS.X that receive the echo or received signal. The relationship between the receive transition structures RTS.X and the receive channels RX.X is stored in the receive information map 35b.

[0186] The radar control unit 16 has an output port 36 for outputting the radar result characteristic RC associated with the estimated reception transition structure RTS.X, ie, the reception evaluation RTS.X.-RC, to the imaging unit 18 via the interface 30.

[0187] In each evaluation cycle, imaging unit 18 receives radar result characteristics RC and associated receive transition structures RTS.X and processes the radar result characteristics RC to determine result information IX associated with the receive transition structures RTS.X. The radar result characteristics RC may be processed, preferably digitally, to obtain result information IX.

[0188] The result information IX is associated with the receive transition structure RTS.X and thus is associated with the receive channel RX.X based on the receive information map 35b. Accordingly, the arithmetic unit 31 assigns the result information IX to the corresponding receive channel RX.X by accessing the receive information map 35b. The transmit information map 35a and / or the receive information map 35b may be stored separately or may be incorporated into the mapping information stored in the data memory 32.

[0189] The arithmetic unit 31 of the imaging unit 18 uses the mapping information in the data memory 32 to associate, preferably digitally, the receive channels RX.X with the corresponding transmit channels TX.X, and in each evaluation cycle assigns result information IX to each overlap area OA.X corresponding to a pair of transmit and receive channels TX.X, RX.X, thereby creating an image of at least a part of the space around the sensor. In particular, a raw data image can be created from a grid of overlap areas OA.X.

[0190] The imaging unit 18 has an output port 38 from which the image can be output to an image processing unit 40. The image processing unit 40 may be part of a common housing with the microwave imaging radar sensor 10. The image processing unit 40 further analyzes the image and reconstructs a processed image.

[0191] The image has a number of fields, each represented by pixels corresponding to a particular relationship, where a particular receive channel RX.X is assigned to a particular transmit channel TX.X, and each pixel is assigned a value associated with the result information IX.

[0192] For example, in the processed image, the values ​​and / or value changes assigned to each pixel can be coded by gray coding, color coding, etc., and graphic image processing and / or filter algorithms can be used to create a graphic image. Also, by taking into account the results of applying signal processing to the result information IX based on the radar result characteristics RC, various images can be created, such as 3D Cartesian images.

[0193] FIG. 9 shows a portion of a sensor 10 having a transmitter unit 12 with a refractive beamformer 20, which is a cylindrical lens housed within a mechanical housing 42 shown in cutaway cross section.

[0194] The mounting configuration of the transmitting unit 12 is the same as that without the mechanical housing 42 and is similar to that of the receiving unit 14 .

[0195] In this example, the transmitter unit 12 is mounted on a single circuit board 25 (e.g., PCB body 26) that has multiple core layers 22 that include a dielectric substrate. The core layers 22 are bonded together by prepreg layers 46 and are surrounded by upper and lower metallization layers 23 that surround the dielectric substrate, providing structural support for the dielectric substrate and ensuring the elevation focusing properties of the refractive beamformer 20.

[0196] The core layers 22 of the transmitting unit 12 form the refractive beamformers 20, each having a cylindrical shape, enabling the transmission of a fan-shaped beam. The dielectric core substrate of the transmitting unit 12 functions as a lens, particularly a gradient index lens. The refractive index of the dielectric is affected by the holes 29 formed in the dielectric core layer 22.

[0197] Because circuit board 25 includes multiple core layers 22, the transmit transition structures TTS.X associated with refractive beamformer 20 may be waveguides 48 and probes 49 embodied as blind vias at different transition locations 27. The transmit transition structures TTS.X convert electrical energy into electromagnetic energy (i.e., microwaves) that are guided by waveguides 48 to refractive beamformer 20.

[0198] The waveguide 48 is integrated with the single circuit board 25. The waveguide 48 is surrounded by sidewalls 50a, 50b formed by metallized upper and lower layers 23, 23, and metallized vias that traverse the core layer 22 and connect the metallized layers 23, allowing the waveguide 48 to direct electromagnetic energy in a specific direction.

[0199] The power line 24 is connected to the radar control unit 16 as previously described.

[0200] The housing 42 of the refractive beamformer 20 is preferably formed from a dielectric substrate and has a torus-like shape. The housing 42 has open surfaces at opposite poles around its central axis of rotation (corresponding to the central axis MT of the transmitting unit 12). In this example, the central hyperboloid of the torus-shaped housing 42 has been removed, resulting in open surfaces at opposite poles of the housing 42. Thus, while the cylindrical lens is radially surrounded by the housing 42, both flat circular surfaces of the cylindrical lens are only partially surrounded by the housing 42 around their edges.

[0201] The housing 42, due to its curvature and dielectric properties, affects the polarization characteristics of the transmitted and received electromagnetic radiation. The housing 42 has the advantage of converting planar electromagnetic radiation into circularly polarized light, which is desirable when analyzing RF waves reflected from irregular objects. Circular polarization allows for more energy to be collected from various echoes for transmission. For example, the human body does not always maintain linear polarization when generating echoes, so a torus-shaped housing 42 can increase the detection sensitivity of the sensor 10.

[0202] The lens housing 42 may be an integral part of the housing of the sensor 10. The integral housing may be manufactured as a single piece, for example, by 3D printing using the same material, in which case the dielectric properties of the entire housing are the same. Alternatively, the interconnect between the sensor housing and the lens housing 42 may have different dielectric properties than the lens housing 42. [Explanation of symbols]

[0203] 10 Microwave imaging radar sensor 12 Transmitting unit 14 Receiving unit 15 evaluation units 16 Radar Control Unit 18 Imaging Unit 20 Refraction Beamformer 21 Refraction Beamformer 22 Core layer 23 Metal layer 24 Power Lines 25 Circuit Board 26 PCB body 27 Transition position 28 Connection Area 29 holes 30 Interface 31 arithmetic unit 32 Data Memory 34 Input port RCU 35a Transmission Information Map 35b Reception Information Map 36 Output port RCU 38 Output port IU 40 Image Processing Unit 42 Housing 44 Radiation Pattern 46 prepreg layers 48 Waveguide 49 Probe 50a sidewall 50b side wall αR Receiving azimuth angle range αS sensor azimuth angle range αT Transmission azimuth angle range βR Receiving angle range βS sensor elevation angle range βT Transmission angle range φR Azimuth angle between receiving beams φT Azimuth angle between transmitting beams BR.X receiving beam BT.X transmission beam D distance D1 First dimension D2 Second dimension EP-R receiving angle face EP-S sensor elevation plane EP-T transmitter corner IX Results Information MT Transmission Unit Center Axis Central axis of MR receiving unit MDR.X Main direction of receiving beam MDT.X Main direction of the transmitting beam OA.X duplicate area RC radar result characteristics RP-R receiving reference plane RP-S sensor reference surface RP-T transmission reference plane RTS.X receive transition structure RTS.X-RC reception evaluation RX.X Receive Channel TTS.X transmit transition structure TTS.X-TX transmission specifications TX.X Transmit Channel VD Field of View VP field of view

Claims

1. A microwave imaging radar sensor (10) for producing an image of at least a portion of a surrounding space, comprising: The sensor (10) comprises at least one transmitting unit (12), a receiving unit (14), and an evaluation unit (15) having an output port (38) for outputting an image, the evaluation unit (15) being connected to the transmitting unit (12) and the receiving unit (14); The image contains fields, The fields are associated with a pair of a transmit channel (TX.X) and a receive channel (RX.X), the at least two transmit channels (TX.X) and the at least two receive channels (RX.X) each correspond to a sector beam (BT.X, BR.X) having a first dimension (D1) significantly greater than a second dimension (D2) and the first dimension (D1) perpendicular to the second dimension (D2); A microwave imaging radar sensor, wherein a field is assigned to a radar result characteristic (RC) provided by a receive channel (RX.X), a sector-shaped receive beam (BR.X) of the receive channel overlapping with a sector-shaped transmit beam (BT.X) of a transmit channel (TX.X) to define an overlap region (OA, OA.X), The transmit channel (TX.X) is associated with a transmit unit (12) having a refractive beamformer (20) including a transmit reference plane (RP-T) along which a sector-shaped transmit beam (BT.X) of the transmit channel (TX.X) is perpendicular to a first dimension (D1) of the transmit beam; The transmitting unit (12) comprises a plurality of transmitting transition structures (TTS.X) associated with the refractive beamformer (20) at different transition positions (27); Each transmit channel (TX.X) is associated with at least one transmit transition structure (TTS.X); The receive channel (RX.X) is associated with a receive unit (14) having a refractive beamformer (21) including a receive reference plane (RP-R) to which a sector-shaped receive beam (BR.X) of the receive channel (RX.X) is perpendicular to a first dimension (D1) of the receive beam; The microwave imaging radar sensor is characterized in that the receiving unit (14) comprises a plurality of receiving transition structures (RTS.X) associated with the refractive beamformer (21) at different transition positions (27), and each receiving channel (RX.X) is associated with at least one receiving transition structure (RTS.X).

2. The microwave imaging radar sensor according to claim 1, The evaluation unit (15) includes a radar control unit (16) and an imaging unit (18) connected to each other; The radar control unit (16) is connected to the transmitting unit (12) and the receiving unit (14) by a power line (24); A microwave imaging radar sensor, wherein the imaging unit (18) includes an output port (38).

3. The microwave imaging radar sensor according to claim 2, Transmitting and / or receiving transition structures (TTS.X, RTS.X) relay electrical energy between the transmission line (24) and the waveguide (48); A microwave imaging radar sensor characterized in that a waveguide (48) propagates electromagnetic energy between a transmitting and / or receiving transition structure (TTS.X, RTS.X) and a respective refractive beamformer (20, 21).

4. The microwave imaging radar sensor according to claim 2 or 3, The radar control unit (16) transmits a signal to a transmit transition structure (TTS.X) or a combination of transmit transition structures (TTS.X) to transmit a transmit signal associated with a particular transmit channel (TX.X); A radar control unit (16) receives the received signal of the corresponding echo received by the receive transition structure (RTS.X) and determines a radar result characteristic (RC) of the received signal; The radar control unit (16) includes an interface (30) having an input port (34) and an output port (36); The input port (34) receives a specification of the addressed transmit transition structure (TTS.X) and the signal characteristics to be provided to the addressed transmit transition structure (TTS.X) of the transmitting unit (12) associated with the transmit channel (TX.X); The output port (36) outputs a set of radar result characteristics (RC) associated with the evaluated receive transition structure (RTS.X) of the receive unit (14) associated with the receive channel (RX.X).

5. The microwave imaging radar sensor according to any one of claims 1 to 4, The sensor (10) has a viewing direction (VD) with a viewing plane (VP) perpendicular thereto; The sensor (10) has a sensor reference plane (RP-S) perpendicular to a viewing plane (VP), A microwave imaging radar sensor characterized in that the transmitting reference plane (RP-T) and the receiving reference plane (RP-R) are perpendicular to the viewing plane (VP).

6. The microwave imaging radar sensor according to any one of claims 1 to 5, The sector beam (BT.X, BR.X) has a main direction (MDT.X, MDR.X) in which the gain is maximum, The principal directions (MDT.X, MDR.X) depend on the orientation of the transition structures (TTS.X, RTS.X) relative to the respective refractive beamformers (20, 21), A microwave imaging radar sensor characterized in that the at least two fan beams (BT.X, BR.X) of the transmitting unit (12) and the receiving unit (14) each have a main direction (MDT.X, MDR.X) broadly oriented in the line of sight (VD), such that the at least two fan beams (BT.X, BR.X) of the transmitting unit (12) and the receiving unit (14) at least partially overlap each other in an overlap region (OA, OA.X).

7. The microwave imaging radar sensor according to any one of claims 2 to 6, The imaging unit (18) is connected to an interface (30) of the radar control unit (16) and configures the inputs of the radar control unit (16) to address a particular combination of transmit channels (TX.X), receives a set of radar result characteristics (RC) of evaluated receive channels (RX.X), and creates an image by relating the received radar result characteristics (RC) to a field, taking into account the addressed transmit channels (TX.X) and the corresponding receive channels (RX.X).

8. The microwave imaging radar sensor according to any one of claims 1 to 7, A microwave imaging radar sensor characterized in that the refractive beam formers (20, 21) are dielectric lenses.

9. The microwave imaging radar sensor according to claim 8, A microwave imaging radar sensor characterized in that the dielectric lens is a gradient index lens.

10. The microwave imaging radar sensor according to claim 9, A microwave imaging radar sensor characterized in that the refractive index distribution lens is a cylindrical generalized Lunenberg lens.

11. The microwave imaging radar sensor according to claim 10, A microwave imaging radar sensor characterized in that the reference planes (RP-T, RP-R) of a cylindrical generalized Lunenberg lens are perpendicular to the central axes (MT, MR) of the lens.

12. The microwave imaging radar sensor according to claim 10 or 11, A microwave imaging radar sensor characterized in that a cylindrical generalized Lunenberg lens has a dielectric constant gradient that varies as a square law of radial position.

13. The microwave imaging radar sensor according to any one of claims 1 to 12, A microwave imaging radar sensor characterized in that the receiving reference plane (RP-R) of the receiving unit (14) and the transmitting reference plane (RP-T) of the transmitting unit (12) intersect with each other, and the intersection angle is between 0° and 90°; 0°≦intersection angle≦90°.

14. The microwave imaging radar sensor according to claim 13, A microwave imaging radar sensor, wherein the crossing angle is between 15° and 90° so as to form a surveillance grid.

15. The microwave imaging radar sensor according to any one of claims 2 to 14, A microwave imaging radar sensor, characterized in that the radar control unit (16) includes a receiving chain connected to the receiving unit (14) and determines signal characteristics received via a plurality of receiving transition structures (RTS.X), and the radar control unit (16) further includes a transmitting chain connected to the transmitting unit (12), and the imaging unit (18) is capable of addressing a plurality of transmitting transition structures (TTS.X) using a transmitting signal.

16. The microwave imaging radar sensor according to any one of claims 2 to 15, A microwave imaging radar sensor, characterized in that the radar control unit (16) executes at least one evaluation cycle to establish a relationship between an addressed transmit transition structure (TTS.X) and an evaluated receive transition structure (RTS.X).

17. 17. The microwave imaging radar sensor according to claim 2, A microwave imaging radar sensor, wherein the imaging unit (18) includes a data memory (32) for storing a plurality of relationships between transmit transition structures (TTS.X) and receive transition structures (RTS.X).

18. The microwave imaging radar sensor according to any one of claims 2 to 17, The imaging unit (18) outputs an image to an image processing unit (40) that maps an image of at least a portion of the space surrounding the sensor as a grid consisting of a plurality of pixels stored in a data memory (32), and each pixel is assigned a relationship between a transmitting transition structure (TTS.X) and a receiving transition structure (RTS.X).

19. 19. The microwave imaging radar sensor according to claim 3, A microwave imaging radar sensor characterized in that the transmitted signal and radar result characteristic (RC) are generated by FMCW.

20. 20. The microwave imaging radar sensor according to claim 1, A microwave imaging radar sensor in which a radar result characteristic (RC) is generated by evaluating a received signal relative to a transmitted signal using the Doppler effect.

21. The microwave imaging radar sensor according to any one of claims 1 to 20, The transmit channel (TX.X) is switched to achieve beam switching, A transmit signal is applied to one transmit channel (TX.X) at a time in each evaluation cycle; A microwave imaging radar sensor characterized in that each transmission channel (TX.X) references one transmission transition structure (TTS.X) or multiple transmission transition structures (TTS.X), in particular adjacent transmission transition structures (TTS.X).

22. The microwave imaging radar sensor according to any one of claims 2 to 21, A microwave imaging radar sensor characterized in that the receiving unit (14), the transmitting unit (12) and the power transmission line (24) are mounted on a single circuit board (25).

23. 23. The microwave imaging radar sensor according to claim 22, The single circuit board (25) includes a PCB body (26) including at least one core layer (22); A microwave imaging radar sensor, characterized in that the PCB body (26) has at least one metallization layer (23) on the top and bottom of the PCB body (26).

24. The microwave imaging radar sensor according to claim 23, At least one core layer (22) is formed from a dielectric substrate; A microwave imaging radar sensor, characterized in that the core layers (22) of the transmitting unit (12) and the receiving unit (14) form respective refractive beamformers (20, 21) having curved profiles.

25. The microwave imaging radar sensor according to claim 23 or 24, A microwave imaging radar sensor, characterized in that at least one waveguide (48) is integrated with a single circuit board (25) and is surrounded by metallized upper and lower layers (23) of a PCB body (26) and metallized vias that connect the metallized layers (23) and function as sidewalls (50a, 50b) of the waveguide (48).

26. The microwave imaging radar sensor according to any one of claims 22 to 25, A microwave imaging radar sensor characterized in that the radar control unit (14) is mounted on a single circuit board (25) and is connected to a transmitting and receiving transition structure (TTS.X, RTS.X).

27. 27. The microwave imaging radar sensor according to any one of claims 1 to 26, A microwave imaging radar sensor characterized in that the refractive beamformer (20, 21) is covered by a lens housing (42) and provides circularly polarized radiation.

28. 28. The microwave imaging radar sensor according to any one of claims 1 to 27, The refractive beam formers (20, 21) are cylindrical lenses, The microwave imaging radar sensor is characterized in that the lens has a first dielectric property and is housed in a torus-shaped lens housing (42) having opening surfaces around the rotation center axis (MT, MR) at the upper and lower poles.

29. The microwave imaging radar sensor according to claim 26 or 28, A microwave imaging radar sensor characterized in that the lens housing (42) is integrated into the housing of the sensor (10).

30. 30. The microwave imaging radar sensor according to any one of claims 1 to 29, A microwave imaging radar sensor (10) characterized in that it comprises a plurality of transmitting units (12) and / or a plurality of receiving units (14) connected to an evaluation unit (15).

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