Radar transceiver device for radar signals

Abstract

Radar transceiver device (1) for radar signals with a frequency-selective radar transmitter unit (2) and / or with a frequency-selective radar receiver unit (3), wherein the frequency-selective radar transmitter unit (2) of the radar transceiver device (1) comprises a digital-to-analog converter (2A) designed to convert a broadband digital signal provided for all transmit channels into an analog transmit signal, a signal modulator (2B) that modulates a signal carrier with the analog transmit signal output by the digital-to-analog converter (2A) to generate a modulated transmit signal, and has at least one frequency-selective component (2C) designed to divide the transmit signal modulated by the signal modulator (2B) into several transmit (TX) channels for transmission as a radar signal, and wherein the frequency-selective radar receiver unit (3) of the Radar transceiver device (1) at least one frequency-selective component (3C),which is designed to combine a received radar signal comprising several receive (RX) channels, a signal demodulator (3B) which demodulates the radar signal combined by the frequency-selective component by means of a signal carrier to generate a demodulated receive signal, and includes at least one analog-to-digital converter (3A) which is designed to sample the received signal demodulated by the signal demodulator (3B) to generate a digital receive signal.

Description

[0001] The invention relates to a radar transceiver device for radar signals and in particular a sensor concept for radar devices with broadband signal generation and frequency-selective TX / RX behavior. State of the art

[0002] Radar detects objects using electromagnetic or radio waves. It can measure not only the distance, but also, in the case of moving objects, the angle and relative speed to the target object.

[0003] DE 10 2013 222 963 A1 relates to a radar antenna comprising a primary radiator, a waveguide element, and a lens, wherein the waveguide element is designed and arranged between the primary radiator and the lens such that the cross-sectional area of ​​the waveguide element on a side facing the primary radiator is smaller than the cross-sectional area of ​​the waveguide element on an opposite side facing away from the primary radiator. Crucially, the primary radiator is designed as an edge-emitting antenna, and the waveguide element is designed and arranged to interact with the edge-emitting antenna such that the waveguide element, at its end facing the edge-emitting antenna, overlaps the edge-emitting antenna on a top surface and an opposite bottom surface.

[0004] German patent DE 11 2018 001 287 T5 relates to a radar technology for measuring distance or relative velocity using a frequency modulation method. This allows for increased distance resolution while preventing a deterioration of the signal-to-noise ratio. The radar circuit comprises a signal generation unit that generates a transmission signal for a transmitting wave, a modulation control unit that controls the frequency modulation of the transmitted signal, a receiving circuit unit that detects a detection signal based on a difference frequency between a received signal from a receiving wave and the transmitted signal, and a signal processing unit that performs analysis based on the detection signal and calculates the distance and relative velocity.

[0005] DE 10 2019 201 374 A1 relates to a method for operating multiple radar sensors in a radar network, in which each transmitted FMCW radar signal is preceded by a CW signal containing binary-coded information about the transmitting radar sensor's transmission parameters and / or other information. In a preferred embodiment, each radar sensor receives corresponding CW signals with information about the transmission parameters of other radar sensors in the radar network, processes the information, and adjusts its own transmission parameters upon detecting a match so that they no longer correspond to the transmission parameters of the other radar sensors. The method enables interference-free operation of multiple radar sensors in a radar network and can also be used with a multistatic radar.

[0006] German patent DE 10 2022 205 109 A1 relates to an electronic device that may include a standing wave ratio (VSWR) sensor arranged along a high-frequency transmission line between a signal generator and an antenna. The VSWR sensor can collect VSWR measurements of high-frequency signals transmitted from the signal generator over the transmission line. The control logic can identify variations in the VSWR measurements over time and compare these variations to a threshold value to determine whether an external object near the antenna is animate or inanimate. The control logic can reduce the maximum transmission power level of the antenna if the external object is animate and can maintain or increase the maximum transmission power level if the external object is inanimate.This can serve to maximize the wireless performance of the electronic device while also ensuring that the device meets legal limits for high-frequency energy exposure. Disclosure of the invention

[0007] According to a first aspect, the invention provides a radar transceiver device for radar signals with a frequency-selective radar transmitter unit and / or with a frequency-selective radar receiver unit; wherein the frequency-selective radar transmitter unit of the radar transceiver device comprises: a digital-to-analog converter designed to convert a broadband digital signal provided for all transmission channels into an analog transmission signal; a signal modulator that modulates a signal carrier with the analog transmit signal output by the digital-to-analog converter to generate a modulated transmit signal; and at least one frequency-selective component designed to split the transmitted signal modulated by the signal modulator into multiple transmit (TX) channels for radiation as a radar signal; and wherein the frequency-selective radar receiver unit of the radar transceiver device comprises: at least one frequency-selective component designed to combine a received radar signal comprising multiple receive (RX) channels; a signal demodulator that demodulates the radar signal combined by the frequency-selective component using a signal carrier to generate a demodulated received signal; and at least one analog-to-digital converter designed to sample the received signal demodulated by the signal demodulator to generate a digital received signal.

[0008] In the device according to the invention, instead of providing one converter per TX channel of a broadband digital radar, a single signal source (DAC) is used, which is divided into several TX channels by a frequency-selective TX path / TX antenna. This allows frequency division multiplexing (FDM) with a single signal source (DAC).

[0009] Instead of implementing N broadband TX and / or RX channels, the radar transceiver device according to the invention preferably requires only a single TX and / or RX channel.

[0010] In the radar transceiver device according to the invention for radar signals, the signal division preferably takes place via passive components.

[0011] Depending on the requirements, in the radar transceiver device according to the invention, the RX path can be implemented in such a way that only one broadband analog-to-digital converter is required, instead of the TX path. Furthermore, both paths (TX side and RX side) of the radar transceiver device can be implemented simultaneously in a frequency-selective manner.

[0012] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective component has a frequency-selective antenna.

[0013] This offers the possibility of a space-saving and efficient implementation of frequency selectivity.

[0014] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective antenna comprises a frequency-selective microstrip antenna, a frequency-selective waveguide antenna or a frequency-selective reflector antenna.

[0015] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective microstrip antenna has a frequency-selective patch antenna with different phase centers per frequency in one dimension.

[0016] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective microstrip antenna has a frequency-selective spiral antenna with different phase centers per frequency in two dimensions.

[0017] For the realization of the radar transceiver device according to the invention, it is advantageous that the transmitting / receiving element, in particular the frequency-selective antenna, has a frequency-dependent phase center, which in turn can also be implemented periodically or non-periodically. The phase center can be frequency-dependent in all three spatial dimensions.

[0018] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the phase centers in the frequency domain are periodically repeated.

[0019] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the phase centers in the frequency domain are not periodically repeated.

[0020] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective microstrip antenna has a frequency-selective antenna with a logarithmically periodic arrangement.

[0021] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective component has frequency-selective signal filters.

[0022] These are preferably passively constructed and allow for a simple and space-saving implementation of frequency selectivity.

[0023] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the frequency-selective component has a frequency-selective active component.

[0024] This could be a signal amplifier. This also allows for a simple and space-saving implementation of frequency selectivity.

[0025] In one possible embodiment of the radar transceiver device according to the invention for radar signals, the signal modulator is designed to perform FMCW modulation of the signal carrier.

[0026] FMCW modulation offers a precise method for measuring distances and can provide detailed information about target objects through its continuous modulation and frequency change.

[0027] In one possible embodiment of the radar transceiver device according to the invention for radar signals, a local oscillator is provided which generates the signal carrier.

[0028] This provided a frequency-stable signal carrier, thus increasing the accuracy of angle and distance estimation.

[0029] The invention further provides a radar device with a radar transceiver device according to the first aspect of the invention and with a signal processing unit for estimating the angle and / or distance of a target object.

[0030] Possible embodiments of the radar transceiver device according to the invention for radar signals are described in more detail below with reference to the attached figures.

[0031] They show: Fig. 1 a schematic block diagram of a possible embodiment of a radar transceiver device according to the invention for radar signals; Fig. 2A a diagram illustrating a system concept with frequency-selective transmitting antenna in a possible embodiment of the radar transceiver device according to the invention for radar signals; Fig. 2B a diagram illustrating a system concept with frequency-selective transmit signal path in another possible embodiment of the radar transceiver device according to the invention for radar signals; Fig. 3 a schematic representation of a frequency-selective patch antenna with different phase centers per frequency in one dimension; Fig. 4 a schematic representation of a frequency-selective spiral antenna with different phase centers per frequency in two dimensions; Fig. 5A-5D Signal spectra to explain the functioning of possible embodiments of the radar transceiver device according to the invention for radar signals.

[0032] A radar transceiver device 1 according to the invention for radar signals comprises a frequency-selective radar transmitter unit 2 and / or a frequency-selective radar receiver unit 3, as shown in Fig. 1 is shown schematically.

[0033] The frequency-selective radar transmitter unit 2 of the radar transceiver device 1 includes a digital-to-analog converter (DAC) 2A designed to convert a broadband digital signal provided for all transmit channels into an analog transmit signal.

[0034] The frequency-selective radar transmitter unit 2 of the radar transceiver device 1 further comprises a signal modulator 2B, which modulates a signal carrier with the analog transmit signal emitted by the digital-to-analog converter (DAC) 2A to generate a modulated transmit signal.

[0035] The frequency-selective radar transmitter unit 2 of the radar transceiver device 1 has at least one frequency-selective component 2C designed to divide the transmit signal modulated by the signal modulator 2B into several transmit (TX) channels for radiation as a radar signal.

[0036] In one possible embodiment, the radar transceiver device 1 according to the invention for radar signals also comprises a frequency-selective radar receiver unit 3.

[0037] The frequency-selective radar receiver unit 3 of the radar transceiver device 1 has at least one frequency-selective component 3C designed to combine a received radar signal comprising multiple receive (RX) channels.

[0038] The frequency-selective radar receiver unit 3 of the radar transceiver device 1 also has a signal demodulator 3B, which demodulates the radar signal combined by the frequency-selective component 3C by means of a signal carrier to generate a demodulated received signal.

[0039] The frequency-selective radar receiver unit 3 of the radar transceiver device 1 further comprises at least one analog-to-digital converter (ADC) 3A, which is designed to sample the received signal demodulated by the signal demodulator 3B to generate a digital received signal.

[0040] In one possible embodiment of the radar transceiver device 1 according to the invention, the frequency-selective component 2C, 3C has a frequency-selective antenna.

[0041] Fig. Figure 2A shows an embodiment of the radar transceiver device 1 with a frequency-selective antenna 2C provided on the transmitter side, which receives a modulated signal from a modulator 2B. The modulated signal can optionally be amplified by a signal amplifier A.

[0042] At the in Fig. In the embodiment shown in Figure 2A, the transmitting unit 2 is implemented in a frequency-selective manner, while the receiving unit 3 is of a conventional design. Each of the M receiving antennas Rx1 to RxM delivers a broadband signal to a demodulator, which demodulates the broadband signal via a low-pass filter (LP) and outputs it to an associated analog-to-digital converter (ADC). The ADC samples the low-pass filtered, demodulated signal and outputs the samples to a signal processing unit (SVE).

[0043] A frequency-selective antenna 2C of the in Fig. 1 and Fig. The radar transceiver device 1 shown in 2A can be implemented in different ways and may, for example, have a frequency-selective microstrip antenna, a frequency-selective waveguide antenna or a frequency-selective reflector antenna.

[0044] In a possible implementation of the in Fig. In the embodiment of the radar transceiver device 1 shown in Figure 2A, the frequency-selective microstrip antenna 2C has a frequency-selective patch antenna with different phase centers PZ per frequency in one dimension, as shown in Figure 2A. Fig. 3 shown schematically.

[0045] In another possible implementation of the in Fig. In the embodiment of the radar transceiver device 1 shown in Figure 2A, the frequency-selective microstrip antenna 2C has a frequency-selective spiral antenna with different phase centers PZ per frequency in two dimensions, as shown in Figure 2A. Fig. 4 is shown schematically.

[0046] In one possible embodiment of the radar transceiver device 1 according to the invention, the phase centers PZ are implemented periodically or non-periodically in the frequency domain.

[0047] In another possible embodiment of the radar transceiver device 1 according to the invention, the frequency-selective microstrip antenna 2C has a frequency-selective antenna with a logarithmically periodic arrangement.

[0048] In another possible embodiment of the radar transceiver device 1 according to the invention for radar signals, the frequency-selective component has frequency-selective signal filters, as shown in Fig. 2B is shown.

[0049] Fig. Figure 2B shows a possible embodiment of the radar transceiver device 1 according to the invention, in which the transmitting side 2 is implemented in a frequency-selective manner by dividing the signal paths and providing frequency-selective bandpass filters (BP) 2C. Furthermore, signal amplifiers A may optionally be employed.

[0050] In another possible embodiment of the radar transceiver device 1 according to the invention for radar signals, the frequency-selective component 2C, 3C has a frequency-selective active component, in particular a signal amplifier.

[0051] In one possible embodiment of the radar transceiver device 1 according to the invention for radar signals, the signal modulator 2B is designed to perform FMCW modulation of the signal carrier ST. In one possible embodiment of the radar transceiver device 1 according to the invention for radar signals, a local oscillator 4 is provided which generates the signal carrier ST.

[0052] In FMCW (Frequency Modulated Continuous Wave) modulation, the signal carrier ST generated by oscillator 4 is modulated. The signal carrier ST in the radar transceiver device 1 is a high-frequency signal that serves as the basis for radar measurements. It is a continuous wave that is transmitted and received within the radar system to obtain information about distant objects. The frequency f of the signal carrier ST is high and typically in the gigahertz (GHz) range to enable the detection of fine details of the target objects. FMCW is a modulation technique in which the frequency f of the continuous carrier signal ST is varied over time. The modulation is continuous and not pulsed, as is the case with conventional radar systems.

[0053] The carrier signal ST is modified by frequency modulation. The carrier signal ST is a continuous, sinusoidal signal with a specific average frequency. The frequency f of the carrier signal ST is varied linearly or non-linearly over a specific time period.

[0054] This can be achieved through a frequency increase (chirp) or frequency modulation over a period of time. In one possible embodiment, the frequency f of the signal carrier ST is linearly increased during a fixed time interval, the so-called chirp cycle (in linear FMCW modulation).

[0055] FMCW modulation enables the radar to measure the range and speed of targets. The process involves transmitting the FMCW signal, which is a continuous, frequency-modulated carrier. The transmitted FMCW signal strikes a target and is reflected. The radar receives the reflected signal and compares it to the transmitted signal. The frequency difference between the transmitted and received signals (the so-called beat signal frequency) is used to calculate the range and speed of the target.

[0056] In an FMCW radar with a radar transceiver device 1, the signal carrier ST has a continuous radio frequency signal generated by the local oscillator (LO) 4, which is modulated by the modulator 2B with a varying frequency (FMCW). This modulation enables the radar to obtain information about the range and speed of target objects by analyzing the time offset and frequency shift of the reflected signal. The FMCW technique provides a precise method for measuring ranges and, through its continuous modulation and frequency variation, can provide detailed information about target objects.

[0057] Broadband digital radar sensors do not yet exist commercially. Conventionally, a DAC is required for each transmit channel (TX) to generate the analog modulation signal for modulator 2B. This significantly increases complexity with a growing number of TX channels / antennas. Frequency selectivity can be implemented at the transmitter side using a frequency-selective component, as is the case, for example, in the... Fig. 2A, Fig. In the embodiments shown in 2B, this can be prevented.

[0058] The radar transceiver device 1 according to the invention, consisting of DACs / ADCs, amplifiers, mixers, filters, and antennas, etc., can be implemented in various frequency-selective ways. Each component in the TX and / or RX path can contribute to the frequency selectivity, as shown in the Fig. 5A-5D is shown schematically.

[0059] Fig. Figures 5A-5D show examples of a possible frequency behavior of a TX / RX path of the radar transceiver device 1 according to the invention with three frequency bands FB1, FB2, FB3.

[0060] Fig. 5A exhibits ideal frequency-selective behavior with three frequency bands FB1, FB2, FB3.

[0061] Fig. 5B shows actual (non-ideal) behavior with non-ideal frequency bands FB.

[0062] Fig. 5C shows periodically distributed frequency bands FB during Fig. 5D shows non-periodically distributed frequency bands FB.

[0063] The frequency-selective behavior can, for example, be periodic ( Fig. 5C) or non-periodic ( Fig. 5D) be repeated so that multiple components of the broadband signal can be radiated via the same path.

[0064] However, an advantage for the realization of the radar transceiver device 1 according to the invention is that the transmitting / receiving element, in particular the frequency-selective antenna 2C, has a frequency-dependent phase center PZ, which in turn can also be implemented periodically or non-periodically. The phase center PZ can be frequency-dependent in all spatial dimensions.

[0065] The implementation of frequency selectivity can be carried out on the transmitting side (TX) and / or on the receiving side (RX) of the radar transceiver device 1 according to the invention.

[0066] Possible embodiments for an implementation on the transmitting side (TX) of a frequency-selective radar transceiver device 1 according to the invention are described in more detail below.

[0067] The frequency-selective radar transmitter unit 2 of the radar transceiver device 1 has at least one frequency-selective component 2C designed to divide the transmit signal modulated by the signal modulator 2B into several transmit (TX) channels for radiation as a radar signal.

[0068] In one possible embodiment of the radar transceiver device 1 according to the invention, the frequency-selective component 2C of the frequency-selective radar transmitter unit 2 comprises a frequency-selective antenna. The frequency-selective antenna 2C can, for example, be a frequency-selective microstrip antenna, a frequency-selective waveguide antenna, or a frequency-selective reflector antenna.

[0069] In one possible embodiment of the radar transceiver device 1 according to the invention, the frequency-selective microstrip antenna 2C has a frequency-selective patch antenna with different phase centers PZ per frequency f in one dimension, as described in Fig. 3 shown schematically.

[0070] In another possible embodiment of the radar transceiver device 1 according to the invention, the frequency-selective microstrip antenna 2C has a frequency-selective spiral antenna with different phase centers per frequency f in two dimensions, as described in Fig. 4 is shown schematically.

[0071] In one possible embodiment of the radar transceiver device 1 according to the invention, the phase centers PZ are implemented periodically or non-periodically in the frequency domain. In the frequency-selective antenna 2C, a broadband signal is applied to an antenna structure. The geometry of the antenna structure results in frequency-dependent phase centers PZ, each of which radiates a different portion of the broadband transmitted signal into the channel.

[0072] For the realization of the radiating elements, the following antenna structures can be used in different embodiments of the radar transceiver device 1 according to the invention: - Microstrip antennas: • Linear patch arrays with different center frequencies (see Fig. 3) • Spiral antenna-like arrangement (see Fig. 4) • Planar log-periodic arrangement • Stacked Patch-like arrangements with significantly different resonant frequencies of the individual patches (variation in the z direction to extend the FoV towards very large azimuth angle offsets) - Waveguide antennas, e.g. arrangement of waveguide slot radiators with changing slot dimensions (slot length, slot width) - Reflector antennas with frequency-selective reflectivity in different areas of the reflector

[0073] Fig. Figure 3 shows a frequency-selective patch antenna 2C with different phase centers PZ per frequency f in one dimension. The in Fig. The patch antenna shown in Figure 3 is a type of microstrip antenna. In one possible embodiment, the patch antenna consists of a conductive patch applied to a dielectric and mounted on a grounded back surface. The frequency-selective patch antenna 2C is designed to exhibit different characteristics at different frequencies f. This can be achieved through different geometric shapes and materials that influence the antenna's resonant frequencies. Furthermore, multiple patch elements can be arranged in specific patterns to generate selective frequency responses.

[0074] The phase center PZ of the antenna is the point from which the electromagnetic waves appear to be radiated. In an ideal antenna, the phase center PZ would be the same for all frequencies f. In practice, however, the phase center PZ can vary depending on the frequency f. The in Fig. The patch antenna 2C shown in Figure 3 is frequency-selective and has different phase centers PZ for different frequencies f. This means that the point from which the waves are emitted changes with the frequency f. This can be influenced by the design of the antenna 2C.

[0075] Fig. Figure 4 shows a frequency-selective spiral antenna with different phase centers PZ per frequency f in two dimensions. The spiral antenna is a type of broadband antenna with a spiral structure. It is characterized by its ability to operate over a wide frequency range while maintaining constant impedance and directivity. Spiral antennas are suitable for applications requiring a large bandwidth.

[0076] Frequency selectivity means that antenna 2C responds differently at different frequencies f. The phase center PZ of an antenna is the point from which the electromagnetic waves appear to radiate. If an antenna has different phase centers for different frequencies f, the point from which the waves radiate changes depending on the frequency. The in Fig. The frequency-selective spiral antenna shown in Figure 4 is designed to exhibit different radiation characteristics at different frequencies. This antenna structure can be achieved through the geometry of the spiral and the design of the antenna surface.

[0077] The in Fig. The spiral antenna shown in Figure 4 preferably consists of a conductive material arranged in a spiral structure. This structure can be Archimedean, logarithmic, or otherwise shaped. The spiral has the property that different frequencies f resonate at different points in the spiral. This results in the phase center PZ varying depending on the frequency f. In the case of the Fig. In the frequency-selective spiral antenna shown in Figure 4, the phase centers PZ can differ by two dimensions (x and y). This means that the position from which the waves are emitted can change along both the x and y axes, depending on the frequency f.

[0078] In another possible alternative embodiment of the radar transceiver device 1 according to the invention for radar signals, the frequency-selective component 2C,3C has frequency-selective signal filters.

[0079] Fig. Figure 2B shows a possible embodiment of the radar transceiver device 1 according to the invention with a transmitter-side implementation of frequency selectivity using signal filters, in particular passive bandpass filters BP. When implementing frequency selectivity using filters, a broadband signal is split into several frequency-selective parallel TX paths, as in the embodiment shown in Figure 2B. Fig. Figure 2B illustrates this. The parallel Tx paths are radiated via individually controlled antennas Tx1 to TxN. This results in different phase centers (PZ) for different frequency components. The filter structures can be implemented, for example, using microstrip technology (e.g., hairpin filters, stubpin filters), as waveguides (e.g., coupled cavity filters with irises), or classically as lumped elements. Depending on the implementation, the signal filter can be located at a different physical component of the device 1. For example, when implemented as a waveguide, it is advantageous to integrate the structure into a waveguide antenna.

[0080] In a further embodiment of the radar transceiver device 1 according to the invention, the frequency selectivity can also be dynamically adjustable by means of active components. This allows, for example, the frequency response to be switched during a measurement, resulting in additional path combinations (classically: more MIMO channels). In one embodiment of the radar transceiver device 1 according to the invention, this can be achieved using varactor diodes, RF MEMS, or variable capacitances with liquid crystals. A combination of several implementations of the frequency-selective active components is possible.

[0081] The system according to the invention, or the radar transceiver device 1 according to the invention, can in principle be divided into a transmit (TX) path 2 and a receive (RX) path 3. The respective paths 2 and 3 include, for example, DACs / ADCs, amplifiers, mixers, filters, and antennas. Frequency selectivity can be implemented either in the TX path 2, in the RX path 3, or simultaneously in both paths 2 and 3 of the radar transceiver device 1.

[0082] The possibility of reducing the physically available number of channels then arises for the respective paths affected. For the TX path of radar transceiver device 1, the number of parallel TX channels is reduced; for the RX path of radar transceiver device 1, the number of parallel RX channels is reduced; and for a combined variant of radar transceiver device 1, parallel TX and RX channels are reduced simultaneously.

[0083] In a transmitter-side implementation of frequency selectivity within the radar transceiver device 1 according to the invention for radar signals, as described in the Fig. 2A, Fig. As shown in Figure 2B, the TX path 2 is frequency-selective, so that a broadband signal from, for example, a single signal source 2A (e.g., a DAC) is distributed across multiple TX antenna phase centers PZ. This frequency selectivity allows the receiver to infer the location of the radiated signal energy and apply an angle estimation. This can be done, for example, using correlation, a Fourier transform, or an AI-based method.

[0084] In a receiver-side implementation of frequency selectivity within the radar transceiver device 1 according to the invention for radar signals, the RX path 3 is designed to be frequency-selective. The broadband TX signal from one or more signal sources is received via a frequency-selective structure with frequency-dependent phase centers (e.g., antenna), combined, and sampled by means of at least one analog-to-digital converter (ADC). Due to the frequency selectivity, the receiver can assign a location of the received signal energy to the TX signals and apply an angle estimation accordingly.

[0085] When combining frequency selectivity on both sides (transmitting on the second side and receiving on the third side), a special characteristic arises in the signal processing by the signal processing unit (SVE). Due to this frequency selectivity, not every transmit phase center can be received by every receive phase center. This means that full MIMO operation is not possible with regard to angle estimation without using a frequency converter in one of the paths. For example, transmit and receive phase centers can be configured with the same frequency, enabling 1:1 transmission (classically, multiple SISO channels), or they can be overlapping, allowing, for example, multiple receive phase centers to fit one transmit phase center, or vice versa (classically, multiple SIMO / MISO channels). Furthermore, in addition to angle estimation, distance estimation can also be performed based on all received frequencies, which improves the overall bandwidth and thus the distance resolution.

[0086] As a special variant, the TX or RX antenna can be implemented using frequency scanning, allowing targeted control with a single or multiple frequencies, e.g., to suppress clutter reflections from other directions, while broadband control illuminates the entire field of view.

[0087] Estimation methods based on the frequency selectivity of the radar transceiver device 1 according to the invention can be performed. For angle estimation, MIMO approaches can be used, which are based on the fact that each RX can assign the received signal to a uniquely identifiable TX. DML methods, correlation, Fourier transform, or related approaches are then applied to this. With high frequency selectivity, these approaches can be used for the radar transceiver device 1 according to the invention.

[0088] In the implementation of the radar transceiver device 1 according to the invention, it may happen that the signals cannot be clearly separated from each other (see Fig. 5B). Furthermore, the phase centers PZ may blend seamlessly into one another, so that each frequency f has its own phase center PZ. Therefore, in this case, it is necessary to adapt the signal evaluation. One possible implementation is, for example, a maximum likelihood method, in which the received signal is compared with a calibration measurement for each angle of incidence. Another possibility is the use of AI-supported algorithms that, through training, achieve an angle estimation.

[0089] Alternatively, the broadband nature of the signal generation can also lead to pre-distortion, which optimizes the coupling factors between the phase centers PZ such that the signals can again be unambiguously assigned to a phase center PZ. This pre-distortion can be implemented analytically or using AI.

[0090] Due to frequency selectivity, it may happen that the full signal bandwidth is not available for evaluation on the receive (RX) side. Therefore, it is still possible to evaluate multiple RX paths (or TX paths) together with respect to their RX signal bandwidth. This improves the distance resolution. Since this evaluation may include the influence of the different TX / RX phase centers, it may be necessary to perform a joint distance and angle evaluation and simultaneously estimate the angle and distance. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 222 963 A1

[0003] DE 11 2018 001 287 T5

[0004] DE 10 2019 201 374 A1

[0005] DE 10 2022 205 109 A1

[0006]

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