# US 2021/0278518 A1 · Novel automotive radar using 3d printed luneburg lens > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278518 A1 - Document ID: US20210278518A1 - Status: Published application - Kind: A1 - Application number: 16/325,111 - Filed: 2017-08-15 - Published: 2021-09-09 - Earliest claimed: 2016-08-15 - Assignees: Arizona Board of Regents on Behalf of the University of Arizona - Applicants: The Arizona Board of Regents On Behalf of the University of Arizona - Inventors: Hao Xin; Min Liang; Siyang Cao - Web page: https://patentgrep.com/patent/US20210278518A1 ## CPC - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - G01S 13/426: {Scanning radar, e.g. 3D radar (G01S13/66 takes precedence)} - G01S 7/03: Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver - G01S 13/931: of land vehicles - G05D 1/0257: {using a radar (radar systems designed for anti-collision purposes between land vehicles or between land vehicle and fixed obstacles G01S13/931)} - H01Q 1/3233: {particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems} - H01Q 15/08: formed of solid dielectric material - H01Q 25/008: {lens fed multibeam arrays} - B33Y 80/00: Products made by additive manufacturing - H01Q 21/29: Combinations of different interacting antenna units for giving a desired directional characteristic (H01Q25/00 takes precedence) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING ## Abstract A high performance, low-cost automotive radar is designed by mounting receivers around a 3D printed Luneburg lens. With this configuration, the antenna radiation pattern is maintained for all angles, (which means no beam deformation). Further, the present radar is capable of performing detection at all azimuth and elevation angles with high angle resolution and broadband operation. The radar adaptively adjusts its spatial sensing pattern, sweeping frequency band, pulse repetition frequency and coherent processing interval according to the environment. This is accomplished by initially performing a rough scan, which updates sensing results via a narrow bandwidth waveform and wide beam scanning. When interested objects are identified, a high-resolution detailed scan is performed in a specific region of interest. In this way, a much more effective detection can be obtained. Moreover, a method of mitigating interference of the 3D printed Luneburg lens based radar and a method of improving the angle resolution using a lens based MIMO approach is disclosed. ## Claims ### Claim 1 An adaptive sensing method for scanning an environment surrounding an autonomous automobile, wherein the environment comprises a plurality of specific regions, the method comprising: (a) providing a millimeter wave automotive radar (201) comprising: (i) one or more millimeter wave transceivers; (ii) a 3D printed Luneburg lens having an upper frequency limit in a millimeter wave range; and (iii) a plurality of antenna feed elements, operatively coupled to the one or more millimeter wave transceivers, mounted to a surface of the 3D printed Luneburg lens, each positioned in a determined direction; and (iv) one or more processing elements operatively coupled to the plurality of antenna feed elements and to the one or more millimeter wave transceivers; (b) performing a rough scan of the environment, the steps comprising: (i) generating one or more wide beam patterns, via the plurality of processing elements, that are transmitted to the environment via the one or more millimeter wave transceivers (202); (ii) receiving a first set of signals, resulting from interactions between the one or more wide beam patterns and the environment, via the one or more millimeter wave transceivers, wherein each signal has a signal strength, wherein the 3D printed Luneburg lens focuses the first set of signals prior to their reception by the plurality of antenna feed elements (203); and (iii) processing the first set of signals via the plurality of processing elements, wherein if the signal strength of a signal processed by a processing element exceeds a first predetermined threshold, then the specific region of the processing element is a region of interest (205); (c) performing a detailed scan of each region of interest, the steps comprising: (i) generating a narrow scanning beam, via the plurality of antenna feed elements, that is transmitted to each region of interest via the one or more millimeter wave transceivers (206); (ii) receiving a second set of signals via the one or more millimeter wave transceivers (208), wherein the second set of signals are a result of interactions between the narrow scanning beam and each region of interest, wherein the 3D printed Luneburg lens focuses the second set of signals prior to their reception by the plurality of antenna feed elements (207); and (iii) processing the second set of signals, via the plurality of processing elements, to determine information about each region of interest (209), wherein use of the 3D printed Luneburg lens for focusing the first and second set of signals before processing results in an improvement in a signal to noise ratio, an angular resolution, and a detection range of the millimeter wave automotive radar compared to conventional planar phased arrays, wherein performance of the rough scan and, subsequently, the detailed scan adaptively adjusts a spatial sensing pattern, a sweeping frequency band, a pulse repetition frequency, and a coherent processing interval according to the environment as the rough scan updates sensing results via the narrow scanning beam of the detailed scan. ### Claim 2 (depends on 1) The method of claim 1, wherein the signal strength of the signal processed by a given processing element exceeds the first predetermined threshold when the signal interacts with one or more objects of interest, wherein processing of the second set of signals yields information about the one or more objects of interest. ### Claim 3 (depends on 2) The method of claim 2, wherein a plurality of first predetermined thresholds is set for a plurality of distances to detect a presence of the one or more objects of interest each residing a distance, of the plurality of distances, away from the millimeter wave automotive radar. ### Claim 4 (depends on 3) The method of claim 3, wherein one or more millimeter wave receivers and one or more millimeter wave transmitters are used in lieu of the one or more millimeter wave transceivers. ### Claim 5 (depends on 4) The method of claim 4, wherein a multiple input multiple output (“MIMO”) technique is employed to improve the angular resolution of the millimeter wave automotive radar, wherein the MIMO technique comprises: (a) measuring a magnitude and a phase of the one or more millimeter wave receivers for each millimeter wave transmitter; (b) calculating a plurality of phase differences for different target directions between each of the millimeter wave transmitters; (c) compensating for the plurality phase differences; and (d) coherently adding a plurality of radar results from different millimeter wave transmitters to generate a scanning beam narrower than a half power beam width of the 3D printed Luneburg lens (104) to realize an improved angular resolution, wherein the scanning beam is transmitted to each region of interest as the narrow scanning beam. ### Claim 6 (depends on 1) The method of claim 1, wherein the one or more wide beam patterns and the narrow scanning beam are transmitted to the environment through one or more channels of a millimeter wave spectrum, wherein an opportunity spectrum access (“OSA”) is estimated to determine an availability of the one or more channels for a given period of time. ### Claim 7 (depends on 6) The method of claim 6, wherein Partially Observable Markov Decision Process is used to estimate the OSA for the millimeter wave automotive radar. ### Claim 8 (depends on 5) The method of claim 5, wherein an interference suppression technique is applied to remove interference from a received signal, including the first and second set of signals, wherein the interference suppression technique is performed in a time domain of the received signal and comprises the steps of: (a) measuring an amplitude of the received signal, (b) determining if the amplitude exceeds a second predetermined threshold, and (c) excising a portion of the amplitude of the received signal exceeding the second predetermined threshold. ### Claim 9 (depends on 1) The method of claim 1, wherein step (c) is iterated a determined number of times, wherein each iteration further narrows a number of the regions of interest and/or yields information about each region of interest in increasing detail. ### Claim 10 (depends on 8) The method of claim 8, wherein each processing element comprises a memory operatively coupled to a processor executing one or more sets of instructions stored in the memory, wherein the one or more sets of instructions comprises generating the one or more wide beam patterns and the narrow scanning beam, processing the first set of signals and the second set of signals, and executing the MIMO and interference techniques, wherein the memory further stores the plurality of first predetermined thresholds and the second predetermined threshold. ### Claim 11 A millimeter wave automotive radar effective for scanning an environment surrounding an autonomous automobile, wherein the environment comprises a plurality of specific regions, the radar comprising: (a) one or more millimeter wave transceivers (102); (b) a 3D printed Luneburg lens (104) having an upper frequency limit in a millimeter wave range; (c) a plurality of antenna feed elements (103), operatively coupled to the one or more millimeter wave transceivers, mounted to a surface of the 3D printed Luneburg lens (104), each positioned in a determined direction; and (d) one or more processing elements (107) operatively coupled to the plurality of antenna feed elements (103) and to the one or more millimeter wave transceivers (102); wherein a rough scan of the environment is performed, via one or more wide beam patterns (101) generated by the one or more processing elements (107), wherein the one or more wide beam patterns (101) are transmitted to the environment via the one or more millimeter wave transceivers (102), wherein a first set of signals (106) are received by the one or more millimeter wave transceivers, wherein the first set of signals (106) are processed by the one or more processing elements (107) to determine one or more regions of interest, wherein a detailed scan is then performed by generating and transmitting a narrow scanning beam to scan the one or more regions of interest, which results in a second set of signals received by the one or more millimeter wave transceivers (102), wherein the second set of signals (106) are processed, via the one or more processing elements (107), to determine information about each region of interest, wherein the 3D printed Luneburg lens (104) focuses the first and second set of signals prior to their reception by the plurality of antenna feed elements (103), wherein said focusing results in an improvement in a signal to noise ratio, an angular resolution, processing speed, and a detection range of the millimeter wave automotive radar compared to conventional planar phased arrays, wherein performance of the rough scan and, subsequently, the detailed scan can adaptively adjust a spatial sensing pattern, a sweeping frequency band, a pulse repetition frequency, and a coherent processing interval according to the environment as the rough scan updates sensing results via the narrow scanning beam of the detailed scan. ### Claim 12 (depends on 11) The system of claim 11, wherein each signal, of the first set of signals (106), has a signal strength, wherein if the signal strength of a signal processed by a processing element exceeds a first predetermined threshold, then the specific region of the processing element is a region of interest, of the one or more regions of interest. ### Claim 13 (depends on 12) The system of claim 12, wherein the signal strength exceeds the first predetermined threshold when one or more objects of interest are in the specific region. ### Claim 14 (depends on 13) The system of claim 13, wherein processing of the second set of signals yields information about the one or more objects of interest. ### Claim 15 (depends on 13) The system of claim 13, wherein a plurality of first predetermined thresholds is set for a plurality of distances to detect a presence of the one or more objects of interest each residing a distance, of the plurality of distances, away from the millimeter wave automotive radar. ### Claim 16 (depends on 11) The system of claim 11, wherein one or more millimeter wave receivers and one or more millimeter wave transmitters are used in lieu of the one or more millimeter wave transceivers. ### Claim 17 (depends on 16) The system of claim 16, wherein a multiple input multiple output (“MIMO”) technique is employed to improve the angular resolution of the millimeter wave automotive radar, wherein the MIMO technique comprises: (a) measuring a magnitude and a phase of the one or more millimeter wave receivers for each millimeter wave transmitter; (b) calculating a plurality of phase differences for different target directions between each of the one or more millimeter wave transmitters; (c) compensating the plurality phase differences; and (d) coherently adding a plurality of radar results from different transmitters to generate a scanning beam narrower than a half power beam width of the 3D printed Luneburg lens (104) to realize an improved angular resolution, wherein the scanning beam is transmitted to each region of interest as the narrow scanning beam. ### Claim 18 (canceled) ### Claim 19 (canceled) ### Claim 20 (depends on 17) The system of claim 17, wherein an interference suppression technique is applied to remove interference from a received signal, including the first and second set of signals, wherein the interference suppression technique is performed in a time domain of the received signal and comprises the steps of: (a) measuring an amplitude of the received signal, (b) determining if the amplitude exceeds a second predetermined threshold, and (c) excising a portion of the amplitude of the received signal exceeding the second predetermined threshold. ### Claim 21 (depends on 11) The system of claim 11, wherein the detailed scan of the one or more regions of interest is performed for a number of iterations, wherein each iteration further narrows a number of the regions of interest and/or yields information about each region of interest in increasing detail. ### Claim 22 (depends on 20) The system of claim 20, wherein each processing element comprises a memory operatively coupled to a processor executing one or more sets of instructions stored in the memory, wherein the one or more sets of instructions comprises generating the one or more wide beam patterns and the narrow scanning beam, processing the first set of signals and the second set of signals, and executing the MIMO and interference techniques, wherein the memory further stores the plurality of first predetermined thresholds and the second predetermined threshold.