# US 10,771,124 B2 · Virtual beam steering using MIMO radar > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,771,124 B2 - Document ID: US10771124B2 - Status: Granted - Kind: B2 - Application number: 16/442,436 - Filed: 2019-06-14 - Published: 2019-12-19 - Granted: 2020-09-08 - Earliest claimed: 2018-06-14 - Assignees: Jun Fang - Applicants: Metawave Corporation - Inventors: Jun Fang - Web page: https://patentgrep.com/patent/US10771124B2 ## CPC - G01S 13/878: {Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector (G01S13/874 takes precedence)} - H04B 7/043: {using best eigenmode, e.g. beam forming or beam steering} - G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) - H04B 7/0413: MIMO systems - H04B 7/046: {taking physical layer constraints into account} - H04B 7/086: {using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming} - G01S 13/582: {adapted for simultaneous range and velocity measurements} - G01S 13/584: {adapted for simultaneous range and velocity measurements} - G01S 13/89: for mapping or imaging - G01S 13/931: of land vehicles - 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 - H04B: TRANSMISSION ## Abstract Examples disclosed herein relate to a Multiple-Input Multiple-Output (MIMO) radar for virtual beam steering. The MIMO radar has a plurality of transmit antennas and a receive antenna array having a plurality of radiating elements. The MIMO radar also includes a digital signal processor (DSP) configured to synthesize a virtual receive array having N×M receive subarrays from the plurality of transmit antennas and the receive antenna array, where N is the number of transmit antennas and M is the number of receiving elements. Other examples disclosed herein relate to a method of virtual beam steering. ## Claims ### Claim 1 A Multiple-Input Multiple-Output (MIMO) radar for virtual beam steering, comprising: a plurality of transmit antennas; a receive antenna array having a plurality of radiating elements; and a digital signal processor (DSP) configured to synthesize a virtual receive array having N×M receive subarrays from the plurality of transmit antennas and the receive antenna array, where N is the number of transmit antennas and M is the number of receiving elements, and wherein the virtual receive array is represented by a manifold matrix that is a function of a geometry of the receive antenna array and a carrier frequency and direction of arrival of the plurality of transmit antennas, and the DSP is configured to apply a transformation matrix to the manifold matrix to generate the virtual receive array. ### Claim 2 (depends on 1) The MIMO radar of claim 1, wherein the manifold matrix is defined as: A = [ g 11 ⁢ e - jw o ⁢ τ 11 … g 1 ⁢ N ⁢ e - jw o ⁢ τ 1 ⁢ N ⋮ ⋱ ⋮ g M ⁢ ⁢ 1 ⁢ e - jw o ⁢ τ M ⁢ ⁢ 1 … g MN ⁢ e - jw o ⁢ τ MN ] , where gij is channel response between ith transmit antenna to jth receive antenna element, wo is a center frequency, and τij is time delay between the ith transmit antenna to the jth receive antenna element, for i=1, 2, . . . , M and j=1, 2, . . . , N. ### Claim 3 (depends on 2) The MIMO radar of claim 2, wherein the time delay τij is defined as: τ ij = 1 c ⁢ d ij ⁢ sin ⁡ ( θ i ) , where dij a distance between the ith element to a reference element, θi is the incident angle that is an angle between a direction of the incident signal received at the ith element and the normal that is perpendicular to a plane of the virtual receive array. ### Claim 4 (depends on 3) The MIMO radar of claim 3, wherein the incident angle is derived from a predetermined direction of arrival for each of the N receive subarrays that constitute the virtual receive array. ### Claim 5 (depends on 1) The MIMO radar of claim 1, wherein the DSP is further configured to apply a linear transformation matrix with interpolation to the manifold matrix to generate an oriented virtual subarray within the virtual receive array. ### Claim 6 (depends on 5) The MIMO radar of claim 5, wherein the DSP is further configured to apply interpolation to signals received by receive elements of the virtual receive array to generate the oriented virtual subarray at a predetermined orientation angle. ### Claim 7 (depends on 1) The MIMO radar of claim 1, wherein the DSP is further configured to calculate the manifold matrix by a least square algorithm when a size of the virtual receive array is smaller than the receive antenna array. ### Claim 8 (depends on 1) The MIMO radar of claim 1, wherein the DSP is further configured to: apply the linear transformation to first transmit antennas of the plurality of transmit antennas to determine second transmit antennas positioned at an angle relative to an original position of the first transmit antennas; and apply the linear transformation to the receive antenna array to determine a second receive array at an angle relative to an original position of the first receive array, wherein the virtual receive array is spaced from the second receive antenna array by a same distance as that between the second transmit antennas. ### Claim 9 (depends on 1) The MIMO radar of claim 1, wherein the DSP is further configured to perform linear transformations on the virtual receive array to create virtual beam steering at a predetermined angle. ### Claim 10 (depends on 9) The MIMO radar of claim 9, wherein the DSP is further configured to send a control signal to the receive antenna array that causes one or more receive beams to steer based at least on the virtual receive array. ### Claim 11 (depends on 1) The MIMO radar of claim 1, wherein each transmit antenna of the plurality of transmit antennas is positioned at a given set of coordinates and are spaced within a relative distance of each other, and wherein the relative distance between each transmit antenna is smaller than a wavelength that increases grating lobe immunity. ### Claim 12 (depends on 11) The MIMO radar of claim 11, wherein the virtual receive array is spaced from the receive antenna array by a same relative distance as that between transmit antennas of the plurality of transmit antennas. ### Claim 13 A method of virtual beam steering, comprising: synthesizing a virtual receive array having N×M receive subarrays from the plurality of transmit antennas and the receive antenna array, where N is the number of transmit antennas and M is the number of receiving elements, wherein the virtual receive array is represented by a manifold matrix that is a function of a geometry of the receive antenna array and a carrier frequency and direction of arrival of the plurality of transmit antennas, and a transformation matrix is applied to the manifold matrix to generate the virtual receive array; and performing a linear transformation on the virtual receive array to create virtual beam steering at a predetermined angle. ### Claim 14 (depends on 13) The method of claim 13, further comprising: applying the linear transformation to first transmit antennas of the plurality of transmit antennas to determine second transmit antennas positioned at an angle relative to an original position of the first transmit antennas; and applying the linear transformation to the receive antenna array to determine a second receive array at an angle relative to an original position of the first receive array, wherein the virtual receive array is spaced from the second receive antenna array by a same distance as that between the second transmit antennas. ### Claim 15 (depends on 13) The method of claim 13, further comprising: applying a linear transformation matrix with interpolation to the manifold matrix to generate an oriented virtual subarray within the virtual receive array. ### Claim 16 (depends on 15) The method of claim 15, wherein applying the linear transformation matrix comprises: applying interpolation to signals received by receive elements of the virtual antenna array to generate the oriented virtual subarray at a predetermined orientation angle. ### Claim 17 (depends on 13) The method of claim 13, further comprising: determining a transformation matrix from the manifold matrix; generating the virtual receive array from the transformation matrix; determining a linear transformation matrix using an optimization criterion that is a function of the manifold matrix and the transformation matrix applied to the manifold matrix; and generating a data set that represents beam steering properties using the determined linear transformation matrix and received signal samples.