US20210382169A1

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Publication number: US20210382169A1
Application number: US17/408,271
Authority: US
Inventors: Maha Achour; Tim Curley; Matthew Harrison
Original assignee: Metawave Corp
Current assignee: Metawave Corp
Priority date: 2017-06-05
Filing date: 2021-08-20
Publication date: 2021-12-09
Also published as: US11105918B2; US20180348365A1

Abstract

The present invention is a nodal radar system having a metamaterial-based object detection system. An intelligent antenna metamaterial interface (IAM) associates specific metamaterial unit cells into subarrays to adjust the beam width of a transmitted signal. The nodal radar system is positioned on infrastructure to complement sensor information from mobile vehicles and devices within an environment.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 15/984,222 entitled “NODAL METAMATERIAL ANTENNA SYSTEM,” filed May 18, 2018 which claims priority to U.S. Provisional Patent Application No. 62/515,045 entitled “INTELLIGENT ANTENNA METAMATERIAL METHOD AND APPARATUS,” filed Jun. 5, 2017; U.S. Patent Application No. 62/613,675 entitled “METHOD AND APPARATUS FOR OBJECT DETECTION USING CONVOLUTIONAL NEURAL NETWORK SYSTEMS,” filed Jan. 4, 2018; and U.S. Provisional Patent Application No. 62/651,050, entitled “METHOD AND APPARATUS ANTENNA WITH DECISION CONTROL”, filed Mar. 30, 2018.

FIELD OF THE INVENTION

The present invention relates to intelligent antennas using metamaterial structures and providing dynamic control of metamaterial unit cells in the metamaterial structures for radar systems.

BACKGROUND

Antennas are used in everyday life for communication systems, sensing devices, radar systems and so forth. Recently there is attention given to autonomous, or self-driving, vehicles. The designs and products contemplated today do not consider all the weather conditions, power consumption constraints and timing required for effective control of a vehicle. There is a need to provide a sensing system that works over the range of road, weather, temperature, visibility, traffic conditions and so forth, while maintaining consistent reliable service.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the present invention are described with respect to the figures. These are not drawn to scale and are drawn to clearly identify what applicant claims as the invention.

FIG. 1 illustrates a nodal radar system, according to embodiments of the present invention.

FIG. 2 illustrates operation of a nodal radar system as inFIG. 1, according to embodiments of the present invention.

FIG. 3 illustrates operation of a nodal radar system as inFIG. 1, according to embodiments of the present invention.

FIG. 4 illustrates a nodal wireless system supporting radar and wireless communications, according to embodiments of the present invention.

FIG. 5 illustrates a metamaterial antenna system, according to embodiments of the present invention.

FIG. 6 illustrates a metamaterial antenna system, according to embodiments of the present invention.

FIG. 7 illustrates a process for operation of a metamaterial antenna system, according to embodiments of the present invention.

FIG. 8 illustrates a metamaterial (MTM) antenna structure, according to embodiments of the present invention.

FIG. 9 illustrates a mapping of a metamaterial antenna structure to locations in a field of view, according to embodiments of the present invention.

FIGS. 10 and 11 illustrate probe-fed metamaterial antenna structures, according to embodiments of the present invention.

FIG. 12 illustrates an embodiment of an MTM antenna configuration, according to embodiments of the present invention.

FIG. 13 illustrates a perspective view of the MTM antenna configuration as inFIG. 12, according to embodiments of the present invention.

FIG. 14 illustrates a sensor fusion system, according to embodiments of the present invention.

FIGS. 15 and 16 illustrate processes for a sensor fusion system as inFIG. 14, according to embodiments of the present invention.

FIG. 17 illustrates a signal flow diagram for operation of a nodal radar system as inFIG. 1, according to embodiments of the present invention.

DETAILED DESCRIPTION

Autonomous driving is quickly moving from the realm of science fiction to becoming an achievable reality. Already in the market are Advanced-Driver Assistance Systems (“ADAS”) that automate, adapt and enhance vehicles for safety and better driving. The next step will be vehicles that increasingly assume control of driving functions such as steering, accelerating, braking and monitoring the surrounding environment and driving conditions to respond to events, such as changing lanes or speed when needed to avoid traffic, crossing pedestrians, animals, and so on.

An aspect of making this work is the ability to detect and classify objects in the surrounding environment at the same or possibly even better level as humans. Humans are adept at recognizing and perceiving the world around them with an extremely complex human visual system that essentially has two main functional parts: the eye and the brain. In autonomous driving technologies, the eye may include a combination of multiple sensors, such as camera, radar, and lidar, while the brain may involve multiple artificial intelligence, machine learning and deep learning systems. The goal is to have full understanding of a dynamic, fast-moving environment in real time and human-like intelligence to act in response to changes in the environment.

In addition to moving vehicles and devices, the present invention presents metamaterial antenna arrays for infrastructure and stationary structures to facilitate additional views, information and warnings to a moving vehicle. The antenna arrays are positioned to scan the area around them and identify objects as a complementary source of information for the vehicle. In addition, these fixed radar systems are flexible and responsive; they may be used to alert to severe weather conditions, such as flooding or snow, they may anticipate actions of a pedestrian or vehicle, and they may predict traffic congestion, alert to safety and/or security concerns, and act as a digital eye for the surrounding area. This information may be used as feedback to the vehicle, to the infrastructure control, to environmental agencies and so forth. In some examples, the radar detects traffic levels and then uses this information to provide real time data to the traffic controls, such as traffic signals. These digital eyes may respond to requests from throughout the environment, such as to interface with Internet of Things (IoT) devices.

The proliferation of devices and sensors enables rapid responses over a range of applications. For example, a radar sensor applied to a traffic light would be able to detect bicycles and pedestrians in specific locations and lanes. The MTM radar disclosed herein may use a coarse scan for such identification. Similarly, an MTM radar on highways would be able to communicate with a vehicle's GPS and provide advance warning of an upcoming exit or lane change. Similarly, an MTM radar sensor near a fueling location may provide an indication to vehicles that this is the last fueling station for a given distance and provide directions for fueling.

The present invention describes an antenna system having an antenna configured with metamaterial (MTM) cells and controlled by an Intelligent Antenna MTM interface (IAM). The antenna system may be used in applications including cellular communication networks, vehicle-to-vehicle communication systems, object detection systems, autonomous vehicle sensor systems, drone control and communication systems, and so forth. The MTM antenna structure is dynamically controlled by the IAM; control may be done by changing the electrical or electromagnetic configuration of the antenna structure. In some embodiments, varactors are coupled to the MTM antenna structure to enable adjustment of the radiation pattern. In some embodiments, the MTM unit cells may be configured into subarrays that have specific characteristics. For use in an autonomous vehicle, the system may perform a coarse focus with a large beam width as an ambient condition, and then narrow the beam width when an echo is received, indicating an object is within the field of view of the antenna structure's radiation pattern. In this way, the larger beam width may sweep the full Field of View (FoV) of the antenna structure, reducing the time to scan the FoV. In some embodiments, the IAM is able to detect the area of the FoV of a detected object and map that to a specific configuration of MTM unit cells and/or subarrays to focus the beam, i.e. narrow the beam width. Additionally, in some embodiments, the specific dimensions and other properties of the detected object, such as traveling velocity with respect to the antenna structure, are analyzed and a next action(s) or course of action(s) is determined. The detected object in some embodiments is then provided as a visual or graphic display, which may act as a back-up security feature for the passenger in the vehicle.

FIG. 1 illustrates anodal radar system10 having at least one sensor located on infrastructure, which in this scenario is a street lamp. In other scenarios, the infrastructure could be any physical location, such as infrastructure along a road including billboards, road signs and the like. Thenodal radar system100 includes an MTM radar antenna array, having an antenna controller to scan a proximate area. Thenodal radar system100 is fixed to the infrastructure and is in communication with wireless technologies and the Internet. In the present embodiment, thenodal radar system100 includes a smart antenna that is able to steer a beam in a variety of directions so as to detect objects within a given area. The beam is steered by control of a plurality of MTM unit cells that form a radiating element. The MTM unit cells are configured for transmission of the radiation beam and for receiving reflections, or echoes, of the radiation beam as it interacts with objects. Thenodal radar system100 includes a control mechanism to adjust the reactance behavior of the MTM unit cells and thereby steer and adjust the radiation beam and receiver. The ability to detect objects and activities within the surrounding area with thenodal radar system100 may be used to complement the radar and other sensors within a vehicle or device. For example, thenodal radar system100 may detect a pedestrian about to cross an intersection and send a communication to vehicles in the area to focus on a specific area where the pedestrian is traveling. The vehicle radar, or other sensor system, is then alerted to focus attention on that area. This enables advanced information for the vehicle control system(s). While the present embodiment provides the ability to steer the beam, some embodiments incorporate fixed radar beams to scan the area at specific transmission angles.

Thenodal radar system100 has an object detection capability to recognize objects and movement within the area. This may be an artificial intelligence system or other method. As thenodal radar system100 operates, it is able to capture real time data and determine if it is operating sufficiently. For example, when thenodal radar system100 sends a message to a vehicle incorrectly identifying a dog in the road, the vehicle may respond with a more specific identification of a cardboard box. Note that thenodal radar system100 may have fewer object recognition capabilities and less processing power than some vehicle radars. In this way, thenodal radar system100 is able to enhance and improve its object recognition capabilities, such as through training of a neural network or expert system, and by capturing real time data from surrounding vehicle radars and other such devices.

FIG. 2 illustrates thenodal radar system100 in operation, whereinnodal radar system100 scans the area withtransmission beams101, which detect cars, people, lamps and so forth. The variety of objects and devices within this environment may change quickly, and so thenodal radar system100 acts as a complement to object detection devices within the vehicles. As illustrated, thenodal radar system100 detects a car in anarea12, another car inarea14, a lamp inarea16 and a person inarea18. Thenodal radar system100 may also detect the other objects in the environment, but these are provided as examples. Once an object is detected, thesystem100 determines a portion of the antenna array to allocate to a scan for that object. This allocation is based on the size of the object, the reflectivity or return signal strength of the object, the location of the object, the velocity of the object and other parameters.

FIG. 3 illustrates continued operation of thenodal radar system100 for scans of moving objects. In some embodiments, thenodal radar system100 uses received radar information to determine a next location of the object and adjusts the scan accordingly. As illustrated, a series ofscans22 are allocated for a vehicle inarea12, a series ofscans24 are allocated for a vehicle inarea14, asingle scan26 is allocated to the stationary street lamp inarea16, and a series ofscans28 are allocated for thepedestrian18. In this way, the nodalradar antenna system100 tracks the location and activity of each object.

Thenodal radar system100 may be collocated with a fixed wireless system, wherein thenodal radar system100 includes object detection capability. While thenodal radar system100 is able to communicate with other devices and vehicles, it is also able to operate independently. Thenodal radar system100 may act in concert with the fixed wireless system, wherein communications from thenodal radar system100 are processed through the fixed wireless system. Within thenodal radar system100 is an object detection module to classify detected objects. This information may also be used to modify behavior of the fixed wireless system, such as to provide non-line of sight signals when there is a large truck or other obstacle to wireless transmission. When such an object is detected, thenodal radar system100 instructs the fixed wireless system accordingly, and in response the fixed wireless system may initiate actions to avoid the dead spot, such as to use a reflect array or other method to continue coverage.

FIG. 4 illustrates an embodiment of anodal wireless system160 supporting a radar operation and wireless communication operation. Anodal radar control150 controls the radar operation and works in collaboration withcommunication system154. Thenodal wireless system160 includes anMTM antenna structure170 having a plurality of MTM unit cells having reactance control mechanisms, such as varactors, which are controlled by anantenna control unit162. The radar and communication operation may be performed by the sameMTM antenna structure170, wherein subarrays are formed for operation. The subarrays may be reconfigured in real time. Thenodal wireless system160 also includes atransceiver180, amicrocontroller182 andmemory164.

Thesystem160 may have multiple antenna arrays withinMTM antenna structure170, for radar and communications. These arrays may be divided into transmit and receive arrays or may be duplex-style where an array is used for both transmit and receive. The signals are generated according to the transceiver operation. For operation of the antenna, including beam forming and beam steering, a rule base anddecision engine166 provides guidance. Theengine166 determines when and where to direct the radiation beams and then determines if the decision was optimum. Theengine166 learns from the behavior of thesystem160 and trains to improve its decision-making. Theobject detection module165 uses radar information to determine if an object is in the area, or field of view, of the radar. Theobject detection module165 may also use information from thewireless communication system154 to identify objects that are causing a dead zone, or to respond to information, such as from a central controller or from a vehicle. Thecommunication system154 may support vehicle-to-device, or V2X, communications to enhance the radar operations. In this way, the vehicle can probe thesystem160 for additional information to better understand the environment and the activity therein.

FIG. 5 illustrates anantenna system200 according to various embodiments of the present invention. Thesystem200 includes anMTM antenna structure110, which includes multiple MTM unit cells, such asMTM unit cell140. EachMTM unit cell140 is an artificially structured element used to control and manipulate physical phenomena, such as electromagnetic (EM) properties of a signal including its amplitude, phase, and wavelength. Metamaterial structures behave as derived from inherent properties of their constituent materials, as well as from the geometrical arrangement of these materials with size and spacing that are much smaller relative to the scale of spatial variation of typical applications. Individual MTM components are considered as unit cells, e.g.,MTM unit cell140. A metamaterial is not a tangible new material, but rather is a geometric design of known materials, such as conductors, that behave in a specific way.

An MTM unit cell, such ascell140, may be composed of multiple microstrips, gaps, patches, vias, and so forth having a behavior that is the equivalent to a reactance element, such as a combination of series capacitors and shunt inductors. Various configurations, shapes, designs and dimensions are used to implement specific designs and meet specific constraints. In some embodiments, the number of dimensional freedom determines the characteristics of theMTM antenna structure110, wherein a device having a number of edges and discontinuities may model a specific-type of electrical circuit and behave in a similar manner. In this way, an MTM unit cell radiates according to its configuration and changes to the reactance parameters of the MTM unit cell change its radiation pattern. Where the radiation pattern is changed to achieve a phase change or phase shift, the resultant structure is a powerful antenna or radar, as small changes to the MTM unit cell result in large changes to the beamform.

TheMTM antenna structure110 may be configured as an array of MTM unit cells, a lattice pattern of MTM unit cells, and so forth. These array formations may then be divided into subarrays, which group unit cells together. The subarray may be controlled by a common controller. For example, in thesubarray145 withinarray143, the MTM unit cells, such ascell141, are all controlled by a single voltage. In this way, a same change is made to the reactance of all cells within asubarray145.

AnTAM50 acts to control the operational parameters of theMTM antenna structure110. In some embodiments, these parameters include voltages applied to individual MTM unit cells, such asunit cell140.IAM50 includes modules and components that capture, measure, store, analyze and provide instructions. The extent of the capabilities of theIAM50 is strong and flexible; as more and more information is required for an application, theIAM50 can build additional capabilities. In this way, theIAM50 is a software programmable module implemented in hardware, having anIAM controller52 that governs actions within theIAM50.

In the present embodiment described herein, the application is for an autonomous car, wherein thesystem100 is a sensing system that uses radar to identify objects. The use of radar provides a reliable way to detect objects in difficult weather conditions. For example, historically a driver will slow down dramatically in thick fog, as the driving speed decreases with decreases in visibility. On a highway in Europe, for example, where the speed limit is 115 km/h, a driver may need to slow down to 40 km/h when visibility is poor. Using the present embodiment, the driver (or driverless car) may maintain the maximum safe speed without regard to the weather conditions. Even if other drivers slow down, the car enabled with the present embodiment will be able to detect those slow-moving cars and obstacles in the way and avoid/navigate around them.

Additionally, in highly congested areas, it is necessary for an autonomous car to detect objects in sufficient time to react and take action. The present invention increases the sweep time of a radar signal so as to detect any echoes in time to react. Supplemental to theMTM antenna structure110 is the nodal radar system, such assystem100 ofFIG. 1, wherein information captured from another point within the environment assists in the ability of the vehicle's radar to perform and make decisions. In rural areas and other areas with few obstacles during travel, theIAM50 adjusts the focus of the beam to a larger beam width, thereby enabling a faster scan of areas where there are few echoes. TheIAM50 may detect this situation by evaluating the number of echoes received within a given time period and making beam size adjustments accordingly. Once an object is detected, theIAM50 determines how to adjust the beam focus. This is achieved by changing the specific configurations and conditions of theMTM antenna structure110. For example, in one scenario the voltages on the varactors are adjusted. In another scenario, a subset of unit cells is configured as a subarray. This configuration means that this set may be treated as a single unit, and all the varactors are adjusted similarly. In another scenario, the subarray is changed to include a different number of unit cells, where the combination of unit cells in a subarray may be changed dynamically to adjust to conditions and operation of the system.

All of these detection scenarios, analysis and reactions may be stored in theIAM50 and used for later analysis or simplified reactions. For example, if there is an increase in the echoes received at a given time of day or on a specific highway, that information is fed into theIAM controller52 to assist in proactive preparation and configuration of theMTM antenna structure110. Additionally, there may be some subarray combinations that perform better, such as to achieve a desired result, and this is stored in theIAM memory54.

In operation, theMTM antenna structure110 provides radar radiation pattern(s) to scan the FoV of thesystem100. In some embodiments, an FoVcomposite data unit112 stores information that describes the FoV. This may be historical data used to track trends and anticipate behaviors and traffic conditions or may be instantaneous or real time data that describes the FoV at a moment in time or over a window in time. The ability to store this data enables theIAM50 to make decisions that are strategically targeted at a particular point or area within the FoV. For example, the FoV may be clear (no echoes received) for five minutes, and then one echo arrives from a specific region in the FoV; this is similar to detecting the front of a car. In response, theIAM50 may determine to narrow the beam width for a more focused view of that sector or area in the FoV. The next scan may indicate the objects' length or other dimension, and if the object is a car, theIAM50 may consider what direction the object is moving and focus the beams on that area. Similarly, the echo may be from a spurious object, such as a bird, which is small and moving quickly out of the path of the car. There are a variety of other uses for the FoVcomposite data112, including the ability to identify a specific type of object based on previous detection.

Theobject detection module114 receives control information from theIAM controller52, and determines the adjustments, if any, to be made. In some embodiments, the scan begins with a coarse scan having a large bandwidth. On object detection, the beam width narrows. The variablebeam dimension module116 responds to theobject detection module114 and may vary the beam width as quickly or slowly as desired. In some embodiments, the beam width is a binary value, and in others it may take on continuous values. Theobject detection module114 instructs thebeam direction module118 where to direct the beam, such as from a subarray. From the received information (echoes) the objectdimension analysis module120 determines parameters and dimensions of the detected object.

Object detection may be enhanced with object classification to identify the type of object and its activity parameters. For example, a deep learning system may be incorporated into theobject detection module114 to identify a person from a car, and to identify the velocity of that object. Such systems train on labelled data and actual radar signals after which they are able to perceive objects with a high probability of certainty. Such object classification systems and capabilities may be additional to the rule base anddecision engine60.

Continuing withsystem100, thetransceiver130 is controlled bycontroller132 and controls the transmit and receive paths to and fromMTM antenna structure110. There may a portion of the unit cells, such asunit cell140, that is dedicated to receive, and another portion that is dedicated to transmit, or theMTM antenna structure110 may be a transmit and receive antenna. In some embodiments, theIAM50 may allocate specific unit cells, or subarrays, as receive only, transmit only or as transmit and receive. There are any number of combinations and designs for these embodiments.

There are many methods that systems that theMTM antenna structure110 may use with respect to theIAM50 for applying, embedding, controlling and so forth. An embodiment for dynamic control of theMTM antenna structure110 is illustrated inFIG. 7.

FIG. 6 illustrates another embodiment of anantenna system300, such as used in a radar system, having a radiatingarray structure200 coupled to anantenna controller112, acentral processor102, and atransceiver110. Atransmission signal controller108 generates the specific transmission signal, such as frequency modulated continuous wave (FMCW), which is used for radar sensor applications as the transmitted signal is modulated in frequency, or phase. The FMCW signal enables radar to measure range to an object by measuring the differences in phase or frequency between the transmitted signal and the received signal, or reflected signal. Other modulation types may be incorporated according to the desired information and specifications of a system and application. Within FMCW formats, there are a variety of modulation patterns that may be used within FMCW, including triangular, sawtooth, rectangular and so forth, each having advantages and purposes. For example, sawtooth modulation may be used for large distances to a target; a triangular modulation enables use of the Doppler frequency, and so forth. The received information is stored in amemory storage unit128, wherein the information structure may be determined by the type of transmission and modulation pattern.

Thetransmission signal controller108 may generate a cellular modulated signal, such as an orthogonal frequency division multiplexing (OFDM) signal. The transmission feed structure may be used in a variety of systems. In some systems, the signal is provided to thesystem100 and thetransmission signal controller108 may act as an interface, translator or modulation controller, or otherwise as required for the signal to propagate through a transmission line system.

The present invention is described with respect to a radar system, where the radiatingstructure200 is a transmission array-fed radiating array, where the signal radiates through slots in the transmission array to the radiating array of MTM elements that radiate a directional signal. Continuing withFIG. 6, the radiatingstructure200 includes individual elements, having animpedance matching element118 and areactance control element120.

In some embodiments a reactance control element includes a capacitance control mechanism controlled byantenna controller112, which may be used to control the phase of a radiating signal from radiating array structures, transmission array structure forelevation122 and transmission array structure for azimuth124. In operation, theantenna controller112 receives information from other modules insystem300 indicating a next radiation beam, wherein a radiation beam may be specified by parameters such as beam width, transmit angle, transmit direction and so forth. Theantenna controller112 determines a voltage matrix to apply to the reactance control mechanisms coupled to the radiating structure to achieve a given phase shift or other parameters. In these embodiments, the radiatingarray structure200 is adapted to transmit a directional beam without using digital beam forming methods, but rather through active control of the reactance parameters of the individual elements that make up the array.Transceiver110 prepares a signal for transmission, such as a signal for a radar device, wherein the signal is defined by modulation and frequency. The signal is received by each element of the radiatingstructure200 and the phase of the radiatingarray structure200 is adjusted by theantenna controller112. In some embodiments, transmission signals are received by a portion, or subarray, of the radiatingarray structure200. These radiating array structures are applicable to many applications, including radar and cellular antennas. The present embodiments consider application in autonomous vehicles as a sensor to detect objects in the environment of the car. Alternate embodiments may use the present inventions for wireless communications, medical equipment, sensing, monitoring, and so forth. Each application type incorporates designs and configurations of the elements, structures and modules described herein to accommodate their needs and goals.

Insystem300, a signal is specified byantenna controller112, which may be in response to Artificial Intelligence (AI)module114 from previous signals, or may be from the interface to sensor fusion104, or may be based on program information frommemory storage128. There are a variety of considerations to determine the beam formation, wherein this information is provided toantenna controller112 to configure the various elements ofarrays122,124, which are described herein. Thetransmission signal controller108 generates the transmission signal and provides same to feeddistribution module116, which provides the signal to feedstructure126 andtransmission arrays122,124.

As illustrated, radiatingstructure200 includes thetransmission arrays122,124, composed of individual radiating elements discussed herein. Thetransmission arrays122,124 may take a variety of forms and are designed to operate in coordination with thefeed distribution module116, whereinindividual radiating elements20 correspond to elements within thetransmission arrays122,124. As illustrated, each of thetransmission arrays122,124 is an 8×16 array ofunit cell elements20, wherein each of theunit cell elements20 has a uniform size and shape; however, some embodiments incorporate different sizes, shapes, configurations and array sizes. When a transmission signal is provided to the radiatingstructure200, such as through a coaxial cable or other connector, the signal propagates through thefeed distribution module116 to thetransmission arrays122,124 for transmission through the air.

Theimpedance matching element118 and thereactance control element120 may be positioned within the architecture offeed distribution module116; one or both may be external to thefeed distribution module116 for manufacture or composition as an antenna or radar module. Theimpedance matching element118 works in coordination with thereactance control element120 to provide phase shifting of the radiating signal(s) fromtransmission arrays122,124. The present invention is a dramatic contrast to the traditional complex systems incorporating multiple antennas controlled by digital beam forming. The present invention increases the speed and flexibility of conventional systems, while reducing their footprint and expanding performance.

As illustrated, there are multiple arrays for transmission, where at least one of the arrays is for transmission in the azimuth, or horizontal, direction, e.g., transmission array structure for azimuth124, and the other is for receiving signal over the elevation of the array, e.g., receive array forelevation122. The two antenna arrays share acommon feed126, but have orthogonal radiation beams. The two antenna arrays may also use separate feeds if desired.

As illustrated inFIG. 7, theprocess201 begins bysystem200 ofFIG. 5 determining if an echo is received by theMTM antenna structure110,step202. If so,system200 extracts the FoV parameters,204, and determines if an object is detected in the path of a vehicle; else thesystem200 continues to transmit beams and listen for echoes. The FoV parameters may include the range from thesystem200 to the detected object, the speed of the object, the size of the object and so forth, in addition to the direction of arrival of the signals reflected by the object. In the present embodiment, theIAM50 identifies the object,206, and may narrow the focus of the transmission beam, and then checks to see if a communication is to be sent to a target vehicle or broadcast to multiple vehicles,208. In the present embodiments,process201 interfaces with a variety of other systems within an application. For example, in a vehicular application, information received at the antenna and the analysis of at least a portion of that data are provided to other modules for processing, such as to a perception layer in an automobile or to a navigation screen.

Thesystem200 then accesses the target or broadcast communication information,210, and sends the message,212. The message is to identify a detected object and assist in vehicle driver assist or autonomous driving. The message may be a simple identification of a location of an object, or may be detailed information about the object and its velocity/acceleration/potential movement. The information may also be to provide an instruction as to how to circumnavigate and avoid a collision, as the nodal radar may see areas in the environment that enable a quick escape route. Thesystem200 may also receive a communication from the vehicle or other device within the environment,218. The received communication may be from another nodal radar system or may be from a wireless communication system. Thesystem200 then determines an action for the target,220, based on the received communication, such as to provide an indication of the capabilities of the vehicle and so forth. The communication from the vehicle may be from a rule base or decision engine that provides a preferred action. Thesystem200 may then continue to communicate with the target vehicle,222 or multiple vehicles/devices.

FIG. 8 illustrates a metamaterial (MTM) antenna structure300 (or a portion of a structure) having a plurality of MTM cells arranged in an array of N×N unit cells, wherein for clarity and discussion herein each unit cell is identified by a row, column index (i,j). The array can be an asymmetric N×M array as well. For simplicity, a symmetric N×N case is described. For example, from the viewer's perspective, the unit cell in the upper corner is identified as340(1,1); and the unit cell in the bottom right is identified as340(N,N). Other configurations are possible based on the application, structure, physics and goals of the antenna structure, such asstructure300.Antenna structure300 is part of an antenna system, that includes other modules, some of which are not shown in this drawing. Similarly, the specific shape of the unit cells may take on any of a variety of shapes that result in the characteristics and behavior of metamaterials and are not restricted to square or rectangular or any other regular shape.

Each of the unit cells340(i,j) in theantenna structure300 may operate individually or as part of a subarray. As illustrated, theIAM350 has associated or grouped specific unit cells into

subarrays

302,304,306 and308. TheIAM350 determines where the radiated beam is to be directed, the shape of the beam and the dimensions of the beam. The beam may be a coarse or large bandwidth beam, a midsized beam or a small, narrow bandwidth beam depending on the situation, the object detected and the timing of the detection, as well as other considerations. TheIAM350 may preconfigure one or more of the subarrays to anticipate a next action, or may use a default configuration, such as to start with a broad bandwidth which enables a faster scan capability or sweep time. For each sweep, the FoV is divided into portions, which may have consistent dimensions, different dimensions or may be dynamically adjusted. In some embodiments, the IAM selects specific directions to have a narrow beam, such as directly in front of the vehicle; other directions, such as on the edges of the FoV may be scanned with a wide beam. These and other design considerations are made by the designer in setting up theIAM350, wherein someIAM350 are flexible and configurable. In the illustrated example, theMTM antenna structure300 has several subarrays that are intended to direct the beam and form the desired radiation pattern.

Once an object is detected, the FoV-to-MTM mapping360 identifies the portion of the FoV for theIAM350 and maps that location to a specific MTM unit cell or subarray that will focus on and capture more information about the object. In some embodiments, theIAM350 has access to various scenarios and may use detected information to predict future conditions on the road. For example, if theMTM antenna structure300 detects a deer running across the road in an area having a known deer path, theIAM350 may predict the direction of the deer, as well as anticipate other deer that may follow. The radiation beams fromantenna structure300 may sweep across the FoV, wherein the visual field of view and the antenna field of view are not necessarily the same. In this case, the antenna FoV may be a 2-D view, whereas objects are typically 3-D. Various systems and configurations enable 3-D object detection and classification through placement of transmit and receive antenna arrays and or combinations of multiple transmit to multiple receive structures.

FIG. 9 illustrates anMTM antenna structure500 having at least one sub-array502 activated to generate beams to capture a specific area orFoV520, corresponding to thesystem10 ofFIG. 1. When thecar14 is detected within anarea506, theIAM550 identifies the associatedportion506 of theFoV520. This is mapped to the portion of theMTM antenna structure500 that will generate a focused beam in that area; and that portion is sub-array502. Similarly,car12 is also identified withinFoV520 in another area;street lamp16 andperson18 are also located withinFoV520. Thesystem100 has a mapping from the FoV to theMTM array560, which may be configured as a Look Up Table (LUT), as a formula, or as another mapping format that configures subarrays of theMTM array500 to generate a beam toward individual portions of theFoV520. In this way, there is low latency dynamic adjustment of the radiation beam for beam forming and beam steering. The ability to capture multiple objects with a single subarray acts to further reduce the delay in detection and communication, reducing the time from detection to action.

As illustrated inFIG. 9, the mapping between theMTM antenna structure500 and theFoV520 is provided by FoV-to-MTM mapping unit560, which includes various entries for such correlation. This type of mapping format may be dynamically adjusted to keep pace with the movement of vehicles; in addition, this information may be stored in a relational database or other device to assist theIAM550 in learning and improving over time. In this way theIAM550 may use artificial intelligence (AI), an expert system, a neural network, or other technology to improve performance of the system for object detection.

As a vehicle travels, there are different FoV snapshots or slices, such as from a near-field to a far-field slice. From the perspective of a vehicle there is a near-field FoV, a far-field FoV, and several mid-field FoVs, which may each be considered as a slice of information. The information may be stored according to angle of arrival, range to the target, velocity of the target, Doppler information from the received signal and so forth. In one embodiment, these are referred to as range-Doppler maps. Each slice corresponds to an instant in time as the car travels. TheIAM550 determines which type of beam is broadcast for each FoV as a function of many parameters, including, for example, the speed of the car and the speed of a detected object in relation to the car. TheIAM550 may determine that for specific conditions, the beams are meant to reach a specific FoV, such as where the car is moving slowly, theFoV520 may be sufficient, but if the car is moving rapidly then there is a desire to reach more than just theFoV520. Weather conditions will have an impact as well, such that if the car will take longer to react, stop or otherwise change the current driving conditions, then theIAM550 may desire to reach the longest FoV to allow the car time to react. This may be utilized for snow or icy conditions, which dramatically impact how quickly a car may decelerate and/or halt.

In some embodiments, a nodal radar system may be positioned on a bill board placed along the road to detect objects traveling along the road. The bill board may have lighting, switched effects, messaging or other power-supplied effects. For power efficiency, the bill board is able to change to a static message that does not use these effects. In some embodiments, the bill board will be able to detect the type of vehicles traveling on a crowded highway and then post an ad that those drivers would like. For example, if there is a faster way to travel for electric vehicles, a bill board may detect times when that lane is empty or sparsely used, while the other lanes are jammed. In this case, the bill board may want to advertise electric vehicles. This ability for infrastructure, such as a stationery bill board, to understand what is happening in its vicinity may be enhanced by communicating with specific vehicles or broadcasting a message to all the vehicles. A communicative billboard may detect a specific driver via wireless signals with the car and may communicate via WiFi, Bluetooth, cellular or other communication method. Using an MTM antenna structure, these billboards are able to understand more about their environment.

A nodal radar may communicate with vehicles, buildings and other devices through a variety of communication protocols. As discussed above, WiFi and so forth may be used. In some embodiments, the radar provides a messaging protocol that is received at the vehicle, such as to direct a radiation beam to a specific target area of the vehicle. Such messaging may be used to initiate a communication or may be used to send a specific message, similar to Morse code or other coded signaling. The signaling may be made to a portion of a vehicle bumper, a metallic or reflective sticker on a vehicle, a mirror, headlamp and so forth.

There may be other sensors that work in collaboration with MTM antenna structures, where each has a special area of detection. In some embodiments a nodal radar system operates in coordination with other sensors, such as a camera sensor, infrastructure sensors, a laser or lidar sensor, vehicle operational sensors, user preference sensors, environmental sensors, a wireless communication module signal and so forth. In a vehicle these various sensors are combined and interpreted through a sensor fusion module that controls coordination of the information from sensors. An IAM may be designed to interface with a sensor fusion module. The camera, or visual, sensor is adapted for capture of objects, environments, and other elements in the FoV of the sensor. The laser sensor acts to identify objects, but its performance deteriorates with distance, weather and light inhibiting conditions. The addition of the MTM antenna sensor provides robust, consistent information when the other types of sensors do not.

Some other considerations for antenna applications, such as for radar antennas used in vehicles, include the antenna design, capabilities, and receiver and transmitter configurations. A typical electronic system with an antenna array consists of two or more antenna elements, beam forming network, and a receiver or transmitter. The beamforming network may consist of a Butler matrix or other antenna arrays combined with phase shifting elements. Many different antenna configurations can be utilized as an antenna element in the antenna array: simple dipole, monopole, printed patch design, Yagi antenna, and so forth. One of the primary goals for antennas mounted on/in the car is to achieve a compact and aesthetic design. Other goals relate to the type of communication signal used for the radar beam. One type of modulation used is Frequency Modulation Continuous Wave (FMCW), which is effective in radar applications, as radar does not need to pulse, but rather transmits continuously. FMCW is a continuous carrier modulated waveform that is transmitted as a continuous periodic function, such as sinusoid, sawtooth, triangular and so forth. The sweep time, or sweep period, T_s, is the time for transmission of one period of the waveform. The signal transmitted during one sweep period is referred to as a chirp. There is a difference in the frequency of the transmit and receive signals that is referred to as the beat frequency, b_f. The range of the antenna, R, is the distance from the antenna to a detected object, and is a function of the sweep period, beat frequency, the speed of light, c, and the sweep bandwidth, B_s. A moving target induces a Doppler frequency shift that enables radar to detect the relative velocity of the target with respect to the antenna. The phase difference between the transmit and receive signals provides location information, while the frequency shift identifies a speed.

In the case of moving objects, the signal phase distortions may impact the performance of the antenna array. One way to offset such distortion is to use multiple subarrays at the Tx and Rx sides to filter out these impurities. Another way is to adjust the antenna calibration on-the-fly to reduce the phase distortion of moving objects.

Traditional phase shifting is used to control the beam of an antenna. Phased array antennas have multiple elements that are fed so as to have a variable phase or time-delay at each element and so that the beam scans from different angles. The multiple elements provide radiation patterns with lower sidelobes and enables careful beam shaping. The beam can be repositioned for more directed and efficient operation.

The present inventions provide an MTM antenna structure that provides phase shifting without the active elements required to change the phase, or in the traditional ways. The MTM antenna structures of various embodiments use the characteristics of the metamaterial shape and configuration to provide phase shift without the use of mechanical or electrical phase shifters.

The MTM antenna arrays of the present invention may be fed by a variety of configurations, such as a probe feed or a substrate integrated waveguide and so forth. In one example of anMTM antenna structure1000, illustrated inFIG. 10, a signal source is provided as aprobe1004, which may be coupled to aground plane1002. Theprobe1004 supplies the source signal for theantenna1000 to generate a modulated EM waveform. Asecond layer1006 is positioned over theground plane1002. Thesecond layer1006 is made of a dielectric material and has anantenna structure1008 configured thereon. Thisantenna1008 is designed to receive the source signal and generate a relatively flat wave front to meet theMTM layer1010. Theantenna1008 may be a dipole antenna or any other antenna capable of generating a relatively uniform and flat wave front across the entirety of thesecond layer1006. The ability to provide the signal to the MTM array or to individual subarrays and/or individual unit cells, enables theMTM antenna1000 to radiate EM beamforms that are steerable. The MTM unit cells are controlled by changes to the reactance behavior of the MTM unit cells, such as through a variable capacitor or varactor coupled between the MTM structures.

Another embodiment is illustrated inFIG. 11, which is a two-layer, probe fedMTM antenna structure1100. As in the example ofFIG. 10, aprobe1104 supplies the signal to aground plane layer1102. In this embodiment, anMTM antenna structure1106 is placed over the ground plane with no middle layer. The source signal is distributed across theground plane1102 such that a relatively flat wave form is presented to theMTM antenna structure1106. TheMTM antenna structure1106 then radiates the transmission signal as described herein, wherein each unit cell may transmit individually or transmit as a sub-array.

Current technology presents a variety of sensors, such as for an automobile that may include various camera, laser, radar, temperature and other sensors. As shown inFIG. 12, asensor fusion controller1210 coordinates and controls operations of the various sensors within thesystem1200. AnMTM antenna sensor1202 provides information on objects detected in the automobile's path and may provide pre-information to other sensors that have not yet triggered or detected. This information may assist other modules and controllers within the automobile to prepare for an action. This effectively pre-configures the automobile by thesensor fusion controller1210.

FIG. 13 is another perspective of the radiatingarray structure424 illustrating the various layers forming the device. The substrate includes a firstconductive layer451, a dielectric layer(s)453, and a super element layer455. The super elements are formed by conductive and non-conductive traces on a top portion of the super element layer455 and by vias formed through the super element layer455 and through the dielectric layer(s)453. The vias (not shown) are lined with conductive material, or may be filled with conductive material, so as to form channels defining thesuper elements452 in super element layer455 and provide a wave guide function to maintain propagation of the signals fed into thesuper elements452. The longitudinal direction of thesuper elements452 in the perspective ofFIG. 13 is illustrated in the y-direction. The signal radiates in the z-direction. Again, note these directions are for explanation purposes only and do not necessarily correlate to absolute horizontal of vertical references.

FIG. 14 illustrates a sensor fusion according to embodiments of the present invention. As illustrated, thesystem1200 includes acamera sensor1204 which will detect visible objects and conditions and is used in rear view cameras that enable the user to better control the vehicle. Thecamera sensor1204 may be used for various functions, including some that are invisible to the user, or driver.Infrastructure sensors1206 may provide information from infrastructure while driving, such as from a smart road configuration, bill board information, traffic alerts and indicators, including traffic lights, stop signs, traffic warnings, and so forth. This is a growing area, and the uses and capabilities derived from this information are immense.Environmental sensor1218 detects various conditions outside, such as temperature, humidity, fog, visibility, precipitation, and so forth. Thelaser sensor1212 detects items outside the vehicle and provides this information to adjust control of the vehicle. This information may also provide information such as congestion on a highway, road conditions, and other conditions that would impact the sensors, actions or operations of the vehicle. Thesensor fusion controller1210 optimizes these various functions to provide an approximately comprehensive view of the vehicle and environments.

Continuing withFIG. 14, acommunication module1208 for communication with other vehicles, referred to as V2V communication, is provided. This information may include information invisible to the user, driver, or rider, and may help vehicles coordinate to avoid an accident.Operational sensors1214 provide information about the functional operation of the vehicle. This may be tire pressure, fuel levels, brake wear, and so forth. Theuser preference sensors1216 may be configured to detect conditions that are part of a user preference. This may be temperature adjustments, smart window shading, and so forth.

Many types of sensors may be controlled by thesensor fusion controller1210. These sensors may coordinate with each other to share information and consider the impact of one control action on another system. In one example, in a congested driving condition, a noise detection module (not shown) may identify that there are multiple radar signals that may interfere with your vehicle. This information may be used byIAM1250 to adjust the beam size of theMTM antenna sensor1202 so as to avoid these other signals and minimize interference.

Anenvironmental sensor1218 may detect that the weather is changing, and visibility is decreasing. In this situation, thesensor fusion controller1210 may determine to configure the sensors to improve the ability of the vehicle to navigate these new conditions. The actions may include turning off camera or laser sensors or reducing the sampling rate of these visibility-based sensors. This effectively places reliance on the sensor(s) adapted for the current situation. In response, theIAM1250 configures theMTM antenna sensor1202 for these conditions as well. For example, theMTM antenna sensor1202 may reduce the beam width to provide a more focused beam, and thus a finer sensing capability.

In some embodiments, thesensor fusion controller1210 may send a direct control to theIAM1250 based on historical conditions and controls. Thesensor fusion controller1210 may also use some of the sensors withinsystem1200 to act as feedback or calibration for the other sensors. In this way, anoperational sensor1214 may provide feedback to theIAM1250 and/or thesensor fusion controller1210 to create templates, patterns and control scenarios. These are based on successful actions or may be based on poor results, where thesensor fusion controller1210 learns from past actions.

FIGS. 15-16 illustrate processes implemented in thesensor fusion controller1210, and actions based on sensor readings. InFIG. 15, a process1300 looks to see if a signal is received from any of the sensors within a system,1302, such assystem1200 ofFIG. 14. If no signal is received, processing continues to listen for sensor signals. When a signal is received,1302, thesensor fusion controller1210 determines the sensor parameters, step1304, which include the information type received from the sensor. This information may be stored for analysis as to actions taken by the vehicle to enable intelligent, flexible, and dynamic control. The process1300 then continues to compare the signal received to data stored by thesensor fusion controller1210,step1306, wherein such data may be stored in memory (not shown) or stored in a networked repository, such as a cloud database and system (not shown). At this point, if a control action is indicated at1308, processing continues to determine if this control action and/or the information received from the sensor will provide early detection for this or another action. This early detection check, step1310, allows the entire sensor ecosystem to take advantage of information from any of the sensors in thesystem1200. If the sensor information may be used for early detection, step1310, then the information is sent to one or more modules,step1312, or is stored in memory as a data point in the current scenario. The system them takes the indicated action,step1314, and returns to listen for signals at1302. If the information is not used for early detection at1310, then processing continues to take the indicated action at1314. If no control action is indicated at1308, processing returns to listen for sensor signals.

FIG. 16 illustrates anotherprocess1400 according to some embodiments, wherein thesensor fusion controller1210 configures sensors and controls for operation at1402. This may be a dynamic step or may be a persistent configuration. When an object is detected by theMTM antenna sensor1202 at step1404, theprocess1400 uses that information to calculate or determine specifics relating to the object with respect to the antenna position. The angle of arrival (AoA) is compared to the transmission angle or is mapped to a subarray in the MTM antenna sensor,1406. This information is used to determine the position of the detected object in 2-D or 3-D space,1408. The range, or distance from the antenna to the object, is a function of the radar chip delay,1410. The information from theMTM antenna sensor1202 and other sensors is used to determine a silhouette and/or footprint of the object,1412. Optionally, information from the sensor(s) may provide an object signature of the object,1414, depending on material and so forth. This may be an indication of the reflectivity of the object. The object signature is a more detailed understanding of the object, which may give dimensions, weight, and so forth. Thesensor fusion controller1210 will access sensor information to determine a control action,1416, and instruct to take action,1418.

A variety of information is determined from theMTM antenna sensor1202; such information may be a function of the modulation waveform and technique, the frequency, the chirp delay, the frequency change of the received signal and so forth. The specific radiation pattern used may be crafted to accomplish specific goals according to the application. Thesensor fusion controller1210 enables such control to optimize the system and reduce the processing required. For example, theMTM antenna sensor1202 may be used to reduce the number of sensor and/or the active time of each sensor. In this way, some sensors may be disabled during certain conditions, and activated on a change in that condition.

The present invention provides a nodal radar system that is configured for placement on a stationary or temporarily stationary location in an environment to complement and supplement information of individual vehicles, devices and so forth. The nodal radar system scans the environment, and may incorporate infrastructure information and data, to alert drivers and vehicles as to conditions. The nodal radar system is able to detect objects and actions within the environment.

In some embodiments, the nodal radar system communicates with other nodal radar units throughout the environment to gain and provide advance notice and warnings of activities, such as a speeding car. The nodal radar system may communicate through over the air, wireless systems, such as cellular, WiFi, Bluetooth and near field communication (NFC) methods. The nodal radar system acts as a complement to the sensor fusion within vehicles in the area. The nodal radar system may be part of a stationary sensor fusion module that includes camera, lidar, ultrasound and so forth, so as to be part of a smart city.

Claims

What is claimed is:

1. A method of operating a radar system, comprising:

transmitting, via a radar unit of the radar system, a radio frequency (RF) beam in an environment of the radar system;

controlling, via a feed distribution module, at least one subarray within the radar unit during the transmitting of the RF beam; and

phase shifting, via a feed structure, the at least one subarray within the radar unit.

2. The method ofclaim 1, further comprising:

adjusting a focus of the RF beam to a larger beam width to enable a faster scan of areas in the environment.

3. The method ofclaim 1, further comprising:

adjusting a focus of the RF beam of the radar unit.

4. The method ofclaim 3, wherein adjusting the focus of the RF beam comprises changing a phase shift of the RF beam.

5. The method ofclaim 3, wherein adjusting the focus of the RF beam comprises controlling a reactance control means.

6. The method ofclaim 1, further comprising:

detecting an object within the environment based on received signals from the environment; and

sending a message to a vehicle based on the detecting.

7. The method ofclaim 6, further comprising:

classifying the detected object based on the received signals.

8. The method ofclaim 1, further comprising:

interpreting received signals in a reflected RF beam from the environment; and

implementing one or more control actions based on the interpreted received signals.

9. The method ofclaim 1, wherein the radar system is fixed to an infrastructure and wherein the infrastructure is a building or a sign board.

10. A nodal radar system, comprising:

a metamaterial radar unit configured to transmit radio frequency (RF) beams in an environment;

a feed structure coupled to the metamaterial radar unit, the feed structure comprising a super element layer having conductive traces and non-conductive traces; and

a metamaterial array control means configured to adjust reactance behavior of the metamaterial radar unit to change a phase of the RF beams.

11. The nodal radar system ofclaim 10, wherein the feed structure comprises a conductive layer having a plurality of discontinuities.

12. The nodal radar system ofclaim 11, wherein the feed structure further comprises a second conductive layer and a dielectric layer configured between the first and second conductive layers.

13. The nodal radar system ofclaim 12, wherein the feed structure further comprises a plurality of vias that are positioned from the first conductive layer to the second conductive layer through the dielectric layer.

14. The nodal radar system ofclaim 13, wherein the plurality of vias define a plurality of super elements within the feed structure.

15. A method of performing radar system operations, comprising:

receiving radar signals via a plurality of sensors of a radar system within an environment;

implementing one or more control actions based on the received radar signals;

controlling one or more subarrays of a metamaterial antenna of the radar system via an intelligent antenna metamaterial (IAM) interface; and

enabling, via the IAM interface, a communication with the metamaterial antenna.

16. The method ofclaim 15, further comprising:

scanning a field of view of the radar system within the environment.

17. The method ofclaim 15, further comprising:

interpreting the received radar signals;

detecting an object based on the interpreting of the received radar signals; and

sending a message to a vehicle after the detecting.

18. The method ofclaim 15, wherein the radar system is configured to collaborate with one or more radar systems within a network of radar systems.

19. The method ofclaim 15, further comprising:

coordinating one or more operations of the plurality of sensors of the radar system.

20. The method ofclaim 15, wherein the radar system is fixed to an infrastructure and wherein the infrastructure is a building or a sign board.