Method and apparatus for millimeter wave antenna array

Abstract

An antenna array system and a method for making the antenna system. The system includes at least two antenna elements serving as transmitter elements, and at least two antenna elements serving as receiver elements. Each of the transmitter antenna and receiver antenna elements include a pair of curved arms, wherein a first arm in the pair of curved arms is configured to be connected from a signal trace of the antenna system. The second arm in the pair of curved arms is configured to be connected to a ground plane.

Claims

1. An antenna array system, comprising: at least two antenna elements serving as transmitter elements; at least two antenna elements serving as receiver elements; and a substrate having one or more metal and insulating layers, wherein each insulating layer is configured to be of a different material from at least one other layer; wherein each of the transmitter antenna and receiver antenna elements include a pair of curved arms, wherein a first arm in the pair of curved arms is configured to be connected from a signal trace of the antenna system; and a second arm in the pair of curved arms is configured to be connected to a ground plane, and wherein the antenna elements of the antenna array system are configured to be arranged in a symmetrical arrangement, where the first arm of each of the at least two antenna elements serving as transmitter elements has a direction of curvature that is symmetrical about an axis with respect to a direction of curvature of the first arm of each of the at least two antenna elements serving as transmitter elements.

2. The antenna array system according to claim 1, wherein the antenna elements of the antenna array system are configured to be arranged using at least one of the following arrangements: a linear arrangement, a non-linear arrangement, a linear and symmetrical arrangement, and a non-linear and symmetrical arrangement.

3. The antenna array system according to claim 1, further comprising a ground element configured to cover at least a portion of one of one or more transmitter elements and a portion of one or more receiver elements with two metal layers, wherein the two metal layers are connected using one or more vias.

4. The antenna array system according to claim 3, further comprising at least one ground plane having a curved outline.

5. The antenna array system according to claim 3, wherein an additional one or more vias is at least one of the following: a connecting metal connected from one ground element to another ground element, and at least another via connected to at least another metal.

6. The antenna array system according to claim 1, further comprising a substrate having at least one of the following shapes: a rectangular shape, a semi-circular shape, a quarter-circular shape, a pie-shaped, a triangular shape, and a trapezoidal shape.

7. The antenna array system according to claim 1, further comprising one or more feeding lines having different line width and/or a plurality of surrounding vias for controlling an impedance of the one or more feeding lines.

8. The antenna array system according to claim 1, wherein one or more curved arms have at least one of the following widths: a uniform width and a non-uniform width.

9. The antenna array system according to claim 1, wherein one or more curved arms have at least one of the following shapes: a semi-circular shape and a pie shape.

10. A method of making an antenna array system, comprising providing a substrate, wherein the substrate includes one or more metal and insulating layers, and wherein each insulating layer is configured to be of a different material from at least one other layer; providing at least two antenna elements serving as transmitter elements; providing at least two antenna elements serving as receiver elements; wherein each of the at least two transmitter antenna elements and the at least two receiver elements include a pair of curved arms, wherein a first arm in the pair of curved arms is configured to be connected from a signal trace of the antenna system; and a second arm in the pair of curved arms is configured to be connected to a ground plane; and assembling the substrate, the at least two transmitter elements, and the at least two receiver elements, wherein the antenna elements of the antenna array system are configured to be arranged in a symmetrical arrangement, where the first arm of each of the at least two antenna elements serving as transmitter elements has a direction of curvature that is symmetrical about an axis with respect to a direction of curvature of the first arm of each of the at least two antenna elements serving as transmitter elements.

11. The method according to claim 10, wherein the antenna elements of the antenna array system are configured to be arranged using at least one of the following arrangements: a linear arrangement, a non-linear arrangement, a linear and symmetrical arrangement, and a non-linear and symmetrical arrangement.

12. The method according to claim 10, further comprising providing a ground element configured to cover at least a portion of one of one or more transmitter elements and a portion of one or more receiver elements with two metal layers, wherein the two metal layers are connected using one or more vias.

13. The method according to claim 12, wherein at least one ground plane has a curved outline.

14. The method according to claim 12, wherein an additional one or more vias is at least one of the following: a connecting metal connected from one ground element to another ground element, and at least another via connected to at least another metal.

15. The method according to claim 10, wherein the substrate includes at least one of the following shapes: a rectangular shape, a semi-circular shape, a quarter-circular shape, a pie-shaped, a triangular shape, and a trapezoidal shape.

16. The method according to claim 10, further comprising providing one or more feeding lines having different line width and/or a plurality of surrounding vias for controlling an impedance of the one or more feeding lines.

17. The method according to claim 10, wherein one or more curved arms have at least one of the following widths: a uniform width and a non-uniform width.

18. The method according to claim 10, wherein one or more curved arms have at least one of the following shapes: a semi-circular shape and a pie shape.

19. The antenna array system according to claim 1, wherein the antenna elements of the antenna array system are configured to be arranged in a non-linear arrangement.

20. The antenna array system according to claim 1, further comprising a chip configured to apply different amplitude and phase to each signal from the at least two antenna elements serving as receiver elements to steer the direction of receiver sensitivity patterns.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The accompanying drawings, which are incorporated in and constitute a part of this specification, show certain aspects of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations. In the drawings,

(2) FIGS. 1a-d illustrate an exemplary millimeter wave antenna array system, according to some implementations of the current subject matter;

(3) FIG. 2a illustrates an exemplary 3D antenna radiation pattern with two antennas (e.g., Tx1 and Tx2 of this exemplary system), each excited with the same signal and the same phase, where the max antenna gain is 8 dBi, according to some implementations of the current subject matter;

(4) FIG. 2b illustrates an exemplary 3D antenna radiation pattern with two antennas (e.g., Tx1 and Tx2 of this exemplary system), each excited with the same signal and different phase (i.e., 180-degree phase delay), thereby providing maximum coverage, according to some implementations of the current subject matter;

(5) FIGS. 3a-d illustrate various exemplary, non-limiting metal shapes of the antenna design in the antenna system shown in FIGS. 1a-d;

(6) FIGS. 4a-c illustrate an exemplary millimeter wave antenna array system, according to some implementations of the current subject matter.

(7) FIG. 5 illustrates various exemplary arrangements of signal arms, according to some implementations of the current subject matter;

(8) FIG. 6 illustrates exemplary configurations of tab end and ground plane, according to some implementations of the current subject matter; and

(9) FIG. 7 illustrates an exemplar method of making an antenna array system, according to some implementations of the current subject matter

DETAILED DESCRIPTION

(10) In some implementations, the current subject matter may provide a millimeter wave antenna array that is capable of generating an enhanced/broad beamforming coverage, as compared to existing antenna systems, such as patch antenna systems, some planar yagi-uda antenna systems, dipole antenna systems, etc., which are typically capable of providing a limited radiation pattern coverage. The current subject matter's millimeter wave antenna array may be easily fabricated on printed circuit board and/or any other multilayer substrate and/or integrated with a complementary metal-oxide-semiconductor (CMOS) chip. Other IC technologies, such as SiGe or GaAs, may also be used for the integrated circuit. In some implementations, the current subject matter may be implemented in various systems/devices, such as, for example, but not limited to, an element to radiate and/or receive radio frequency electromagnetic signals, a 60 GHz WiGig system, a millimeter wave system, a short range frequency modulated continuous wave/continuous wave (FMCW/CW) radar sensor(s), a 5G wireless communication system, a beamforming antenna array system, an endfire antenna for a wireless communication system, mobile telephone(s), smartphone(s), laptop(s), computers, other device for wireless 60 GHz/microwave/millimeter wave band and beamforming/beam scanning applications, a personal area network, a security scanner, a radio telescope, an imaging device, intersatellite communications, a point-to-point communications system, a point-to-multipoint communications system, a ground-based and/or airborne vehicular communications system, a thickness gauge system such as for manufacturing, and/or any other systems, devices, etc.

(11) The band of spectrum between 30 gigahertz (GHz) and 300 GHz is considered to be the millimeter wave band. Millimeter wave is also known as extremely high frequency (EHF) or very high frequency (VHF) by the International Telecommunications Union (ITU). Millimeter waves have short wavelengths in the range from 10 millimeters to 1 millimeter. They have high atmospheric attenuation and are absorbed by gases in the atmosphere, thereby reducing the range and strength of these waves. Further, various atmospheric conditions, such as, rain, moisture (humidity), impact performance and reduce signal strength, which is also known as rain fade. Because of the waves' short range (i.e., approximately one kilometer), millimeter waves travel by line of sight, and thus, its high-frequency wavelengths can be blocked by physical objects (e.g., trees, structures, buildings, etc.).

(12) FIGS. 1a-d illustrate an exemplary millimeter wave antenna array system 100, according to some implementations of the current subject matter. The system 100 may be an endfire antenna array that may be fabricated on a multi-layer printed-circuit board (PCB) substrate 102 and electrically connected to a chip or a die 104. The electrical interconnect may accomplished using a solder bump similar to that illustrated as bump 132. The IC (chip/die 104) may have variety of signals and interconnect (which may include digital signals, IF signals, control signals, power and ground). The bumps 132 (as shown in FIGS. 1b and 1c) may connect to top, and/or middle and/or bottom metal layers either directly or through vias. The top, middle, or bottom metal may, for example, be a signal trace, a power plane, or a ground plane. The PCB substrate 102 may include a first receive antenna 106, a second receive antenna 108, a first transmit antenna 112, and a second transmit antenna 116. Each antenna is constructed with a signal and ground arm as exemplified by signal arm 110 and ground arm 114 of a first transmit antenna 112. The antenna system will also have a feeding/matching network. The feeding network may be an interconnect between the signal/ground arms and the IC pads. The feeding network may have a controlled impedance and may be balanced in length.

(13) As shown in FIG. 1b, using the antenna system 100, a signal may be transmitted from the signal pad (e.g., Tx1 signal pad 122, Tx2 signal pad 124) to the second layer metal, and connected to one arm of an antenna (e.g., Tx1 signal may be transmitted using signal path of Tx1 136, and Tx2 signal may be transmitted using signal path of Tx2 138). The ground signal may be interconnected from the ground pad(s) (e.g., Gnd pad 126, Gnd pad 128) to the top layer metal using a bump (e.g., the bump associated with Gnd pad 128) and connected using a via(s) (e.g., via 134) to the bottom ground metal. In general, the ground may form a return path and not necessarily a transmission path. The ground may be connected with one or more vias to the ground plane in order to provide a low inductance, low resistance, and return path.

(14) In some implementations, each metal layer may be insulated using a “substrate” insulating material. There are many material choices having a wide range of cost and performance that may be used for this purpose. In general, an antenna fabricated on a PCB, as discussed herein, may require a substrate with good to high thermal/electrical stability and a low loss. By way of a non-limiting example, FR-4, Rogers, etc. materials may be used.

(15) In some implementations, the antenna system 100 may be compact and may have a wide bandwidth and low voltage standing wave ratio (VSWR). Further, while FIGS. 1a-d illustrate an exemplary implementation of 1×4 linear antenna array arrangement, the current subject matter antenna array system are not limited to such one dimensional arrangement. The current subject matter's antenna design may be used as single antenna and/or as multiple M×N antenna array(s), where M and N may be any integer number.

(16) In some implementations, the chip or a die 104 may include a radio frequency integrated circuit (RFIC), and/or any other RF circuitry/chip/die, etc. In some implementations, the chip 104 may be a flip-chip integrated on an additional substrate or mounted directly to top level metal of the PCB as shown in FIG. 1c. The bump ball 132 may be used for connection between pads (e.g., pads 122-130 (as shown in FIG. 1b)) on a chip and a metal on the PCB/substrate. Additionally, the antenna signal pad (e.g., pads 122, 124, as shown in FIG. 1b) may be connected to a middle layer using one or multiple vias. As shown in FIG. 1c, the IC may be connected to the PCB. In alternate implementations, an IC may be mounted to a different substrate, where that substrate may be mounted to the PCB. A complete assembly may include layers of metal and an insulating material corresponding to a PCB, where each individual layer of insulating material may be a substrate. The antenna signal feed lines may connect to a middle layer metal using vias. In some implementations, the connection may be to the top layer metal which may then be connected to the middle layer metal using a via, e.g., a metal pad may be placed on the top layer metal with a short stub to a via.

(17) While FIGS. 1a-d illustrate the PCB/substrate 102 having three metal layers, the current subject matter may have any desired number of metal layers. By way of a non-limiting example, the PCB/substrate 102 may have between one and eleven metal layers. A substrate between each such metal layer may be manufactured from the same and/or different materials, e.g., FR-4, RO4003, RO4350, Teflon, LTCC, duroid, and any other materials that may have low loss tangent properties.

(18) In some implementations, the distance between vias (e.g., vias 134) may be smaller than the free space wavelength to prevent the millimeter wave signal from leaking out and to provide isolation between two transmitter signals (e.g., Tx1 and Tx2), two receiver signals (e.g., Rx1 and Rx2), and isolation between transmitter or receiver signals and the other switching signals on the PCB. For full-duplex systems, the vias may also provide antenna transmit and receive isolation. Sidewalls of via 134 may be metal-coated to achieve an electrical connection. In some exemplary, non-limiting, implementations, the metal coating may be copper, gold, and/or any other conductive metal, and/or any combination thereof.

(19) In some implementations, the system 100 may also include various low frequency signal components, such as, baseband signal, intermediate frequency (IF) signal, digital control and data signals, DC power, etc. Such components may be placed under the chip 104 and may be separated using via(s) (e.g., via 134) to prevent signal interference. Further, the chip 104 may be configured to generate different amplitude and phase (or time-delayed) signals to each transmit antenna array element (e.g., Tx1, Tx2, etc.), and thus, different antenna radiation patterns may be transmitted by the system 100. Similarly, chip 104 may be configured to apply different amplitude and phase (or time-delay) to each signal from the receive antenna array elements (e.g., Rx1, Rx2, etc.) to steer the direction of the receiver sensitivity patterns. Various circuit components that may or may not be integrated into the chip (e.g., LO, phase rotator, RF phase shifter, etc.) may be used in generating the different antenna phase and radiation/receive patterns. Exemplary radiation patterns are shown in FIGS. 2a-b. FIG. 2a illustrates an exemplary 3D antenna radiation pattern 200 with two antennas excited with the same in phase signal, where the max antenna gain is 8 dBi. FIG. 2b illustrates an exemplary 3D antenna radiation pattern 202 with two antennas excited with the same signal and 180-degree phase delay between the two signal paths, thereby providing the maximum steering angle. In some implementations, a Tx and Rx antenna may have same or similar transmit/receive patterns. Further, when a phase delay is applied, the patterns may be steered in different directions. The steering may produce additional lobes, as shown in FIG. 2b. In some implementations, the receiver gain may be same or similar to the transmitter gain, e.g., 8 dBi. A 180 degree phase shift may be simulated to test a maximum steering angle and/or resulting antenna pattern.

(20) In some implementations, the current subject matter may be configured to implement one or more aspects of a phased array system. A phased array system may be a computer-controlled array of antennas that may electronically steer a generated beam of radio waves to point in different directions without physically moving the antennas. In an antenna array, a transmitted radio frequency current may be fed to individual antennas in the system with a correct phase relationship so that waves from separate antennas may be added to increase radiation in a desired direction and suppress radiation in other unwanted direction(s). In a phased array, the transmitted power may be fed to antennas through computer-controlled phase shifters, which electronically alter phase to steer the beam of radio waves to a different direction. There are two types of phased arrays: a dynamic phased array (active or passive based on a type of amplifier used), which is an array of variable phase shifters for moving the beam, and a fixed phased array (active or passive), where beam's position is stationary with respect to array's face and the entire antenna is moved. The above different types of phase arrays relay on different beamforming techniques. A time-domain beamformer introduces time delays using a delay-and-sum technique that delays an incoming signal from each array element by a predetermined amount of time, and then adds them together. Some frequency beamformers separate different frequency components in the received signal into multiple frequency bins allowing the main lobe to simultaneously point in different directions when different delay and sum beamformers are applied to each frequency bin. Other frequency domain beamformers use of spatial frequency by taking and processing discrete samples from each individual array element to generate multiple different discrete phase shifts, thereby simultaneously forming evenly spaced beams.

(21) In some implementations, the current subject matter may be configured to provide an enhanced range of beam steering through use of curved arms, ground planes, etc., as discussed herein.

(22) FIGS. 3a-d illustrate various exemplary, non-limiting metal shapes of the antenna design in the antenna system 100 shown in FIGS. 1a-d. For example, FIG. 3a illustrates antenna signal arm 310 and ground arm 314 being formed using a semi-circle trace 300. The width of the trace may be uniform, tapered, piecewise linear, and/or any other pattern. The bottom metal may form the other antenna arm and may be disposed in any desired relation to the signal arm. For example, as shown in FIG. 3a, directions of curvature of the arms 310 and 314 may be opposite to one another about an axis that is parallel to the plane of the layers. Alternatively, the directions of curvatures of the arms 310 and 314 may mirror each other. In some implementations, the curvatures of all arms 310 may curve in the same direction or different directions. Similarly, the curvatures of all arms 314 may curve in the same or different directions.

(23) Exemplary arm configurations or arrangements 502-508 of the arms 310 and/or 314 are shown in FIG. 5. Configuration 502 illustrates a linear (e.g., in the same plane) configuration of the arms (e.g., ground arms, antenna arms, and/or both), whereby curvatures of all arms may be configured to curve in the same general direction. As can be understood, the radius of the curvature of each arm may vary and/or may be the same. Configuration 504 illustrates a linear and symmetrical configuration of the arms (e.g., ground, antenna, and/or both), whereby directions of curvatures of two of the arms are different from directions of curvatures of two other arms (i.e., symmetrical about an axis 505). Configuration 506 illustrates a non-linear arrangement of the arms (e.g., ground, antenna, and/or both). Non-linear arrangement may be due to the plane (e.g., ground plane), from which the arms are extending, being curved or pie-shaped, as shown in the configuration 506. Here, the directions of curvatures of the arms may be similar to the configuration 502, i.e., pointing in the same general direction. As can be understood, the radius of curvature of each arm may be different and/or same with respect to the other arms. Configuration 508 illustrates a non-linear (similar to configuration 506) and symmetrical arrangement (similar to configuration 504) of the arms. As can be understood, the configurations of the antenna arms are not limited to those shown in FIG. 5, e.g., the non-linear arrangement may include an irregular shaped plane, where arms may be arrangement symmetrically, anti-symmetrical, and/or in any other fashion.

(24) In some implementations, referring back to FIG. 3a, the antenna arms may also be formed using a top metal. In some exemplary, non-limiting, implementations, the signal and ground arms 310, 314 may be “flipped” 180 degrees from one another (e.g., different layers may form the arms, directions of curvatures from one arm 310 to another arm 310, from one arm 314 to another arm 314, as well as between arms 310 and 314 may vary). Variations of arrangements of arms may be implemented to provide an enhanced beam steering coverage and/or flexibility. Curved corners of the ground plane covering the feed line region may be included to improve the range of beam steering. FIGS. 3b-d illustrate additional details of the antenna system 100 shown. In particular, FIG. 3b illustrates an exemplary portion of the curved corner top layer ground metal 142. FIG. 3c illustrates exemplary transmission signal arms (paths 136, 138) and a portion of the associated feedline network(s) (pads 122, 124) for the system 100. FIG. 3d illustrates a portion of the curved corner bottom layer ground metal 142 with connected ground arms 114, 314.

(25) FIGS. 4a-c illustrates an exemplary antenna system 400, according to some implementations of the current subject matter. The antenna system 400 may be similar to the antenna systems shown in FIGS. 1a-3d and discussed above. The antenna system 400 may include a PCB 404, one or more curved Tx/Rx/Gnd arms 410 and a tab 420. The system 400 may include additional components similar to those discussed above in connection with FIGS. 1a-3d. The tab 420 may be an extension of the PCB 404 (e.g., without top, middle, or bottom metal and without a protective solder mask coating). The tab 420 may be configured to provide an antenna gain. In some exemplary implementations, tab's edges may also be curved (exemplary curved configurations are shown in FIG. 6). The Tx/Rx/Gnd arms 410 may be configured to be embedded (e.g., partially or completely) in the tab 420.

(26) FIG. 6 illustrates exemplary configurations of tab end and ground plane. Configuration 602 illustrates a rectangular arrangement that may be used for the tab end. Configuration 604 illustrates a generally rectangular arrangement having curved or circular ends (quarter-circular), which may be used for ground planes. Configuration 606 is a rectangle having a pie-shaped or arcuate side (e.g., less than 180 degrees arc) and configuration 608 is also a rectangle with an arcuate side, where the arc is more than 180 degrees. These configurations may be used for the ground plane and/or the tab end. Configuration 610 is a triangular arrangement (that may be used for fourth and/or fifth sides) and configuration 612 is a trapezoidal arrangement (that may be used for fourth, fifth and/or sixth sides).

(27) In some implementations, the current subject matter relates to an antenna array system. The antenna array system may include at least two antenna elements serving as transmitters and two antenna elements serving as receiver elements. The antenna system may also include a pair of curved arms, where one arm may be connected from a signal trace of the antenna system and the other arm may be connected to a ground plane. The antenna array system may have a linear arrangement, a non-linear arrangement, a linear and symmetrical arrangement, and/or a non-linear and symmetrical arrangement. Further, the antenna system may include a PCB having multiple metal and substrate layers, where each substrate layer may be either the same material and/or different material from the other layers.

(28) In some implementations, the ground element may be configured to cover the signal elements using two metal layers and may be connected using vias to a ground portion of one of the transmitter antenna elements. The ground element's outline may be curved. The vias may be a connecting metal connected from one ground metal to other ground metal, and/or connected to more metals. The signal line may be a metal covered by two ground plane on the top and ground and vias.

(29) In some implementations, the substrate may have at least one of the following shapes: a rectangle shape, a semi-circle shape, a quarter circle shape on the corner, a pie-shaped, a triangular shape, and a trapezoidal shape and/or any other shape, and/or any combination thereof.

(30) In some implementations, the antenna system may include one or more feeding lines that may have different line width and different space of surrounding vias for controlling the feeding line impedance.

(31) In some implementations, the antenna elements may have a curved arm with uniform and/or not uniform width. The curve of the arm may have a semi-circle curve and/or pie shape. As can be understood, any curvature/shaped areas of metal may be used for signal/ground arms for the purposes of providing an enhanced beam steering coverage.

(32) In some implementations, the current subject matter relates to a method for making an antenna system, as shown in FIG. 7. At 702, a substrate may be provided. At 704, at least two antenna elements serving as transmitter elements may be provided. At 706, at least two antenna elements serving as receiver elements may also be provided. Each of the two transmitter antenna elements and the two receiver elements may include a pair of curved arms, wherein a first arm in the pair of curved arms may be configured to be connected from a signal trace of the antenna system. The second arm in the pair of curved arms may be configured to be connected to a ground plane. At 708, the substrate, the two transmitter elements, and the two receiver elements may be assembled.

(33) Although ordinal numbers such as first, second, and the like can, in some situations, relate to an order; as used in this document ordinal numbers do not necessarily imply an order. For example, ordinal numbers can be merely used to distinguish one item from another. For example, to distinguish a first event from a second event, but need not imply any chronological ordering or a fixed reference system (such that a first event in one paragraph of the description can be different from a first event in another paragraph of the description).

(34) The foregoing description is intended to illustrate but not to limit the scope of the invention, which is defined by the scope of the appended claims. Other implementations are within the scope of the following claims.

(35) The implementations set forth in the foregoing description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detail above, other modifications or additions are possible. In particular, further features and/or variations can be provided in addition to those set forth herein. For example, the implementations described above can be directed to various combinations and sub-combinations of the disclosed features and/or combinations and sub-combinations of several further features disclosed above.