Patent Application
20240022003
This U.S. patent application claims priority under 35 U.S.C. § 119 to: Indian Patent Application No. 202221040497, filed on Jul. 14, 2022. The entire contents of the aforementioned application are incorporated herein by reference.
The disclosure herein generally relates to meta-surface antenna system, and, more particularly, to a multi-port multi-functional meta-surface coplanar antenna system for beam steering control.
With the advent of ubiquitous connectivity services and introduction of 5G in communication, antenna engineering design challenges have undergone a paradigm shift in terms of their robustness requirements and performance diversity applications. For high frequency wireless communication under 5G scenarios coming with the millimeter wave (mm-wave) systems, the primary hurdle is of path loss at higher frequencies, which limits the radiators' application to short-range usage. Therefore, for free license 5G bands such as the FR2 band of frequencies (ranging around 28 GHz), high-gain, highly directive antennas are suggested for practical installation. Along with the maintainability of such high-gain characteristics of the concerned radiators, deflecting and controlling beam patterns play a vital role in communication engineering for attributes such as quality of service, immunity against interference, system security and economic usage of system power.
Mechanical and/or electronic solutions are available as the most conventional ones, for introducing such beam steering functionalities for the concerned radiators, but they do come with some inherent costs for their installation. For such mechanical solutions, the performance speed will be less, and bulkier structures will be required to be fitted with the radiators in order to incorporate the mechanical steering facilities. Integration of active electronic components over the radiating structures to incorporate a beam-steering performance will come at the cost of the system's net radiation gain, which is affected by the presence of the electronic components inside the region of radiation. For electronic and/or phased array systems, although high switching speed can be achieved, for the latter case the transceiver architecture becomes more complex to design and deliver for general usage.
Embodiments of the present disclosure present technological improvements as solutions to one or more of the above-mentioned technical problems recognized by the inventors in conventional systems.
In an aspect, there is provided a multi-port multi-functional meta-surface coplanar antenna system comprising: a set of coplanar antennas having a set of antenna ports positioned on a first side of a substrate and communicating with a Radio Frequency (RF) input to receive and transmit radio waves; a set of Gradient Refractive Index Meta-surface (GRIM) disposed on the first side of the substrate at a pre-defined gap and at a pre-defined offset from the set of antennas along a direction of the radio waves, wherein the GRIM is configured to tilt the radio waves in a desired direction, wherein each GRIM comprises a set of metamaterial unit cells having a rectangular stub at center of each metamaterial unit cell; a switched time-delay network (STDN) unit connected to the set of coplanar antennas and configured for phase shifting the radio waves wherein the STDN unit having one or more radio frequency cables and two or more Single Pole Double Throw (SPDT) switches; and a controller unit in communication with the STDN unit wherein the controller unit comprises: one or more data storage devices configured to store instructions; one or more communication interfaces; and one or more hardware processors operatively coupled to the one or more data storage devices via the one or more communication interfaces, wherein the one or more hardware processors are configured to be operated by the instructions to: obtain a pre-defined excitation matrix such that the pre-defined excitation matrix programs phase gradient values of radio waves using the STDN unit for beam steering control by exciting one or more antenna ports amongst the set of antenna ports, wherein the beam steering control is one or more of (i) steering of beams of the radio waves (ii) obtaining a set of beam patterns of the radio waves and (iii) controlling beam-width of the radio waves.
In another aspect, there is provided a processor implemented method comprising the steps of: positioning a set of coplanar antennas having a set of antenna ports on a first side of a substrate and cooperating with a Radio Frequency (RF) input to receive and transmit radio waves; disposing a set of Gradient Refractive Index Meta-surface (GRIM) on the first side of the substrate at a pre-defined gap and at a pre-defined offset from the set of coplanar antennas along a direction of the radio waves and configuring to tilt the radio waves in a desired direction wherein each GRIM comprises a set of metamaterial unit cells having a rectangular stub at center of each metamaterial unit cell; connecting a switched time-delay network (STDN) unit to the set of coplanar antennas and configuring for phase shifting the radio waves wherein the STDN having one or more radio frequency cables and two or more Single Pole Double Throw (SPDT) switches; and obtaining a pre-defined excitation matrix by a controller unit, that the pre-defined excitation matrix programs phase gradient values of radio waves using the STDN unit for beam steering control by exciting one or more antenna ports wherein the beam steering control is one or more of (i) steering of beams of the radio waves (ii) obtaining a set of beam patterns of the radio waves and (iii) controlling beam-width of the radio waves.
In accordance with an embodiment of the present disclosure, the pre-defined gap and the pre-defined offset is optimized based on parametric simulations.
In accordance with an embodiment of the present disclosure, each GRIM is disposed on the first side of the substrate at the pre-defined gap and the pre-defined offset from at most two coplanar antennas amongst the set of antennas.
In accordance with an embodiment of the present disclosure, the set of coplanar antennas are periodically positioned at an equidistance from each other along the length of the substrate.
In accordance with an embodiment of the present disclosure, the phase shifting of radio waves is performed with a 180-degree phase difference being introduced between the one or more antenna ports using the STDN.
In accordance with an embodiment of the present disclosure, the set of beam patterns are one or more of (i) single (ii) dual or (iii) triple.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles:
Exemplary embodiments are described with reference to the accompanying drawings. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the scope of the disclosed embodiments.
Integration of meta-structures or meta-surfaces with the primary radiators for beam-tilting applications is being seen as a viable low-cost alternative to complex mechanical or electronically controlled techniques. Metamaterials are periodically placed artificial structures having certain exquisite qualities which are not readily available in nature. However, these help us to effectively control wave propagation in a medium. Such meta-surfaces do also come with their limitations and for such cases often the meta-structures or surfaces are loaded with additional electronic components to further fine tune or control the beam-tilting performance, thus making the system complex and intricate once more like the available solutions. Also, in most cases the integrated meta-surfaces are presented as 3D complete structures with the geometrical shapes often extending beyond multiple layers of the substrate, making it even more difficult for fabrication.
The disclosed multi-port multi-functional meta-surface coplanar antenna system is built utilizing the design concept of two antennas loaded with a Gradient Refractive Index Meta-surface (GRIM) surface at the front end as a building block for an extended composite system. The antennas and the GRIM surface are placed on the same side of a substrate. They are periodically placed side by side to increase the number of ports and further enhance the functional diversity of the combined structure. The disclosed design has a zero presence of lumped electronic components which is conceived on a single side of the substrate with beam steering control to be obtained by simple switching of port excitations. To enhance the diversity of the said control, phase gradients are introduced in some cases between the selected ports. However, for all such cases a 180-degree phase difference has only been introduced to conceive beam diversity characteristics.
In the context of the subject disclosure, definitions of certain expressions and their usage are as explained herein below.
Referring now to the drawings, and more particularly to
The multi-port multi-functional meta-surface coplanar antenna system 100 further comprises a set of Gradient Refractive Index Meta-surface (GRIM) (104[1] . . . [M]) disposed on the first side of the substrate at a pre-defined gap and at a pre-defined offset from the set of antennas along a direction of the radio wave. The GRIM is configured to tilt the radio waves in a desired direction, wherein each GRIM comprises a set of metamaterial unit cells having a rectangular stub at center of each metamaterial unit cell. Each GRIM is disposed on the first side of the substrate at the pre-defined gap and the pre-defined offset from at most two coplanar antennas amongst the set of antennas. The pre-defined gap and the pre-defined offset is optimized based on parametric simulations.
The antenna and the meta-surface are printed on RT Duroid 5880 substrate having a dielectric constant of 2.2 and a thickness of 0.7 mm. Different multi-port configurations are shown in
The multi-port multi-functional meta-surface coplanar antenna system is explained further henceforth with respect to the 2-port, 4-port and 8-port integrated coplanar antenna and GRIM structures. However, the concept of utilizing two antennas loaded with a GRIM surface at the front and the entire combination being on the same side of the substrate, that can be periodically placed side by side has an advantage to increase the number of ports further greater than 8 and enhance the functional diversity of the structure.
The multi-port multi-functional meta-surface coplanar antenna system 100 further comprises a switched time-delay network (STDN) unit 106 connected to the set of coplanar antennas and configured for phase shifting the radio waves. The STDN comprises one or more radio frequency cables and two or more Single Pole Double Throw (SPDT) switches. The phase shifting of radio waves is performed with a 180-degree phase difference being introduced between the one or more antenna ports using the STDN.
The multi-port multi-functional meta-surface coplanar antenna system 100 further comprises a controller unit 110 in communication with the STDN unit 106 wherein the controller unit comprises one or more data storage devices or memory 110A configured to store instructions; one or more communication interfaces 1106; and one or more hardware processors 110C operatively coupled to the one or more data storage devices via the one or more communication interfaces 1106, wherein the one or more hardware processors 110C are configured by the instructions to perform beam steering control.
The one or more hardware processors 110C can be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, graphics controllers, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor(s) are configured to fetch and execute computer-readable instructions stored in the memory. In the context of the present disclosure, the expressions ‘processors’ and ‘hardware processors’ may be used interchangeably. In an embodiment, the one or more hardware processors 110C can be implemented in a variety of computing systems, such as laptop computers, notebooks, hand-held devices, workstations, mainframe computers, servers, a network cloud and the like.
In an embodiment, the communication interface(s) or input/output (I/O) interface(s) 1106 may include a variety of software and hardware interfaces, for example, a web interface, a graphical user interface, and the like and can facilitate multiple communications within a wide variety of networks N/W and protocol types, including wired networks, for example, LAN, cable, etc., and wireless networks, such as WLAN, cellular, or satellite. In an embodiment, the I/O interface(s) can include one or more ports for connecting a number of devices to one another or to another server.
The one or more data storage devices or memory 110A may include any computer-readable medium known in the art including, for example, volatile memory, such as static random-access memory (SRAM) and dynamic random-access memory (DRAM), and/or non-volatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes.
In an embodiment, the one or more hardware processors 110C are configured to obtain a pre-defined excitation matrix such that the pre-defined excitation matrix programs phase gradient values of radio waves using the STDN unit 106 for beam steering control by exciting one or more antenna ports amongst the set of antenna ports. The beam steering control is one or more of (i) steering of beams of the radio waves (ii) obtaining a set of beam patterns of the radio waves and (iii) controlling beam-width of the radio waves. The set of beam patterns are one or more of (i) single (ii) dual or (iii) triple. The achieved beam controlling mechanism is not merely on beam tilting but also over the number of beams obtained, the beam-width of individual radiation patterns and their tilting angles.
Since commercial phase shifters are essentially narrowband in nature, the STDNs are utilized as a combination of two RF cables of different length, and two Single Pole Double Throw (SPDT) switches. The difference between the lengths of the cables is λ/2, λ corresponding to the central frequency of the operating band (between 26 GHz to 29 GHz).
CPW-fed Yagi-Uda antenna configurations, with GRIM surfaces ahead of them facilitate beam-tilting operation. This is performed by switching the signal excitations at the ports or by incorporating phase gradients between the selective port combinations. A wide range of beam patterns are generated and controlled in a real-time and granular manner. The concept of excitation matrix helps to choose the port combinations and the phase gradient introduced between them (if required) in a mathematical manner. For example, for an 8-port integrated coplanar antenna and GRIM shown in
In an embodiment, the excitation matrix for the 2-port integrated coplanar antenna and GRIM is defined as,
where aii implies excitation of the ith port only, the phase gradient is undefined. The element ai,j describes the excitation of the ith port and the jth port respectively containing the value of the phase gradient β to be introduced between them. Table 4 shows the non-trivial radiation patterns related to the excitation matrix.
Similarly, in an embodiment, the excitation matrix for the 4-port integrated coplanar antenna and GRIM is defined as,
(2)
where, aii implies excitation of the ith port only, concept of phase gradient is undefined. The element ai,j describes the excitation of the ith port and the jth port respectively containing the value of the phase gradient β to be introduced between them. Table 5 shows the non-trivial radiation patterns related to the excitation matrix.
In a similar manner, the excitation matrix for the 8-port integrated coplanar antenna and GRIM is defined.
In accordance with an embodiment of the present disclosure, the method 700 comprises, positioning, at step 702, a set of coplanar antennas (102[1 . . . N]) having a set of antenna ports on a first side of a substrate and cooperating with a Radio Frequency (RF) unit 108 to receive and transmit radio waves. A set of Gradient Refractive Index Meta-surface (GRIM) (104[1] . . . [M]) is disposed at step 704 on the first side of the substrate at a pre-defined gap and at a pre-defined offset from the set of coplanar antennas along a direction of the radio waves and configuring to tilt the radio waves in a desired direction wherein each GRIM comprises a set of metamaterial unit cells having a rectangular stub at center of each metamaterial unit cell. At step 706, a switched time-delay network (STDN) unit 106 is connected to the set of coplanar antennas and configuring for phase shifting the radio waves wherein the STDN unit having one or more radio frequency cables and two or more Single Pole Double Throw (SPDT) switches. Further at step 708, a pre-defined excitation matrix is obtained by a controller unit, such that the pre-defined excitation matrix programs phase gradient values of radio waves using the STDN for beam steering control by exciting one or more antenna ports wherein the beam steering control is one or more of (i) steering of beams of the radio waves (ii) obtaining a set of beam patterns of the radio waves and (iii) controlling beam-width of the radio waves.
EXPERIMENTAL EVALUATION: Dynamic beam tilting performance with respect to port excitation(s) for 2-port integrated coplanar antenna and GRIM is provided in Table 6 below.
Similarly, dynamic beam tilting performance with respect to port excitation(s) for 4-port integrated coplanar antenna and GRIM and 8-port integrated coplanar antenna and GRIM is given in Table 7 and Table 8 respectively below.
When all the eight ports of the 8-port integrated coplanar antenna and GRIM are excited but with a 180-degree phase difference between the ports 1, 2, 3, 4 and 5, 6, 7, 8 respectively, a highly directive beam with a gain value of 11.5 dB and with a sharp 3 dB beamwidth of 10 degree was obtained. A comparison amongst the operational attributes achieved through the 8-port integrated coplanar antenna and GRIM is shown in Table 9 below.
Where * is a particular case where performance has been observed by exciting all the eight ports of the structure but with a 180-degree phase difference between the ports 1, 2, 3, 4 and 5, 6, 7, 8 respectively.
The input reflection characteristics for the 2-port, 4-port and 8-port coplanar antenna and GRIM are shown in
The written description describes the subject matter herein to enable any person skilled in the art to make and use the embodiments. The scope of the subject matter embodiments is defined by the claims and may include other modifications that occur to those skilled in the art. Such other modifications are intended to be within the scope of the claims if they have similar elements that do not differ from the literal language of the claims or if they include equivalent elements with insubstantial differences from the literal language of the claims.
It is to be understood that the scope of the protection is extended to such a program and in addition to a computer-readable means having a message therein; such computer-readable storage means contain program-code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The hardware device can be any kind of device which can be programmed including e.g., any kind of computer like a server or a personal computer, or the like, or any combination thereof. The device may also include means which could be e.g., hardware means like e.g., an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination of hardware and software means, e.g., an ASIC and an FPGA, or at least one microprocessor and at least one memory with software processing components located therein. Thus, the means can include both hardware means and software means. The method embodiments described herein could be implemented in hardware and software. The device may also include software means. Alternatively, the embodiments may be implemented on different hardware devices, e.g., using a plurality of CPUs.
The embodiments herein can comprise hardware and software elements. The embodiments that are implemented in software include but are not limited to, firmware, resident software, microcode, etc. The functions performed by various components described herein may be implemented in other components or combinations of other components. For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can comprise, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The illustrated steps are set out to explain the exemplary embodiments shown, and it should be anticipated that ongoing technological development will change the manner in which particular functions are performed. These examples are presented herein for purposes of illustration, and not limitation. Further, the boundaries of the functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed. Alternatives (including equivalents, extensions, variations, deviations, etc., of those described herein) will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Such alternatives fall within the scope of the disclosed embodiments. Also, the words “comprising,” “having,” “containing,” and “including,” and other similar forms are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
Furthermore, one or more computer-readable storage media may be utilized in implementing embodiments consistent with the present disclosure. A computer-readable storage medium refers to any type of physical memory on which information or data readable by a processor may be stored. Thus, a computer-readable storage medium may store instructions for execution by one or more processors, including instructions for causing the processor(s) to perform steps or stages consistent with the embodiments described herein. The term “computer-readable medium” should be understood to include tangible items and exclude carrier waves and transient signals, i.e., be non-transitory. Examples include random access memory (RAM), read-only memory (ROM), volatile memory, nonvolatile memory, hard drives, CD ROMs, DVDs, flash drives, disks, and any other known physical storage media.
It is intended that the disclosure and examples be considered as exemplary only, with a true scope of disclosed embodiments being indicated by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202221040497 | Jul 2022 | IN | national |
