Many transmission systems, such as wireless systems, operate in an ever-expanding sphere of connectivity. Mobile data traffic demands continue to grow every year, challenging wireless systems to provide greater speed, connect more devices, have lower latency, and transmit more and more data at once. Users now expect instant wireless connectivity regardless of the environment and circumstances, whether it is in an office building, a public space, an open preserve, or a vehicle. Wireless connectivity is available in a wide range of devices with efficiency requirements. In these devices and applications, there is a desire to reduce the power consumption, spatial footprint and computing power for operation of the wireless antenna and transmission structure.
The present application may be more fully appreciated in connection with the following detailed description taken in conjunction with the accompanying drawings, which are not drawn to scale and in which like reference characters refer to like parts throughout, and wherein:
Methods and apparatuses for a Metastructure Switched Antenna (“MSA”) in a wireless device are disclosed. A MSA is positioned within a wireless device so as to improve the coverage available for the wireless device. A metastructure, as generally described herein, is an engineered structure with electromagnetic properties not found in nature. In various examples, a MSA has an array of non- or semi-periodic structures that are spatially distributed to provide a specific phase and frequency distribution and capable of controlling and manipulating EM radiation at a desired direction. The MSA array is fed and controlled so as to switch its transmission beams to one of multiple positions.
In various examples, a wireless device may include multiple MSAs positioned at the perimeter of the device, wherein the device determines which antenna to use in a given situation. This considers where the device is located, where the user is holding the device, the communication type used in the device, the environmental noise, and so forth. The device selects an MSA for transmission and then determines the best transmission angle/phase shift for its transmission beam. In various examples, this may involve cycling through multiple phase shifts to determine the best beam.
It is appreciated that, in the following description, numerous specific details are set forth to provide a thorough understanding of the examples. However, it is appreciated that the examples may be practiced without limitation to these specific details. In other instances, well-known methods and structures may not be described in detail to avoid unnecessarily obscuring the description of the examples. Also, the examples may be used in combination with each other.
Wireless device 100 also includes MSA controller 110 to determine phase shifts for transmission beams generated from MSA 102. MSA controller 110 may also serve to select an MSA to use in a given situation when the wireless device has multiple MSAs. This considers where the device is located, where the user is holding the device, the communication type used in the device, the environmental noise, and so forth.
In operation, one or more MSAs may transmit multiple RF beams, which are switchable to multiple positions as illustrated with wireless device 300 having MSA E 302, MSA F 304, MSA G 306 and MSA H 308 positioned at its corners. MSA controller 310 selects which MSA or MSAs out of MSAs 302-308 will be used for transmission at any given time. Once the selection is made, MSA controller 310 selects the desired directions for the transmission beams. Switching between directions is implemented by the phase shifters in the RFIC layer 106 shown in
Attention is now directed to
The MSA 414 radiates the signal through a structure consisting of three main layers: (1) feed network layer 416; (3) RFIC layer 418; and (4) MSA array 422. In some examples, a transmission array structure 420 implemented with transmission lines with a plurality of slots and discontinuities for radiating the input signal to the MSA array 422 may be implemented. In other examples, the MSA array 422 itself may be considered to be a transmission array structure, where the input signal is transmitted from the feed network layer 416 to the RFIC layer 418 before it reaches the cells in MSA array 422. A connector (not shown) may be used to couple the transmission signal from the transmission signal controller 404 for transmission to the feed network layer 416.
In various examples, the feed network layer 416 is a corporate feed structure having a plurality of transmission lines for transmitting the signal to the RFIC layer 418 and MSA array 422. The RFIC layer 418 is implemented as a MMIC and includes phase shifters (e.g., a varactor, a set of varactors, a phase shift network, or a vector modulator architecture) to achieve any desired phase shift from 0° to 360°. The RFIC layer 418 may also include transitions from the feed network layer 416 to the RFIC layer 418 and from the RFIC layer 418 to the MSA array 422 (or to the transmission array structure 420, when present). Note that as illustrated, there is one MSA 414 in system 400. However, as shown in
In operation, the antenna controller 408 receives information from other modules in system 400 (e.g., an MSA controller) indicating a next RF beam, wherein an RF beam may be specified by parameters such as beam width, transmit angle, transmit direction and so forth. The antenna controller 408 directs the RFIC layer 418 to generate RF beams with the desired beam parameters. Transceiver 406 prepares a signal for transmission, wherein the signal is defined by modulation and frequency. The signal is received by the MSA 414 and the desired phase shifts are adjusted at the direction of the antenna controller 408 in communication with the MSA controller in the wireless device. The signal propagates through the feed network layer 416 to the MSA array 422 of metastructure cells (e.g., cell 424) for transmission through the air. Each cell or subarray of cells may be coupled to a set of phase shifters in the RFIC layer 418 for controlling their phase.
In some examples, the cells in MSA array 422 are metamaterial (“MTM”) cells. An MTM cell is an artificially structured element used to control and manipulate physical phenomena, such as the electromagnetic properties of a signal including its amplitude, phase, and wavelength. Metamaterial cells 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.
A metamaterial is a geometric design of a material, such as a conductor, wherein the shape creates a unique behavior for the device. An MTM cell 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 examples, the number of dimensional degrees of freedom determines the characteristics of a cell, wherein a cell having a number of edges and discontinuities may model a specific-type of electrical circuit and behave in a given manner. In this way, an MTM cell radiates according to its configuration. Changes to the reactance parameters of the MTM cell result in changes to its radiation pattern. Where the radiation pattern is changed to achieve a phase change or phase shift, the resultant structure is a powerful antenna, as small changes to the MTM cell can result in large changes to the beamform. The MSA array of cells 422 can be configured so as to form a beamform or multiple beamforms involving subarrays of the cells or the entire array.
The MTM cells 422 may include a variety of conductive structures and patterns, such that a received transmission signal is radiated therefrom. In some examples, each MTM cell may have unique properties. These properties may include a negative permittivity and permeability resulting in a negative refractive index; these structures are commonly referred to as left-handed materials (“LHM”). The use of LHM enables behavior not achieved in classical structures and materials, including interesting effects that may be observed in the propagation of electromagnetic waves, or transmission signals. Metamaterials can be used for several interesting devices in microwave and terahertz engineering such as antennas, sensors, matching networks, and reflectors, such as in telecommunications, automotive and vehicular, robotic, biomedical, satellite and other applications. For antennas, metamaterials may be built at scales much smaller than the wavelengths of transmission signals radiated by the metamaterial. Metamaterial properties come from the engineered and designed structures rather than from the base material forming the structures. Precise shape, dimensions, geometry, size, orientation, arrangement and so forth result in the smart properties capable of manipulating electromagnetic waves by blocking, absorbing, enhancing, or bending waves.
In some examples, in lieu of the RFIC layer 418, each MTM cell may include a reactance control mechanism (e.g., a varactor) to change the capacitance and/or other parameters of the MTM cell. By changing a parameter of the MTM cell, the resonant frequency is changed, and therefore, the array 422 may be configured and controlled to direct beams to multiple positions. An example of such a cell is illustrated in
Attention is now directed to
In the illustrated example, there are 32 coupling paths, corresponding to 32 rows of MSA array cells. Alternate examples may use traditional or other waveguide structures or transmission signal guide structures. Coupling matrix 600 has 5 levels, wherein in each level the transmission paths are doubled: level 4 has 2 paths, level 3 has 4 paths, level 2 has 8 paths, level 1 has 16 paths, and level 0 has 32 paths. In various examples, the RFIC layer 418 of FIG. 4 may be embedded in each transmission line, e.g., RFIC 606, to change the reactance and thus the phase of a transmission line such as transmission line 604.
Referring now to
It is appreciated that the previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other examples without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
This application claims priority to U.S. Provisional Application No. 62/618,045, filed on Jan. 16, 2018, and incorporated herein by reference.
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Number | Date | Country | |
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20190221929 A1 | Jul 2019 | US |
Number | Date | Country | |
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62618045 | Jan 2018 | US |