Single-layer wide-angle impedance matching (WAIM)

Abstract

This application describes a single-layer wide-angle impedance matching (WAIM) and a method of using it. In one embodiment, the antenna includes: an aperture having a plurality of antenna elements operable to radiate radio frequency (RF) energy; and a single-layer wide-angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 027,190, filed May 19, 2020, and U.S. Non-Provisional Patent Application No. 17 / 322,602, filed May 17, 2021, which are incorporated herein by reference in their entirety. Technical Field

[0003] The embodiments of this application relate to the technical field of satellite communications, and more specifically, the embodiments of this application relate to a wide-angle impedance matching (WAIM) structure used in a satellite antenna. Background Technology

[0004] Antenna gain is one of the most critical parameters in satellite communication systems, as it determines network coverage and speed. More specifically, higher gain means better coverage and higher speed, which is crucial in a competitive satellite market. Antenna gain in the receive (Rx) band is often critical because the received power at the antenna is very low on the satellite side. This becomes even more critical at the scanning angles of planar electronically scanned antennas due to increased attenuation and lower antenna gain compared to the broadside case, making higher gain a vital parameter for shutting down the connection between the antenna and the satellite. Gain is also important in the transmit (Tx) band, as lower gain means more power needs to be supplied to the antenna to achieve the desired signal strength, resulting in higher costs, higher temperatures, higher thermal noise, and so on.

[0005] One type of antenna used in satellite communications is the radial aperture slot array antenna. Recently, there have been many improvements to the performance of this type of antenna. One of the parameters limiting the radiation efficiency of these antennas is the impedance mismatch between the antenna aperture and free space. If this mismatch is high at the scan angle, this additional loss of radiation efficiency leads to poorer scan loss. The WAIM structure mitigates this problem by providing appropriate impedance matching.

[0006] The use of dipole loads in radial aperture slot array antennas has already been mentioned. This type of load can improve radiation efficiency by providing impedance matching. It can also be used to offset frequency response. The slot dipole concept has also been applied to radial aperture slot array antennas to improve antenna directivity, including improving the overall return loss performance of the antenna, especially for antennas operating in a wide area. Summary of the Invention

[0007] This application describes a single-layer wide-angle impedance matching (WAIM) and a method of using it. In one embodiment, the antenna includes: an aperture having a plurality of antenna elements operable to radiate radio-frequency (RF) energy; and a single-layer wide-angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space. Attached Figure Description

[0008] The described embodiments and their advantages can be best understood by referring to the following description taken in conjunction with the accompanying drawings. These drawings are in no way intended to limit any changes in form and detail that may be made to the embodiments by those skilled in the art without departing from the spirit and scope thereof.

[0009] Figures 1A-1B An embodiment of a single-layer wide-angle impedance matching (WAIM) structure is shown.

[0010] Figures 2A-2C The optional methods for mounting the WAIM structure in various alignments on the aperture are shown.

[0011] Figures 2D-2F This demonstrates the flexibility of achieving the same performance using various feature sizes.

[0012] Figure 3 An embodiment of a single-layer WAIM structure is shown, demonstrating improvements in gain and scan loss.

[0013] Figure 4 This is a flowchart of an example of the process for designing a single-layer WAIM structure.

[0014] Figures 5A-5C An optional capacitive surface for the WAIM structure is shown.

[0015] Figure 6 An aperture with an array of one or more antenna elements is shown, arranged in a concentric loop around the input feed of a cylindrical feed antenna.

[0016] Figure 7 A perspective view of a row of antenna elements including a ground plane and a reconfigurable resonator layer is shown.

[0017] Figure 8A An embodiment of a tunable resonator / slot is shown.

[0018] Figure 8B A cross-sectional view of one embodiment of the physical antenna aperture is shown.

[0019] Figure 9A A portion of the first iris plate layer is shown, with the location corresponding to the slit.

[0020] Figure 9B A portion of the second iris plate layer containing the slit is shown.

[0021] Figure 9C A patch is shown on a portion of the second iris plate layer.

[0022] Figure 9D A top view of a portion of the slot array is shown.

[0023] Figure 10 A side view of one embodiment of a cylindrical feed antenna structure is shown.

[0024] Figure 11 Another embodiment of an antenna system with an outgoing wave is shown.

[0025] Figure 12 An embodiment of the arrangement of the matrix drive circuit relative to the antenna elements is shown.

[0026] Figure 13 An embodiment of a TFT package is shown.

[0027] Figure 14 This is a block diagram of another embodiment of a communication system having simultaneous transmission and reception paths. Detailed Implementation

[0028] In the following description, numerous details are set forth to provide a more thorough explanation of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the invention.

[0029] A novel wide-angle impedance matching (WAIM) structure for aperture antennas and its usage are described. The WAIM structure improves the radiation efficiency of the aperture antenna by providing appropriate impedance matching between the antenna aperture and free space. The improvement in scan loss is also due to providing better matching at the scan angle. In one embodiment, the impedance matching is a function of frequency, scan angle, and polarization of the propagating wave, as the antenna aperture impedance and free space impedance vary with these parameters.

[0030] In one embodiment, the WAIM design characteristics depend on the type of antenna aperture. In one embodiment, the antenna aperture is part of a leaky antenna and has a subwavelength radiating slot. In another embodiment, the antenna aperture is a metasurface of multiple antenna elements that radiate radio frequency (RF) energy. Such antenna elements can be surface-scattering metamaterial antenna elements. Examples of liquid crystal (LC)-based surface-scattering metamaterial antenna elements are described in more detail below. However, the antenna element is not limited to LC-based antenna elements. For example, in another embodiment, the antenna element is a varactor diode-based metamaterial antenna element, where the varactor diode is used to tune the radiating slot antenna element. The equivalent circuit model of a radiating surface with a subwavelength radiating slot is a parallel resonator with a small resistive portion. Therefore, the impedance curve on the Smith chart is a circle towards the short segment, representing the frequency. In one embodiment, an L-type matching network including parallel capacitors and series inductors provides appropriate impedance matching for this configuration.

[0031] In one embodiment, the WAIM structure is a single-layer structure of a two-dimensional periodic array of subwavelength capacitive films. In one embodiment, the structure is printed on a dielectric substrate and separated from the aperture by dielectric spacers (e.g., foam, etc.). A key advantage of the single-layer WAIM structure described herein over the prior art is that it can be easily prototyped and assembled at very low cost.

[0032] Embodiments of the WAIM structure offer other key advantages, including lower manufacturing costs and a simpler assembly process. In one embodiment, because the design comprises a single-layer structure, this results in lower manufacturing costs compared to alternatives, eliminates stringent tolerances on several physical dimensions, and reduces the complexity of the assembly process. There is also flexibility in selecting the dimensions of its impedance matching components, allowing them to be chosen well within the tolerances of manufacturing technology.

[0033] Furthermore, and importantly, the embodiments described herein do not require any positional / rotational alignment between their impedance matching elements and antenna aperture elements. This results in lower costs because it eliminates positional tolerances and also simplifies the assembly process. Moreover, since it does not rely on the alignment between its impedance matching elements and antenna elements, the design provides highly repeatable RF performance.

[0034] Furthermore, the same RF performance can be achieved with various pixel sizes. This enables the use of cost-effective manufacturing techniques that do not require strict tolerances for feature dimensions. For example, in one embodiment, the WAIM structure includes a substrate with components screen-printed on it. In this case, the use of screen printing is a very low-cost alternative to printed circuit board (PCB) technology.

[0035] Note that a single-layer WAIM structure can be used with multiple different antenna apertures. Examples of aperture antennas are described in more detail below. Note that the disclosed WAIM structure can be used with antenna apertures other than those described below.

[0036] In one embodiment, the single-layer WAIM structure includes an L-shaped impedance network implemented by capacitive surfaces separated from the aperture by dielectric spacers. In some embodiments, the capacitive impedance surfaces utilize a 2D array of subwavelength elements. Subwavelength elements can be one or more of many different types. Some examples are subwavelength diaphragms, dipoles, split ring resonators (SRRs), etc.

[0037] Figure 1A An embodiment of a WAIM structure is illustrated. In this embodiment, a single-layer WAIM structure 100 is situated above an antenna aperture comprising a metasurface with a plurality of antenna elements 101. In one embodiment, the antenna elements 101 include slot resonators (e.g., surface-scattering metamaterial antenna elements, RF radiating antenna elements, etc.). The WAIM structure 100 includes a two-dimensional (2D) array of subwavelength square diaphragms 102. In one embodiment, the diaphragms 102 are subwavelength diaphragms to ensure that this structure, as a metasurface, acts as a capacitor layer. In one embodiment, the diaphragms 102 are capacitor diaphragms. In one embodiment, the diaphragms 102 are printed on a substrate. In one embodiment, the WAIM structure 100 is separated from the aperture by dielectric spacers or foam.

[0038] It can be used Figure 1B The equivalent circuit model shown is used to model the WAIM structure. (Refer to...) Figure 1B In the model, the capacitor diaphragm 102 is modeled by parallel capacitors, and the aperture and the spacer between the diaphragm 102 are modeled by a short portion of the transmission line.

[0039] There are several reasons for needing this type of single-layer WAIM structure. First, there is flexibility in choosing physical parameters to achieve the same performance. The inherent capacitance of the surface is a function of the physical dimensions of the diaphragm and the surrounding medium. Equation (1) shows a first-order approximation for calculating the capacitance value of the normally incident wave:

[0040]

[0041] For more information on this formula, see Luukkonen et al., “Simple and accurate analytical model of planargrids and high-impedance surfaces comprising metal strips or patches,” IEEE Journal of Antennas and Propagation, Vol. 56, No. 6, pp. 1623-1632, June 2008. In this equation, s is the gap spacing between adjacent diaphragms, and D is the periodicity. This equation shows that the same capacitance can be achieved through multiple sets of gap spacings and periodicities, as long as they are much smaller than the wavelength. This is important because it allows for the selection of parameters based on manufacturing tolerances.

[0042] Second, the impedance of this surface is independent of the antenna's scanning plane (i.e., phi). This is due to the 90-degree rotational symmetry of the structure and the fact that the intrinsic capacitance is formed by the electric field between the parallel edges of adjacent diaphragms. This characteristic is desirable in some antennas with rotationally symmetric apertures.

[0043] Third, in one embodiment, the surface impedance of the WAIM structure is a function of the scan angle and the polarization of the propagating wave. If properly designed, the WAIM structure provides impedance matching between the antenna aperture and free-space impedance for the two orthogonal polarizations (i.e., TE and TM) at various scan angles.

[0044] Fourth, in one embodiment, the WAIM structure is very broadband. Therefore, it can potentially provide impedance matching for apertures with broadband radiating elements or multiple radiating elements with different frequencies. This feature is important in some antennas where the aperture is filled with multiple radiating elements.

[0045] One embodiment of the design process for a WAIM structure is based on Figure 1B The equivalent circuit model is shown. In this model, all parameters are functions of the wave polarization and the scan angle. Equations (2) and (3) show how the transmission line impedance varies as a function of the scan angle and polarization. (This refers to the free space impedance at the wide face). These equations are also valid for free space.

[0046]

[0047] Equations (4) and (5) show how the capacitance of orthogonal polarization changes with the scanning angle. It is the capacitor at the wide end.

[0048]

[0049] Assuming the properties of the dielectric substrate are predefined, the key parameters in the design are the foam thickness and capacitance. These values ​​are defined in a way that allows the design to provide the desired impedance matching across all scanning angles and to support both transverse electric (TE) and transverse magnetic (TM) polarization. This is a general solution because any other polarization can be decomposed into these two orthogonal polarizations.

[0050] Next, the selected parameters in the equivalent circuit model are mapped to physical parameters. Note that... It is only the thickness of the dielectric spacer (e.g., foam, dielectric laminate, polyester, polycarbonate, glass, honeycomb spacer, etc.). The capacitance is mapped to the diaphragm size and periodicity using equation (1).

[0051] Note that in one embodiment, an adhesive is used to attach the monolayer WAIM structure to the dielectric spacer. In one embodiment, an adhesive is used to attach the dielectric spacer to the antenna aperture. In one embodiment, the dielectric layer has a height of 60 mils (thousandths of an inch). Alternatively, the dielectric layer may be of other dimensions (e.g., 1.5 mm). In an alternative embodiment, the monolayer WAIM structure, dielectric layer, and antenna layer are not attached together but are in contact with each other. In this case, other antenna components (e.g., a radome) hold these components in place.

[0052] In one embodiment, a single layer of WAIM is fabricated on top of the dielectric layer. In another embodiment, the single layer of WAIM is screen-printed onto the dielectric layer. This reduces two layers to one.

[0053] The embodiments of the WAIM structure disclosed herein have many advantages. For example, as mentioned above, the proposed design does not require any positional / rotational alignment. Figures 2A-2C Various alignment methods for mounting the WAIM at the aperture are shown. In this case, the WAIM structure in each of these embodiments comprises a square capacitor diaphragm of the same size.

[0054] Reference Figure 2A The single-layer WAIM structure 201 includes a 2D array of capacitor diaphragms 203 located on an aperture having antenna elements 202. The diaphragms 203 in the 2D array are square and patterned on an array aligned in both horizontal and vertical directions. (See reference...) Figure 2BThe single-layer WAIM structure 211 includes a 2D array of capacitor diaphragms 213 on an aperture having antenna elements 212. Figure 2B 2D arrays and Figure 2A It is the same as the one in the original text, except that it has been rotated by 22.5°. (See reference.) Figure 2C The single-layer WAIM structure 221 includes a 2D array of capacitor diaphragms 223 on an aperture having antenna elements 222. Figure 2C 2D arrays and Figure 2A It is the same as in the original, except that it has been rotated 45° (relative to the original). Figure 2B The 2D array in the image was rotated by 22.5°.

[0055] Similarly, as discussed, the same performance can be achieved using a 2D array of capacitor diaphragms with different diaphragm widths and periodicities. Figures 2D-2F Examples of single-layer WAIM structures achieving the same performance using various feature sizes are shown. (Refer to...) Figure 2D The single-layer WAIM structure 231 includes a 2D array of capacitor films 233 situated on an aperture having antenna elements 232. The films 233 in the 2D array are square and patterned on an array aligned in both horizontal and vertical directions. (See reference...) Figure 2E The single-layer WAIM structure 241 includes a 2D array of capacitor diaphragms 243 on an aperture having antenna elements 242. However, Figure 2E The size of the diaphragm in the 2D array is smaller than Figure 2A The membrane. (Refer to...) Figure 2F The single-layer WAIM structure 251 includes a 2D array of capacitor diaphragms 253 on an aperture having antenna elements 252. In this case, Figure 2F The size of the diaphragm in the 2D array is smaller than Figure 2E The membrane (therefore smaller) Figure 2D (The membrane in the middle).

[0056] In one embodiment, the capacitor diaphragm is a metal (e.g., copper, silver, etc.) on a substrate (e.g., a printed circuit board (PCB) (e.g., FR4, etc.), polycarbonate, glass, etc.). In one embodiment, the substrate comprises polyester when the patch is screen-printed. The diaphragm can have various thicknesses. In one embodiment, the thickness of the diaphragm is 17 μm, 35 μm, etc. In one embodiment, each square diaphragm is 200 mils by 200 mils. However, as mentioned above, other sizes (e.g., 250 mils × 250 mils, etc.) can be used.

[0057] The WAIM embodiment disclosed herein improves radiation efficiency by providing appropriate impedance matching between the antenna aperture and free space. This improvement in radiation efficiency leads to an improvement in antenna gain. Figure 3Gain measurements are shown at 60 degrees and wide facet in the TE plane (H-pol) on an example antenna aperture. (Refer to...) Figure 3 The test results are shown at the three sub-bands. The dashed line shows the measurement without the WAIM structure, and the solid line shows the gain with the WAIM structure installed. Significant improvements were observed when the WAIM structure was installed in both the wide band and the scan band. Since the gain improvement was more significant than in the wide band, the scan loss was also greatly improved.

[0058] Figure 4 This is a flowchart illustrating an example of the process for designing a single-layer WAIM structure. (Refer to...) Figure 4 The process begins by determining the antenna aperture impedance for various scan angles and polarizations (processing block 401). In one embodiment, this is performed using analytical and full-wave Floquet model simulations, and is performed using inputs that include all antenna elements (e.g., all receiving and transmitting radiating elements on the aperture), scan angle, and polarization (410).

[0059] Once the antenna aperture impedance for various scanning angles and polarizations has been determined, the processing logic inputs the parameter values ​​into the WAIM equivalent circuit model (processing block 402). In one embodiment, the model input includes the results of performing an analytical ABCD matrix calculation (411). The outputs are the electrical parameters of the circuit model. In one embodiment, these outputs include the transmission line lengths and capacitance values ​​in the equivalent circuit model.

[0060] The processing logic then maps the electrical parameters to the physical parameters (processing block 403). In one embodiment, this is done in a manner known in the art using a first-order approximation formula or a full-wave simulation (412). Once the mapping is complete, the processing logic performs a full-wave aperture simulation on the design (processing block 404).

[0061] Many alternative embodiments exist. For example, the WAIM structure disclosed herein can be used with any antenna aperture having a subwavelength radiating element array. Furthermore, the same element geometry can be extended to WAIM structures with multiple layers as impedance matching networks.

[0062] Furthermore, as mentioned above, capacitive surfaces can be realized using 2D arrays of various subwavelength elements. Figures 5A-5C An example of a WAIM structure with optional configurations is shown. (See reference...) Figure 5A The single-layer WAIM structure 500 includes a 2D pattern of a square capacitor diaphragm 501. (See reference...) Figure 5B The single-layer WAIM structure 510 includes a 2D pattern of a hexagonal capacitor film 511. (See reference...) Figure 5CThe single-layer WAIM structure 520 includes a 2D pattern of an open-ring resonator (SSR) 521. Other shaped capacitor elements can also be used.

[0063] Example of an antenna system

[0064] In one embodiment, the flat panel antenna is part of a metamaterial antenna system. Embodiments of a metamaterial antenna system for a communications satellite earth station are described. In one embodiment, the antenna system is a component or subsystem of a satellite earth station (ES) operating on a mobile platform (e.g., aviation, maritime, terrestrial, etc.) using Ka-band or Ku-band frequencies for civilian commercial satellite communications. It should be noted that embodiments of the antenna system can also be used for earth stations not on mobile platforms (e.g., fixed or mobile earth stations).

[0065] In one embodiment, the antenna system uses surface scattering metamaterials technology to form and manipulate transmit and receive beams via individual antennas.

[0066] In one embodiment, the antenna system consists of three functional subsystems: (1) a waveguide structure consisting of a cylindrical wave feed architecture; (2) an array of wave scattering metamaterial units as part of the antenna elements; and (3) a control structure for commanding the formation of an adjustable radiation field (beam) from the metamaterial scattering elements using the holographic principle.

[0067] Antenna elements

[0068] Figure 6 A schematic diagram of one embodiment of a cylindrical feed holographic radial aperture antenna is shown. (Refer to...) Figure 6 The antenna aperture has one or more arrays 601 of antenna elements 603 arranged in a concentric loop surrounding an input feed 602 of a cylindrical feed antenna. In one embodiment, the antenna element 603 is a radio frequency (RF) resonator that radiates RF energy. In one embodiment, the antenna element 603 includes Rx and Tx irises that are staggered and distributed across the entire surface of the antenna aperture. Examples of such an antenna element are described in more detail below. It should be noted that the RF resonator described herein can be used in antennas that do not include a cylindrical feed.

[0069] In one embodiment, the antenna includes a coaxial feed for providing a cylindrical wave feed via an input feed 602. In one embodiment, the cylindrical wave feed architecture feeds excitation to the antenna from a center point, and the excitation propagates outward from the feed point in a cylindrical manner. That is, the cylindrical feed antenna generates an outwardly traveling concentric feed wave. Nevertheless, the shape of the cylindrical feed antenna surrounding the cylindrical feed can be circular, square, or arbitrary. In another embodiment, the cylindrical feed antenna generates an inwardly traveling feed wave. In this case, the feed wave most naturally originates from a circular structure.

[0070] In one embodiment, antenna element 603 includes an iris, and Figure 6 An aperture antenna is used to generate a main beam shaped by excitation from a cylindrical feed wave to radiate the iris through a tunable liquid crystal (LC) material. In one embodiment, the antenna can be excited to radiate a horizontally or vertically polarized electric field at a desired scan angle.

[0071] In one embodiment, the antenna element comprises a set of diaphragm antennas. This set of diaphragm antennas comprises an array of scattering metamaterial elements. In one embodiment, each scattering element in the antenna system is part of a unit cell consisting of a lower conductor, a dielectric substrate, and an upper conductor, embedded in a complementary inductive-capacitive resonator (“complementary LC” or “CELC”) etched or deposited on the upper conductor. As those skilled in the art will understand, in the context of CELC, LC refers to inductance-capacitance, not liquid crystal.

[0072] In one embodiment, a liquid crystal (LC) is disposed in a gap around the scattering element. This LC is driven by the direct-drive embodiment described above. In one embodiment, the liquid crystal is encapsulated in each cell, separating the lower conductor associated with the gap from the upper conductor associated with its film. The liquid crystal has a dielectric constant as a function of the orientation of the molecules comprising the liquid crystal, and the orientation of the molecules (and therefore the dielectric constant) can be controlled by adjusting the bias voltage across the liquid crystal. Utilizing this characteristic, in one embodiment, the liquid crystal integrates an on / off switch for transmitting energy from the waveguide to the CELC. When the switch is on, the CELC transmits electromagnetic waves like a small electronic dipole antenna. It should be noted that the teachings herein are not limited to liquid crystals operating in a binary manner for energy transfer.

[0073] In one embodiment, the feed geometry of the antenna system allows the antenna elements to be at a 45-degree (45°) angle to the wave vector in the wave feed. It should be noted that other positions can be used (e.g., a 40° angle). This position of the elements enables control over the free-space waves received or transmitted / radiated by the elements. In one embodiment, the antenna elements are arranged with an element spacing of a free-space wavelength less than the antenna's operating frequency. For example, if there are four scattering elements per wavelength, the elements in a 30 GHz transmit antenna would be approximately 2.5 mm (i.e., 1 / 4 of the 10 mm free-space wavelength at 30 GHz).

[0074] In one embodiment, the two sets of elements are perpendicular to each other and, if controlled to the same tuning state, simultaneously possess equal-amplitude excitation. Rotating them relative to the feed wave excitation by + / - 45 degrees can achieve both desired characteristics simultaneously. Rotating one set by 0 degrees and the other by 90 degrees will achieve the vertical target but not the equal-amplitude excitation target. Note that 0 degrees and 90 degrees can be used to achieve separation when feeding an array of antenna elements in a single structure from both sides.

[0075] The amount of radiated power from each cell is controlled by applying a voltage (potential across the LC channel) to the diaphragm using a controller. The traces on each diaphragm are used to supply voltage to the diaphragm antenna. This voltage is used to tune or demodulate capacitors, thereby adjusting the resonant frequency of individual elements to achieve beamforming. The required voltage depends on the liquid crystal mixture used. The voltage tuning characteristics of the liquid crystal mixture are primarily described by the threshold voltage at which the liquid crystal begins to be affected by voltage and the saturation voltage; above this threshold voltage, no major tuning of the liquid crystal occurs. These two characteristic parameters can be varied for different liquid crystal mixtures.

[0076] In one embodiment, as described above, a matrix driver is used to apply voltage to the diaphragm so that each unit can be driven separately from all other units without requiring a separate connection for each unit (direct drive). Due to the high density of components, a matrix driver is the most efficient method for processing each unit individually.

[0077] In one embodiment, the control structure of the antenna system has two main components: an antenna array controller, including driving electronics for the antenna system, located below the wave scattering structure, and a matrix driver switch array dispersed throughout the radiating RF array to avoid interfering with the radiation. In one embodiment, the driving electronics for the antenna system includes a commercial off-the-shelf LCD controller used in commercial television equipment, which adjusts the bias voltage of each scattering element by regulating the amplitude or duty cycle of the AC bias signal for the element.

[0078] In one embodiment, the antenna array controller further includes a microprocessor running software. The control architecture may also include sensors (e.g., a GPS receiver, a three-axis compass, a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer, etc.) to provide position and orientation information to the processor. The position and orientation information may be provided to the processor through other systems within the earth station and / or may not be part of the antenna system.

[0079] More specifically, the antenna array controller controls which components are disconnected, which are connected, and at what phase and amplitude level they are at the operating frequency. By applying voltage, the components are selectively demodulated for frequency operation.

[0080] For transmission, the controller supplies an array of voltage signals to the RF diaphragm to generate a modulation or control pattern. The control pattern causes the elements to change to different states. In one embodiment, polymorphic control is used, where various elements are switched on and off to different levels, further approximating a sinusoidal control mode rather than a square wave (i.e., a sinusoidal gray modulation mode). In one embodiment, some elements radiate more than others, rather than some elements radiating and others not radiating. Variable radiation is achieved by applying specific voltage levels, which adjusts the dielectric constant of the liquid crystal to different amounts, thereby variably demodulating the elements and causing some elements to radiate more than others.

[0081] The generation of a focused beam through a metamaterial array of elements can be explained by the phenomena of constructive and destructive interference. If individual electromagnetic waves meet in free space with the same phase, they add together (constructive interference); and if they meet in free space with opposite phases, they cancel each other out (destructive interference). If the slots in a slot antenna are positioned such that each successive slot is located at a different distance from the excitation point of the guided wave, the scattered wave from the element will have a different phase than the scattered wave from the previous slot. If the slots are spaced one-quarter of the guided wave wavelength apart, each slot will scatter a wave with a one-quarter phase delay from the previous slot.

[0082] By using an array and applying holographic principles, the number of constructive and destructive interference patterns that can be generated can be increased, allowing the beam to theoretically point in any direction, positive or negative 90 degrees (90°) from the line of sight of the antenna array. Therefore, by controlling which metamaterial units are switched on or off (i.e., by changing the patterns of which units are switched on and off), different constructive and destructive interference modes can be generated, and the antenna can change the direction of the main beam. The time required to switch the cells on and off determines the speed at which the beam can switch from one position to another.

[0083] In one embodiment, the antenna system generates a controllable beam for an uplink antenna and a controllable beam for a downlink antenna. In one embodiment, the antenna system uses metamaterial technology to receive the beam, decode signals from the satellite, and form a transmit beam directed towards the satellite. In one embodiment, the antenna system is an analog system, as opposed to antenna systems that use digital signal processing to electronically form and control the beam (e.g., phased array antennas). In one embodiment, particularly when compared to a conventional satellite dish antenna receiver, the antenna system is considered a flat and relatively low-profile "surface" antenna.

[0084] Figure 7A perspective view of a row of antenna elements, including a ground plane and a reconfigurable resonator layer, is shown. The reconfigurable resonator layer 1230 includes an array of tunable slots 1210. The array of tunable slots 1210 can be configured to point the antenna in a desired direction. Each of the tunable slots can be tuned / adjusted by changing the voltage across the liquid crystal.

[0085] The control module 1280 is coupled to the reconfigurable resonator layer 1230 to change the cross-section of the resonator. Figure 8A The voltage of the liquid crystal in the liquid crystal is used to modulate the array of tunable slots 1210. Control module 1280 may include a field-programmable gate array (“FPGA”), a microprocessor, a controller, a system-on-a-chip (SoC), or other processing logic. In one embodiment, control module 1280 includes logic circuitry (e.g., a multiplexer) to drive the array of tunable slots 1210. In one embodiment, control module 1280 receives data including specifications of a holographic diffraction pattern to be driven onto the array of tunable slots 1210. The holographic diffraction pattern can be generated in response to the spatial relationship between the antenna and the satellite, such that the holographic diffraction pattern controls the downlink beam (and, if the antenna system performs a transmission) in the appropriate communication direction. Although not drawn in each figure, a control module similar to control module 1280 can drive each array of tunable slots described in the figures of this disclosure.

[0086] Radio frequency (“RF”) holography may also be implemented using similar techniques where a desired RF beam can be generated when an RF reference beam encounters an RF holographic diffraction pattern. In the case of satellite communications, the reference beam is in the form of a feed wave, such as feed wave 1205 (approximately 20 GHz in some embodiments). To convert the feed wave into a radiated beam (for transmission or reception purposes), an interference pattern is calculated between the desired RF beam (target beam) and the feed wave (reference beam). The interference pattern is driven onto an array of tunable slits 1210 as a diffraction pattern, such that the feed wave is “guided” to the desired RF beam (with the desired shape and orientation). In other words, the feed wave encountering the holographic diffraction pattern “reconstructs” the target beam formed according to the design requirements of the communication system. The holographic diffraction pattern contains the excitation of each element and is calculated... ,in For the wave equation of waveguide and Here is the wave equation for the outgoing wave.

[0087] Figure 8AAn embodiment of the tunable slit 1210 is shown. The tunable slit 1210 includes an iris / slit 1212, a radiating diaphragm 1211, and a liquid crystal 1213 disposed between the iris / slit 1212 and the diaphragm 1211. In one embodiment, the radiating diaphragm 1211 is co-located with the iris / slit 1212.

[0088] Figure 8B A cross-sectional view of one embodiment of the physical antenna aperture is shown. The antenna aperture includes a ground plane 1245 and a metal layer 1236 included within an iris layer 1232 in a reconfigurable resonator layer 1230. In one embodiment, Figure 8B Antenna aperture includes Figure 8A Multiple tunable slits 1210. Iris / slit 1212 is defined by an opening in the metal layer 1236. Such as Figure 8A The feed wave 1205 can have a microwave frequency compatible with satellite communication channels. The feed wave propagates between the ground plane 1245 and the resonator layer 1230.

[0089] The reconfigurable resonator layer 1230 also includes a spacer layer 1233 and a diaphragm layer 1231. The spacer layer 1233 is disposed between the diaphragm layer 1231 and the iris layer 1232. Note that in one embodiment, a spacer may replace the spacer layer 1233. In one embodiment, the iris layer 1232 may be a printed circuit board (“PCB”) including a copper layer as a metal layer 1236. In one embodiment, the iris layer 1232 is glass. The iris layer 1232 may be other types of substrates.

[0090] An opening can be etched into the copper layer to form the iris / slit 1212. In one embodiment, in... Figure 8B In this embodiment, the iris layer 1232 is electrically coupled to another structure (e.g., a waveguide) via a conductive bonding layer. It should be noted that, in this embodiment, the iris layer is not electrically coupled via a conductive bonding layer, but rather bonded using a non-conductive bonding layer.

[0091] The diaphragm layer 1231 can also be a PCB comprising metal as a radiating diaphragm 1211. In one embodiment, the pad layer 1233 includes spacers 1239 that provide mechanical supports to define the dimensions between the metal layer 1236 and the diaphragm 1211. In one embodiment, the spacers are 75 micrometers, but other sizes (e.g., 3 to 200 mm) can be used. As described above, in one embodiment, Figure 8B The antenna aperture includes multiple tunable resonators / slots, such as tunable slot 1210, which includes... Figure 8AThe resonator layer 1230 comprises a diaphragm 1211, a liquid crystal 1213, and an iris / slit 1212. The cavity for the liquid crystal 1213A is defined by a spacer 1239, an iris layer 1232, and a metal layer 1236. When the cavity is filled with liquid crystal, the diaphragm layer 1131 can be laminated onto the spacer 1239 to seal the liquid crystal within the resonator layer 1230.

[0092] The voltage between the diaphragm layer 1231 and the iris layer 1232 can be modulated to tune the liquid crystal in the gap between the diaphragm and the slit (e.g., tunable slit 1210). Adjusting the voltage across the liquid crystal 1213 changes the capacitance of the slit (e.g., tunable slit 1210). Therefore, the reactance of the slit (e.g., tunable slit 1210) can be changed by altering the capacitance. The resonant frequency of the tunable slit 1210 is also determined according to the equation... Change, among which Let L be the resonant frequency of the tunable slot 1210, and let L and C be the inductance and capacitance of the tunable slot 1210, respectively. The resonant frequency of the tunable slot 1210 affects the energy radiated by the feed wave 1205 propagating through the waveguide. As an example, if the feed wave 1205 is 20 GHz, the resonant frequency of the tunable slot 1210 can be adjusted (by changing the capacitance) to 17 GHz, such that the tunable slot 1210 is essentially uncoupled from the energy from the feed wave 1205. Alternatively, the resonant frequency of the tunable slot 1210 can be adjusted to 20 GHz, such that the tunable slot 1210 couples the energy from the feed wave 1205 and radiates that energy into free space. Although the given example is binary (fully radiated or completely non-radiated), voltage variance over a multi-value range allows for comprehensive grayscale control of the reactance and therefore the resonant frequency of the tunable slot 1210. Therefore, the energy radiated from each tunable slit 1210 can be precisely controlled, allowing a detailed holographic diffraction pattern to be formed through the array of tunable slits.

[0093] In one embodiment, the tunable slots in a row are spaced λ / 5 apart from each other. Other spacing can be used. In one embodiment, each tunable slot in a row is spaced λ / 2 apart from the nearest tunable slot in the adjacent row, and therefore, the oriented tunable slots in different rows are spaced λ / 4 apart; however, other spacings (e.g., λ / 5, λ / 6.3) are possible. In another embodiment, each tunable slot in a row is spaced λ / 3 apart from the nearest tunable slot in the adjacent row.

[0094] The embodiments utilize reconfigurable metamaterials techniques described in, for example, U.S. Patent Application No. 14 / 550,178, filed November 21, 2014, entitled "Dynamic Polarization and Coupling Control from a Steerable Cylindrically Fed Holographic Antenna," and U.S. Patent Application No. 14 / 610,502, filed January 30, 2015, entitled "Ridged Waveguide Feed Structures for Reconfigurable Antenna."

[0095] Figures 9A to 9D An embodiment of different layers for creating a slot array is shown. The antenna array includes layers located such as... Figure 6 The example ring shown contains antenna elements within the ring. It's important to note that in this example, the antenna array has two different types of antenna elements, used for two different frequency bands.

[0096] Figure 9A A portion of the first iris plate layer is shown, corresponding to the location of the slit. The circles are open areas / slits in the metallization on the bottom side of the iris substrate / glass and are used to control the coupling of the element to the feed (feed wave). It should be noted that this layer is optional and is not used in all designs. Figure 9B A portion of the second iris plate layer containing the slit is shown. Figure 9C A membrane is shown on a portion of the second iris plate layer. Figure 9D A top view of a portion of the slot array is shown.

[0097] Figure 10 A side view of one embodiment of a cylindrical feed antenna structure is shown. The antenna uses a double-layer feed structure (i.e., two-layer feed structure) to generate an inward traveling wave. In one embodiment, the antenna includes a circular shape, but this is not required. That is, a non-circular inward traveling structure can be used. In one embodiment, Figure 10The antenna structures described include, for example, the coaxial feed described in U.S. Patent Application No. 2015 / 0236412, filed November 21, 2014, entitled "Dynamic Polarization and Coupling Control from a Steerable Cylindrically Fed Holographic Antenna".

[0098] Reference Figure 10 Coaxial pin 1601 is used to excite the antenna at a lower field level. In one embodiment, coaxial pin 1601 is a readily available 50Ω coaxial pin. Coaxial pin 1601 is coupled (e.g., bolted) to the bottom of the antenna structure, i.e., ground plane 1602.

[0099] Separated from the ground plane 1602 is the gap conductor 1603, which serves as an internal conductor. In one embodiment, the ground plane 1602 and the gap conductor 1603 are parallel to each other. In one embodiment, the distance between the ground plane 1602 and the gap conductor 1603 is "0.1 to 0.15". In another embodiment, this distance can be... , where λ is the wavelength of the traveling wave at the operating frequency.

[0100] The ground plane 1602 is separated from the gap conductor 1603 by a spacer 1604. In one embodiment, the spacer 1604 is a foam or similar air spacer. In one embodiment, the spacer 1604 comprises a plastic spacer.

[0101] On top of the gap conductor 1603 is a dielectric layer 1605. In one embodiment, the dielectric layer 1605 is a plastic. The purpose of the dielectric layer 1605 is to slow down the traveling wave relative to free space. In one embodiment, the dielectric layer 1605 slows down the traveling wave relative to free space by 30%. In one embodiment, the refractive index range suitable for beamforming is 1.2-1.8, where the refractive index of free space is defined as equal to 1. Other dielectric spacer materials, such as plastics, can be used to achieve this effect. It should be noted that materials other than plastics can be used, as long as they achieve the desired wave reduction effect. Alternatively, a material with a distributed structure can be used as the dielectric layer 1605, such as a periodic sub-wavelength metal structure that can be machined or photolithographically defined.

[0102] RF array 1606 is located on top of dielectric layer 1605. In one embodiment, the distance between gap conductor 1603 and RF array 1606 is "0.1 to 0.15". In another embodiment, this distance can be... ,in It is the effective wavelength in the medium at the design frequency.

[0103] The antenna includes sides 1607 and 1608. Sides 1607 and 1608 are angled to allow traveling waves fed from coaxial pin 1601 to propagate via reflection from the region below the gap conductor 1603 (spacer layer) to the region above the gap conductor 1603 (dielectric layer). In one embodiment, sides 1607 and 1608 are at a 45° angle. In an alternative embodiment, sides 1607 and 1608 may be replaced with a continuous radius to achieve reflection. Although Figure 10 The diagram shows a side portion at a 45-degree angle, but other angles can also be used to achieve signal transmission from the lower feed to the upper feed. That is, considering that the effective wavelength in the lower feed is typically different from the effective wavelength in the upper feed, some deviation from the ideal 45° angle can be used to aid transmission from the lower feed level to the upper feed level. For example, in another embodiment, the 45° angle is replaced by a single stepped section. The step at one end of the antenna surrounds a dielectric layer, a gap conductor, and a spacer layer. Two identical stepped sections are located at the other end of these layers.

[0104] In operation, when a feed wave is delivered from coaxial pin 1601, the wave travels concentrically outward from coaxial pin 1601 within the region between ground plane 1602 and gap conductor 1603. The concentrically emitted wave is reflected by sides 1607 and 1608 and travels inward within the region between gap conductor 1603 and RF array 1606. Reflection from the circular perimeter edge keeps the wave in phase (i.e., it is an in-phase reflection). Dielectric layer 1605 slows down the traveling wave. At this point, the traveling wave begins to interact with and excite the elements in RF array 1606 to achieve the desired scattering.

[0105] To terminate the traveling wave, the antenna includes a terminal 1609 at the geometric center of the antenna. In one embodiment, terminal 1609 includes a pinned terminal (e.g., a 50Ω pin). In another embodiment, terminal 1609 includes an RF absorber that terminates unused energy to prevent it from being reflected back through the antenna's feed structure. These can be used on top of the RF array 1606.

[0106] Figure 11 Another embodiment of an antenna system with an outgoing wave is shown. (Refer to...) Figure 11 Two ground planes 1610 and 1611 are substantially parallel to each other, with a dielectric layer 1612 (e.g., a plastic layer, etc.) between them. An RF absorber 1619 (e.g., a resistor) couples the two ground planes 1610 and 1611 together. A coaxial pin 1615 (e.g., 50Ω) feeds the antenna. An RF array 1616 sits on top of the dielectric layer 1612 and the ground plane 1611.

[0107] In operation, the feed wave is fed through coaxial pin 1615 and travels concentrically outward, interacting with the elements of RF array 1616.

[0108] Figure 10 and Figure 11 Cylindrical feeds in the antenna improve the antenna's service angle. In one embodiment, the antenna system has a service angle of 75 degrees (75°) with respect to the line of sight in all directions, instead of ±45 degrees azimuth (±45°Az) and ±25 degrees elevation (±25°E1). As with arbitrary beamforming antennas comprising multiple individual radiators, the overall gain of the antenna depends on the gain of the constituent elements, which are themselves angle-dependent. When using conventional radiating elements, the overall gain of the antenna typically decreases as the beam moves further away from the line of sight. At a 75-degree deviation from the line of sight, a significant gain drop of approximately 6 dB is expected.

[0109] Embodiments of antennas with cylindrical feeds address one or more problems. These problems include: significantly simplifying the feed structure compared to antennas fed using a cooperative distributor network, thereby reducing the required antenna and the total antenna feed; maintaining high beam performance through simpler control (extending all the way to simple two-state control), thereby reducing sensitivity to manufacturing and control errors; providing more favorable sidelobe modes compared to linear feeds because the cylindrical directional feed wave results in spatially distinct sidelobes in the far field; and allowing dynamic polarization, including allowing left-hand circular polarization, right-hand circular polarization, and linear polarization, without the need for a polarizer.

[0110] Array of wave scattering units

[0111] Figure 10 RF array 1606 and Figure 11 The RF array 1616 includes a wave scattering subsystem comprising a set of diaphragm antennas (i.e., scatterers) that function as radiators. This set of diaphragm antennas comprises an array of scattering metamaterial elements.

[0112] In one embodiment, each scattering element in the antenna system is part of a cell consisting of a lower conductor, a dielectric substrate, and an upper conductor, which is embedded in a complementary inductor-capacitor resonator (“complementary LC” or “CELC”) etched or deposited on the upper conductor.

[0113] In one embodiment, liquid crystal (LC) is injected into the gap around the scattering element. The liquid crystal is encapsulated in each cell, and the lower conductor associated with the gap is separated from the upper conductor associated with its film. The liquid crystal has a dielectric constant as a function of the orientation of the molecules comprising the liquid crystal, and the orientation of the molecules (and therefore the dielectric constant) can be controlled by adjusting the bias voltage across the liquid crystal. Utilizing this property, the liquid crystal acts as an on / off switch for transferring energy from the waveguide to the CELC. When the switch is on, the CELC emits electromagnetic waves like a small electronic dipole antenna.

[0114] Controlling the thickness of the liquid crystal (LC) improves beam switching speed. Reducing the gap between the lower and upper conductors (the thickness of the liquid crystal) by fifty percent (50%) increases the speed by four times. In another embodiment, the thickness of the liquid crystal results in a beam switching speed of approximately 14 milliseconds (14 ms). In one embodiment, the LC is doped in a manner known in the art to improve responsiveness, making a 7 millisecond (7 ms) requirement achievable.

[0115] The CELC element responds to a magnetic field applied to a plane parallel to the CELC element and perpendicular to the CELC gap complement. When a voltage is applied to the liquid crystal in the metamaterial scattering cell, the magnetic field component of the guided wave causes magnetic excitation of the CELC, which in turn generates an electromagnetic wave of the same frequency as the guided wave.

[0116] The phase of the electromagnetic wave generated by a single CELC can be selected by the position of the CELC on the guided wave vector. Each element generates a wave that is in phase with the guided wave parallel to the CELC. Because the CELC is smaller than the wavelength, when the outgoing wave passes below the CELC, its phase is the same as the phase of the guided wave.

[0117] In one embodiment, the cylindrical feed geometry of the antenna system allows the CELC elements to be at a 45-degree angle to the wave vector in the wave feed. This position of the elements enables control over the polarization of the free-space waves generated or received by the elements. In one embodiment, the CELCs are arranged with an element spacing of less than the free-space wavelength of the antenna's operating frequency. For example, if there are four scattering elements per wavelength, the elements in a 30 GHz transmit antenna would be approximately 2.5 mm (i.e., 1 / 4 of the 10 mm free-space wavelength at 30 GHz).

[0118] In one embodiment, CELC is implemented using a diaphragm antenna comprising a diaphragm co-located on a slot, with liquid crystal between the slot and the diaphragm. In this respect, the metamaterial antenna functions similarly to a slot (scattering) waveguide. With a slot waveguide, the phase of the outgoing wave depends on the position of the slot relative to the guided wave.

[0119] Unit Layout

[0120] In one embodiment, the antenna elements are arranged on the cylindrical feed antenna aperture in a manner that allows the system matrix drive circuitry. The arrangement of the elements includes the arrangement of transistors for the matrix driver. Figure 12 An embodiment of the arrangement of the matrix drive circuit relative to the antenna elements is shown. (Refer to...) Figure 12 Row controller 1701 is coupled to transistors 1711 and 1712 via row selection signals Row1 and Row2, respectively, and column controller 1702 is coupled to transistors 1711 and 1712 via column selection signal Column1. Transistor 1711 is also coupled to antenna element 1721 via a connection to diaphragm 1731, and transistor 1712 is coupled to antenna element 1722 via a connection to diaphragm 1732.

[0121] In an initial approach to implementing a matrix drive circuit on a cylindrical feed antenna with cells arranged in an irregular grid, two steps are performed. In the first step, cells are arranged on a concentric ring, and each cell is connected to a transistor, which is placed next to the cell and acts as a switch to drive each cell individually. In the second step, the matrix drive circuit is constructed so that each transistor is connected to a unique address when needed by the matrix drive method. Because the matrix drive circuit is constructed using row and column traces (similar to an LCD), but the cells are arranged on a ring, there is no systematic method for assigning a unique address to each transistor. This mapping problem results in a very complex circuit covering all transistors and a significant increase in the number of physical traces required for routing. Due to the high cell density, these traces interfere with the antenna's RF performance due to coupling effects. Moreover, due to the complexity of the traces and the high packaging density, routing the traces cannot be accomplished using commercially available placement tools.

[0122] In one embodiment, the matrix drive circuitry is predefined before the cells and transistors are arranged. This ensures that the number of traces required to drive all cells is minimized, and each cell has a unique address. This strategy reduces the complexity of the drive circuitry and simplifies wiring, thereby improving the antenna's RF performance.

[0123] More specifically, in one approach, in a first step, cells are arranged on a regular rectangular grid consisting of rows and columns describing the unique address of each cell. In a second step, the cells are grouped and transformed into concentric circles while preserving their addresses and connections to the rows and columns defined in the first step. The goal of this transformation is not only to place the cells on the rings but also to maintain a constant distance between cells and between rings throughout the entire aperture. Several methods exist for grouping cells to achieve this goal.

[0124] In one embodiment, the TFT package is used to implement arrangement and unique addressing in a matrix driver. Figure 13 An embodiment of a TFT package is shown. (Refer to...) Figure 13 The TFT and holding capacitor 1803 are shown having input ports and output ports. Two input ports are connected to trace 1801 and two output ports are connected to trace 1802 to connect the TFTs together using rows and columns. In one embodiment, the row and column traces intersect at a 90° angle to reduce and potentially minimize coupling between the row and column traces. In one embodiment, the row and column traces are on different layers.

[0125] Example of a full-duplex communication system

[0126] In another embodiment, the combined antenna aperture is used for a full-duplex communication system. Figure 14 This is a block diagram of another embodiment of a communication system having simultaneous transmit and receive paths. Although only one transmit path and one receive path are shown, the communication system may include more than one transmit path and / or more than one receive path.

[0127] Reference Figure 14 Antenna 1401 includes two spatially staggered antenna arrays, which, as described above, can operate independently to transmit and receive simultaneously at different frequencies. In one embodiment, antenna 1401 is coupled to duplexer 1445. Coupling can be achieved through one or more feed networks. In one embodiment, in the case of a radially fed antenna, duplexer 1445 combines the two signals, and the connection between antenna 1401 and duplexer 1445 is a single broadband feed network that can support the frequencies of both.

[0128] Duplexer 1445 is coupled to low-noise downconverter (LNB) 1427, which performs noise filtering, downconversion, and amplification functions in a manner known in the art. In one embodiment, LNB 1427 is in an outdoor unit (ODU). In another embodiment, LNB 1427 is integrated into an antenna device. LNB 1427 is coupled to modem 1460, which is coupled to computing system 1440 (e.g., computer system, modem, etc.).

[0129] Modem 1460 includes an analog-to-digital converter (ADC) 1422 coupled to LNB 1427 to convert the received signal output from duplexer 1445 into digital format. Once converted to digital format, the signal is demodulated by demodulator 1423 and decoded by decoder 1424 to obtain coded data on the received wave. The decoded data is then sent to controller 1425, which in turn sends the decoded data to computing system 1440.

[0130] The modem 1460 also includes an encoder 1430, which encodes data to be transmitted from the computing system 1440. The encoded data is modulated by a modulator 1431 and then converted into an analog signal by a digital-to-analog converter (DAC) 1432. The analog signal is then filtered by a BUC (up-converter and high-pass amplifier) ​​1433 and provided to one port of a duplexer 1445. In one embodiment, the BUC 1433 is located in an outdoor unit (ODU).

[0131] The duplexer 1445, operating in a manner known in the art, provides the transmit signal to the antenna 1401 for transmission.

[0132] The controller 1450 controls the antenna 1401, which includes an array of two antenna elements on a single composite physical aperture.

[0133] The communication system will be modified to include the aforementioned combiner / arbitrator. In this case, the combiner / arbitrator is located after the modem but before the BUC and LNB.

[0134] It is important to note that Figure 14 The full-duplex communication system shown has many applications, including but not limited to internet communication and vehicle communication (including software updates).

[0135] This article describes many example implementations.

[0136] Example 1 is an antenna comprising: an aperture having multiple antenna elements operable to radiate radio frequency (RF) energy; and a single-layer wide-angle impedance matching (WAIM) structure coupled to the aperture to provide impedance matching between the antenna aperture and free space.

[0137] Example 2 is an antenna of Example 1, which may optionally include: a single-layer WAIM structure comprising a capacitive impedance surface of a two-dimensional (2D) array of subwavelength elements.

[0138] Example 3 is an antenna of Example 2, which may optionally include: a 2D array of subwavelength elements including capacitor diaphragms.

[0139] Example 4 is an antenna of Example 3, which may optionally include: the capacitor diaphragm is a square diaphragm.

[0140] Example 5 is an antenna of Example 3, which may optionally include: the capacitor diaphragm is a hexagonal diaphragm.

[0141] Example 6 is an antenna of Example 2, which may optionally include: a subwavelength element that is an open-loop resonator or a dipole.

[0142] Example 7 is an antenna of Example 1, which may optionally include: a single-layer WAIM structure including a substrate, and subwavelength elements of the single-layer WAIM structure being screen-printed on the substrate.

[0143] Example 8 is an antenna of Example 1, which may optionally include: a single-layer WAIM structure separated from the aperture by at least one dielectric spacer.

[0144] Example 9 is an antenna of Example 8, which may optionally include: the impedance of a single-layer WAIM structure based on the characteristics of the single-layer WAIM structure and the physical dimensions of the surrounding medium of the single-layer WAIM structure.

[0145] Example 10 is an antenna of Example 1, which may optionally include: the impedance of a single-layer WAIM structure is a function of the scanning angle and the polarization of the propagating wave, and is independent of the scanning plane of the antenna.

[0146] Example 11 is an antenna of Example 1, which may optionally include a single-layer WAIM structure with rotational symmetry.

[0147] Example 12 is the antenna of Example 1, with the aperture including a metasurface.

[0148] Example 13 is an antenna comprising: a metasurface having multiple antenna elements operable to radiate radio frequency (RF) energy; and a single-layer wide-angle impedance matching (WAIM) structure coupled to an aperture to provide impedance matching between the antenna aperture and free space, the single-layer WAIM structure having a capacitive impedance surface having a two-dimensional (2D) array of subwavelength elements.

[0149] Example 14 is an antenna of Example 13, which may optionally include: a 2D array of subwavelength elements including capacitor diaphragms.

[0150] Example 15 is an antenna of Example 14, which may optionally include: the capacitor diaphragm is a square diaphragm or a hexagonal diaphragm.

[0151] Example 16 is an antenna of Example 13, which may optionally include: a subwavelength element that is an open-loop resonator or a dipole.

[0152] Example 17 is an antenna of Example 13, which may optionally include: a single-layer WAIM structure including a substrate, and subwavelength elements of the single-layer WAIM structure being screen-printed on the substrate.

[0153] Example 18 is an antenna of Example 13, which may optionally include: a single-layer WAIM structure separated from the aperture by at least one dielectric spacer.

[0154] Example 19 is an antenna of Example 18, which may optionally include: the impedance of a single-layer WAIM structure based on the characteristics of the single-layer WAIM structure and the physical dimensions of the surrounding medium of the single-layer WAIM structure.

[0155] Example 20 is an antenna of Example 13, which may optionally include: the impedance of a single-layer WAIM structure is a function of the scan angle and the polarization of the propagating wave, and is independent of the scan plane of the antenna.

[0156] Example 21 is an antenna comprising: a metasurface having a plurality of antenna elements operable to radiate radio frequency (RF) energy; a dielectric layer coupled to the metasurface; and a single-layer wide-angle impedance matching (WAIM) structure coupled to the dielectric layer to provide impedance matching between the antenna aperture and free space, wherein the single-layer WAIM structure includes a substrate having a two-dimensional (2D) array of capacitive elements screen-printed thereon.

[0157] Certain parts of the detailed description above are presented in terms of algorithms and symbolic representations of operations on data bits within computer memory. These algorithmic descriptions and representations are the means by which those skilled in the art of data processing most effectively communicate the substance of their work to others skilled in the art. Algorithms are, and generally are, considered as self-consistent sequences of steps leading to desired results. These steps are those requiring physical operations on physical quantities. Typically, though not always necessary, these quantities take the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, and otherwise manipulated. It has proven convenient, primarily for general reasons, to refer to these signals as bits, values, elements, symbols, characters, items, numbers, etc.

[0158] However, it should be remembered that all these and similar terms are associated with appropriate physical quantities and are merely convenient notations applied to those quantities. Unless otherwise stated, as will be apparent from the following discussion, it can be understood that throughout the description, the use of terms such as “processing” or “computing” or “operation” or “determining” or “displaying” refers to the actions and processing of a computer system or similar electronic computing device, which manipulates and transforms data represented as physical (electronic) quantities within the registers and memory of the computer system into other data similarly represented as physical quantities within the computer system's memory or registers or other such information storage, transmission, or display devices.

[0159] The present invention also relates to means for performing the operations described herein. Such means may be specifically constructed for the desired purpose, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in a computer. Such a computer program may be stored in a computer-readable storage medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, CD-ROMs and magneto-optical disks, read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic cards or optical cards, or any type of medium suitable for storing electronic instructions, and each is coupled to a computer system bus.

[0160] The algorithms and displays presented herein are not inherently related to any particular computer or other device. Various general-purpose systems can be used with the programs based on the teachings herein, or it may prove convenient to construct more specialized devices to perform the required method steps. The necessary structures for various such systems will appear from the following description. Furthermore, this invention is not described with reference to any particular programming language. It should be understood that the teachings of the invention described herein can be implemented using various programming languages.

[0161] Machine-readable media include any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form. Examples of machine-readable media include read-only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory devices; and so on, for...

[0162] While many variations and modifications of the invention will undoubtedly become apparent to those skilled in the art after reading the foregoing specification, it should be understood that any particular embodiment illustrated and described is by no means intended to be limiting. Therefore, reference to details of various embodiments is not intended to limit the scope of the claims, which themselves only set forth those features considered essential to the invention.

Claims

1. An antenna, comprising: The aperture has multiple antenna elements that can be operated to radiate radio frequency energy, i.e., RF energy; as well as A single-layer wide-angle impedance matching structure, namely a single-layer WAIM structure, is coupled to the aperture and separated from multiple antenna elements of the aperture to provide impedance matching between the antenna aperture and free space. The single-layer WAIM structure includes a capacitive impedance surface of a two-dimensional array (2D array) of subwavelength elements, and The subwavelength element includes a 2D array of capacitor films.

2. The antenna according to claim 1, wherein the capacitor diaphragm is a square diaphragm.

3. The antenna of claim 1, wherein, The capacitor diaphragm is a hexagonal diaphragm.

4. The antenna of claim 1, wherein, The single-layer WAIM structure includes a substrate, and the subwavelength element of the single-layer WAIM structure is screen-printed on the substrate.

5. The antenna of claim 1, wherein, The single-layer WAIM structure is separated from the aperture by at least one dielectric spacer.

6. The antenna according to claim 5, wherein, The impedance of the single-layer WAIM structure is based on the characteristics of the single-layer WAIM structure and the physical dimensions of the surrounding medium.

7. The antenna according to claim 1, wherein, The impedance of the single-layer WAIM structure is a function of the scanning angle and the polarization of the propagating wave, and is independent of the scanning plane of the antenna.

8. The antenna according to claim 1, wherein, The single-layer WAIM structure has rotational symmetry.

9. The antenna of claim 1, wherein the aperture comprises a metasurface.

10. An antenna, comprising: Metasurfaces have multiple antenna elements that can be operated to radiate radio frequency energy, i.e., RF energy; as well as A single-layer wide-angle impedance matching structure, namely a single-layer WAIM structure, is coupled to the aperture and separated from multiple antenna elements of the metasurface to provide impedance matching between the antenna aperture and free space. The single-layer WAIM structure has a capacitive impedance surface, which has a two-dimensional array, i.e., a 2D array, of subwavelength elements. The subwavelength element includes a 2D array of capacitor films.

11. The antenna according to claim 10, wherein, The capacitor diaphragm is a square diaphragm or a hexagonal diaphragm.

12. The antenna according to claim 10, wherein, The single-layer WAIM structure includes a substrate, and the subwavelength element of the single-layer WAIM structure is screen-printed on the substrate.

13. The antenna according to claim 10, wherein, The single-layer WAIM structure is separated from the aperture by at least one dielectric spacer.

14. The antenna according to claim 13, wherein, The impedance of the single-layer WAIM structure is based on the characteristics of the single-layer WAIM structure and the physical dimensions of the surrounding medium.

15. The antenna of claim 10, wherein the impedance of the single-layer WAIM structure is a function of the scanning angle and the polarization of the propagating wave, and is independent of the scanning plane of the antenna.

16. An antenna, comprising: Metasurfaces have multiple antenna elements that can be operated to radiate radio frequency energy, i.e., RF energy; A dielectric layer is coupled to the metasurface; as well as A single-layer wide-angle impedance matching structure, i.e., a single-layer WAIM structure, is coupled to the dielectric layer and separated from multiple antenna elements of the metasurface to provide impedance matching between the antenna aperture and free space. The single-layer WAIM structure includes a substrate having a two-dimensional array, i.e., a 2D array, of capacitive elements screen-printed on the substrate. The capacitor element comprises a 2D array of capacitor films.

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