JP7174101B2 - Antenna with high RF tuning, wide temperature operating range, and low viscosity radio frequency liquid crystal (RFLC) mixture - Google Patents

Description

(priority)
This patent application is entitled "High RF Tuning, Wide Temperature Operating Range, and Low Viscosity Radio Frequency Liquid Crystal (RFLC) Mixtures," filed May 20, 2016 to Corresponding Provisional Patent Application Serial No. 62/339,550. claims priority to and is incorporated by reference.

TECHNICAL FIELD Embodiments of the present invention relate to the field of radio frequency (RF) devices with liquid crystal (LC), and more specifically, embodiments of the present invention provide high RF tuning suitable for use in metamaterial tuned antennas. and radio frequency (RF) devices with low viscosity.

Recently, surface scattering antennas and other such radio frequency devices have been disclosed using liquid crystal (LC)-based metamaterial elements as part of the device. In the case of antennas, LCs are used as part of the antenna elements for tuning the antenna elements. The performance of such devices depends, at least in part, on the LC used. Therefore, it is desirable to develop LCs with properties that improve the performance of devices using the LCs.

のうちの１種以上の混合物を含む。
本発明は、以下で与えられる詳細な説明及び添付の本発明の種々の実施形態の図面からより完全に理解されるが、それらは本発明を特定の実施形態に限定すると解釈すべきではなく、単に説明及び理解のためのものである。 A device is disclosed that includes a radio frequency (RF) liquid crystal (RFLC) mixture with improved performance. In one embodiment, improved performance includes high RF tuning, wide temperature operating range and low viscosity. In one embodiment, the device comprises an antenna element array having a plurality of antenna elements and each antenna element includes an antenna having a liquid crystal (LC) structure, the LC structure comprising at least proton, hydrogen (H), or hetero Laterally functionalized at one or more of the atoms of:

including mixtures of one or more of
While the present invention will be more fully understood from the detailed description given below and the accompanying drawings of various embodiments of the invention, they should not be construed to limit the invention to particular embodiments, It is for illustration and understanding only.

Fig. 3 shows a representation of the relative orientation of the LC nematic phase with respect to incident microwave radiation; FIG. 2A shows a computer modeling-based representation of field orientation and concentration inside a single element of meta-network antenna technology. FIG. 2B is a photograph of a representative meta-network antenna technology single element. 4 shows a representation of resonant frequency tuning; Approximate results obtained from radio frequency (RF) tuning studies combined with Δn estimates made using a simple linear combination model are shown. Thermal (differential scanning calorimeter) traces of selected LC mixtures are shown. Thermal (differential scanning calorimeter) traces of selected LC mixtures are shown. Thermal (differential scanning calorimeter) traces of selected LC mixtures are shown. Thermal (differential scanning calorimeter) traces of selected LC mixtures are shown. Thermal (differential scanning calorimeter) traces of selected LC mixtures are shown. FIG. 1 shows a plan view of one embodiment of a coaxial feed used to provide a cylindrical wave feed; Fig. 3 shows an aperture with one or more arrays of antenna elements arranged concentrically around the input feed of a cylindrical fed antenna; 1 shows a perspective view of a row of antenna elements including a ground plane and a reconfigurable resonator layer; FIG. Figure 3 shows one embodiment of a tunable resonator/slot; FIG. 4B illustrates a cross-sectional view of one embodiment of a physical antenna aperture. Figure 11 shows one embodiment of different layers for making a slotted array. Figure 11 shows one embodiment of different layers for making a slotted array. Figure 11 shows one embodiment of different layers for making a slotted array. Figure 11 shows one embodiment of different layers for making a slotted array. FIG. 11 illustrates a side view of one embodiment of a cylindrically-fed antenna structure; Fig. 3 shows another embodiment of an antenna system with outgoing waves; Fig. 3 shows one embodiment of the layout of the matrix drive circuit for the antenna elements; 1 illustrates one embodiment of a TFT package. 1 is a block diagram of one embodiment of a communication system for simultaneous dual reception in a television system; FIG. Figure 3 is a block diagram of another embodiment of a communication system with simultaneous transmit and receive paths;

Radio frequency (RF) devices containing liquid crystal (LC) mixtures and methods for using the same are disclosed. In one embodiment, the RF device can include an antenna, phased array, or optical modulator. In one embodiment, the LC mixture is a radio frequency liquid crystal (RFLC) mixture comprising pi-conjugated mesogenic (liquid crystal) compounds. In one embodiment, RFLCs are suitable for use as active elements in meta-network antenna technology. To be useful in meta-network antenna technology, the RFLC mixture has high voltage tunable RF dielectric anisotropy (optical Δη≧0.3, RF Δε≧1.33), acceptable temperature stability properties, (− It exhibits long-term storage stability up to 40°C, clearing point > 125°C), low RF loss (Δε/Tanσ > 75), and acceptable viscoelasticity (γ1/κ3 < 15).

For purposes herein, "tuning range" is defined as the amount of change in RF permittivity Δε(RF), and for optical applications this is defined as Δn.

In one embodiment, the liquid crystal mixtures disclosed herein are highly birefringent liquid crystals. High birefringence is typically recognized in the art as Δn>0.3. These include, but are not limited to, 1) antenna applications such as holographic antennas, reflect arrays and phased arrays based on resonant elements, and 2) spatial light modulators such as those used in LIDAR (optical imaging detection and ranging). It can be used in several applications, including For high birefringence liquid crystals to be useful in the above applications, they need to exhibit fast switching times and high tuning ranges.

Embodiments of the present invention include a series of liquid crystal mixtures that combine large radio frequency (RF) dielectric tuning (high birefringence) with low melting points and low rotational viscosities. In one embodiment, the LC mixture has a low melting point of −63° C. and a high clearing point of 135° C. combined with a rotational viscosity of ˜13. These key innovations allow these materials to offer fast switching speeds and operate at low temperatures. This is generally difficult because increasing birefringence is usually accompanied by increased viscosity and a high melting point. These materials allow the operation of antenna active elements and thus the construction of antenna arrays.

In one embodiment, the liquid crystal used has 1) good dielectric tuning (optical Δη≧0.3, RF Δε>1.33), 2) acceptable relaxation time (˜20 ms, γ1/κ3≦15 ), 3) suitable temperature characteristics (long-term storage stability below −40° C., clearing point≧125° C.), and 4) reasonable RF loss (Δε/Tan δ≧75). This combination of properties is relatively unique. Any of these properties can be optimized independently. However, it is extremely difficult to realize a material that satisfies all requirements at the same time. Such materials (mixtures) and design strategies are therefore inherently unique and valuable.

Most liquid crystals in commercial use are not monomolecular structures. They consist of a mixture of several chemical compounds each exhibiting unique physical and chemical properties. Thus, molecular-level structure/property relationships are used to design unimolecular structures with appropriate polarity and polarization anisotropy. These same structure/property relationships are simultaneously used to create condensed phases (liquid crystal mesophases) that meet all operational requirements.

Embodiments of the present invention not only provide specific chemical “recipes” for useful LC mixtures, but also a series of methods that can be used to create novel mixtures with rationally designed properties. It also provides general concepts.

The specific chemical structures provided can be used in multiple mixture "recipes" to adjust specific chemical and physical properties. The established general structure/property relationships can be used to design novel materials with significantly improved performance characteristics.

In one embodiment, the high birefringence liquid crystals disclosed herein create large length/width polarization anisotropy at the molecular level. In one embodiment, this is achieved by creating a long, rigid pi-electron conjugated core (eg, tolan). Such molecules by themselves (unfunctionalized) have very high melting points due to strong intermolecular interactions. In one embodiment, a long carbon tail is added at one end to lower the melting point and favor nematic (liquid crystal) phase formation. At the opposite end, polar groups such as isothiocyanate (NCS), trifluoromethoxy ( _OCF3 ), cyano (CN), bromide ( Br), or trifluorophenyl (C ₆ H ₂ F ₃ ) is used.

This idea can be represented by the general structures (GS1, GS2, GS3, and GS4) above. For GS1, GS2, and GS4, the core is represented by m units. This core can be laterally functionalized, most commonly with protons, H, and/or heteroatoms such as fluorine (F), bromine (Br), or chlorine (Cl). Other groups such as alkyl groups, e.g. methyl _{( CH3} ), ethyl _{( CH2CH3} ) _, propyl _{( CH2CH2CH3} ), or methoxy (OCH3), ethoxy ( _OCH2CH3 ) _{, Propoxy} ( _OCH2CH3 ) or trifluoromethoxy ( _OCF3 ) can also be introduced at various R positions. Such lateral functionalization modifies intermolecular interactions to favor smectic phase formation and/or to modify rotational viscosity γ, elastic constant κ, and melting point T _m . Lengthening the core (increasing m) increases birefringence as a general rule. In this case A is a saturated carbon chain as seen in structures 1-6 below, or alkoxy (OC _n H _(2n+1) ), or similarly functionalized cyclohexyl and/or phenyl moieties is either The longer the carbon chain, the lower the melting point in general. where B is a second alkyl or alkoxy chain, or isothiocyanate (NCS), trifluoromethoxy ( _OCF3 ), cyano (CN), bromide (Br), or trifluorophenyl is any of the polar groups such as Structure GS3 shows complementary structural motifs in which Z and Y represent independent single or triple bonds.

上記スキーム１の６種の構造において、液晶混合物は、上記構造の何れか又は全てを含有し、ここでＤ＝ＣＨ₂、Ｏ、Ｓ、Ｓｅであり、Ｒ１－Ｒ１２＝Ｃ_nＨ_(2n+1)、Ｈ、Ｆ、Ｃｌ、ＳＣ_nＨ_(2n+1)、ＳｅＣ_nＨ_(2n+1)、Ｂｒであり、Ｘ＝ＮＣＳ、Ｆ、Ｂｒ、Ｃｌ、Ｈである。 (Preparation of liquid crystal mixture)
Below are exemplary embodiments of six LC chemistries that can be used as metamaterial elements within antenna elements in antennas.

In the six structures of Scheme 1 above, the liquid crystal mixture contains any or all of the structures above, where D=CH ₂ , O, S, Se and R1-R12=C _n H _{(2n+ 1)} , H, F, Cl, SC _n H _(2n+1) , SeC _n H _(2n+1) , Br and X = NCS, F, Br, Cl, H.

None of the compounds shown as structures 1-6 in Scheme 1 are liquids at room temperature. To be liquid crystals, the mixture must be liquid within the useful operating temperature range. a mixture of analogous compounds such as compounds represented by general structures GS1, GS2, GS3 and specific structures 1-6, weighing specific amounts of each compound and mixing them together to form a liquid at room temperature; It is then prepared by heating until the compounds are melted and miscible with each other. Suitable mixtures do not resolidify (solidify) at room temperature. Mixtures can be as simple as mixing one specific basic structure with different lengths of carbon chains (n=1-7), or many different structures have been added in varying weight percentages. It can be complicated.

Basic structures such as exemplified by 1-6 and/or GS1/GS2 may differ not only in terms of physical properties, but also in terms of birefringence Δn. Therefore, mixtures containing different weight percentages will also have different optical properties. For purposes herein, the base mixture can be tailored as described above to have specific physical and optical properties.

(Naming of structures and common units)
Structures 1-6 all have common subunits.

Structure 1 is known as cyclohexyl-phenyl. It consists of a cyclohexyl ring and a phenyl ring attached to each other. The n on the left represents the number of carbons present in the saturated hydrocarbon tail. The number of carbons generally varies between n=1 and n=7, where n=1 is methyl, n=2 is ethyl, n=3 is propyl, n=4 is butyl, n=5 is pentyl, n=6 is hexyl, n=7 is heptyl. In one embodiment, D is carbon and 2 hydrogens (an additional carbon is added), X=NCS and n=4. In such cases Structure No. 1 is designated as pentyl-cyclohexylphenyl isocyanate. When the same basic structure is retained and D is changed to oxygen, the structure is named butoxy-cyclohexylphenyl isocyanate.

Structure 2 is referred to herein as tolane. A tolan is basically two phenyl rings with a triple bond at either end. Using the same nomenclature as above, in one embodiment, when D=CH ₂ and X=NCS, Structure No. 2 is named pentyl-isothiocyanatotrane.

Structure 3 is a combination of structures 1 and 2. This is referred to herein as cyclohexyl-tolane. In one embodiment, D= _CH2 and X=NCS. In this case structure 3 is named pentyl-isothiocyanatocyclohexyl-tolane.

Structure 4 is referred to herein as phenyl-tolane. A phenyl ring is added to the basic tolan structure. In one embodiment, D= _CH2 and X=NCS. In this case structure 4 is referred to as pentyl-isothiocyanatophenyl-tolan.

Structure 5 is referred to herein as phenyl-bis-tolane. It has two triple bonds between the phenyl group and another phenyl ring. In one embodiment, D= _CH2 and X=NCS. In this case structure 5 is named pentyl-isothiocyanatophenyl-bistrane.

Structure 6 is referred to herein as a terphenyl and has three phenyl rings attached to each other. In one embodiment, D= _CH2 and X=NCS. In this case structure 6 is named pentyl-isothiocyanatoterphenyl.

（ＬＣ単分子及び混合物の試験結果）

Scheme 2 below shows another set of mixtures for use in the antennas disclosed herein. Each of the mixtures includes the use of NCS end groups.

(LC single molecule and mixture test results)

As discussed above, useful liquid crystal mixtures are prepared by combining several unique basic structures (LC units) in various weight percentages. Scheme 2 shows a library of synthetically prepared LC monomers for this study. Table 1 shows the temperature characteristics of the LC simple substance shown in Scheme 2. The term "melting" is used to describe the melting point, the temperature at which a compound undergoes a phase change from a crystalline solid to a liquid. The term "freezing" refers to the freezing point, ie the temperature at which solidification reoccurs when cooled at a linear rate of 10°C/min. The birefringence Δn is given where obtained. The clearing point represents the temperature at which the nematic phase becomes isotropic (and visually changes in appearance from opalescent to clear). From inspection of Table 1, the lowest melting LC alone, 4TOLCl, melts at 44.4°C. This is well above room temperature (~19°C). Similarly, the highest clearing point is indicated by 111.7o.

Table 2 shows various mixtures made using this compound library. The weight percentage of each compound is given and the resulting temperature and tuning characteristics are given.

It can be further illustrated by inspection of Table 2 that the LC simplex library shown in Scheme 2 can be used to make mixtures that freeze at temperatures as low as -64°C and become clear at temperatures as high as 153°C. These values are comparable to the widest nematic temperature range reported so far.

Figures 1 and 2A-2C illustrate tuning concepts associated with meta-network antenna technology. This concept is best illustrated in terms of a single element, one of many that make up a meta-network element array based antenna according to one embodiment. A nematic phase liquid crystal mixture as discussed herein is embedded within a single element of meta-network antenna technology. FIG. 1 shows a representation of the relative orientation of the LC nematic phase to incident microwave radiation. When an electric field is applied, the LC changes its orientation, thus giving rise to Δf corresponding to the equation given in FIG. 1 with its Δn. This Δf determines the behavior of the antenna technology.

FIG. 2A shows a computer modeling-based representation of field orientation and concentration inside a single element of meta-network antenna technology. FIG. 2B is a photograph of a representative meta-network antenna technology single element. FIG. 2C shows a representation of the resonant frequency tuning indicated as Δf in Tables 2 and 3. FIG.

FIG. 3 shows approximate results obtained from RF tuning studies combined with Δn estimation performed using a simple linear combination model. Plotting 13.1 and 13.2 using linear combination analysis, the Δn for 13.1 and 13.2 can be estimated to be 0.37 and 0.34, respectively. Plotting this against its average tuning result, it must reach Δn˜0.4 in order to tune at ˜1.85 GHz.

As noted earlier, the simplest way to increase Δn is to increase the amount of the highest Δn mixture component (TFNCST1 in this case). However, this solution does not maintain good thermal performance unless the entire mixture is reformulated. For example, 13.1 exhibits the highest Δn among the mixtures given in Table 2, but also the narrowest nematic temperature range. To address this, several new mixtures were tested. The most successful mixture to date was 13.8. This mixture has an estimated Δn ~ 0.39 - ~ 0.4. 13.8 exhibits a very wide nematic temperature range and has a particularly high clearing point. This is accompanied by some viscosity increase, but the increase is not dramatic. To address this, the amount of 5CHBT can be increased without significantly reducing Δn. Bulk testing at -20°C shows that 13.8 appears to remain quite stable even at this temperature.

ここで示す混合物の場合、Δε（Δｎ）が増大するにつれて、ＲＦ損失も増大することに留意されたい。しかしながら、１３．８の場合、この損失は、依然としてメタネットワーク・アンテナ技術にとっては許容できるものである。 (microwave loss and tuning measurement)

Note that for the mixtures shown here, as Δε(Δn) increases, so does RF loss. However, for 13.8, this loss is still acceptable for meta-network antenna technology.

Figures 4-8 show thermal (differential scanning calorimeter) traces of selected LC mixtures.
These values correspond to those shown in Table 2.

The LC described above can be included in an antenna embodiment having the following features.

(Example of antenna embodiment)
The techniques described above can be used with flat panel antennas. Embodiments of such planar antennas are disclosed. A planar antenna includes one or more arrays of antenna elements over an antenna aperture. In one embodiment, the antenna elements include liquid crystal cells. In one embodiment, the planar antenna is a cylindrically-fed antenna that includes a matrix drive circuit for uniquely addressing and driving each of the antenna elements that are not arranged in rows and columns. Note that the feed need not be circular. In one embodiment, the elements are arranged in a ring.

In one embodiment, an antenna aperture having one or more arrays of antenna elements is composed of multiple segments coupled together. A combination of segments, when coupled together, form a closed concentric ring of antenna elements. In one embodiment, the concentric rings are concentric with respect to the antenna feed.

(Outline of Embodiment of Antenna System)
In one embodiment, the planar antenna is part of a metamaterial antenna system. Embodiments of a metamaterial antenna system for a communications satellite ground station are described. In one embodiment, the antenna system is a satellite operating on a mobile platform (e.g., air, sea, land, etc.) operating using either Ka-band frequencies for civil commercial satellite communications or Ku-band frequencies. A component or subsystem of an Earth Station (ES). Note that embodiments of the antenna system can also be used in ground stations (eg, fixed ground stations or portable ground stations) that are not on mobile platforms.

In one embodiment, the antenna system uses surface scattering metamaterial technology to form and direct transmit and receive beams through separate antennas. In one embodiment, the antenna system is an analog system, as opposed to an antenna system that uses digital signal processing to form and steer the beam electronically (such as a phased array antenna).

In one embodiment, the antenna system has three functional subsystems: (1) a waveguide structure consisting of a cylindrical wave-fed architecture, (2) an array of wave-scattering metamaterial unit cells that are part of the antenna element. and (3) a control structure that directs the formation of tunable radiation fields (beams) from metamaterial scattering elements using holographic principles.

(Example of waveguide structure)
FIG. 9 shows a top view of one embodiment of a coaxial feed used to provide a cylindrical wave feed. Referring to FIG. 9, the coaxial feed includes a center conductor and an outer conductor. In one embodiment, a cylindrical wave feed architecture feeds the antenna from a central point with an excitation that radiates cylindrically outward from the feed point. That is, the cylindrical feed antenna produces outward traveling concentric feed waves. Nevertheless, the shape of the cylindrical feed antenna around the cylindrical feed can be circular, square, or any shape. In another embodiment, a cylindrical feed antenna produces an inwardly traveling feed wave. In such cases, the feed wave originating from a circular structure is the most natural.

FIG. 10 shows an aperture with one or more arrays of antenna elements arranged in concentric rings around the input feed of a cylindrically-fed antenna.

(antenna element)
In one embodiment, the antenna elements comprise a group of patch antennas. This group of patch antennas includes 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 bottom conductor, a dielectric substrate, and a top conductor, the top conductor being a complementary dielectric etched or deposited on the top conductor. It incorporates an electrically induced capacitive resonator (“complementary electrical LC” or “CELC”). As will be appreciated by those skilled in the art, LC in the context of CELS refers to inductance-capacitance, as opposed to liquid crystal.

In one embodiment, a liquid crystal (LC) is placed in the gap around the scattering element. The liquid crystal is driven by the direct drive embodiment described above. In one embodiment, a liquid crystal is encapsulated within each unit cell and separates the bottom conductor associated with the slot from the top conductor associated with its patch. Liquid crystals have a dielectric constant that is a function of the orientation of the molecules that comprise the liquid crystal, and the orientation of the molecules (and thus the dielectric constant) can be controlled by adjusting the bias voltage across the liquid crystal. In one embodiment, using this property, the liquid crystal integrates an on/off switch for energy transfer from the guided wave to the CELC. When switched on, the CELC emits electromagnetic waves like an electrically small dipole antenna. Note that the teachings herein are not limited to having liquid crystals that operate in a binary manner with respect to energy transfer.

In one embodiment, the feed geometry of this antenna system allows the antenna elements to be positioned at a forty-five degree (45°) angle to the wave vector of the wave feed. Note that other positions (eg, 40° angle) may be used. This position of the element allows control of free-space waves received by or transmitted/radiated from the element. In one embodiment, the antenna elements are spaced at an element spacing of less than the free-space wavelength of the antenna's operating frequency. For example, if there are 4 scattering elements per wavelength, the elements in a 30 GHz transmit antenna would be approximately 2.5 mm (ie, 1/4 of 10 mm free space wavelength at 30 GHz).

In one embodiment, the two sets of elements are perpendicular to each other and have equal amplitude excitation simultaneously when controlled to the same tuning state. By rotating them ±45 degrees relative to the excitation of the feed wave, both desired functions are achieved simultaneously. By rotating one set by 0 degrees and the other by 90 degrees, the vertical goal is achieved, but not the equal amplitude excitation goal. Note that 0 and 90 degrees can be used to achieve isolation when feeding a single structure antenna element array from two sides.

The amount of power emitted from each unit cell is controlled by applying a voltage (potential across the LC channel) to the patch using a controller. A trace for each patch is used to supply voltage to the patch antenna. Voltages are used to tune or detune the capacitance and thus the resonant frequency of the individual elements to achieve beamforming. The required voltage depends on the liquid crystal mixture used. The voltage tuning properties of liquid crystal mixtures are mainly described by a threshold voltage above which the liquid crystal begins to be affected by voltage, and a saturation voltage above which increases in voltage do not result in significant tuning of the liquid crystal. These two characteristic parameters may change for different liquid crystal mixtures.

In one embodiment, as discussed above, matrix drive is used to energize the patch, isolating each cell from all other cells without having a separate connection for each cell. drive (direct drive). Due to the high density of elements, matrix driving is an efficient way to address each cell individually.

In one embodiment, the control structure of the antenna system has two main components: the antenna array controller, which contains the drive electronics for the antenna system, below the wave scattering structure; Matrix driven switching arrays are interspersed throughout the radiating RF array so as not to interfere with the radiation. In one embodiment, the control structure of the antenna system has two main components: the controller, which contains the drive electronics for the antenna system, below the wave scattering structure, while the matrix drive The switching arrays are interspersed throughout the radiating RF array so as not to interfere with the radiation. In one embodiment, the drive electronics for the antenna system is used in commercial television equipment that adjusts the bias voltage to each scattering element by adjusting the amplitude or duty cycle of the AC bias signal to the scattering element. with a commercially available off-the-shelf LCD controller.

In one embodiment, the antenna array controller also contains a microprocessor that executes software. The control structure may also incorporate sensors (eg, GPS receiver, 3-axis compass, 3-axis accelerometer, 3-axis gyro, 3-axis magnetometer, etc.) that provide position and orientation information to the processor. The position and orientation information may be provided to the processor by other systems within the ground station and/or may not be part of the antenna system.

More specifically, the controller controls which elements are turned off and which are turned on at the operating frequency, and at what phase and amplitude levels. The elements are selectively detuned for frequency actuation by voltage application.

For transmission, the controller supplies an array of voltage signals to the RF patch to generate modulation or control patterns. Control patterns change the elements to different states. In one embodiment, multi-state control is used in which different elements are turned on and off to different levels as opposed to a square wave (i.e. sinusoidal gray shade modulation pattern) and Approximate a sinusoidal control pattern. In one embodiment, some elements radiate more strongly than others, rather than some elements radiating and some not. Variable emission is achieved by applying a specific voltage level, which adjusts the dielectric constant of the liquid crystal to varying amounts, thereby variably detuning the elements to shift some elements from others. Emit more than the element.

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

This array can be used to increase the number of patterns of constructive and destructive interference that can be generated, so using holographic principles, theoretically ±90° from the boresight of the antenna array. The beam can be directed in any direction of 90 degrees. Thus, by controlling which metamaterial unit cells are turned on or off (i.e., by varying the pattern of which cells are turned on and which are turned off), constructive interference and Different patterns of destructive interference can be produced and the antenna can redirect the main beam. The time required to turn the unit cell on and off is determined by the speed at which the beam can be switched from one position to another.

In one embodiment, the antenna system produces one steerable beam for the uplink antenna and one steerable beam for the downlink antenna. In one embodiment, the antenna system uses metamaterial technology to receive beams, decode signals from satellites, and form transmit beams directed at the satellites. In one embodiment, the antenna system is an analog system, as opposed to an antenna system that uses digital signal processing to electrically form and direct the beam (such as a phased array antenna). In one embodiment, the antenna system is considered a planar, relatively low-profile "planar" antenna, especially compared to conventional satellite dish-based receivers.

FIG. 11 shows a perspective view of a row of antenna elements including a ground plane and a reconfigurable resonator layer. Reconfigurable cavity layer 1230 includes an array of tunable slots 1210 . An 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.

Control module 1280 is coupled to reconfigurable resonator layer 1230 to modulate the array of tunable slots 1210 by varying the voltage across the liquid crystal in FIG. Control module 2180 may include a field programmable gate array (“FPGA”), microprocessor, or other processing logic. In one embodiment, control module 1280 includes logic circuitry (eg, multiplexers) to drive the array of tunable slots 1210 . In one embodiment, control module 1280 receives data containing specifications for the holographic diffraction pattern driven onto array of tunable slots 1210 . A holographic diffraction pattern is generated according to the spatial relationship between the antenna and the satellite so that it directs the downlink beam (and uplink beam, if the antenna system is transmitting) in the proper direction for communication. can be made Although not depicted 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.

Radio frequency (“RF”) holography is also possible using similar techniques that can generate the desired RF beam when the RF reference beam encounters the RF holographic diffraction pattern. For satellite communications, the reference beam is in the form of a feed such as feed 1105 (approximately 20 GHz in some embodiments). To convert the feed wave into a beam of radiation (either for transmission or reception purposes), an interference pattern is calculated between the desired RF beam (object beam) and the feed wave (reference beam). The interference pattern is driven onto the array of tunable slots 1210 as a diffraction pattern such that the feed wave is "steered" into the desired RF beam (having the desired shape and direction). In other words, the feed wave encountering the holographic diffraction pattern "reconstructs" the object beam, which is shaped according to the design requirements of the communication system. The holographic diffraction pattern contains the excitation of each element, using w _in as the wave equation in the waveguide and w _out as the wave equation for the outgoing wave, by w _hologram =w _in *w _out Calculated.

FIG. 12 shows one embodiment of a tunable resonator/slot 1210. FIG. Tunable slot 1210 includes iris/slot 1212 , radiating patch 1211 , and liquid crystal 1213 disposed between iris 1212 and patch 1211 . In one embodiment, radiating patch 1211 is co-located with iris 1212 .

FIG. 13 shows a cross-sectional view of one embodiment of the physical antenna aperture. Antenna aperture includes ground plane 1245 and metal layer 1236 in iris layer 1233 included in reconfigurable resonator layer 1230 . In one embodiment, the antenna aperture of FIG. 4 includes multiple tunable resonators/slots 1210 of FIG. Iris/slot 1212 is defined by an opening in metal layer 1236 . A feed wave, such as feed wave 1205 in FIG. 2, may have a microwave frequency compatible with a satellite communication channel. A feed wave propagates between the ground plane 1245 and the resonator layer 1230 .

Reconfigurable resonator layer 1230 also includes gasket layer 1232 and patch layer 1231 . A gasket layer 1232 is positioned between the patch layer 1231 and the iris layer 1233 . Note that spacers can replace the gasket layer 1232 in one embodiment. In one embodiment, iris layer 1233 is a printed circuit board (PCB) that includes a copper layer as metal layer 1236 . In one embodiment, iris layer 1233 is glass. Iris layer 1233 may be other types of substrates.

An opening can be etched in the copper layer to form slot 1212 . In one embodiment, iris layer 1233 is conductively coupled to another structure (eg, waveguide) of FIG. 4 by a conductive bonding layer. Note that in one embodiment, the iris layer is not conductively bonded by a conductive bonding layer, but instead is interfacially bonded to a non-conductive bonding layer.

Patch layer 1231 can also be a PCB containing metal as radiation patch 1211 . In one embodiment, gasket layer 1232 includes spacers 1239 that provide a dimensional mechanical standoff between metal layer 1236 and patch 1211 . In one embodiment, the spacers are 75 microns, but other sizes (eg, 3-200 mm) can be used. As noted above, in one embodiment, the antenna aperture of FIG. 13 includes a plurality of tunable resonators/slots, such as tunable resonators/slots 1210, which are patch 1211 , liquid crystal 1213 and iris 1212 . A chamber for liquid crystal 1213 is defined by spacers 1239 , iris layer 1233 and metal layer 1236 . Once the chamber is filled with liquid crystal, a patch layer 1231 can be laminated over the spacers 1239 to seal the liquid crystal within the cavity layer 1230 .

に従って変化し、ここで、ｆはスロット１２１０の共振周波数であり、Ｌ及びＣは、それぞれスロット１２１０のインダクタンス及びキャパシタンスである。スロット１２１０の共振周波数は、導波路を伝播する給電波１２０５から放射されるエネルギーに影響を及ぼす。一例として、給電波１２０５が２０ＧＨｚである場合、スロット１２１０の共振周波数を１７ＧＨｚに調節して（キャパシタンスを変化させることにより）、スロット１２１０が給電波１２０５からのエネルギーを実質的に結合させないようにすることができる。これに代えて、スロット１２１０の共振周波数を２０ＧＨｚに調節して、スロット１２１０が給電波１２０５からのエネルギーを結合させ、そのエネルギーを自由空間に放射するようにすることができる。与えられた実施例は２値的（完全な放射又は全くの無放射）であるが、スロット１２１０のリアクタンス及び従って共振周波数の完全グレイスケール制御は、多値範囲にわたる電圧変化を使用して可能である。従って、各スロット１２１０から放射されるエネルギーは、精密に制御可能なので、同調可能スロットのアレイによって精緻なホログラフィック回折パターンを形成することができる。 The voltage between patch layer 1231 and iris layer 1233 can be modulated to tune the liquid crystal in the gap between patch and slot (eg, tunable resonator/slot 1210). Adjusting the voltage across liquid crystal 1213 changes the capacitance of the slot (eg, tunable resonator/slot 1210). Thus, changing the capacitance can change the reactance of the slot (eg, tunable resonator/slot 1210). The resonant frequency of slot 1210 is also:

where f is the resonant frequency of slot 1210 and L and C are the inductance and capacitance of slot 1210, respectively. The resonant frequency of slot 1210 affects the energy radiated from feed wave 1205 propagating in the waveguide. As an example, if feed 1205 is 20 GHz, the resonant frequency of slot 1210 is adjusted to 17 GHz (by varying the capacitance) so that slot 1210 does not substantially couple energy from feed 1205. be able to. Alternatively, the resonant frequency of slot 1210 can be adjusted to 20 GHz so that slot 1210 couples energy from feed wave 1205 and radiates that energy into free space. Although the examples given are binary (fully radiating or totally non-radiating), full grayscale control of slot 1210 reactance and thus resonant frequency is possible using voltage variation over a multi-value range. be. Thus, the energy emitted from each slot 1210 can be precisely controlled so that an array of tunable slots can produce elaborate holographic diffraction patterns.

In one embodiment, the tunable slots within a column are separated from each other by λ/5. Other intervals can also be used. In one embodiment, each tunable slot in a column is separated from the nearest tunable slot in an adjacent column by λ/2, thus commonly oriented tunable slots in different columns. are spaced by λ/4, but other spacings are possible (eg, λ/5, λ/6.3). In another embodiment, each tunable slot in a column is separated from the nearest tunable slot in adjacent columns by λ/3.

Embodiments of the present invention address the multi-aperture needs of the market by applying Dynamic Polarization and Coupling Control from a Steerable Cylindrically Fed Holographic Antenna, filed Nov. 21, 2014. No. 14/550,178, entitled "Dynamic Polarization and Coupling Control", and "Ridged Waveguide Feed Structures for Reconfigurable Antenna", filed Jan. 30, 2015. 14/610,502 entitled "Ridged Waveguide Feed Structure".

Figures 14A-D show one embodiment of different layers for making a slotted array. An antenna array includes antenna elements positioned in a ring, such as the exemplary ring shown in FIG. Note that in this example, the antenna array has two different types of antenna elements used for two different types of frequency bands.

FIG. 14A shows the first iris substrate layer with positions corresponding to the slots. Referring to Figure 14A, the circles are open areas/slots in the metallization on the bottom side of the iris substrate for controlling the coupling of the elements to the feed. Note that this layer is an optional layer and not used in all designs. FIG. 14B shows a portion of the second iris substrate layer containing slots. FIG. 14C shows a patch covering part of the second iris substrate layer. FIG. 14D shows a top view of a portion of the slotted array.

FIG. 15 shows a side view of one embodiment of a cylindrically-fed antenna structure. The antenna uses a double-layer feed structure (ie, a two-layer feed structure) to generate an inward traveling wave. In one embodiment, the antenna includes a circular profile, although this is not required. That is, a non-circular inward traveling wave can be used. In one embodiment, the antenna structure of FIG. 15 includes the coaxial feed of FIG.

Referring to FIG. 15, coaxial pin 1601 is used to excite the field at the lower level of the antenna. In one embodiment, coaxial pin 1601 is a readily available 50Ω coaxial pin. Coaxial pin 1601 is coupled (eg, bolted) to the bottom of the antenna structure, which is conductive ground plane 1602 .

An inner conductor, interstitial conductor 1603 , is spaced from the conductive ground plane 1602 . In one embodiment, conductive ground plane 1602 and interstitial conductor 1603 are parallel to each other. In one embodiment, the distance between ground plane 1602 and gap conductor 1603 is between 0.1 inch and 0.15 inch. In another embodiment, this distance can be λ/2, where λ is the wavelength of the traveling wave at the operating frequency.

Ground plane 1602 is separated from gap conductor 1603 by spacer 1604 . In one embodiment, spacer 1604 is a foam or pneumatic spacer. In one embodiment, spacer 1604 comprises a plastic spacer.

On top of the interstitial conductor 1603 is a dielectric layer 1605 . In one embodiment, dielectric layer 1605 is plastic. The purpose of dielectric layer 1605 is to slow down the traveling wave relative to the free space velocity. In one embodiment, dielectric layer 1605 slows down traveling waves by 30% relative to free space. In one embodiment, the range of refractive indices suitable for beamforming is from 1.2 to 1.8, and free space, by definition, has a refractive index equal to one. For example, other dielectric spacer materials such as plastics can be used to achieve this effect. Note that materials other than plastic can be used as long as they achieve the desired wave-moderating effect. Alternatively, a material with a dispersive structure, such as a periodic sub-wavelength metal structure that can be defined by machining or lithography, can be used as dielectric 1605 .

RF array 1606 is on top of dielectric 1605 . In one embodiment, the distance between interstitial conductors 1603 and RF array 606 is 0.1 to 0.15 inches. In another embodiment, this distance can be λeff/2, where λeff is the effective wavelength in the medium at the design frequency.

The antenna includes sides 1607 and 1608 . Sides 1607 and 1608 are angled such that the traveling wave feed from coaxial pin 1601 propagates by reflection from the region below interstitial conductor 1603 (spacer layer) to the region above interstitial conductor 1603 (dielectric layer). . In one embodiment, the angle of sides 1607 and 1608 is a 45 degree angle. In an alternate embodiment, sides 1607 and 1608 can be replaced with continuous radii to achieve reflection. Although FIG. 15 shows angled sides having an angle of 45 degrees, other angles can be used to achieve signal propagation from the lower feed level to the upper feed level. That is, given that the effective wavelength of the bottom feed is generally different from the effective wavelength of the top feed, any deviation from the ideal 45 degree angle is used to convert from the bottom feed level to the top feed level. can help with transmission. For example, in another embodiment the 45 degree angle is replaced with a single step. A step on one end of the antenna encircles the dielectric layer, the interstitial conductor, and the spacer layer. The same two steps are present at the other ends of these layers.

In operation, when a feed wave is provided from coaxial pin 1601 , the feed wave travels concentrically outward from coaxial pin 1601 in the region between ground plane 1602 and gap conductor 1603 . Concentric outgoing waves are reflected by sides 1607 and 1608 and travel inward in the region between interstitial conductor 1603 and RF array 1606 . Reflections from the edges of the circular perimeter cause the waves to remain in phase (ie, the reflections are in-phase reflections). The traveling wave is slowed down by dielectric layer 1605 . At this point, the traveling wave begins to interact and excite the elements of RF array 1606 to obtain the desired scattering.

A termination 1609 is included in the antenna at the geometric center of the antenna to terminate the traveling wave. In one embodiment, termination 1609 includes pin terminations (eg, 50Ω pins). In another embodiment, termination 1609 includes an RF absorber that terminates unused energy and prevents it from reflecting back through the antenna's feed structure. These can be used on top of the RF array 1606 .

FIG. 16 shows another embodiment of the antenna system with outgoing waves. Referring to Figure 16, two ground planes 1610, 1611 are substantially parallel to each other and have a dielectric layer 1612 (eg, a plastic layer, etc.) between the ground planes. An RF absorber 1619 (eg, a resistor) couples the two ground planes 1610 and 1611 together. A coaxial pin 1615 (eg, 50Ω) feeds the antenna. RF array 1616 resides on top of dielectric layer 1612 and ground plane 1610 .

In operation, a feed wave is fed through coaxial pin 1615 and travels concentrically outward to interact with the elements of RF array 1616 .

The cylindrical feed in both antennas of FIGS. 15 and 16 improves the service angle of the antenna. In one embodiment, the antenna system is positioned from boresight in all directions instead of a service angle of plus or minus 45 degrees azimuth (±45 degrees Az) and plus or minus 25 degrees elevation (±25 degrees El). It has a service angle of seventy-five degrees (75°). As with any beamforming antenna constructed from a number of individual radiators, the overall antenna gain depends on the gains of the constituent elements which are themselves angle dependent. If common radiating elements are used, the overall antenna gain typically decreases as the beam is directed away from boresight. A significant gain drop of about 6 dB is expected at 75 degrees off boresight.

Embodiments of antennas with cylindrical feeds solve one or more problems. These greatly simplify the feed structure compared to antennas fed using a common divider network, and thus reduce the overall required antenna and antenna feed, and coarser control ( reducing the sensitivity to manufacturing and control errors by maintaining high beam performance with a cylindrically oriented feed wave that is spatially diverse in the far field. providing a more advantageous sidelobe pattern compared to a linear feed, as it results in more sidelobes, and left-handed circular polarization, right-handed circular polarization, and linear polarization without the need for a polarizer. and C. enabling the polarization to be dynamic.

(array of wave scattering elements)
RF array 1606 of FIG. 15 and RF array 1616 of FIG. 16 include wave scattering subsystems that include a group of patch antennas (ie, scatterers) that act as radiators. This group of patch antennas includes an array of scattering metamaterial elements.

In one embodiment, each scattering element in the antenna system comprises a bottom conductor, a dielectric substrate, and a top conductor incorporating a complementary electrically induced capacitive resonator (“complementary electrical LC” or “CELC”). A complementary inductive capacitive resonator is etched or deposited on the top conductor.

In one embodiment, liquid crystal (LC) is injected into the gap around the scattering element. A liquid crystal is encapsulated in each unit cell and separates the bottom conductors associated with the slots from the top conductors associated with the patches. Liquid crystals have a dielectric constant that is a function of the orientation of the molecules that make up the liquid crystal, and the orientation of the molecules (and thus the dielectric constant) can be controlled by adjusting the bias voltage across the liquid crystal. Using this property, the liquid crystal acts as an on/off switch for energy transfer from the guided wave to the CELC. When switched on, the CELC radiates electromagnetic waves like an electrically small dipole antenna.

By controlling the thickness of the LC, the beam switching speed is increased. A fifty percent (50%) reduction in the gap (thickness of the liquid crystal) between the bottom and top conductors results in a four-fold increase in speed. In another embodiment, the liquid crystal thickness results in a beam switching speed of approximately fourteen milliseconds (14 ms). In one embodiment, the LC is doped in a manner well known in the art to improve responsivity and to meet the seven millisecond (7ms) requirement.

A CELC element responds to a magnetic field applied parallel to the plane of the CELC element and perpendicular to the CELC gap complement. When a voltage is applied to the liquid crystal in the metamaterial scattering unit cell, the magnetic field component of the guided wave induces magnetic excitation of the CELC, resulting in the generation of electromagnetic waves at the same frequency as the guided wave.

The phase of electromagnetic waves produced by a single CELC can be selected by the position of the CELC on the guided wave vector. Each cell produces a wave in phase with the guided wave parallel to the CELC. Since the CELC is smaller than the wavelength, the output wave has the same phase as the guided wave as it passes under the CELC.

In one embodiment, the cylindrical feed geometry of this antenna system allows the CELC elements to be positioned at a forty-five degree (45°) angle to the wave vector in the feed. The position of this element allows control of the polarization of the free-space wave generated from or received by the element. In one embodiment, the CELCs are arranged with an element spacing less than the free-space wavelength of the antenna's operating frequency. For example, if there are four scattering elements per wavelength, the elements for a 30 GHz transmit antenna would be approximately 2.5 mm (ie, 1/4 of the 10 mm free-space wavelength of 30 GHz).

In one embodiment, CELC is implemented using patch antennas comprising patches juxtaposed over slots and liquid crystals between the patch antennas. In this respect, the metamaterial antenna acts like a slot (scattering) waveguide. For slot waveguides, the phase of the output wave depends on the position of the slot relative to the guided wave.

(cell arrangement)
In one embodiment, the antenna elements are arranged on the aperture plane of the cylindrical feed antenna to enable a systematic matrix drive circuit. The arrangement of cells includes the arrangement of transistors for matrix driving. FIG. 17 shows one embodiment of the arrangement of the matrix drive circuit for the antenna elements. Referring to FIG. 17, row controller 1701 is coupled to transistors 1711, 1712 via row select signals Row1 and Row2, respectively, and column controller 1702 is coupled to column select signal Column1. to transistors 1711 and 1712 via . Transistor 1711 is also coupled to antenna element 1721 via connection to patch 1731 and transistor 1712 is coupled to antenna element 1722 via connection to patch 1732 .

In a first approach in which unit cells are placed in an irregular grid to realize a matrix drive circuit on a cylindrically-fed antenna, two steps are performed. In the first step, the cells are arranged in concentric rings, each of which is connected to a transistor arranged beside the cell, which acts as a switch to drive each cell separately. In a second step, a matrix drive circuit is constructed to connect every transistor with a unique address as required by the matrix drive scheme. Matrix drive circuits are built by row and column traces (similar to LCDs), but since the cells are arranged in a ring, there is no systematic way to assign a unique address to each transistor. This mapping problem results in a very complex circuit to cover all the transistors, greatly increasing the number of physical traces to route. Due to the high cell density, these traces interfere with the RF performance of the antenna due to coupling effects. Also, due to the complexity and packing density of traces, routing of traces cannot be done by commercially available layout tools.

In one embodiment, the matrix drive circuit is predefined before the cells and transistors are placed. This ensures the minimum number of traces required to drive all cells each with a unique address. This scheme reduces the complexity of the driver circuitry and simplifies routing, which improves the RF performance of the antenna.

More specifically, in one approach, in a first step, cells are arranged on a square grid made up of rows and columns representing a unique address for each cell. In a second step, the cells are grouped and transformed into concentric circles while maintaining the cell addresses and connectivity to rows and columns defined in the first step. The purpose of this transformation is not only to arrange the cells on rings, but also to keep the cell-to-cell distance and the ring-to-ring distance constant over the aperture plane. There are several methods of grouping cells to achieve this goal.

In one embodiment, TFT packages are used to allow placement and unique addressing in a matrix drive circuit. FIG. 18 shows one embodiment of a TFT package. Referring to FIG. 18, TFTs and holding capacitors 1803 are shown with input and output ports. There are two input ports connected to trace 1801 and two output ports connected to trace 1802, using rows and columns to connect the TFTs together. In one embodiment, the row traces and column traces intersect at a 90° angle to reduce, and possibly minimize, coupling between the row and column traces. In one embodiment, row traces and column traces are present on different layers.

(Exemplary System Embodiment)
In one embodiment, the multiple antenna aperture plane is used in a television system operating in conjunction with a set top box. For example, in the case of dual receive antennas, satellite signals received by the antennas are fed to a set-top box (eg, DirectTV receiver) of a television system. More specifically, multiple antenna operation can simultaneously receive RF signals at two different frequencies and/or polarizations. That is, one subarray of elements is controlled to receive RF signals at one frequency and/or polarization, and another subarray is controlled to receive signals at another different frequency and/or polarization. be done. These differences in frequency or polarization represent different channels received by the television system. Similarly, two antenna arrays can be controlled to two different beam positions to receive channels from two different locations (e.g., two different satellites) to receive multiple channels simultaneously. .

Figure 19 is a block diagram of one embodiment of a communication system that performs dual reception simultaneously in a television system. Referring to FIG. 19, antenna 1401 includes two spatially interleaved antenna aperture planes operable independently to simultaneously perform dual reception at different frequencies and/or polarizations as described above. include. Although only two spatially interleaved antenna operations are discussed, TV systems have more than two antenna apertures (e.g., 3, 4, 5, etc.). Note that it is possible to

In one embodiment, antenna 1401 comprising two interleaved slot arrays is coupled to diplexer 1430 . This combination can include one or more feed networks that receive signals from the elements of the two slot arrays and produce two signals that are provided to diplexer 1430 . In one embodiment, diplexer 1430 is a commercial diplexer (eg, model PB1081WA Ku-band Sitocom diplexer manufactured by A1 Microwave).

Diplexer 1430 is coupled to a pair of low noise block downconverters (LNBs) 1426, 1427, which perform noise filtering functions, downconversion functions and amplification in a manner well known in the art. In one embodiment, LNBs 1426, 1427 reside in an outdoor unit (ODU). In another embodiment, the LNBs 1426, 1427 are integrated into the antenna device. LNBs 1426 , 1427 are coupled to set top box 1402 which is coupled to television 1403 .

Set-top box 1402 includes a pair of analog-to-digital converters (ADCs) 1421, 1422 coupled to LNBs 1426, 1427 to convert the two signals output from diplexer 1430 to digital form.

Once converted to digital form, the signal is demodulated by demodulator 1423 and decoded by decoder 1424 to obtain the data encoded on the received wave. The decoded data is then sent to controller 1425 , which sends the data to television 1403 .

Controller 1450 controls antenna 1401 comprising interleaved slot array elements of both antenna aperture planes on a single multiple physical aperture plane.

(Example of full-duplex communication system)
In another embodiment, the compound antenna aperture is used in a full-duplex communication system. Figure 20 is a block diagram of another embodiment of a communication system with simultaneous transmit and receive paths. Although only one transmit path and one receive path are shown, a communication system may include more than one transmit path and/or more than one receive path.

Referring to FIG. 20, antenna 1401 includes two spatially interleaved antenna arrays operable independently to transmit and receive simultaneously on different frequencies as described above. In one embodiment, antenna 1401 is coupled to diplexer 1445 . This coupling may be by one or more feeding networks. In one embodiment, for radially-fed antennas, diplexer 1445 combines the two signals and the connection between antenna 1401 and diplexer 1445 is a single broadband feed network capable of carrying both frequencies. .

Diplexer 1445 is coupled to low noise block downconverter (LNB) 1427, which performs noise filtering, downconversion, and amplification functions in a manner well known in the art. In one embodiment, LNB 1427 resides in an outdoor unit (ODU). In another embodiment, LNB 1427 is integrated into the antenna device. LNB 1427 is coupled to modem 1460 which is coupled to computing system 1440 (eg, computer system, modem, etc.).

Modem 1460 includes an analog-to-digital converter (ADC) 1422 coupled to LNB 1427 to convert the received signal output from diplexer 1445 to digital form. Once converted to digital form, the signal is demodulated by demodulator 1423 and decoded by decoder 1424 to obtain the encoded data on the received wave. The decrypted data is then sent to controller 1425 , which sends the data to computing system 1440 .

Modem 1460 also includes an encoder 1430 that encodes data transmitted from computing system 1440 . The encoded data is modulated by modulator 1431 and then converted to analog by digital-to-analog converter (DAC) 1432 . The analog signal is then filtered by BUC (upconvert and high pass amplifier) 1433 and fed to one port of diplexer 1445 . In one embodiment, BUC 1433 resides in an outdoor unit (ODU).

Diplexer 1445, operating in a manner well known in the art, provides a transmit signal to antenna 1401 for transmission.

Controller 1450 controls antenna 1401, which includes two arrays of antenna elements over a single multiple physical aperture plane.

Note that the full-duplex communication system illustrated in FIG. 20 has several applications including, but not limited to, Internet communication, vehicle communication (including software updates), and the like.

Some portions of the above detailed descriptions are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is generally thought here to be a self-consistent sequence of steps leading to a desired result. These steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, signs, terms, numbers, or the like.

Note, however, that all of these terms and similar terms are intended to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. As will be apparent from the following description, terms such as "process" or "operate" or "calculate" or "determine" or "display" are utilized throughout the description unless otherwise specified. The description refers to data represented as physical (electronic) quantities in the registers and memory of a computer system as physical quantities in the memory or registers of that computer system or other such information storage, transmission or display device. It will be recognized to refer to the actions and processing of a computer system or similar electronic computing device that manipulates and transforms other data that are similarly represented.

The present invention also relates to apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such computer programs may be any type of disk including, but not limited to, floppy disk, optical disk, CD-ROM, and magneto-optical disk, read only memory (ROM), random access memory (RAM), EPROM, EEPROM, The computer readable storage medium may be stored on a computer readable storage medium such as a magnetic or optical card, or any type of medium suitable for storing electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove advantageous to construct more specialized apparatus to perform the required method steps. . The required structure for a variety of these systems will appear from the description below. Additionally, the present invention is not described in relation to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein.

A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (eg, a computer). For example, a machine-readable medium includes read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory devices, and the like.

While many variations and modifications of the invention will no doubt become apparent to those skilled in the art after reading the foregoing description, any specific embodiments shown and described by way of illustration should be taken as limiting. Please understand that it is not. Therefore, references to details of various embodiments are not intended to limit the scope of the claims, which recite only those features regarded as essential to the invention.

Claims (28)

A liquid crystal (LC) comprising an antenna feed section for inputting a feed wave and an antenna element array having a plurality of metamaterial surface scattering antenna elements, each antenna element acting as an active element controlling resonance in each antenna element. structure, wherein the LC structure comprises a mixture with voltage tunable RF dielectric anisotropy with optical Δη≧0.3 and RF Δε≧1.33 and at least protons, hydrogen (H), or hetero are laterally functionalized on one or more of the atoms, A, B, Rx and Rz represent one or more chemical elements or compounds, Y and Z represent single or triple bonds, and m is an integer and further A includes CH, O, S, or Se bound to CnH(2n+i), where n is an integer, as follows:

and controlling the metamaterial surface scattering antenna elements to be turned on and off by controlling the liquid crystal (LC) of each of the metamaterial surface scattering antenna elements. wherein the liquid crystal (LC) of each antenna element includes a controller operating as an on/off switch for transmission of energy from the feed, wherein each metamaterial surface scattering antenna element is a holographic beam. An antenna, characterized in that it is operable together and controlled to form beams for frequency bands for use in steering . Antenna according to claim 1, characterized in that said heteroatom comprises at least one selected from the group consisting of fluorine (F), bromine (Br), or chlorine (Cl). 2. Antenna according to claim 1, characterized in that Rx, Ry and Rz comprise one or more alkyl groups. The one or more alkyl groups are methyl (CH ₃ ), ethyl (CH ₂ CH ₃ ), propyl (CH ₂ CH ₂ CH ₃ ), or methoxy (OCH ₃ ), ethoxy (OCH ₂ CH ₃ ), propoxy (OCH ₂ CH ₃ ), or trifluoromethoxy (OCF ₃ 4. An antenna according to claim 3, comprising one or more selected from the group consisting of: A is a saturated carbon chain, alkoxy (OC _n H. _(2n+1) ), cyclohexyl or phenyl moieties. Antenna according to claim 1, characterized in that B is either a secondary alkyl, alkoxy chain or a polar group. the polar group is a heteroatom, cyano (CN), or isothiocyanate (NCS), trifluoromethoxy (OCF) ₃ ), cyano (CN), bromide (Br), or trifluorophenyl (C ₆ H. ₂ F. ₃ 7. Antenna according to claim 6, characterized in that it comprises: Said mixture comprises:

wherein D is CH ₂ , O, S, or Se, and R1-R12 are equal to C _n H. _(2n+1) , H, F, Cl, SC _n H. _(2n+1) , SeC _n H. _(2n+1) , or Br, X is equal to NCS, F, Br, Cl, or H, and n is an integer. 9. Antenna according to claim 8, characterized in that n is equal to 1-7. 9. Antenna according to claim 8, characterized in that in structure 1 D is one carbon and two hydrogens, X equals NCS and n equals four. 9. Antenna according to claim 8, characterized in that in structure 1 D is one oxygen and two hydrogens, X equals NCS and n equals four. 9. Antenna according to claim 8, characterized in that in structure 2, X equals NCS. 9. Antenna according to claim 8, characterized in that in structure 3, X equals NCS. 9. Antenna according to claim 8, characterized in that in structure 4, X equals NCS. 9. Antenna according to claim 8, characterized in that in structure 5, X equals NCS. 9. Antenna according to claim 8, characterized in that in structure 6, X equals NCS. the feed wave propagates concentrically from the antenna feed section;
The antenna is
a plurality of slots;
a plurality of patches, each of said patches being co-located over and spaced from slots within said plurality of slots with LC cells to form a patch/slot pair; A slot pair is a plurality of patches that are turned on or off based on the application of voltages to patches within the pair as specified by a control pattern;
2. The antenna of claim 1, further comprising: said antenna element being part of a tunable slotted array comprising a plurality of slots, each slot being tuned to provide a desired scattering at a given frequency, said tunable slot 2. Antenna according to claim 1, characterized in that the elements in the indexed array are arranged in one or more rings. An antenna having a liquid crystal (LC) structure, comprising an antenna feeding section for inputting a feeding wave, an antenna element array having a plurality of antenna elements, and operating as an active element for controlling resonance in each of the antenna elements, The LC structure is a mixture with voltage tunable RF dielectric anisotropy of optical Δη≧0.3, RF Δε≧1.33 and the following compounds:

and controlling the metamaterial surface scattering antenna elements to be turned on and off by controlling the liquid crystal (LC) of each of the metamaterial surface scattering antenna elements. wherein the liquid crystal (LC) of each antenna element includes a controller operating as an on/off switch for transmission of energy from the feed, wherein each metamaterial surface scattering antenna element is a holographic beam. An antenna, characterized in that it is operable together and controlled to form beams for frequency bands for use in steering. 20. Antenna according to claim 19, characterized in that said mixture comprises at least seven of said compounds. 20. Antenna according to claim 19, characterized in that said mixture comprises at least eight of said compounds. 20. Antenna according to claim 19, characterized in that said mixture comprises at least nine of said compounds. 20. An antenna according to claim 19, characterized in that said mixture comprises at least 11.7h, 11.7i and 111.7h. 24. Antenna according to claim 23, characterized in that the mixture also contains at least 111.7n and 111.7o. 24. Antenna according to claim 23, characterized in that the mixture also contains at least 4TOLCl or FNCST1. the feed wave propagates concentrically from the antenna feed section;
a plurality of slots;
a plurality of patches, each of said patches being co-located over and spaced from slots within said plurality of slots with LC cells to form a patch/slot pair; A slot pair is a plurality of patches that are turned on or off based on the application of voltages to patches within the pair as specified by a control pattern;
20. An antenna according to claim 19, further comprising: 20. An antenna according to claim 19, wherein the antenna elements are controlled and operable together to form beams for frequency bands for use in holographic beam steering. said antenna element being part of a tunable slotted array comprising a plurality of slots, each slot being tuned to provide a desired scattering at a given frequency, said tunable slot 20. Antenna according to claim 19, characterized in that the elements in the indexed array are arranged in one or more rings.

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