Antenna array

Abstract

A tunable patch antenna unit cell includes an antenna patch, at least one dielectric substrate, a first electrode, a second electrode, tunable dielectric material arranged within a cavity that is at least partially defined by the dielectric substrate, with the tunable dielectric material operably coupled to the antenna patch, the first electrode, and the second electrode.

Description

Antenna ArrayCross-Reference To Related Applications[1] This application claims the benefit of U.S. Provisional Application No. 63 / 466,423 filed February 17, 2023 and U.S. Provisional Application No. 63 / 602741 filed November 27, 2023, each of which is hereby incorporated by reference in its entirety.Background[2] Embodiments relate to antenna arrays that include multi-layer circuit boards for microwave and RF beam-steering, with applications such as communications, imaging, RADAR, and directed energy.[3] Worldwide coverage for mobile telephones cannot be met with terrestrial cellphone towers, which are impractical in rural areas and at sea. Geostationary satellites suffer from signal delay (i.e., latency) due to the long distance that signals travel to and from the satellites located almost 36000 km above Earth. Low earth orbit (LEO) satellite constellations are considerably closer at 160 to 2,000 km above Earth. As a result, LEO satellites have the potential to provide global mobile telephone coverage with significantly reduced delay. Furthermore, high speed data services offered via LEO satellites have the potential to replace and / or supplement cable and optical fiber networks around the globe.[4] It is desirable for small form-factor antennas such as those found in mobile phones and unmanned systems to communicate directly with a LEO satellite. A tradeoff between antenna power and antenna aperture area must be made. Power is limited on the ground by handset battery and in orbit by solar cell area. Similarly, the area of an antenna aperture is limited on the ground by portability, but, in contrast, the area of a satellite antenna aperture can be made much larger (e.g., 10 m2, 3.5 m diam). The satellite antenna area is constrained by the size of the payload bay of the launch vehicle. Satellite antennas are routinely folded up for launch and unfolded in orbit.[5] Large-area antennas can be used on satellites not only for communications, but also for upward- or downward-looking RADAR, power beaming, SAR-imaging, and a range of other applications. New technologies can enable lightweight, low-cost, large-area antennas for these applications along with potential terrestrial applications (e.g., RF arrays for base stations, wireless access points, phased arrays)Summary[6] An embodiment of the subject matter described herein includes an embodiment of a circuit board (or portion thereof) that defines a cavity for a stimulus responsive material (such as liquid crystal and other tunable dielectric material) as described and claimed below.[7] Embodiments include a microwave and / or radio frequency (RF) reflectarray beamsteering antenna comprising a horn and a circuit board portion that defines a cavity for a stimulus responsive tunable dielectric material such as liquid crystal whose dielectric constant can be altered via electrical control. Alternative embodiments include non-reflectarray architectures such as conventional and classical antenna arrays.[8] To achieve these and other advantages, embodiments may include a tunable microstrip antenna patch that includes at least one planar dielectric substrate having a first surface and a second surface, defining a thickness therebetween, wherein the first surface is at least substantially parallel to the second surface, a first electrode disposed on the first surface, a second electrode spaced across the thickness from the first electrode and disposed at least substantially parallel thereto, a liquid crystal reservoir disposed in a cavity that is defined by the planar dielectric substrate, the first electrode and the second electrode and a ground plane disposed parallel to the at least one planar dielectric substrate.[9] Embodiments may include a tunable microstrip antenna patch with a plurality of planar dielectric substrates, wherein the plurality of planar dielectric substrates form a vertical stack, each stacked at least substantially parallel to the plurality of planar dielectric substrates, at least one patch antenna disposed on at least one of the plurality of planar dielectric substrates, a liquid crystal reservoir disposed within the stack, at least one electrode disposed on at least one planar dielectric substrates. Optionally at least one thermal element disposed on at leastone planar dielectric substrate, at least one controller in communication with the at least one electrode and / or the at least one thermal element. A ground plane may be disposed parallel to the plurality of planar dielectric substrates.

[0010] Embodiments may include a tunable microstrip antenna patch including a plurality of planar dielectric substrates, wherein the plurality of planar dielectric substrates form a vertical stack, each planar dielectric substrate disposed parallel to the plurality of planar dielectric substrates, at least one patch antenna disposed on at least one of the plurality of planar dielectric substrates, a first liquid crystal reservoir disposed at a first location in the stack and a second liquid crystal reservoir disposed at a second location in the stack, the first location spaced from the second location orthogonally to the plurality of planar dielectric substrates, at least one electrode disposed on at least one planar dielectric substrates, optionally at least one thermal element disposed on at least one planar dielectric substrates, at least one controller in communication with the at least one electrode and / or the at least one thermal element. A ground plane disposed parallel to the plurality of planar dielectric substrates.

[0011] Embodiments may include a tunable microstrip patch antenna including a plurality of planar dielectric substrates, wherein the plurality of planar dielectric substrates form a vertical stack, each planar dielectric substrate disposed parallel to the plurality of planar dielectric substrates, a patch antenna disposed on at least one of the plurality of planar dielectric substrates, a liquid crystal reservoir disposed within the stack, wherein the liquid crystal reservoir extends through at least two planar dielectric substrates, a first electrode disposed on at least one planar dielectric substrates proximate a first side of the liquid crystal reservoir, a second electrode disposed on at least one planar dielectric substrates proximate a second side of the liquid crystal reservoir, wherein the second side is spaced from the first side orthogonally to the planar dielectric substrates within the stack, optionally at least one thermal element disposed on at least one planar dielectric substrates, at least one controller in communication with the at least one electrode and / or the at least one thermal element. A ground plane may be disposed parallel to the plurality of planar dielectric substrates.

[0012] Embodiments may include a tunable microstrip antenna patch including a plurality of planar dielectric substrates, wherein the plurality of planar dielectric substrates form a verticalstack, each planar dielectric substrate disposed parallel to the plurality of planar dielectric substrates, at least one patch antenna disposed on at least one of the plurality of planar dielectric substrates, a first liquid crystal reservoir disposed at a first location in the stack and a second liquid crystal reservoir disposed at a second location in the stack, the first location spaced from the second location orthogonally to the plurality of planar dielectric substrates, wherein the first liquid crystal reservoir is a first volume and the second liquid crystal reservoir is a second volume, the first volume larger than the second volume, a plurality of electrodes disposed on at least one planar dielectric substrate, optionally a plurality of thermal elements disposed on at least one planar dielectric substrates, at least one controller in communication with at least one electrode of the plurality of electrodes and / or at least one thermal element of the plurality of thermal elements. A ground plane may be disposed parallel to the plurality of planar dielectric substrates.

[0013] In various embodiments, a tunable patch antenna unit cell is provided. A tunable patch antenna unit cell includes a multi-layer circuit board portion that defines, within the multi-layer circuit board portion, a cavity for receiving a tunable dielectric material; an antenna patch; an upper electrode arranged within the multi-layer circuit board portion; a lower electrode arranged within the multi-layer circuit board portion; and a tunable dielectric material reservoir arranged within the cavity, the tunable dielectric material reservoir comprising a tunable dielectric material that is operably coupled to the antenna patch, the upper electrode, and the lower electrode. The tunable patch antenna unit cell has an axis and is configured along the axis in a relative order of the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

[0014] The tunable dielectric material reservoir may include at least two layers of the tunable dielectric material, the at least two layers arranged at least partially between the upper and lower electrodes. The tunable dielectric material reservoir may further include a via that spans the at least two layers.

[0015] The multi-layer circuit board portion may at least partially define one of a tunable dielectric material inlet channel that is fluidly coupled with the cavity and a tunable dielectric material outlet channel that is fluidly coupled with the cavity. The multi-layer circuit boardportion may at least partially define the tunable dielectric material inlet channel in a first dielectric layer of the multi-layer circuit board portion and the tunable dielectric material outlet channel in a second dielectric layer of the multi-layer circuit board portion, the first and second dielectric layers being different layers of the multi-layer circuit board portion.

[0016] The tunable patch antenna unit cell may further include at least one parasitic patch that is operably coupled to the antenna patch. The tunable dielectric material reservoir may at least partially envelope the at least one parasitic patch. The tunable patch antenna unit cell may include an upper parasitic patch and a lower parasitic patch. The tunable dielectric material reservoir may include an upper layer and a lower layer, the upper layer at least partially envelops the upper parasitic patch and the lower layer at least partially envelops the lower parasitic patch.

[0017] The tunable patch antenna unit cell may further include at least one thermal element that is thermally coupled to the tunable dielectric material reservoir. The tunable patch antenna unit cell may include at least one of an active thermal element and / or a passive thermal element. The at least one thermal element may include a phase change material. The tunable patch antenna unit cell may further include at least one insulator layer disposed adjacent to the antenna patch. The tunable patch antenna unit cell may be configured along the axis in a relative order of the at least one insulator layer, the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

[0018] The tunable patch antenna unit cell may be configured along the axis in a relative order of the antenna patch, the at least one insulator layer, the upper electrode, the tunable dielectric material reservoir, and the lower electrode. The tunable dielectric material may include a liquid crystal material. The upper electrode may be a ground electrode and the lower electrode may be a hot electrode. The antenna patch may be arranged on, in, or near a peripheral surface of the multi-layer circuit board portion. The tunable patch antenna unit cell may be configured along the axis that may be orthogonal to at least one layer of the multi-layer circuit board portion.

[0019] The multi-layer circuit board portion may comprise a plurality of dielectric substrate layers. The tunable patch antenna unit cell may be configured, along the axis, in the relativeorder comprising the antenna patch, a dielectric substrate layer of the plurality of dielectric substrate layers, the upper electrode, the tunable dielectric material reservoir, and the lower electrode. The plurality of dielectric substrate layers may include at least one high-frequency circuit board layer and at least one baseband frequency circuit board layer. The tunable patch antenna unit cell may be configured, along the axis, in the relative order comprising the antenna patch, the at least one high-frequency circuit board layer, the upper electrode, the tunable dielectric material reservoir, the lower electrode, and the at least one baseband frequency circuit board layer.

[0020] The tunable patch antenna unit cell may further include a middle electrode, wherein the upper electrode is a first biasing electrode, the lower electrode is a second biasing electrode, and the middle electrode is a ground electrode. The tunable patch antenna unit cell may be configured along the axis in a relative order of the antenna patch, the first biasing electrode, a first layer of the at least two layers of the tunable dielectric material, the ground electrode, a second layer of the at least two layers of the tunable dielectric material, and the second biasing electrode.[211 In various embodiments, a tunable patch antenna unit cell is provided. A tunable patch antenna unit cell includes a multi-layer circuit board portion that defines, within the multi-layer circuit board portion, at least one cavity for receiving a tunable dielectric material; an antenna patch; a first electrode disposed within the multi-layer circuit board; a second electrode disposed within the multi-layer circuit board; and a tunable dielectric material reservoir arranged within the at least one cavity. The tunable dielectric material reservoir comprising a tunable dielectric material that is operably coupled to the antenna patch, the first electrode, and the second electrode.

[0022] The multi-layer circuit board portion may further define at least two subcavities of the at least one cavity and a via channel that fluidly couples the at least two subcavities, thereby providing a channel for the tunable dielectric material to flow from a first subcavity of the at least two subcavities to a second subcavity of the at least two subcavities. The multi-layer circuit board portion may at least partially define at least an upper cavity and a lower cavity for receiving the tunable dielectric material and the tunable dielectric material reservoir include anupper layer and a lower layer that are respectively arranged in the upper cavity and the lower cavity.[231 The tunable dielectric material reservoir may further include a via that spans the upper layer and the lower layer. The multi-layer circuit board portion may at least partially define a tunable dielectric material inlet channel that is fluidly coupled with the at least one cavity and a tunable dielectric material outlet channel that is fluidly coupled with the at least one cavity. The first electrode may be an upper electrode and the second electrode may be a lower electrode. The tunable patch antenna unit cell has an axis and may be arranged, along the axis, in a relative order of the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode. A tunable patch antenna array may comprise a plurality of tunable patch antenna unit cells. The plurality of tunable patch antenna unit cells may be arranged with a pitch that is shorter than an RF operational frequency wavelength of the tunable patch antenna array. A tunable patch antenna array system may comprise the tunable patch antenna array. A reflectarray antenna may comprise the tunable patch antenna array system.[241 In various embodiments, a tunable patch antenna array includes a multi-layer circuit board that defines a plurality of unit cell cavities for receiving tunable dielectric material, each of the plurality of unit cell cavities arranged within a respective tunable patch antenna unit cell, the multi-layer circuit board further defining a plurality of tunable dielectric material channels, each tunable dielectric material channel arranged between a respective pair of the plurality of unit cell cavities, thereby fluidly coupling at least the respective pair of the plurality of unit cell cavities.[251 The multi-layer circuit board may define, for each of the plurality of unit cell cavities, at least two subcavities. The multi-layer circuit board may define, for each of the plurality of unit cell cavities, an upper subcavity and a lower subcavity. The respective tunable patch antenna unit cells may include a first plurality of tunable patch antenna cells dimensioned to operate at at least a first frequency and a second plurality of tunable patch antenna cells dimensioned to operate at at least a second frequency, the first and second frequencies differing.

[0026] The tunable patch antenna array may include the tunable dielectric material arranged in the plurality of unit cell cavities and the tunable dielectric material channels. The tunable dielectric material may include a liquid crystal material.

[0027] The multi-layer circuit board may define at least a first subarray of unit cell cavities for receiving the tunable dielectric material, each of the first subarray unit cell cavities arranged within the respective tunable patch antenna unit cell, and the plurality of the tunable dielectric material channels are at least arranged such that the first subarray of unit cell cavities are fluidly coupled.

[0028] The multi-layer circuit board may define at least a first array of unit cell cavities for receiving the tunable dielectric material, each of the first array unit cell cavities arranged within the respective tunable patch antenna unit cell, and the plurality of the tunable dielectric material channels are at least arranged such that the first array of unit cell cavities are fluidly coupled.

[0029] In various embodiments, a method for manufacturing a tunable patch antenna array is provided. A plurality of cavities is formed in a circuit board. A plurality of tunable dielectric material channels that fluidly couple the plurality of cavities are formed. The tunable dielectric material to the plurality of cavities and the plurality of tunable dielectric material channels are provided, thereby forming the tunable patch antenna array.

[0030] The circuit board may include a plurality of layers. Forming the plurality of cavities may include forming a first plurality of cavities on a first circuit board layer of the plurality of layers and a second plurality cavities on a second circuit board layer of the plurality of layers. The method may further include forming a plurality of via channels, each arranged for fluidly coupling a respective pair of the first plurality and the second plurality of cavities. Providing the tunable dielectric material step may include flowing the tunable dielectric material through the first plurality and the second plurality of cavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby forming the tunable patch antenna array.

[0031] In various embodiments, a method for manufacturing a tunable patch antenna array is provided. The method includes forming an upper array of upper subcavities on a first circuit board layer and a lower array of lower subcavities on a second circuit board layer; forming aplurality of via channels arranged for fluidly coupling a respective upper subcavity to a respective lower subcavity; and providing tunable dielectric material to the upper and lower subcavities and the plurality of via channels, thereby providing a plurality of tunable patch antenna array unit cells, each comprising a multi-layer tunable dielectric material.

[0032] The method may further include forming a plurality of tunable dielectric material channels that each fluidly connect a respective pair of the upper subcavities of the tunable patch antenna array unit cells or a respective pair of the lower subcavities of the tunable patch antenna array unit cells, wherein the providing the tunable dielectric material step includes flowing the tunable dielectric material through the upper and lower subcavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby providing the plurality of tunable patch antenna array unit cells.

[0033] The method may further include forming a plurality of upper tunable dielectric material channels that each fluidly couple a respective pair of the upper subcavities of the tunable patch antenna array unit cells; and forming a plurality of lower tunable dielectric material channels that each fluidly couple a respective pair of the lower subcavities of the tunable patch antenna array unit cells, wherein the providing the tunable dielectric material step comprises flowing the tunable dielectric material through the upper and lower subcavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby providing the plurality of tunable patch antenna array unit cells.

[0034] It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the disclosed subject matter claimed.

[0035] The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the disclosed subject matter. Together with the description, the drawings serve to explain the principles of the disclosed subject matter.Brief Description of the Drawings

[0036] The description will be more fully understood with references to the following figures and data graphs, which are presented as various embodiments of the disclosure and should not be construed as a complete recitation of the scope of the disclosure, wherein:

[0037] FIG. 1 illustrates a reflectarray antenna system.

[0038] FIGs. 2, 3, and 4 are cross-sectional views of tunable patch antenna unit cells.

[0039] FIG. 5 is a cross-sectional view of a tunable patch antenna unit cell.

[0040] FIG. 6 is a perspective view of a tunable patch antenna unit cell.

[0041] FIG. 7 depicts modeled phase performance results of a tunable patch antenna unit cell.

[0042] FIG. 8 depicts modeled antenna loss results of a tunable patch antenna unit cell.

[0043] FIGs. 9 and 10 respectively depict a linear array of tunable patch antenna unit cells and example dielectric constants at a 30 degree scan angle for said array.

[0044] FIG. 11 depicts modeled linear array beam patterns results for four scan target angles.

[0045] FIG. 12 shows a 2D array of tunable patch antenna unit cells.

[0046] FIG. 13 is a cross-sectional view of a multi-layer circuit board with multiple tunable patch antenna unit cells.

[0047] FIG. 14 is a cross-sectional view of a multi-layer circuit board with multiple tunable patch antenna unit cells.

[0048] FIG. 15 is a cross-sectional view of multi-layer circuit board with multiple tunable patch antenna unit cells.

[0049] FIG. 16 is a cross-sectional view of a multi-layer circuit board with various dielectric substrates.

[0050] FIG. 17 illustrates various tunable dielectric element arrangements.

[0051] FIG. 18 illustrates various packaged tunable tunable dielectric electronic components.

[0052] FIGs. 19, 20, and 21 are cross-sectional views of multi-layer circuit boards.

[0053] FIGs. 22-1 to 22-15 illustrate steps in a fabrication process of a multi-layer circuit board.

[0054] FIGs. 23A and 23B respectively illustrate top and perspective views of an antenna array.

[0055] FIGs. 24 to 29 illustrate antenna array fill patterns.Detailed Description

[0056] As used herein, a "relative order" of elements, layers, and / or components means an arrangement order along a direction and / or (notational) axis, which may run orthogonal with respect to said elements, layers, and / or components. Other elements, layers, and / or components may reside between the stated order, while maintaining the stated relative order of, for example, being above (e.g., an (relative) upper layer) or below (e.g., a (relative) lower layer) the recited elements, layers, and / or components.

[0057] "High frequency" generally encompasses frequencies in the radio frequency (RF) and microwave frequency ranges. Thus, "high frequency" may encompass several hundred megahertz (MHz) to several tens of gigahertz (GHz) or higher.

[0058] "Operably coupled" includes coupling that facilitates a component or element's functionality, including thermal coupling, mechanical coupling, electrical coupling, electromagnetic coupling (e.g., RF coupling, establishing and / or maintaining static, quasi static, and / or other EMF), and / or a combination thereof.

[0059] The terms "unit cell" and "tunable patch antenna unit cell" will be used interchangeably.

[0060] "Tunable dielectric" material refers to material with dielectric constants that can be varied or otherwise manipulated via electronic or other techniques.

[0061] "Cavity" may refer to a discrete cavity arranged within a unit cell or fluidly coupled subcavities within a unit cell. Multiple unit cell cavities and / or subcavities may be formed in different layers of a circuit board.

[0062] "Envelop" or "enveloping" can refer to elements covering each other. For example, a first layer that envelops or that is enveloping a second layer can mean that the first layer is covering the second layer.

[0063] A "phase-change material" can refer to a material and / or substance that is capable of releasing or absorbing a sufficient amount of energy at phase transition to provide heating or cooling.

[0064] "Adjacent" can mean close to or near to an element. For example, if a first layer of material is adjacent to a second layer of material, then the second layer of material may be close to the first layer of material, with possibly other layers of material and / or elements between the first and second layers of material.

[0065] "Peripheral surface" can refer to an external surface of an element. For example, a peripheral surface of the multi-layer circuit board may be the external surface of the multi-layer circuit board.

[0066] A "subcavity" can refer to a portion of a cavity within a larger cavity, where a "cavity" can refer to an empty space within an element, such as one that is otherwise a solid object. For example, a multi-layer circuit board may include cavities and subcavities.

[0067] One or more embodiments disclosed herein relates to a multi-layer circuit board that defines a cavity for a stimulus-responsive tunable dielectric material such as liquid crystal. The multi-layer circuit board can be arranged as a reflectarray beam-steering antenna for microwave and / or radio frequencies. The reflectarray comprises a horn and a circuit board with one or more cavities that are impregnated with a stimulus-responsive tunable dielectric material such as liquid crystal.

[0068] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a tunable microstrip antenna patch.

[0069] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a stacked tunable microstrip antenna patch.

[0070] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a multi-layer dielectric substrate with an embedded electromagnetic phase-controlling device.

[0071] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of an immobilized tunable dielectric element that permits the loading of a tunable dielectric material into multiple layers of dielectric substrates.

[0072] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a functional spacer that serves at least one additional function in addition to maintaining a gap in a reservoir of tunable material.

[0073] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a packaged steerable variable dielectric electronic component for surface-mounted dielectric substrates.

[0074] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a radio frequency (RF) reflectarray beam-steering antenna comprising a source of radiation, a horn, a multi-layer printed circuit board with one or more cavities that are impregnated with a stimulus responsive tunable dielectric material such as liquid crystal to send and / or receive signals. The layers that define the cavity of each reflectarray element may include electrodes that alter an electric field in order to change the optical properties of the liquid crystal in the cavity. The electrodes associated with each cavity may be individually controlled by separate and / or group control signals regulated by electronic circuitry from a power source via metal traces.

[0075] For example, and without limitation, an embodiment of the subject matter described herein includes an embodiment of a wideband reflectarray with surface-mounted tunable dielectric constant electronic components.

[0076] Radio frequency (RF) and microwave electromagnetic waves are used for communications and radar because frequencies can be selected that propagate through the atmosphere with low attenuation losses from humidity, precipitation, and clouds in contrast to optical waves.

[0077] Microwave frequencies generally span from 300 MHz to 300 GHz which correspond to wavelengths of approximately 1 mm to 1 m. Radio frequencies generally span from 20 kHz (limit of human audible range) to approximately 300 MHz. The terms "microwave" and "RF" may be used interchangeably to generally describe electromagnetic radiation appropriate for communications, RADAR, and other applications, unless otherwise specified.

[0078] A reflectarray is a highly directional antenna that can be designed to send and receive RF signals with high gain, low losses, and low cross polarization. Reflectarrays can be manufactured in flat panels that are more compact than parabolic antennas, thereby making reflectarrays attractive for space applications, among other applications where physical footprint and weight are to be minimized. Reflectarray antennas comprise an array of reflecting elements, such as microstrip patches, arranged in a specific pattern. The antenna radiates electromagnetic energy by reflecting the energy from an incident wave generated by a feed element off the reflecting elements in the array.

[0079] A working principle of a reflectarray antenna can be understood in terms of wavefront manipulation. An incident wave is generated by a feed element (e.g., horn) 12 and impinges on the reflecting elements (not shown) in the antenna array 14 as shown in Fig. 1, which depicts a reflectarray 10. The reflecting elements are designed to alter the incident wave phase so that each element's reflected wavefronts are independently steered. The individual beams 16 may combine by superposition to produce a directional beam with a desired radiation pattern. By controlling the phase of the reflected wavefronts, the beam direction and gain of the antenna array 14 can be adjusted. In a reconfigurable reflectarray, each element can be individually adjusted electronically to steer the beam or change its shape.

[0080] Reconfigurable reflectarray elements may utilize resonant patch elements that can be varied in size, in shape, in reactance (e.g., with varactor diodes), and in dielectric constant to change the resonant frequency and therefore the reflection phase.

[0081] The reflection coefficient of each reflecting element is typically adjusted to produce the desired phase shift. This can be done by controlling the shape, size, and orientation of the reflecting elements, as well as the distance between the elements. By carefully designing thereflectarray 10, the antenna array 14 can produce a highly directional beam with a high gain and low sidelobes, making it useful for applications such as wireless communication and radar systems.

[0082] Due to reciprocity, the process may be reversed for RF reception: the reflectarray 10 receives a beam, and the individual reflectarray elements are controlled to steer the beam to the horn 12. The horn 12 is coupled to a waveguide which is further coupled to a detector or source (not shown) for receive and transmit signals, respectively. With a properly designed reflectarray 10, it is possible to transmit and receive one or more frequencies simultaneously.

[0083] In summary, a reflectarray 10 reflects electromagnetic energy from an incident wave generated by a feed element(s) off a set of reflecting elements arranged in a specific pattern (e.g., antenna array 14). The reflecting elements are designed to alter the phase of the incident wave, and may be arranged to provide a highly directional beam with a high gain and low sidelobes.

[0084] Each element in the antenna array 14 may modify the reflection phase by adjusting the incident wave's reflection coefficient. The reflection coefficient is a complex quantity that represents the ratio of complex amplitude of the reflected wave to the incident wave. The magnitude of the reflection coefficient determines the amount of power reflected, while the reflection coefficient's phase determines the reflected wave's phase shift.

[0085] The phase shift of the reflected wave is proportional to the difference in the incident wave's phase and the reflection coefficient's phase. By controlling the reflection coefficient of each element of the antenna array 14, the phase shift of the reflected wave can be adjusted.

[0086] For example, if the reflection coefficient of one element is set to a phase of 0 degrees, then the reflected wave from that element will be in phase with the incident wave. On the other hand, if the reflection coefficient of another element is set to a phase of 90 degrees, then the reflected wave from that element will be out of phase with the incident wave by one quarter cycle. Generally, a reflection coefficient magnitude that results in the desired phase shift is advantageous to minimize antenna losses.

[0087] By adjusting the reflection coefficient of each element of the antenna array 14, the phase of the reflected wave can be controlled. This allows the reflectarray 10 to produce a highly directional beam with a desired gain and phase distribution. In this way, each element of the antenna array 14 modifies the reflection phase by controlling the incident wave's reflection coefficient.

[0088] A patch microstrip antenna is a type of antenna element that can be arrayed to produce a reflectarray. The element consists of a microstrip patch separated from the ground plane by a dielectric layer. The patches can take any shape including but not limited to rectangular, square, triangular, circular, annular, and elliptical. The patch is generally made of metal (e.g. copper, silver, or gold), but graphene can also be used. The dielectric layer can be any substrate such as a circuit board with a dielectric core material. Typically, a circuit board has a relatively low dielectric constant of approximately 2.0 to 10.0, which improves efficiency. The ground plane conducts electrical current when the patch antenna generates an electromagnetic field.

[0089] In operation, power is fed to the microstrip patch with a contacting coupling or an electromagnetic coupling causing it to radiate due to the fringing fields between the edges of the patch and ground plane. Depending on the shape of patch, some edges radiate more than others.

[0090] Patch microstrip antennas tend to have a narrow bandwidth, which is a measure of the range of frequencies over which the antenna operates effectively.

[0091] The operational bandwidth of a patch antenna may be increased in many ways. A thick dielectric layer of low dielectric constant may be desirable to increase the antenna's bandwidth and efficiency. In addition, the design of the patch geometry can increase bandwidth. The length of the patch may measure on the order of one-third to one-half of an (operating) RF wavelength within the dielectric layer (substrate), and increasing the width reduces impedance and increases bandwidth. Furthermore, other shapes (e.g., rounded shapes, slots, and fractal patterns) can all be utilized advantageously to increase bandwidth. In addition, a smaller (partial) ground plane may increase bandwidth, as does the inclusion of dynamic resonators and parasitic elements. Co-locating multiple patches (optionally of different sizes and shapes)on the same dielectric layer may increase bandwidth. Lowering the dielectric constant of the substrate may not only increase the bandwidth, but also opens the possibility of tuning the antenna and enhance beamforming characteristics.

[0092] Antenna array elements can take advantage of materials with tunable dielectric constants to independently change the effective permittivity and separately tune the backscattered phases of each element. Some materials have tunable dielectric constants that can be varied in response to a stimulus such as a temperature change or an electric field. Materials such as graphene, barium strontium titanate (an example of a ferroelectric material), and liquid crystals (both in liquid phase and as polymer) evince electric field-dependent dielectric properties.

[0093] A layer of a liquid crystal can be used to modify the dielectric constant of the dielectric layer of each element as a function of an applied voltage that creates an electric field in which liquid crystals change orientation and thereby change dielectric properties. The effect of the change in dielectric constant is to modify the patch element surface current distribution which causes the patch element to change its resonating frequency. Electrodes are used to create the electric field that changes the orientation of the molecules of liquid crystal.

[0094] Liquid crystals are available commercially by numerous chemical manufacturers. For example, Merck KGaA subsidiary EMG Electronics, offers a product licriOn™ that is applicable for electronically steered antennas. They also supply a product, K15, that is a nematic phase liquid crystal material. Sigma Aldrich also offers liquid crystal products.

[0095] With proper selection of the patch dimensions, the tunable dielectric modifies the reflected phase of the signal. Increasing the dielectric constant increases the effective size of the metal patch, while reducing the dielectric constant reduces the effective size of the patch. These changes result in more or less power stored in the configuration, thus modifying the Q of the structure. The 'Q.' of an antenna is the measure of the power stored in the reactive field relative to the radiated power. The higher the Q, the longer the energy is stored in the antenna, and the more the phase is delayed. Thus, changing the voltage bias between certain microstrip electrodes controls the scattered phase of the antenna.

[0096] Such antenna array elements may be designed to have a phase variation of close to 360 degrees, thereby providing a scanning reflectarray antenna. It may include an array of reflector elements, each of which may be adjusted (independently and / or via groups) with a controller to change the direction of the RF signals transmitted or received by the antenna. This allows the antenna to scan or focus its beam in different directions, providing improved coverage and increased gain compared to traditional, fixed-directional antennas.Tunable patch antenna unit cell

[0097] Tunable patch antenna unit cells 200, 300, and 400 are respectively shown in FIGs. 2, 3, and 4. Unit cells 200, 300, and 400 include a tunable dielectric material reservoir 206, dielectric substrate 202, upper electrode 204a, and lower electrode 204b, or, in the case of unit cell 400, upper electrode 404 and ground plane 406. Tunable dielectric material reservoir 206 is sandwiched between electrodes 204a and 204b or electrode 404 and ground plane 406, wherein at least one electrode serves as a resonator. That is, in some embodiments, upper electrode 204a is both an antenna patch and an electrode. Dielectric substrate thickness 208 may be, for example, 10 mill (i.e., 10 thousandths of an inch or 0.254 mm). Substrate 202 may be or include a microwave substrate material such as LTCC materials, polytetrafluoroethylene (PTFE)-based materials, and / or woven glass reinforced hydrocarbon / ceramic materials (e.g., Rogers Corporation RO4350B™ laminates).

[0098] Unit cell 300 includes upper thermal element 302a and lower thermal element 302b. Unit cell 400 includes upper thermal element 302a. Electrodes 204a and 204b may serve as resonators for RF signal transmission and reception. The electrodes 204a and 204b can be different shapes and / or sizes. The electrodes 204a and 204b can be controlled via an applied bias voltage (e.g. from a controller, switches, etc.). Optionally, unit cells 200, 300, and / or 400 may further include a spacer (not shown) arranged between electrodes 204a and 204b (or electrode 404 and ground plane 406) to prevent electrical shorting by maintaining a minimum distance. A spacer can also serve other functions such as thermal regulation and dielectric constant variation as disclosed further below.

[0099] Thermal elements 302a and 302b are arranged to thermally regulate tunable dielectric material reservoir 206. Because liquid crystal performance is temperature-dependent, thermal elements 302a and / or 302b may heat and / or cool tunable dielectric material reservoir 206 to maintain its temperature within an acceptable range. That is, thermal elements 302a and 302b are thermally coupled with tunable dielectric material reservoir 206. In some embodiments, thermal elements 302a and / or 302b thermally couple with tunable dielectric material reservoir 206 via substrate 202. Additionally or alternatively, a thermal element may be directly thermally coupled to an LC reservoir and / or a cavity thereof.

[0100] Thermal elements 302a and / or 302b may be passive (e.g., phase change material), active (e.g., thermoelectric (TE) devices, resistive heating), or a combination thereof. In one embodiment, thermal elements may take the form of resistive heaters; heating may be utilized in harsh environments such as outer space. For active thermal element embodiments, electric power from a power source (not shown) may be provided for operating, for example, resistance heaters and / or TE devices. In another embodiment, the thermal elements 302a and / or 302b may be thermistors. Optionally, the thermal elements 302a and / or 302b and electrodes 204a, 204b, and / or 404 are powered by a shared power source (e.g., a battery).

[0101] In yet another embodiment, thermal elements 302a and / or 302b may be arranged as heat exchangers. Optionally, the heat exchanger may reject heat to the ambient environment by radiation, convection, and conduction using fins. In another embodiment, a heat exchanger may transport heat via a phase change material and / or fluid. Example fluids may include an ambient fluid such as air or it may be a circulating thermal fluid such as glycol. In another embodiment, the thermal elements 302a and / or 302b are coolers and / or heaters such as thermoelectric devices that utilize the Peltier effect to create a heat flux at the junction of 2 dissimilar metals; these devices may also be used for heating.

[0102] For unit cell 400, electrode 404 is operationally coupled to a ground plane 406, thereby establishing, in some embodiments, electrode 404's impedance and eigenmodes (e.g., resonant frequencies). PCBs and other circuit board substrates are typically equipped with a ground plane. The ground plane 406 may optionally be patterned underneath the liquid crystal reservoir 206.

[0103] Electrodes 204a, 204b, 404 and / or ground plane 406 may include metals such as copper, silver, gold, and aluminum as well as other materials such as tin-doped indium oxide (ITO). Films of ITO are transparent to microwaves, so may be arranged as a ground electrode. ITO can be deposited on a substrate by reactive RF sputtering.

[0104] In some embodiments, a tunable antenna unit cell may include a dielectric substrate layer that is arranged between at least an antenna patch (e.g., a microstrip patch) and a tunable dielectric material reservoir. FIG. 5 shows tunable patch antenna unit cell 500, which includes multi-layer circuit board portion 501.

[0105] Unit cell 500 may be configured, along (notational) axis 503, in a relative order of high- frequency circuit board layers 502a, 502b, and 502c, ground plane 514, and baseband circuit board layers 504a, 504b, and 504c. High-frequency circuit board layers 502a, 502b, and 502c may be adapted to operate with signals in the RF and / or microwave range. These frequency ranges typically range from several hundred megahertz (MHz) to several tens of gigahertz (GHz) or even higher. Baseband circuit board layers 504a, 504b, and 504c may be adapted to operate with signals that are relatively lower with respect to the signals of the high-frequency circuit board layers 502a, 502b, and 502c: "baseband" typically is a band of signal frequencies that has not been modulated to higher frequencies. Example high-frequency substrate materials may include polytetrafluoroethylene (PTFE)-based materials, and / or woven glass reinforced hydrocarbon / ceramic materials. Example baseband substrate materials may include FR4 and similar materials made of woven fiberglass and covered with epoxy.

[0106] Unit cell 500 may be further configured, along (notational) axis 503, in a relative order of antenna patch 508, upper electrode 510, liquid crystal (LC) reservoir 511, and lower electrode 512. Although antenna patch 508 and LC reservoir 511 are shown to share common central axis (that is, vertically aligned with respect to axis 503), in alternative embodiments, antenna patch 508 and reservoir 511 may be offset with respect to axis 503. Similarly, although axis 503 is arranged orthogonally with respect to multi-layer circuit board portion 501, relative order of components, layers, and / or elements may be defined by non-orthogonal axes with respect to a multi-layer board portion and / or substrates, components, layers, and / or elements thereof.

[0107] Thermal elements 506a may be arranged on a peripheral surface of circuit board portion 501 or embedded within circuit board portion 501, including arrangements that are relatively near LC reservoir 511. Thermal element 506b may be arranged below ground plane 514.Control lines to the electrodes and thermal elements are not shown.

[0108] One of electrodes 510 and 512 may be electrically coupled with the ground plane. Although ground plane 514 is shown separately from electrodes 510 and 512, a lower electrode may be a common electrode for a plurality of unit cells and is thus arranged as a ground plane.

[0109] Baseband circuit board layers 504a, 504b, and 504c may include circuits such as base band circuitry (not shown) for controlling elements of unit cell 500, including, for example, an adjustable power supply with controller and switching circuits. Such circuity may be located below ground plane 514 for, among other things, suppressing electromagnetic interference with the elements of high-frequency circuit board layers 502a, 502b, and 502c, particularly LC reservoir 511 and operably coupled elements thereof.

[0110] Controller 516 may apply or cause to apply control signals to one or both of electrodes 510 and 512 for tuning a dielectric constant of LC reservoir 511.

[0111] FIG. 6 shows unit cell 600 in a perspective view. Unit cell 600 may be dimensioned for operating at around, for example, the 60 GHz band. For example, unit cell dimension 614 may be on the order of approximately 2.5 mm, which is approximately half the wavelength of 60 GHz (ca. 5 mm). In this view, circuit board portion 602 is transparently shown to further show the elements that reside within and / or below circuit board portion 602.

[0112] Unit cell 600 includes, in relative order, antenna patch 604, circuit board portion 602, and ground plane 612. Arranged within circuit board portion 602, in relative order, is upper electrode 606a, liquid crystal reservoir 608, and lower electrode 610. Although antenna patch 604, electrode 606a, and LC reservoir 608 are shown with a circular geometry, embodiments can include other shapes (e.g., rectangular, fractal, and / or irregular or non-symmetrical shapes). Electrode 606a includes traces 606b for electrically coupling with vias or other elements of unit cell 600 (not shown).

[0113] FIG. 7 depicts modeled phase performance results of a tunable patch antenna unit cell (e.g., unit cell 600). The left graft 702 shows the phase performance in the 60 GHz band for different unit cell dimensions (i.e., from 2.409 mm to 3.983 mm). Each frequency demonstrates that a 360-degree phase shift is possible, which affords considerable flexibility in beam-forming techniques for an array of unit cells. Right graft 704 shows a measurement of variation in phase error over the frequency bandwidth. A unit cell may be designed to operate at 60 GHz, where the phase error is the lowest and increases with increasing frequency difference from 60 GHz.

[0114] FIG. 8 shows modeled antenna loss results of a tunable patch antenna unit cell that was optimized for 60 GHz. The model evaluates the reflection of the two polarizations at normal incidence. The antenna loss is low: less than 1 dB at 60 GHz. Power efficiency is high. The cross coupling is near -45dB. This patch antenna unit cell exhibits much lower loss than standard MMIC technology.

[0115] Several unit cells can be arranged to form an array. FIG. 9 shows linear array 900, which comprises unit cells LCdk and LC2 - LC8. FIG. 10 shows their respective dielectric constants for a 30 degree scan angle. For an incident plane wave, each unit cell of array 900 may be individually tuned in order to optimize a reflected wave at a 30 degree angle. FIG. 10 shows the values of the dielectric constants that will achieve a coherent beam at 30 degrees. The dielectric constant values range from 2.4 to 4.0. The various dielectric constants of a respective unit cells' LC reserivoir may not vary (across array 900) in a linear fashion.

[0116] FIG. 11 depicts modeled linear array beam patterns results for four scan target angles: 10 (graph 1102), 20 (graph 1104), 30 (graph 1106), and 40 degrees (graph 1108). A simulation was performed of uniform planewave excitation of linear array 900 at several frequencies within the 60 GHz band (57 to 63 GHz) for each target angle. Plots were made of relative power that emanates versus reflection angle for each frequency. The x-axes show scan angle in degrees, and the y-axes show relative power in d Bi (decibel relative to isotropic). The relative power indicates the forward gain of an antenna. Each plot shows a salient primary lobe at the target angle for each frequency. Linear array 900 is shown to reflect a beam at the target angles for every frequency with minor variation across the frequency band.

[0117] Two dimensional arrays are desirable for reflectarrays, transmitarrays, and conventional arrays. FIG. 12 shows an array system 1200, which includes a two-dimensional (2D) array 1202 of tunable patch antenna unit cells 1204 and controller 1210. Array 1202 includes unit cells 1204 with the same cell / component size, however, differing sizes are possible. For example, a dual-band array may feature two differently sized antenna patches for communicating on different frequencies. In some embodiments, a substrate may feature two interleaved arrays that are co-located and interspersed on the substrate. Spacing between corresponding elements (i.e., the pitch) of unit cells 1204 of array 1202 may be on the order of a half wavelength (lambda / 2) of an RF operational frequency (e.g., a modulated transmission or reception signal), which allows for high-density packing of unit cells 1204.

[0118] Unit cell outline 1206 is a hexagonal shape, but other outline shapes are possible. Lattice vectors 1208 show the arrangement pattern of unit cells 1204 on substrate 1212. Although unit cells 1204 are shown as the same size, in some embodiments, unit cells may be at least two different sizes (e.g., one size that is optimized for transmitting signals and one size that is optimized for receiving signals).

[0119] FIG. 13 is a cross-sectional view of multi-layer circuit board portion 1300 with multiple tunable patch antenna unit cells 1301, 1303, and 1305. Unit cells 1301 and 1305 share the same sized antenna patch 1306, electrode 1312, LC reservoir 1318, and thermal element 1324. Unit cell 1303 shows a narrower antenna patch 1308, electrode 1314, LC reservoir 1320, and thermal element 1326. Unit cells 1301, 1303, and 1305 are arranged across multi-layer high- frequency circuit board 1302, ground plane 1307, and multi-layer baseband circuit board 1304. One size may be used for transmiting signals and the other may be used for reciving signals for an array antenna.

[0120] Advantages of the disclosed arrays may include one or more of lightweight, low manufacturing cost, operational across a wide band of spectrum, highly directional Rx / Tx beams, low profile, compact, and highly scalable manufacturing thereof.Multiple Patch Antenna Unit Cells[1211 One way to increase bandwidth may be arranging, within a unit cell, multiple antenna patches. Multiple antenna patches may also enable dual / multiple band operation.

[0122] FIG. 14 is a cross-sectional view of multi-layer circuit board portion 1400 with tunable patch antenna unit cell 1401. On or in multi-layer high-frequency circuit board 1402, unit cell 1401 includes differently sized antenna patchs 1406 and 1408, electrodes 1410 and 1414, and LC reservoir 1412. Ground plane 1403 is arranged between multi-layer high-frequency circuit board 1402 and multi-layer baseband circuit board 1404.

[0123] FIG. 15 is a cross-sectional view of multi-layer circuit board portion 1500 with tunable patch antenna unit cell 1501. On or in multi-layer high-frequency circuit board 1502, unit cell 1501 includes antenna patchs 1510, 1518, and 1526; electrodes 1512, 1516, 1520, 1524, 1528, and 1532; and LC reservoir 1514, 1522, and 1530. Ground plane 1506 is arranged between multi-layer high-frequency circuit board 1502 and multi-layer baseband circuit board 1504.

[0124] Here the unit cell elements are shown as different in size with the smaller (e.g., narrower) elements above the larger (e.g., wider) elements. Although the unit cell elements are depicted in FIG. 15 as aligned, unit cell elements can be offset from one another. For example, liquid crystal reservoirs 1514, 1522, and 1530 can be offset from their respective antenna patches 1510, 1518, and 1526.

[0125] A working principle of a tunable patch antenna may be understood in terms of the electromagnetic field distribution. When a microwave or RF signal is incident on an antenna patch, said element resonates (typically withing a given bandwidth), generating an electromagnetic field in the surrounding space. The electromagnetic field of an upper antenna patch may operably couple to lower antenna patches and / or lower electrodes at, for example, a controllable resonant frequency. The electromagnetic field is typically strongest at the surface of antenna patch and decreases with distance from the antenna patch.

[0126] Once again, thermal elements can be located at any desired location throughout the stackup. The liquid crystal reservoir may use a spacer, but none is shown. In one embodiment,the bottom electrode is electrically connected to the ground plane. In another embodiment, multiple patch antennas are located in the same plane adjacent to one another.

[0127] In addition to the stacked configuration, the frequency bandwidth of a stacked patch microstrip antenna can also be increased in many ways similar to a single (planar) patch microstrip antenna: by increasing dimensions of the patches and dielectric layers, by adding dynamic resonators, and by including numerous patches in each plane.

[0128] Furthermore, increasing the number of stacked patches may widen the frequency bandwidth. A broad bandwidth antenna may require more tunable layers in which each antenna patch resonates at different respective frequencies.

[0129] LC reservoirs 1514, 1522, and 1530 may be independently controlled. In some embodiments, a lookup table may be utilized for tuning the LC reservoirs 1514, 1522, and 1530.

[0130] In general, control systems can dynamically change the voltage bias applied to an LC reservoir to generate a desired beam positions and / or shape. In some embodiments, each unit cell of an antenna array includes a control signal line that is operably coupled to a controller (e.g., a hot electrode and / or signal lines coupled thereto).Multi-Layer Dielectric Substrate with Variable Dielectric Material

[0131] FIG. 16 is a cross-sectional view of multi-layer circuit board portion 1600 with tunable patch antenna unit cells 1606, 1608, 1610, and 1612. On or in multi-layer high-frequency circuit board 1502, unit cells 1606, 1608, 1610, and 1612 respectively include antenna patchs 1614, 1622, 1634, and 1642; electrodes 1616, 1620, 1624, 1628, 1632, 1636, 1640 and 1644; and LC reservoir 1618, 1626, 1630, 1638, and 1646. Ground plane 1603 is arranged between multilayer high-frequency circuit board 1602 and multi-layer baseband circuit board 1604.

[0132] LC reservoirs 1618, 1626, 1630, 1638, and 1646 may be independently controlled. In some embodiments, a lookup table may be utilized for tuning the LC reservoir 1618, 1626, 1630, 1638, and 1646 of a respective unit cell 1606, 1608, 1610, and 1612.

[0133] In general, control systems can dynamically change the voltage bias applied to an LC reservoir to generate a desired beam positions and / or shape. In some embodiments, each unit cell of an antenna array includes a control signal line that is operably coupled to a controller (e.g., a hot electrode and / or signal lines coupled thereto).

[0134] Embodiments may include dielectric substrates made of ceramics. For example, low temperature cofired ceramic (LTCC) technology. One or more dielectric layers can serve as structural members that may fully or partially define a cavity, which is loaded in full or in part with variable dielectric material. The cavity height may be designed with a tradeoff between a thin layer of variable dielectric material which is advantageous for quick response time and a thicker layer which favors a wider range of tuning.

[0135] For unit cell 1606, a cavity (not shown) may be formed in multiple layers of multi-layer high-frequency circuit board 1602. Electrodes 1616 and 1620 may be arranged within or further define the cavity for LC reservoir 1618.

[0136] Unit cell 1608 defines two discreet cavities (not shown) respectively formed in a different layer of multi-layer high-frequency circuit board 1602. LC reservoir 1626 and 1630 are stacked with electrode 1628 and a portion of circuit board 1602 arranged in between. In some embodiments, LC reservoirs 1626 and 1630 are independently controllable for wideband operation, however, in other embodiments, multiple stacked reservoirs can be controlled by one control signal. In some embodiments, one electrode between two sacked reservoirs (e.g., electrode 1628) may be arranged to create an electric field that affects both reservoirs. That is, electrode 1628 may be operably coupled to both LC reservoirs 1626 and 1630.

[0137] For example, electrodes 1624 and 1632 may be both "hot" or biasing electrodes that receive a biasing signal (e.g., from a controller) and electrode 1628 may be a common ground electrode arranged therebetween. As such, a first electric field (for reservoir 1626) may be established between electrode 1624 and 1628 and a second electric field (for reservoir 1630) may be established between electrode 1628 and electrode 1632. Electrodes 1624 and 1632 may receive a common biasing signal or differing biasing signals.

[0138] Unit cell 1610 includes a single cavity (not shown) formed in at least two substrate layers of multi-layer high-frequency circuit board 1602 for LC reservoir 1638.

[0139] Unit cell 1612 includes a single cavity (not shown) for LC reservoir 1646 is formed through multiple layers of multi-layer high-frequency circuit board 1602.

[0140] The aforementioned embodiments disclose possible configurations and arrangements to form a tunable antenna unit cell in multiple dielectric substrate layers. Although all dielectric substrate layers are depicted with the same height, embodiments may include substrate layers of varying heights.

[0141] For cases in which a liquid phase liquid crystal occupies cavities in dielectric substrate layers, said cavities may be sealed. In one embodiment, a polymer film is applied. Optionally, cavities are coated with a polymer film such a polyimide to encourage alignment of the liquid crystal elements in the unbiased state. Furthermore, features to load the liquid phase liquid crystal such as trenches are envisioned. A temporary filler material may be used to fill the trenches during the bonding of multiple layers together in order to maintain the trench dimensions; the filler material is removed afterwards. Trenches are sealed after loading the reservoirs with liquid crystals.Tunable dielectric Element (VDCE) Arrangements

[0142] Manufacturing an array of tunable elements in multiple layers of dielectric substrates with a liquid phase variable dielectric material in cavities requires additional steps (fill, load, seal) and special handling procedures. In addition, making dedicated trenches for filling the variable dielectric fluid is required as well as sealing the trenches afterwards. To obviate many of these steps, various solutions are envisioned that generally immobilize a variable dielectric material in order to facilitate assembly and to produce more uniform tunable elements.

[0143] A cavity can be filled with a variable dielectric material such as liquid crystal in nonliquid form for easier handling prior to bonding. In one embodiment, liquid crystal gel is loaded into cavities. In another embodiment, a solid form of liquid crystal is loaded. The solid may take 1the form of a liquid crystal polymer (LCP) that has been tailored to fit inside the cavity. In another exemplary embodiment, the cavity is filled with frozen liquid crystal (optionally that is contained in a gel or other material) prior to bonding.

[0144] Another solution is to utilize a cavity that contains tunable dielectric material when loading the elements into the cavities prior to bonding. Such a tunable dielectric element (VDCE) comprises a housing that contains a tunable dielectric material such as liquid crystal. The housing may define the cavity.

[0145] The VDCE housing may take on any shape or size. The VDCE housing may be made of a polymer. The polymer may be designed for thermal performance (e.g., to resist high temperature.) Embodiments may include flexible polymers and rigid polymers. A rigid polymer VDCE housing may take the form of a hollow button-shaped disk or a capsule that can be loaded with tunable dielectric material.

[0146] In one exemplary embodiment, the housing may be made of liquid crystal polymer that is filled with liquid crystal in liquid phase.

[0147] FIG. 17 illustrates various tunable dielectric element arrangements. VDCE 1702 includes liquid crystal reservoir LC arranged within cavity C. Cavity C may be defined by a discrete housing H, dielectric layers, electrodes, or a combination thereof. VDCE 1704 includes spacer S. VDCE 1706 includes a lower thermal element TE1, and VDCE 1708 includes side thermal elements TE2 and TE3. VDCE 1710 includes functional spacer FS, which is described in more detail below. The Housing H feature denoted in dashed lines shows it as an optional feature of a VDCE.

[0148] VDCE 1712 includes antenna patch Pl. VDCE 1714 includes antenna patches P3 and P4, thereby defining aperture A. VDCE 1716 includes dielectric layer D, which arranged between upper antenna patch P5 and lower antenna patch P6. VDCE 1718 includes liquid crystal reservoir LC arranged between antenna patches P7 and P8. In some embodiments, VDCEs are arranged to fill cavities in multi-layered dielectric substrates. In some embodiments, VDCEs may be surface mounted on circuit boards.

[0149] The immobilized tunable dielectric material concepts are advantageous for mass production because they allow a material such as liquid crystal in liquid phase to be picked and placed like an electronic component with an automated machine on or in a dielectric substrate.

[0150] A method of manufacture is envisioned in which immobilized elements of tunable dielectric material are loaded onto dielectric substrates prior to bonding.Functional Spacers for Tunable dielectric Elements

[0151] Spacers in devices that contain liquid crystals maintain a uniform gap between elements and between circuit board layers. They may be electrically insulating to prevent shorting, tolerant of vibration, and possibly porous (e.g., granules, mesh, cylinders, spheres, spiral pattern in plane).

[0152] Spacers with additional functionality may be integrated with tunable elements. In one embodiment, a functional spacer comprises a tunable material such as a liquid crystal polymer or an electro-optic crystal. In another embodiment, a functional spacer comprises an absorbent material to absorbs liquid crystal and to discourage leaking (e.g. foam or sponge). In another embodiment, a functional spacer comprises a thermal regulation element. In another embodiment, a function spacer comprises a reactive component that modifies the dielectric constant of an element.

[0153] Tunable VDCE embodiments may include electrodes, leads that are operably coupled to said electrodes, and possibly further features. One benefit may be to simplify the manufacturing of antenna arrays such as reflectarrays by making tunable patch elements into standard electronic components that can be mounted on or integrated with a dielectric substrate such as a PCB using, for example, standard surface-mounting or through-hole techniques including automated assembly.

[0154] FIG. 18 illustrates various packaged tunable tunable dielectric electronic components.VDCE 1802 includes a liquid crystal reservoir LC packaged in housing H with electrodes El and E2 and leads LI and L2. In alternative embodiments, an electro-optic crystal is packaged in ahousing with integrated electrodes and leads. Embodiment leads may be arranged for through- hole mounting and / or surface-mounting.

[0155] Liquid crystal embodiment materials may include liquid phase and solid state (e.g., polymer) liquid crystal. VDCEs 1804, 1806, 1808, and 1810 show internal electrodes E3 and E4, leads LI and L2 partially arranged within housing H, and spacer S, which occludes, in these schematic views, the LC reservoir (not shown). VDCEs 1804, 1806, and 1808 include antenna patch P. In some embodiments, one or more of electrodes El - E4 may be arranged as a resonator. VDCEs 1808The size and shape of the antenna patches, electrodes, and LC reservoir can be designed for specific frequencies and / or optimized for response time versus range of phase shift. VDCE 1810 includes thermal element TE operably coupled to leads L3 and L4.

[0156] In some embodiments, multiple independently controlled tunable elements are arranged in one package. An array of tunable elements may be co-packaged in a device featuring several leads to control several electrodes that control several tunable elements. Such an arrayed component may be packaged into a surface-mountable antenna. The elements can have different sizes and shapes (e.g., for send and receive, and for broadband operation). The tunable elements may be located side-by-side or in a stack.

[0157] FIG. 19 is a cross-sectional view of multi-layer circuit board portion 1900 with tunable patch antenna unit cells 1901 and 1903, which each include antenna patch 1908, upper electrode 1910, upper LC reservoir layer 1912, optional upper parasitic elements 1922, LC via 1916, optional lower parasitic elements 1924, lower LC reservoir layer 1914, and lower electrode 1926 arranged on or in high-frequency circuit board layers 1902. Ground plane 1905 is arranged between layers 1902 and baseband circuit board layers 1904. Upper and lower parasitic elements 1922 and 1924, partially enveloped by upper and lower LC reservoir layers 1912 and 1914, may increase the operable bandwidth of unit cells 1901 and 1903. Upper LC reservoir layer 1912 and lower LC reservoir layer 1914 are arranged in a respective subcavity (not shown) of multi-layer circuit board portion 1900.

[0158] High-frequency circuit board layers 1902 of multi-layer circuit board portion 1900 define tunable dielectric material inlet channel 1928, which is arranged to flow, during a loading step,tunable dielectric material to tunable dielectric material inlet 1930 of unit cell 1901 and fill upper LC reservoir layer 1912, LC via 1916, and lower LC reservoir layer 1914 of unit cell 1901. The tunable dielectric material may further flow out of tunable dielectric material outlet 1932 to tunable dielectric material inlet 1930 across tunable dielectric material channel 1934.Channel 1934 provides a channel to apply and / or flow tunable dielectric material between at least unit cells 1901 and 1903. In some embodiments, a tunable dielectric material channel may be operably coupled to three or more unit cells. Tunable dielectric material may further flow through unit cell 1903 and flow out tunable dielectric material outlet 1932 and tunable dielectric material outlet channel 1936. In some arrangements, a tunable dielectric material channel may be an inlet channel, and outlet channel, or both, as shown by channel 1934, which is an outlet channel for unit cell 1901 and an inlet channel for unit cell 1903.

[0159] In one embodiment, electrodes 1910 and 1926 may form a "hot-ground" electric pair operably coupled— via, for example, static, quasi-static, and / or other fields— with LC reservoir layers 1912 and 1914. Optionally, insulator layer 1907 may be applied on or above antenna patches 1908 and thermal element TE may be arranged within layers 1902.

[0160] FIG. 20 is a cross-sectional view of multi-layer circuit board portion 2000 with tunable patch antenna unit cells 2001 and 2003, which shows antenna patches 2010 arranged on (or otherwise above) insulation layer 2008. Tunable dielectric material channels 2002, 2004, and 2006 may be the same or substantially the same thickness as a layer of high-frequency circuit board layers 1902.

[0161] FIG. 21 is a cross-sectional views of multi-layer circuit board portion 2100 with tunable patch antenna unit cells 2102, with high-frequency circuit board layers 2104 and baseband frequency circuit board layers 2106. In relative order along axis 2103, unit cell 2102 includes antenna patch 2108, dielectric layer 2104a, ground electrode 2114, upper LC reservoir layer 2116, optional upper parasitic patch 2122, dielectric layer 2104c, optional lower parasitic patch 2124, lower LC reservoir layer 2118, hot electrode 2128 (e.g., a biasing electrode), dielectric layer 2106a, ground plane 2107, dielectric layer 2106b, dielectric layer 2106c, bias circuit 2132, and solder mask layer 2106d. Circuit board portion 2100 further includes LC via 2120, adhesive2118, dielectric layers 2104b, 2104d, and 2106b, ground electrode via feature 2110, ground electrode via 2112, and hot electrode via 2130.

[0162] FIGs. 22-1 to 22-15 illustrate steps in a fabrication process of a multi-layer circuit board portion 2200, which includes patch layer 2202P, upper dielectric layer 2202, ground layers 2202G, upper LC layer 2204, spacer layer 2206, lower LC layer 2208, bias layer 2210, copper layer 2210C, and lower dielectric layers 2212, with upper copper layer 2212UC and lower copper layer 2212LC.

[0163] As shown in FIG. 22-1, a fabrication sequence may begin with un-patterned bare multilayer circuit board portion 2200. Some layers have copper cladding. Two types of circuit boards may be used such as high frequency material of composite laminates (e.g., RO4350B) and low frequency material of FR-4 compatible epoxy laminates (e.g., FR-408). The height of each layer may be standard COTS values available from a board manufacturer.

[0164] Referring to FIG. 22-2, forming antenna patch 2214, ground electrode 2216, bias electrode 2218, and pad 2220 may include copper patterning techniques with several sub-steps such as photoresist application, photolithography exposure, develop, etch, strip, oxidize, and inspection. The final copper patterns are depicted in FIG. 22-2. Note that the ground electrode diameter is smaller than (lower) the bias electrode diameter; the adjacent pad makes the ground electrode appear larger in cross section. A passivation layer may be applied to copper surfaces, especially those in contact with liquid crystal (electrodes) or air (antenna patch).

[0165] In some embodiments, oxidation passivates copper electrodes. In FIG. 22-3, a coverlay CL such as polyimide film and / or a board adhesive is applied to ground electrode 2216.Polyimide or other passivation layer can be mechanically treated to assist with the alignment of liquid crystal material. Coverlay CL may be applied in two steps: an adhesive film application followed by a polyimide film application.

[0166] In FIG. 22-4, adhesive layer A is tacked to the liquid crystal reservoir layers 2204 and 2208. A flexible adhesive such as Rogers 3232 is used because of its low thickness (0.02 mm) and low flow. In FIG. 22-5, through-holes are made through adhesive A and layers 2204 and 2208 to create upper and lower subcavities UC and LC for liquid crystal material. Patterningthrough adhesive A and solid board simultaneously results in perfect alignment of the prepreg and reservoirs. Hole-formation may be via a laser. In some embodiments, a 0.75:1 (board:hole) aspect ratio is achieved.

[0167] In FIG. 22-6, via channel 2222 is formed for fluidly coupling upper and lower subcavities UC and LC. This step can reduce or eliminate the degree of channel redundancy of the tunable dielectric material channels. For example, a single continuous path for flowing or otherwise applying tunable dielectric material may alternate between layers 2204 and 2208.

[0168] In FIG. 22-7, a sub-assembly is created by tacking reservoir layers 2204 and 2208 together. In FIG. 22-8, tunable dielectric material channel 2224 is made in adhesive layer A. Channel 2224 is depicted as accessing only one side, but a fill path may traverse both sides of a unit cell. In FIG. 22-9, partially cured (low flow) prepreg layer PL is inserted between the low frequency layers 2212. In FIG. 22-10, a hot press may be used to bond layers together. The different shading of the adhesive and prepreg layers indicates bonding and curing.

[0169] In FIG. 22-11 electrode via channels 2224 and 2226 are formed. In FIG. 22-12, via channels 2224 and 2226 may be plated with an electroless copper process to form vias. In FIG. 22-13, via channels 2224 and 2226 are plugged with epoxy. In FIG. 22-14, solder mask SM is applied on the bottom layer, optionally adding a conformal coating (not shown), and performing solder reflow. In FIG. 22-15, liquid crystal may be flowed or otherwise applied using, for example, a vacuum fill process. The loading port may then then be plugged with epoxy plug P.

[0170] FIGs. 23A and 23B respectively illustrate top and perspective views of antenna array 2300, which includes tunable patch antenna unit cells 2302 and tunable dielectric material channels 2304. Portion 2306 of FIG. 23A outlines the apoximate area shown in FIG. 23B. FIGs. 23A and 23B omit circuit substrate layers below antenna patch 2302P to shown the structures and features of unit cells 2302 such as ground via G operably coupled to upper electrode UE, LC reservoir LC, and upper and lower tunable dielectric material channels channels 2304U and2304L.

[0171] FIGs. 24 to 29 illustrate antenna array fill patterns. The shown arrays may be subarrays of a larger antenna array. FIG. 24 shows antenna array 2400 with tunable patch antenna unit cells 2402 and tunable dielectric material channels 2404 forming a single, continuous serpentine fill pattern. FIG. 25 shows antenna array 2500 with tunable patch antenna unit cells 2502 and tunable dielectric material channels 2504 forming a single, continuous spiral fill pattern. In some embodiments, tunable dielectric material source is coupled to input unit cell 2502i. A pressure differential may be formed between input unit cell 2502i and output cell 2502o, thereby inducing the tunable dielectric material to flow from input unit cell 2502i to output cell 2502o. The filling step may be confirmed as complete when tunable dielectric material flows out (an output) of output cell 2502o. Output and input unit cells may be utilized in various combination for other array fill patterns (e.g., the fill patterns of FIGs. 24 and 26 to 29). Alternatively or additionally, an array may be placed in a liquid crystal bath and a vacuum applied and released for filling the unit cell reservoirs.

[0172] FIG. 26 shows antenna array 2600 with tunable patch antenna unit cells 2602 and tunable dielectric material channels 2604 forming a single branch fill pattern for filling each branch B of array 2600. FIG. 27 shows antenna array 2700 with tunable patch antenna unit cells 2702 and tunable dielectric material channels 2704 forming a grid fill pattern with multiple parallel channels. FIG. 28 shows antenna array 2800 with tunable patch antenna unit cells 2802 and tunable dielectric material channels 2804 forming a honeycomb fill pattern. FIG. 29 shows antenna array 2900 with tunable patch antenna unit cells 2902 and tunable dielectric material channels 2904 forming a lattice fill pattern, with maximum connectivity between and among unit cells 2902.Reflectarray Beam-Steering Antenna Embodiments

[0173] A reflectarray may comprise a feed horn and an array of ultra-low-cost elements (unit cells) fabricated on a circuit board (e.g., a PCB). A unit cell may include a top metal disk (an antenna patch) and two embedded metal disks with liquid crystal material between them. By altering the potential across the lower metal disks, the dielectric constant of the liquid crystal material is altered, thereby providing a phase delay in a retransmitted signal.

[0174] In a transmit mode, a signal may be generated by a feed horn, which is arranged to illuminate the antenna array. The antenna array absorbs the RF energy, phase shifts the signal, and then retransmits the signal in the desired direction. The reflectarray can direct energy in multiple directions simultaneously. Multi-beam operation may be accomplished by replacing a feed horn with a MIMO or phased array antenna. Each of the beams generated by the horn is then reflected by the same angle, creating multiple beams on the ground or other destination.

[0175] In one embodiment, a reflectarray antenna comprises an array of elements comprising tunable dielectric material embedded in multiple dielectric layers in cavities defined by through-holes and trenches. Optionally, one or more elements feature stacked tunable patch elements. Optionally, one or more elements feature a thermal element. The dielectric material may be prepackaged as a VDCE.

[0176] In another embodiment, a reflectarray antenna comprises an array of elements comprising tunable dielectric material surface-mounted on a dielectric substrate.

[0177] In general, those skilled in the art will recognize that the various aspects of inventions described herein can be implemented, individually and / or collectively, in whole and / or in part, by a wide range of hardware, software, elements and electronic circuitry. Any combination thereof can be considered as being composed of various types of "circuitry" which herein refers to having at least one discrete electrical circuit, or one integrated circuit, or one application specific integrated circuit, or one general purpose computing device configured by software, or a memory device, or a circuit. Those who are skilled in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof. Those who are skilled in the art will recognize that hardware and elements such as digital interfaces, signal processors, multiplexers, power sources, laser sources, photodetectors, etc., can be successfully implemented by a wide array of technologies.

[0178] In some embodiments, a controller can be in operative communication with any device, component, subcomponent, system, electrode, power source, and any associated circuitry or any other electronic or electromagnetic devices or components, and with any switches, relays, transformers, inverters, power sources, light sources, photo detectors, regulators, and other electrical components, and any other components to selectively operate the disclosed device ordevices according to a desired method. Control connections can be made through wired electrical conditions or through wireless connections. In some embodiments, the controller can be configured to operate the system according to specified parameters (e.g., to vary a voltage in order to alter the dielectric constant of a material in order to create a phase shift in order to steer a beam). A controller may include one or more processors for operating the system.[1791 Unless otherwise defined herein, terms of technical or scientific nature used in the embodiments and natures of the present disclosure are attributed their ordinary meanings that are generally understood one of ordinary skill in the art to which the present disclosure belongs. Numerical descriptions using the words "first,", second,", etc., in this disclosure are not intended to indicate importance, quantity, or order, but rather to distinguish one element from another unless otherwise specified. The words "comprise," or "include," or the like mean that the object, element, or item contains the object, element, or item and equivalents thereof, but does not exclude the presence of other objects, elements, or items. The terms "coupled," "connected," and "in communication with" are not limited to physical or mechanical connections, but may include electrical, optical, fluidic, or other connections, whether direct or indirect. When used in reference to drawings, the words "upper," "lower," "right," "left", and the like indicate relative positional relationships; when the absolute position of the described object is changed, the relative relationships describing position may also change accordingly. Furthermore, an element such as a layer, film, region, substrate, etc., is referred to positionally (e.g. "on,", "under," "beside") other intervening elements may be present the therebetween.

[0180] It will also be understood by those skilled in the art that various changes may be made to the exemplary embodiment or embodiments disclosed herein, and modifications may be made to the teachings of the present disclosure without departing from the essential scope thereof. In addition, equivalents may be substituted for elements of embodiments without departing from the scope of the present disclosure. Therefore, it is intended that the present disclosure not be limited to the particular embodiment or embodiments disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.

Claims

ClaimsWhat is claimed is:

1. A tunable patch antenna unit cell comprising: a multi-layer circuit board portion that defines, within the multi-layer circuit board portion, a cavity; an antenna patch; an upper electrode arranged within the multi-layer circuit board portion; a lower electrode arranged within the multi-layer circuit board portion; and a tunable dielectric material reservoir arranged within the cavity, the tunable dielectric material reservoir comprising a tunable dielectric material that is operably coupled to the antenna patch, the upper electrode, and the lower electrode, wherein the tunable patch antenna unit cell has an axis and is configured along the axis in a relative order of the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

2. The tunable patch antenna unit cell of claim 1, wherein the tunable dielectric material reservoir comprises at least two layers of the tunable dielectric material, the at least two layers arranged at least partially between the upper and lower electrodes.

3. The tunable patch antenna unit cell of claim 2, wherein the tunable dielectric material reservoir further comprises a via that spans the at least two layers.

4. The tunable patch antenna unit cell of any one of claims 1-3, wherein the multi-layer circuit board portion at least partially defines one of a tunable dielectric material inlet channel that is fluidly coupled with the cavity and a tunable dielectric material outlet channel that is fluidly coupled with the cavity.

5. The tunable patch antenna unit cell of claim 4, wherein the multi-layer circuit board portion at least partially defines the tunable dielectric material inlet channel in a first dielectric layer of the multi-layer circuit board portion and the multi-layer circuit board portion at least partially defines the tunable dielectric material outlet channel in a second dielectric layer of the multi-layer circuit board portion, the first and second dielectric layers being different layers of the multi-layer circuit board portion.

6. The tunable patch antenna unit cell of any one of claims 1-5, further comprising at least one parasitic patch that is operably coupled to the antenna patch.

7. The tunable patch antenna unit cell of claim 6, wherein the tunable dielectric material reservoir at least partially envelops the at least one parasitic patch.

8. The tunable patch antenna unit cell of claim 6 or claim 7, wherein the tunable patch antenna unit cell comprises an upper parasitic patch and a lower parasitic patch.

9. The tunable patch antenna unit cell of claim 8, wherein the tunable dielectric material reservoir comprises an upper layer and a lower layer, the upper layer at least partially envelops the upper parasitic patch and the lower layer at least partially envelops the lower parasitic patch.

10. The tunable patch antenna unit cell of any one of claims 1-9, further comprising at least one thermal element that is thermally coupled to the tunable dielectric material reservoir.

11. The tunable patch antenna unit cell of claim 10, wherein the tunable patch antenna unit cell comprises at least one of an active thermal element and a passive thermal element.

12. The tunable patch antenna unit cell of claim 10, wherein the at least one thermal element comprises a phase change material.

13. The tunable patch antenna unit cell of any one of claims 1-12, further comprising at least one insulator layer disposed adjacent to the antenna patch.

14. The tunable patch antenna unit cell of claim 13, wherein the tunable patch antenna unit cell is configured along the axis in a relative order of the at least one insulator layer, the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

15. The tunable patch antenna unit cell of claim 13, wherein the tunable patch antenna unit cell is configured along the axis in a relative order of the antenna patch, the at least one insulator layer, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

16. The tunable patch antenna unit cell of any one of claims 1-15, wherein the tunable dielectric material comprises a liquid crystal material.

17. The tunable patch antenna unit cell of any one of claims 1-16, wherein the antenna patch is arranged on a peripheral surface of the multi-layer circuit board portion.

18. The tunable patch antenna unit cell of any one of claims 1-17, wherein the tunable patch antenna unit cell is configured along the axis that is orthogonal to at least one layer of the multi-layer circuit board portion.

19. The tunable patch antenna unit cell of any one of claims 1-18, wherein the multi-layer circuit board portion comprises a plurality of dielectric substrate layers; and the tunable patch antenna unit cell is configured, along the axis, in the relative order of the antenna patch, a dielectric substrate layer of the plurality of dielectric substrate layers, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

20. The tunable patch antenna unit cell of claim 19, wherein the plurality of dielectric substrate layers comprises at least one high-frequency circuit board layer and at least one baseband frequency circuit board layer; and the tunable patch antenna unit cell is configured, along the axis, in the relative order of the antenna patch, the at least one high-frequency circuit board layer, the upper electrode, the tunable dielectric material reservoir, the lower electrode, and the at least one baseband frequency circuit board layer.

21. The tunable patch antenna unit cell of any one of claims 1-20, wherein the upper electrode is a ground electrode and the lower electrode is a hot electrode.

22. The tunable patch antenna unit cell of any one of claims 2-20, further comprising a middle electrode, wherein the upper electrode is a first biasing electrode, the lower electrode is a second biasing electrode, and the middle electrode is a ground electrode, and the tunable patch antenna unit cell is configured along the axis in a relative order of the antenna patch, the first biasing electrode, a first layer of the at least two layers of the tunable dielectric material, the ground electrode, a second layer of the at least two layers of the tunable dielectric material, and the second biasing electrode.

23. A tunable patch antenna unit cell comprising: a multi-layer circuit board portion that defines, within the multi-layer circuit board portion, at least one cavity;an antenna patch; a first electrode disposed within the multi-layer circuit board portion; a second electrode disposed within the multi-layer circuit board portion; and a tunable dielectric material reservoir arranged within the at least one cavity, the tunable dielectric material reservoir comprising a tunable dielectric material that is operably coupled to the antenna patch, the first electrode, and the second electrode.

24. The tunable patch antenna unit cell of claim 23, wherein the multi-layer circuit board portion further defines at least two subcavities of the at least one cavity and a via channel that fluidly couples the at least two subcavities, thereby providing a channel for the tunable dielectric material to flow from a first subcavity of the at least two subcavities to a second subcavity of the at least two subcavities.

25. The tunable patch antenna unit cell of claim 23, wherein the multi-layer circuit board portion at least partially defines at least an upper cavity and a lower cavity for receiving the tunable dielectric material and the tunable dielectric material reservoir comprises an upper layer and a lower layer that are respectively arranged in the upper cavity and the lower cavity.

26. The tunable patch antenna unit cell of claim 25, wherein the tunable dielectric material reservoir further comprises a via that spans the upper layer and the lower layer.

27. The tunable patch antenna unit cell of claim 23, wherein the multi-layer circuit board portion at least partially defines a tunable dielectric material inlet channel that is fluidly coupled with the at least one cavity and a tunable dielectric material outlet channel that is fluidly coupled with the at least one cavity.

28. The tunable patch antenna unit cell of any one of claims 23-27, wherein the first electrode is an upper electrode and the second electrode is a lower electrode and the tunable patch antenna unit cell has an axis and is arranged along the axis in a relative order of the antenna patch, the upper electrode, the tunable dielectric material reservoir, and the lower electrode.

29. A tunable patch antenna array comprising a plurality of tunable patch antenna unit cells of any one of claims 1 - 28.

30. The tunable patch antenna array of claim 29, wherein the plurality of tunable patch antenna unit cells are arranged with a pitch that is shorter than an RF operational frequency wavelength of the tunable patch antenna array.

31. A tunable patch antenna array system comprising the tunable patch antenna array of claim 29 or 30.

32. A tunable patch antenna array comprising a multi-layer circuit board that defines a plurality of unit cell cavities for receiving tunable dielectric material, each unit cell cavity arranged within a respective tunable patch antenna unit cell, the multi-layer circuit board further defining a plurality of tunable dielectric material channels, each tunable dielectric material channel arranged between a respective pair of the plurality of unit cell cavities, thereby fluidly coupling at least the respective pair of the plurality of unit cell cavities.

33. The tunable patch antenna array of claim 32, wherein the multi-layer circuit board defines, for each of the plurality of unit cell cavities, at least two subcavities.

34. The tunable patch antenna array of claim 32, wherein the multi-layer circuit board defines, for each of the plurality of unit cell cavities, an upper subcavity and a lower subcavity.

35. The tunable patch antenna array of claim 32, wherein the respective tunable patch antenna unit cells comprise a first plurality of tunable patch antenna cells dimensioned to operate at at least a first frequency and a second plurality of tunable patch antenna cells dimensioned to operate at at least a second frequency, the first and second frequencies differing.

36. The tunable patch antenna array of claim 32, further comprising the tunable dielectric material arranged in the plurality of unit cell cavities and the plurality of tunable dielectric material channels.

37. The tunable patch antenna array of claim 36, wherein the tunable dielectric material comprising a liquid crystal material.

38. The tunable patch antenna array of any of claims 32 to 37, wherein the multi-layer circuit board defines at least a first subarray of unit cell cavities for receiving the tunable dielectric material, each of the first subarray unit cell cavities arranged within the respective tunable patch antenna unit cell, and the plurality of the tunable dielectric material channels are at least arranged such that the first subarray of unit cell cavities are fluidly coupled.

39. The tunable patch antenna array of any of claims 32 to 37, wherein the multi-layer circuit board defines at least a first array of unit cell cavities for receiving the tunable dielectric material, each of the first array unit cell cavities arranged within the respective tunable patch antenna unit cell, and the plurality of the tunable dielectric material channels are at least arranged such that the first array of unit cell cavities are fluidly coupled.

40. A method for manufacturing a tunable patch antenna array, the method comprising: forming a plurality of cavities in a circuit board; forming a plurality of tunable dielectric material channels that fluidly couple the plurality of cavities; and providing a tunable dielectric material to the plurality of cavities and the plurality of tunable dielectric material channels, thereby forming the tunable patch antenna array.

41. The method of claim 40, wherein the circuit board comprises a plurality of layers, forming the plurality of cavities comprises forming a first plurality of cavities on a first circuit board layer of the plurality of layers and a second plurality cavities on a second circuit board layer of the plurality of layers, the method further comprising forming a plurality of via channels, each arranged for fluidly coupling a respective pair of the first plurality and the second plurality of cavities, wherein providing the tunable dielectric material step comprises flowing the tunable dielectric material through the first plurality and the second plurality of cavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby forming the tunable patch antenna array.

42. A method for manufacturing a tunable patch antenna array, the method comprising: forming an upper array of upper subcavities on a first circuit board layer and a lower array of lower subcavities on a second circuit board layer; forming a plurality of via channels arranged for fluidly coupling a respective upper subcavity to a respective lower subcavity; and providing tunable dielectric material to the upper and lower subcavities and the plurality of via channels, thereby providing a plurality of tunable patch antenna array unit cells, each comprising a multi-layer tunable dielectric material.

43. The method of claim 42, further comprising forming a plurality of tunable dielectric material channels that each fluidly connect a respective pair of the upper subcavities of the tunable patch antenna array unit cells or a respective pair of the lower subcavities of thetunable patch antenna array unit cells, wherein the providing the tunable dielectric material step comprises flowing the tunable dielectric material through the upper and lower subcavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby providing the plurality of tunable patch antenna array unit cells.

44. The method of claim 42, further comprising: forming a plurality of upper tunable dielectric material channels that each fluidly couple a respective pair of the upper subcavities of the tunable patch antenna array unit cells; and forming a plurality of lower tunable dielectric material channels that each fluidly couple a respective pair of the lower subcavities of the tunable patch antenna array unit cells, wherein the providing the tunable dielectric material step comprises flowing the tunable dielectric material through the upper and lower subcavities, the plurality of via channels, and the plurality of tunable dielectric material channels, thereby providing the plurality of tunable patch antenna array unit cells.

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