Abstract: A MIMO communication system is provided. The system may include a first antenna comprising a first cavity, a first plurality of RF ports for generating a feed wave within the first cavity, and a first plurality of sub-wavelength artificially structured material elements as arranged on a surface of the first cavity as RF radiators. The first antenna is configured to generate a plurality of radiation patterns respectively corresponding to the first plurality of ports. The system may also include a second antenna comprising a second cavity and a second plurality of sub-wavelength artificially structured material elements arranged on a surface of the second cavity.

Abstract: An apparatus includes a traveling-wave antenna array comprising a plurality of adjacent metamaterial surface antennas comprising a waveguide or a cavity, each adjacent metamaterial surface antenna comprising an array of metamaterial radiators coupled to a surface of the waveguide or the cavity, each metamaterial radiator comprising an individually addressable tunable component that can be tuned over a spectral bandwidth to generate different radiation patterns. The apparatus further includes a phase diversity feed coupled to the traveling-wave antenna array and configured to provide adjustable phase diverse input to two or more of the plurality of adjacent metamaterial surface antennas, the phase diverse input comprising a first phase for a first traveling-wave antenna and a second phase for a second traveling-wave antenna, the first phase being different from the second phase, wherein the phase diverse input is-selected to suppress grating lobes for a directed beam pattern selected for transmission.

Abstract: According to various embodiments, systems and methods for spatial sampling in proximity to the Nyquist limit in traveling-wave antenna systems are disclosed. An apparatus can include a traveling-wave antenna array comprising a plurality of adjacent traveling-wave antennas that each include a plurality of tunable elements that are spaced at, near, or above a Nyquist limit spacing to form an array of tunable elements. The apparatus also includes a phase diversity feed coupled to the traveling-wave antenna array that is configured to provide input to the traveling-wave antenna array including phase diverse input to two or more of the plurality of adjacent traveling-wave antennas. Further, the apparatus includes a plurality of grayscale tuning elements configured to tune the plurality of tunable elements along one or more ranges of one or more tuning variables to form one or more specific output radiation patterns through the traveling-wave antenna array based on the input.

Abstract: According to various embodiments, an array of elements forms an artificially-structured material. The artificially-structured material can also include an array of tuning mechanisms included as part of the array of elements that are configured to change material properties of the artificially-structured material on a per-element basis. The tuning mechanisms can change the material properties of the artificially-structured material by changing operational properties of the elements in the array of elements on a per-element basis based on one or a combination of stimuli detected by sensors included in the array of tuning mechanisms, programmable circuit modules included as part of the array of tuning mechanisms, data stored at individual data stores included as part of the array of tuning mechanisms, and communications transmitted through interconnects included as part of the array of elements.

Abstract: A superconductor device includes a high superconductivity transition temperature enhanced from the raw material transition temperature. The superconductor device includes a matrix material and a core material. The enhancing matrix material and the core material together create a system of strongly coupled carriers. A plurality of low-dimensional conductive features can be embedded in the matrix. The low-dimensional conductive features (e.g., nanowires or nanoparticles) can be conductors or superconductors. An interaction between electrons of the low-dimensional conductive features and the enhancing matrix material can promote excitations that increase a superconductivity transition temperature of the superconductor device.

Abstract: Systems and methods for designing, optimizing, patterning, forming, and manufacturing symphotic structures are described herein. A symphotic structure may be formed by identifying a continuous refractive index distribution calculated to convert each of a plurality of input reference waves to a corresponding plurality of output object waves. The continuous refractive index distribution can be modeled as a plurality of subwavelength voxels. The system can calculate a symphotic pattern as a three-dimensional array of discrete dipole values to functionally approximate the subwavelength voxels. A symphotic structure may be formed with a volumetric distribution of dipole structures. A dipole value, such as a dipole moment (direction and magnitude) of each dipole is selected for the volumetric distribution to convert a plurality of input reference waves to a target plurality of output object waves.

Abstract: A device is presented for use in power distribution networks, for limiting transient overvoltages during backfeed on a network primary feeder whose feeder breaker is open and whose network protector fails to open. The device is self-contained and self-protecting, and limits the transient voltages due to an arcing single line-to-ground fault by inserting a resistance into the zero-sequence network of the primary feeder. Limiting transient overvoltages reduces damage to and prevents failures of various network components, and in particular, prevents multiple insulation failures during backfeed and reduces failures during backfeed in microprocessor network protector relays on the secondary side of network transformers whose protectors are open. In addition, the device reduces transient overvoltages associated with re-energizing a network primary feeder by closing the station breaker when all network protectors on the feeder are open, as occurs when restoring a network primary feeder that has been out of service.

Abstract: According to various embodiments, systems and methods for spatial sampling in proximity to the Nyquist limit in traveling-wave antenna systems are disclosed. An apparatus can include a traveling-wave antenna array comprising a plurality of adjacent traveling-wave antennas that each include a plurality of tunable elements that are spaced at, near, or above a Nyquist limit spacing to form an array of tunable elements. The apparatus also includes a phase diversity feed coupled to the traveling-wave antenna array that is configured to provide input to the traveling-wave antenna array including phase diverse input to two or more of the plurality of adjacent traveling-wave antennas. Further, the apparatus includes a plurality of grayscale tuning elements configured to tune the plurality of tunable elements along one or more ranges of one or more tuning variables to form one or more specific output radiation patterns through the traveling-wave antenna array based on the input.

Abstract: According to various embodiments, systems and methods for suppressing grating lobes in a traveling-wave antenna system are disclosed. An apparatus can include a traveling-wave antenna array comprising a plurality of adjacent traveling-wave antennas. The apparatus also can include a phase diversity feed coupled to the traveling-wave antenna array. The phase diversity feed can be configured to provide phase diverse input to two or more of the plurality of adjacent traveling-wave antennas.

Abstract: A MIMO communication system is provided. The system may include a first antenna comprising a first cavity, a first plurality of RF ports for generating a feed wave within the first cavity, and a first plurality of sub-wavelength artificially structured material elements as arranged on a surface of the first cavity as RF radiators. The first antenna is configured to generate a plurality of radiation patterns respectively corresponding to the first plurality of ports. The system may also include a second antenna comprising a second cavity and a second plurality of sub-wavelength artificially structured material elements arranged on a surface of the second cavity.

Abstract: Various examples of out-of-plane multicolor waveguide holography systems, methods of manufacture, and methods of use are described herein. In some examples, a multicolor waveguide holography system includes a planar waveguide to convey optical radiation between a grating coupler and a metasurface hologram. The grating coupler may be configured to couple out-of-plane optical radiation of three different color incident at three different angles into the planar waveguide. The combined multicolor optical radiation may be conveyed by the waveguide to the metasurface hologram. The metasurface hologram may diffractively decouple the three colors of optical radiation for off-plane propagation to form a multicolor holographic image in free space.

Abstract: A single frequency, or very narrow frequency band, microwave imaging system is described herein. A microwave imaging system can include an array transmitter; an array receiver; and a computing device that receives signals detected from the array receiver, transforms the signals received by the array receiver into independent spatial measurements, constructs an image using the independent spatial measurements, and outputs a reconstructed image. The array transmitter and the array receiver may each have a plurality of independently controllable metasurface resonant elements.

Abstract: Various examples of out-of-plane multicolor waveguide holography systems, methods of manufacture, and methods of use are described herein. In some examples, a multicolor waveguide holography system includes a planar waveguide to convey optical radiation between a grating coupler and a metasurface hologram. The grating coupler may be configured to couple out-of-plane optical radiation of three different color incident at three different angles into the planar waveguide. The combined multicolor optical radiation may be conveyed by the waveguide to the metasurface hologram. The metasurface hologram may diffractively decouple the three colors of optical radiation for off-plane propagation to form a multicolor holographic image in free space.

Abstract: A MIMO communication system is provided. The system may include a first antenna comprising a first cavity, a first plurality of RF ports for generating a feed wave within the first cavity, and a first plurality of sub-wavelength artificially structured material elements as arranged on a surface of the first cavity as RF radiators. The first antenna is configured to generate a plurality of radiation patterns respectively corresponding to the first plurality of ports. The system may also include a second antenna comprising a second cavity and a second plurality of sub-wavelength artificially structured material elements arranged on a surface of the second cavity.

Abstract: A separable component assembly is disclosed. The separable component assembly can include a first component having a first interface portion. The separable component assembly can also include a second component coupled to the first component. The second component can have a second interface portion. In addition, the separable component assembly can include a seal disposed between the first and second interface portions. The seal can have a first interface surface associated with the first interface portion. The seal can also have a second interface surface in contact with the second interface portion. Additionally, the seal can have a peel initiator defining a discontinuity in a portion of the second interface surface. Upon separation of the first and second components from one another, the discontinuity can create a stress concentration in the second interface surface that initiates peeling of the second interface surface away from the second interface portion.

Abstract: A separable component assembly is disclosed. The separable component assembly can include a first component having a first interface portion. The separable component assembly can also include a second component coupled to the first component. The second component can have a second interface portion. In addition, the separable component assembly can include a seal disposed between the first and second interface portions. The seal can have a first interface surface associated with the first interface portion. The seal can also have a second interface surface in contact with the second interface portion. Additionally, the seal can have a peel initiator defining a discontinuity in a portion of the second interface surface. Upon separation of the first and second components from one another, the discontinuity can create a stress concentration in the second interface surface that initiates peeling of the second interface surface away from the second interface portion.

Abstract: Thermally-sensitive hardware is at least partially enclosed within a container in which reactants for a solid-solid endothermic chemical reaction are disposed, surrounding at least a portion of the thermally-sensitive hardware. The reactants or a structure including the reactants are positioned between the thermally-sensitive hardware and a heat source, such as an external surface of a missile traveling through atmospheric gases at extremely high speed and experiencing extreme frictional heating. The reactants absorb heat during the solid-solid endothermic reaction to thermally protect the thermally-sensitive hardware. The reactants are preferably selected to absorb heat of at least 5 kilo-Joules per gram (kJ/g) during the solid-solid endothermic chemical reaction.

Abstract: Systems and methods are disclosed herein for printed cavities for computational microwave imaging and methods or use. According to an aspect, an imaging system includes a printed cavity having a layer having a first surface and a second surface. The printed cavity defines multiple apertures that extend between the first surface and the second surface. The printed cavity also includes a substrate being attached to the first surface of the layer. The substrate is also configured to be fed a guided wave that excites the apertures to produce a radiation pattern for illuminating a scene. The imaging system also include one or more antennas configured to generate a signal for imaging based on the illuminated scene.

Abstract: A MIMO communication system is provided. The system may include a first antenna comprising a first cavity, a first plurality of RF ports for generating a feed wave within the first cavity, and a first plurality of sub-wavelength artificially structured material elements as arranged on a surface of the first cavity as RF radiators. The first antenna is configured to generate a plurality of radiation patterns respectively corresponding to the first plurality of ports. The system may also include a second antenna comprising a second cavity and a second plurality of sub-wavelength artificially structured material elements arranged on a surface of the second cavity.

Abstract: A metasurface antenna can be configured to focus a paraxial beam, such as a Gaussian beam, on a target within a Fresnel zone region. The focused beam can be used to wirelessly deliver power to the target.