Metamaterials are described which can be employed with satellites, e.g., small sats, to increase the observability of such satellites. Any type of suitable metamaterial can be used. In exemplary embodiments fractal-based patterns or structures may be used.

Systems and techniques are described that provide for enhanced gain and radiation characteristics of antennas. The systems and techniques employ layers or cards of fractal plasmonic surfaces to provide gain to the antennas. The fractal plasmonic surfaces each include a close-packed arrangements of resonators having self-similar or fractal shapes, which may be referred to as “fractal cells.” The cards can be held by a frame adapted to fit an antenna. The FPS cards can provide benefits for gain, field emission, directivity, increased bandwidth, power delivery, and/or heat management. One or more dielectric layers or cards may be used to enhance gain and/or directivity characteristics.

Various examples are provided that are related to fractal-based reactive impedance surfaces. These surfaces allow for miniaturization of antennas. In one example, a fractal rectangular reactive impedance surface (FR-RIS) includes a plurality of fractal rectangular (FR) patches having an outer edge defined by a fractal rectangular pattern that is repeated along each side of inner FR patches of the plurality of FR patches. The fractal rectangular pattern of a FR patch matches with the fractal rectangular pattern of an adjacent FR patch. An antenna can include a planar antenna disposed over the FR-RIS.

Novel directional antennas are disclosed which utilize plasmonic surfaces (PS) that include or present an array of closely-spaced parasitic antennas, which may be referred to herein as “parasitic arrays” or fractal plasmonic arrays (FPAs). These plasmonic surfaces represent improved parasitic directional antennas relative to prior techniques and apparatus. Substrates can be used which are transparent and/or translucent.

In accordance with one or more embodiments, an antenna system includes a dielectric antenna having a feedpoint and an aperture. A fractal patch antenna is configured to receive a signal via a feedline and to generate an electromagnetic wave in response to the signal. A waveguide is configured to couple the electromagnetic wave to the feedpoint, wherein the dielectric antenna is configured to radiate a free space wireless signal from the aperture in response to the electromagnetic wave.

Antenna systems are described which provide means of mitigating the undesirable transmission line effect(s) by using fractal metamaterials in close proximity to an antenna, with both the antenna and fractal metamaterials being positioned a conductive surface, which may be inside or adjacent to a cavity. The fractal metamaterial can include an array of close spaced (e.g., less than 1/10 wavelength separation) resonant structures of a fractal shape, resonant at or near the intended frequency of use of the antenna. The fractal metamaterial can reverse the phase of the reflected wave so that the metal cavity no longer produces an out of phase current induced by the antenna. Without the cavity being out of phase to the antenna, the transmission line effect is mitigated substantially and the antenna performance can accordingly be enhanced. Further embodiments omit a cavity and locate a fractal metamaterial and antenna(s) adjacent to an underlying conductive surface.

Vivaldi tapered slot and Vivaldi horn antennas that feature or include fractal plasmonic surfaces (FPS) are described. Vivaldi slot antennas are described which include a conductive surface defining a tapered slot, with the conductive surface including a plurality of fractal resonators which form or constitute a fractal plasmonic surface (FPS). In some embodiments the fractal resonators can be defined by slots. In some embodiments the fractal resonators can include self-complementary features. In exemplary embodiments, two Vivaldi horn antennas may be used for a Vivaldi horn antenna. The two Vivaldi FPS antennas can be arranged in a crossed or cross configuration such that the two antennas are essentially perpendicular to one another and are therefore able to receive and transmit two orthogonal polarizations of radiation. The two antennas can be fed by separate respective feed lines. The two antennas can be mounted inside of a horn or casing.

Disclosed is a vehicular antenna, which includes an antenna module having an antenna patch, a reflector installed to be spaced apart from the antenna patch by a predetermined distance to maximize a gain of an electromagnetic wave radiated from the antenna patch at a specific angle, and a dielectric substance inserted and installed between the antenna patch and the reflector.

Aspect of the present disclosure are directed to methods and apparatus producing enhanced radiation characteristics, e.g., wideband behavior, in or for antennas and related components by providing concentric sleeves, with air or dielectric material as a spacer, where the sleeves include one or more conductive layers, at least a portion of which includes fractal resonators closely spaced, in terms of wavelength. A further aspect of the present disclosure is directed to surfaces that include dual-use or multiple-use apertures. Such aperture engine surfaces can include a first layer of antenna arrays, a second layer including a metal-fractal backplane player, and a third layer including solar cells for solar cell or solar oriented power collection. Fractal metamaterial ribbons with multiple closely-packed fractal resonators are also disclosed.

Fractal plasmonic arrays are described that operate at millimeter-based wavelengths and that include a thin-film sheet, preferably optically transparent or optically translucent, attached either on the inside or outside of a window or laminated in layers within, adjacent to, or outside a window.