A radar system having a transmitting antenna including a plurality of linear arrays of transmitting antenna elements arranged on a generatrix of a truncated cone or on a cylindrical surface; a signal generator block operatively connected to the transmitting antenna and adapted to feed the transmitting antenna; a receiving antenna having a plurality of groups of linear arrays of receiving antenna elements arranged on the generatrix of the truncated cone or on the cylindrical surface, in which each group of linear arrays of receiving antenna elements is circumferentially interposed between a first and a second linear array of transmitting antenna elements; a signal processor operatively connected to the receiving antenna, where the signal generator block is adapted and configured to feed the transmitting antenna so that the first and the second linear arrays of transmitting antenna elements emit a first and a second electromagnetic radiation, respectively, at a first and a second frequencies different from each other.

A system for subsurface transmission includes an array of very low frequency (VLF) transmitter nodes supported by semi-autonomous maritime, airborne, or space platforms spaced at regular intervals from their nearest neighbors and phased to localize VLF coverage to some desired area on a body of water.

A floating observation system includes a floating platform. The floating platform includes an upper deck, upright posts, a device compartment, a ballast compartment, a radome structure and a device installation base. Top ends of the upright posts are connected to the upper deck, and bottom ends of the upright posts are connected to the device compartment. The ballast compartment is connected to the device compartment. The radome structure is borne on the upper deck. The device installation base is arranged on an outer surface of the floating platform. Various types of auxiliary devices are borne by the upper deck and the device compartment on the floating platform. Various observation devices borne by the device installation base are arranged on the outer surface of the floating platform to observe different kinds of information and to observe spaces above, on and under water, thus meeting a demand for comprehensive observation in all dimensions.

A floating observation system includes a floating platform. The floating platform includes an upper deck, upright posts, a device compartment, a ballast compartment, a radome structure and a device installation base. Top ends of the upright posts are connected to the upper deck, and bottom ends of the upright posts are connected to the device compartment. The ballast compartment is connected to the device compartment. The radome structure is borne on the upper deck. The device installation base is arranged on an outer surface of the floating platform. Various types of auxiliary devices are borne by the upper deck and the device compartment on the floating platform. Various observation devices borne by the device installation base are arranged on the outer surface of the floating platform to observe different kinds of information and to observe spaces above, on and under water, thus meeting a demand for comprehensive observation in all dimensions.

A unit cell can be used for a metasurface, metamaterial, or beamforming antenna. The unit cell includes a metal layer attached to a substrate. The metal layer defines an iris opening for the unit cell. One or more tunable capacitance devices are positioned within or across the iris opening. Each tunable capacitance device is to tune resonance frequency of the unit cell. Mass transfer technologies or self-assembly processes may be used to position the tunable capacitance devices.

An antenna module configured for use on an underwater vehicle is disclosed. The antenna module includes an array of spiral antennas fabricated on a multi-layer substrate that provides wide-band RF communication with direction finding (DF) capability. The antenna module can also include other antennas fabricated on the same multi-layer substrate, such as one or more global positioning system (GPS) receivers, an ultra-high frequency/very-high frequency (UHV/VHF) antenna, or one or more iridium antennas. The antenna module may further include a water-proof housing that is coupled to the outside hull of an undersea vehicle via a coupling mechanism. The coupling mechanism allows the antenna module to rotate between a stowed position against the hull and a deployed position that extends the antennas out away from the undersea vehicle. The antenna module is curved or flexible so it can stow against a corresponding curved hull of the undersea vehicle.

A unit cell can be used for a metasurface, metamaterial, or beamforming antenna. The unit cell includes a metal layer attached to a substrate. The metal layer defines an iris opening for the unit cell. One or more tunable capacitance devices are positioned within or across the iris opening. Each tunable capacitance device is to tune resonance frequency of the unit cell. Mass transfer technologies or self-assembly processes may be used to position the tunable capacitance devices.

An antenna arrangement includes a directional antenna assembly, the directional antenna assembly comprising a directional antenna intended to be mounted on an interface delimited by a stationary support structure, the directional antenna generally extending according to a main axis perpendicular to the plane defined by the interface, wherein the antenna arrangement further comprises a rotatable base mounted on the interface, the rotatable base comprising a pole integral with the rotatable base, the pole extending in the direction of the main axis, the rotatable base being rotatable about the main axis 11, a rotation of the rotatable base actuating the rotation of the pole about the main axis.

An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly from the ferromagnetic medial portion, a respective electrically conductive winding surrounding each of the ferromagnetic arms, and an electrically conductive patch element adjacent the ferromagnetic core.

The system for an antenna assembly for use on unmanned underwater vehicles (UUV). The antennas are low-cost, lightweight, single-use, and have a small form factor amenable to use on a micro-UUV. A central post and pivotally attached arms form an antenna (e.g., a monopole) that is lifted via an aerial, kite, or the like, when deployed from the UUV to extend the line of site of the antenna several meters above the surface of the water. In some cases, the antenna may be used on a number of UUVs in a swarm formation.