In a general aspect, a receiver is disclosed for sensing radio frequency (RF) electromagnetic radiation. The receiver includes a dielectric body having an array of cavities ordered periodically to define a photonic crystal structure in the dielectric body. The dielectric body also has a region in the array of cavities that defines a defect in the photonic crystal structure. An elongated slot through the region extends from a slot opening in a surface of the dielectric body at least partially through the dielectric body. The receiver also includes a vapor or a source of the vapor in the elongated slot as well as an optical window covering the elongated slot. The optical window has a window surface bonded to the surface of the dielectric body to form a seal about the slot opening.

In a general aspect, a radar system includes a photonic crystal receiver. In some aspects, the radar system includes a transmitter station configured to emit probe signals of RF electromagnetic radiation into a region. The radar system also includes a receiver station configured to process return signals of RF electromagnetic radiation from the region. The return signals are based on probe signals scattered from one or more objects in the region. The receiver station includes a photonic crystal receiver formed of dielectric material. The photonic crystal receiver includes an antenna structure, a photonic crystal structure, and a vapor. The receiver station also includes an optical system and a data processing subsystem. The optical system is configured to generate spectroscopic data based on optical signals from the photonic crystal receiver. The data processing subsystem is configured to generate a time series of property data based on the spectroscopic data.

A method of transmitting data on an antenna includes: receiving an indication of orientation of a housing from an orientation sensor, the housing having an antenna coupled thereto; determining an orientation of the housing based on the indication of orientation the housing; actuating an electric motor to change an orientation of the antenna based on the orientation of the housing; electrically connecting the antenna to a transmitter; and transmitting data from the transmitter on the antenna.

A device for receiving and re-radiating electromagnetic signals. The device includes at least a wave guide with a first set of slot radiators for receiving electromagnetic signals, and a second set of slot radiators for transmitting electromagnetic signals generated on the basis of the received electromagnetic signals in the waveguide. The first set of slot radiators includes one or more slot radiators, and the second set of slot radiators includes one or more slot radiators. The device also relates to a method for receiving and re-radiating electromagnetic signals by a device including at least a waveguide, and the use of the device as a repeater of electromagnetic signals, for transferring electromagnetic signals through a structure, and/or as a building product.

A radar antenna device (16) having an antenna arrangement (19) that is accommodated in a housing (17) and is provided with a protective plate (20) for being separated with respect to a furnace atmosphere formed within a furnace chamber, said protective plate (20) being disposed on the housing, a radar-transparent limp material layer (21) comprising pores being disposed as a shield at a distance upstream of the protective plate (20) in such a manner that a space which is separated by the material layer (21) with respect to the furnace chamber is formed, a fluid line opening into said space for applying a fluid flow to the material layer (21).

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.

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.

An antenna device is provided, which includes a first substrate, and a second substrate facing and spaced with the first substrate in a distance. At least one working element disposed between the first substrate and the second substrate, wherein the at least one working element is filled with a modulation material. At least one buffer element is connected with the at least one working element for adjusting the amount of the modulation material in the at least one working element.

The invention provides a phased array antenna, which includes a core board, as well as an antenna module and a radio frequency module respectively arranged at two sides of the core board, where the radio frequency module includes a device attached to a surface far away from the core board and a circuit layer electrically connected to the device, and the device and the circuit layer at least form a phase control unit to control a phase of each antenna unit in the antenna module and a beam synthesis unit to control a beam shape of the phased array antenna.

A patch antenna array system for monitoring vital signs of people in a closed environment, the patch antenna array system including three patches, the farfield pattern of which is shaped in the E-plane by series-feeding and in the H-plane by parallel-feeding to attain a heart-shaped pattern compensating free-space losses due to larger distances.