A luminaire includes: a light-emitting module; a base having a front surface on which the light-emitting module is disposed; a cover which is translucent and covers the light-emitting module: a controller which is disposed on a back surface of the base and controls the light-emitting module; a first antenna which transmits and receives a first polarized wave; and a control wire which connects the controller and the first antenna. The control wire includes an exposed portion which is a portion of the control wire in a longitudinal direction of the control wire and which is disposed between the base and the cover to transmit and receive a second polarized wave that differs from the first polarized wave in a polarization direction.

A luminaire includes: a light-emitting module; a base having a front surface on which the light-emitting module is disposed; a cover which is translucent and covers the light-emitting module: a controller which is disposed on a back surface of the base and controls the light-emitting module; a first antenna which transmits and receives a first polarized wave; and a control wire which connects the controller and the first antenna. The control wire includes an exposed portion which is a portion of the control wire in a longitudinal direction of the control wire and which is disposed between the base and the cover to transmit and receive a second polarized wave that differs from the first polarized wave in a polarization direction.

A steerable, high-power microwave antenna includes: a forward-traveling, leaky-wave feed antenna; a trans-reflecting conical-sectional reflector disposed spaced-apart and above said leaky-wave feed antenna and having a conical surface facing said leaky-wave feed antenna and formed of a plurality of electrical conductors held in parallel order in a grill; and a twist-reflector pivotally mounted opposite and spaced-apart from said conical surface of said trans-reflecting conical-sectional reflector. The twist-reflector is adapted to receive microwave energy reflected to it from said conical surface of said trans-reflecting conical-sectional reflector and to rotate the polarization of said microwave energy and reflect said microwave energy back to said trans-reflecting conical-sectional reflector for passing through said trans-reflecting conical-sectional reflector and forming a narrow, pencil-like beam of high energy radiation in polarized form extending outward from said conical surface of said trans-reflecting conical-sectional reflector.

Lower-limit frequency reflection characteristics of a horn antenna are improved even though element spacing, of less than or equal to one wavelength, is a spacing at which grating lobes do not occur in an antenna radiation pattern. The horn antenna includes a horn antenna and a conductor grid that divides an aperture A of the horn antenna in a grid pattern and that electrically connects to an inner surface of the horn antenna at the aperture A of the horn antenna. Width of the conductor grid in a direction orthogonal to a horn antenna aperture plane differs from electrical length of the path of the horn antenna of the conductor grid portion at the frequency of power supplied to the horn antenna.

A modulated MTS antenna including a metasurface fabricated from metallized cylinders on a ground plane. The antenna structure can be designed to operate in the Gigahertz or Terahertz frequency band and to have a well defined directivity. The MTS antenna may be micromachined out of a silicon wafer using deep reactive ion etching (DRIE).

According to an embodiment, an image forming apparatus includes a sheet conveyance unit that is configured to transport a print medium along a conveyance path. An antenna is configured to emit radio waves towards a predetermined portion of the conveyance path. A controller is configured to control the antenna to emit the radio waves towards the predetermined portion with a polarization direction set according to a type of the print medium being transported by the sheet conveyance unit. The print medium may have, for example, one or more wireless tags thereon or therein.

A first waveguide guides a first radio wave whose electric field is vibrated in a first direction along a second direction. A second waveguide guides the first radio wave along the second direction and is cascade connected to the first waveguide. An input and output end multiplexes the first radio waves from the first and second waveguides and outputs the multiplexed radio wave, and outputs the first radio wave branched off from a radio wave from outside to the first and second waveguides. A first waveguide shift portion is shifted from the first waveguide in the first direction. A second waveguide shift portion is shifted from the second waveguide in the first direction. The vibration directions of electric fields of radio waves passing through the end parts of the first and second waveguide shift portions are rotated by 90° about a third direction.

A metasurface includes a dielectric material, a ground plane on a back side of the dielectric material; and at least one conductive element on a top surface of the dielectric material, wherein the at least one conductive element includes at least one of a ground-backed dipole or a slot array.

A metasurface includes a dielectric material, a ground plane on a back side of the dielectric material; and at least one conductive element on a top surface of the dielectric material, wherein the at least one conductive element includes at least one of a ground-backed dipole or a slot array.

An antenna system for a global navigation satellite system reference base station is disclosed.

The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane.

Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained.

The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings.

The antenna system can provide a positioning accuracy of +/−1 mm, an order of magnitude improvement over previous designs.