The present invention provides a waveguide slot array antenna having an excitation slot arrangement radiating a signal corresponding to an operating frequency in a radiation plate, the waveguide slot array antenna comprising: a first auxiliary radiation plate installed on a main radiation plate and rotating a polarization plane of a signal radiated from the excitation slot arrangement of the main radiation plate; and a second auxiliary radiation plate installed on the first auxiliary radiation plate and distributing and radiating the signal, the polarization plane of which has been rotated in the first auxiliary radiation plate.

An omni-directional horizontally polarized antenna system is provided that can include an omni-directional vertically polarized antenna and a plurality of linear polarization filters concentrically surrounding the omni-directional vertically polarized antenna. The omni-directional vertically polarized antenna can generate a vertically polarized field, and the plurality of linear polarization filters can progressively rotate the vertically polarized field 90° to form a horizontally polarized field outside of the plurality of linear polarization filters.

A vehicle includes: an antenna; a polarization adjuster configured to change a first polarized wave emitted through the antenna; and a controller configured to receive a wireless signal from a portable user device through the antenna, to identify a second polarized wave emitted from the portable user device based on the wireless signal, and to control the polarization adjuster such that the first polarized wave matches the second polarized wave.

An omni-directional horizontally polarized antenna system is provided that can include an omni-directional vertically polarized antenna and a plurality of linear polarization filters concentrically surrounding the omni-directional vertically polarized antenna. The omni-directional vertically polarized antenna can generate a vertically polarized field, and the plurality of linear polarization filters can progressively rotate the vertically polarized field 90° to form a horizontally polarized field outside of the plurality of linear polarization filters.

A linear-to-circular polarizer includes a meanderline polarizer having a plurality of meanderline conductor patterns, and a gridline polarizer having a plurality of conductors arranged in a grid pattern. The gridline polarizer is spaced apart from the meanderline polarizer by a first prescribed distance and the gridline polarizer is spaced apart from a planar antenna aperture of a planar antenna by a second prescribed distance.

The disclosure is directed to an antenna device (1) comprising a printed circuit board (2) and a thereon arranged electronic component (3). The antenna device (1) comprises at least two individual antenna elements (12) which are interconnected to the electronic component (3) configured to transmit and receive a signal. The antenna elements (12) each comprise at least one waveguide channel (9) interconnecting in the antenna assembly (6). A first waveguide aperture (10) is arranged at a back face (16) of the antenna assembly (6). Said first waveguide aperture (10) is interconnected to the electronic component (3) and configured to transmit and/or receive a signal. A second waveguide aperture (11) is arranged at a front face (17) of the waveguide assembly (6) and is also configured to transmit and/or receive a signal.

A reflection reducing apparatus includes a dielectric base plane (30), a first patch group, a second patch group, and a ground plate (40). A plurality of first conductive patches (10) each resonate in a first direction (a) and a second direction () which are different in resonant length from each other. A plurality of second conductive patches include a first direction-oriented patch (20a) and a second direction-oriented patch (20b) which are different in resonant length from each other. The second conductive patches are arranged along an outer periphery of the first patch group at an interval away from the first patch group.

An antenna includes a plurality of waveguide antenna elements arranged in a first array configured to operate with a first polarization. The antenna also includes a plurality of waveguide output ports arranged in a second array configured to operate with a second polarization. The second polarization is different from the first polarization. The antenna further includes a polarization-modification layer with channels defined therein. The polarization-modification layer is disposed between the waveguide antenna elements and the waveguide output ports. The channels are oriented at a first angle with respect to the waveguide antenna elements and at a second angle with respect to the waveguide output ports. The channels are configured to receive input electromagnetic waves having the first polarization and transmit output electromagnetic waves having a first intermediate polarization. The waveguide output ports are configured to receive input electromagnetic waves and radiate electromagnetic waves having the second polarization.

An ultra-wideband linear-to-circular polarizer is disclosed. In accordance with embodiments of the invention, the polarizer includes a plurality of cascaded waveplates having biaxial permittivity or cascaded anisotropic sheet impedances. Each waveplate/sheet has a principal axis rotated at different angles relative to an adjacent waveplate/sheet about a z-axis of a 3-dimensional x, y, z coordinate system. Each waveplate is composed of a unit cell of an artificial anisotropic dielectric. Each sheet impedance is composed of an anisotropic metallic pattern. The polarizer further includes impedance matching layers disposed adjacent the cascaded waveplates/sheets.

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.