Electromagnetic fields within a waveguide can be expressed in terms of the complex amplitudes of the electromagnetic modes it supports. The electromagnetic fields can be shaped by controlling the complex amplitudes of modes. Here, mode-converting metasurfaces are designed to transform a set of incident modes on one side to a different set of desired modes on the opposite side of the metasurface. A mode-converting metasurface comprises multiple inhomogeneous (spatially-varying) reactive electric sheets that are separated by dielectric spacers. The reactance profile of each electric sheet to perform the needed mode conversion is found through optimization. The optimization routine takes advantage of a multimodal solver that uses two main concepts: modal network theory and a discrete Fourier transform algorithm. With modal network theory, the modes can be translated between the electric sheets using matrix multiplication. Additionally, modal network theory accounts for the multiple reflections between the reactive electric sheets, as well as coupling between the sheets.

Electromagnetic fields within a waveguide can be expressed in terms of the complex amplitudes of the electromagnetic modes it supports. The electromagnetic fields can be shaped by controlling the complex amplitudes of modes. Here, mode-converting metasurfaces are designed to transform a set of incident modes on one side to a different set of desired modes on the opposite side of the metasurface. A mode-converting metasurface comprises multiple inhomogeneous (spatially-varying) reactive electric sheets that are separated by dielectric spacers. The reactance profile of each electric sheet to perform the needed mode conversion is found through optimization. The optimization routine takes advantage of a multimodal solver that uses two main concepts: modal network theory and a discrete Fourier transform algorithm. With modal network theory, the modes can be translated between the electric sheets using matrix multiplication. Additionally, modal network theory accounts for the multiple reflections between the reactive electric sheets, as well as coupling between the sheets.

The present technology relates to a communication device, a communication method, and an electronic apparatus enabling a signal to be transmitted regardless of a polarization direction of a communication device which is a communication partner so that interference in a signal can be suppressed. A communication device includes: a communication unit that performs transmission of a first signal and a second signal by electromagnetic coupling with another communication device and is able to change each of a direction of a first polarized wave used for the transmission of the first signal and a direction of a second polarized wave used for the transmission of the second signal; and a transmission control unit that sets the direction of the first polarized wave and the direction of the second polarized wave in accordance with the other communication device. The present technology can be applied to, for example, a communication device transmitting a millimeter wave signal.

The present technology relates to a communication device, a communication method, and an electronic apparatus enabling a signal to be transmitted regardless of a polarization direction of a communication device which is a communication partner so that interference in a signal can be suppressed. A communication device includes: a communication unit that performs transmission of a first signal and a second signal by electromagnetic coupling with another communication device and is able to change each of a direction of a first polarized wave used for the transmission of the first signal and a direction of a second polarized wave used for the transmission of the second signal; and a transmission control unit that sets the direction of the first polarized wave and the direction of the second polarized wave in accordance with the other communication device. The present technology can be applied to, for example, a communication device transmitting a millimeter wave signal.

A multiband antenna feed, an antenna incorporating the multiband antenna feed and a method are disclosed. An apparatus, comprises: a first port which may be configured to convey a first signal at a first frequency. A second port may configured to convey a second signal at a second frequency. The second frequency may be higher than the first frequency. A third port may be configured to convey the first signal and the second signal with a feed for a multiband antenna. The third port may have an inner waveguide and a coaxial waveguide. A first network may couple the first port with the coaxial waveguide and may be configured to propagate the first signal between the first port and the coaxial waveguide. A second network may couple the second port with the inner waveguide and may be configured to propagate the second signal between the second port and the inner waveguide.

A square waveguide (1) has four ridges (6a, 6b, 7a, 7b). The cross section of the square waveguide (1) perpendicular to a waveguide axial direction is square. Inside the square waveguide (1), two rectangular waveguide terminals (4, 5) are formed by partitioning the inside along the waveguide axial direction. A septum phase plate (2) formed to get narrower stepwisely as its gets closer to a square waveguide terminal (3) opposite to the rectangular waveguide terminals (4, 5) is provided. A projecting portion (8) is provided on a part of a ridge (7b) formed on a ridge-side wall surface opposite to a wall surface, the septum phase plate (2) being joined to the wall surface in a part where the septum phase plate has largest width, the projecting portion (8) being larger than other parts of the ridge (7b) in a cross-sectional shape perpendicular to the waveguide axial direction.

Provided is a dielectric waveguide having a good reflection characteristic also in a band on a low frequency side of a center frequency of a given operation band. A dielectric waveguide (1) includes: a waveguide region (12) which is defined by a first wide wall (21), a second wide wall (22), a first narrow wall (23), a second narrow wall (24), and a short wall (25) and which is filled with a dielectric; and a mode conversion section (31) which includes a columnar conductor (34) extending from a surface of the waveguide region (12) toward an inside of the waveguide region (12). A width (W.sub.2) of the short wall (25) is configured to be greater than a waveguide width (W.sub.1) at a location (x=x.sub.1) at which the columnar conductor (34) is provided.

Provided is a dielectric waveguide having a good reflection characteristic also in a band on a low frequency side of a center frequency of a given operation band. A dielectric waveguide (1) includes: a waveguide region (12) which is defined by a first wide wall (21), a second wide wall (22), a first narrow wall (23), a second narrow wall (24), and a short wall (25) and which is filled with a dielectric; and a mode conversion section (31) which includes a columnar conductor (34) extending from a surface of the waveguide region (12) toward an inside of the waveguide region (12). A width (W.sub.2) of the short wall (25) is configured to be greater than a waveguide width (W.sub.1) at a location (x=x.sub.1) at which the columnar conductor (34) is provided.

Technologies for a long-lived 3D multimode microwave cavity are disclosed. In the illustrative embodiment, a series of overlapping holes are drilled into a monolithic block of aluminum forming a cavity. The dimensions of the cavity formed by the overlapping holes can be made long by drilling a long series of holes in a row and can be made high by drilling holes a certain depth into the cavity. if two dimensions of the cavity are bigger than the diameter of the holes used to create the cavity, then the cavity can support electromagnetic waves that cannot propagate through the holes, leading to a long lifetime in the cavity. A superconducting qubit or other non-linear element can be inserted into the cavity, which can controllably interact with each of several modes of the cavity. In this way, the modes of the cavity can act as components in a quantum memory.

Technologies for a long-lived 3D multimode microwave cavity are disclosed. In the illustrative embodiment, a series of overlapping holes are drilled into a monolithic block of aluminum forming a cavity. The dimensions of the cavity formed by the overlapping holes can be made long by drilling a long series of holes in a row and can be made high by drilling holes a certain depth into the cavity. if two dimensions of the cavity are bigger than the diameter of the holes used to create the cavity, then the cavity can support electromagnetic waves that cannot propagate through the holes, leading to a long lifetime in the cavity. A superconducting qubit or other non-linear element can be inserted into the cavity, which can controllably interact with each of several modes of the cavity. In this way, the modes of the cavity can act as components in a quantum memory.