According to the present invention, provided is a communication apparatus including a radiation source (10) that radiates an electromagnetic wave, and a first phase control plate (11) that is disposed at a position of a distance L.sub.1 in a radio wave radiation direction from the radiation source (10). In the first phase control plate (11), a phase of a transmitted electromagnetic wave differs according to a distance from a representative point on the first phase control plate (11). The radiation source (10) is able to supply power up to a position separated from the representative point on the first phase control plate (11) by L.sub.1/2.

An antenna includes a horn including an axial waveguide and a circular radome including a central cavity. The circular radome is configured to protrude into the axial waveguide. The antenna further includes a coil element provided over a coil frame and configured to fit inside the central cavity. The horn includes a conical structure having multiple circular chokes that are configured to shape a beam of the antenna to provide a desired gain by reducing sidelobes.

A blind mate waveguide flange includes a mating surface for interfacing with a waveguide probe interface. The mating surface includes a choke flange and a first opening to one end of a waveguide transition section. The choke flange includes a choke groove separating a peripheral region of the mating surface from an inner region of the mating surface. The inner region is recessed relative to the peripheral region to provide an air gap upon mating with another mating surface. The first opening has a first shape. The blind mate waveguide flange further includes a waveguide connection interface that includes a second opening at an opposite end of the waveguide transition section for interfacing with a waveguide. The second opening has a second shape such that the waveguide transition section provides a transition from the first shape to the second shape.

An apparatus includes a first waveguide configured to propagate electromagnetic energy along a propagation direction. The apparatus further includes a first waveguide flange configured to selectively operate in one of a plurality of modes. When operating in a first mode, the apparatus radiates at least a portion of the electromagnetic energy from the first waveguide via at least one radiating feature of the first waveguide flange. The at least one radiating feature is located on a surface of the first waveguide flange that is perpendicular to the propagation direction. Additionally, when operating in a second mode, the apparatus conducts at least a portion of the electromagnetic energy from the first waveguide to a subsequent element (e.g., a second waveguide). The at least one radiating feature is shorted to a portion of the subsequent element when operating in the second mode.

The present invention relates to a polarimetric radar, consisting of a transmission assembly that emits circularly polarized waves by means of transmission antennas and a receiver assembly that receives the reflected circularly polarized wave components by means of an antenna assembly. A plurality of two-channel receivers are provided as the receiver assembly, which simultaneously receive clockwise-rotating and anti-clockwise-rotating circularly polarized signal components, which are provided for digital beam shaping downstream of the antenna assembly. The invention further relates to a method for object classification.

A waveguide device for use in propagating an electromagnetic wave of a band having a shortest wavelength m in free space includes: a first electrically conductive member having an electrically conductive surface and a first throughhole; a second electrically conductive member including a plurality of electrically conductive rods each having a leading end opposing the electrically conductive surface, the second electrically conductive member having a second throughhole which overlaps the first throughhole as viewed along an axial direction of the first throughhole; and an electrically-conductive waveguiding wall at least partially surrounding a space between the first throughhole and the second throughhole and being surrounded by the plurality of electrically conductive rods, the waveguiding wall allowing the electromagnetic wave to propagate between the first throughhole and the second throughhole. The height of the waveguiding wall is less than m/2. The distance between an electrically conductive rod among the plurality of electrically conductive rods that is adjacent to the waveguiding wall and the outer periphery of the waveguiding wall is less than m/2.

An electromagnetic wave transmission device includes a transmission line module and a hollow waveguide module. The transmission line module includes: a plurality of electrically conductive members stacked with interspaces therebetween, the plurality of electrically conductive members including three or more electrically conductive members; and a plurality of artificial magnetic conductors each located between two adjacent electrically conductive members among the plurality of electrically conductive members. Among the plurality of electrically conductive members, at least one electrically conductive member located between two endmost electrically conductive members is shaped as a plate having at least one slit. The at least one slit extends to an edge of the at least one electrically conductive member. The hollow waveguide module includes at least one hollow waveguide having an aperture plane which is opposed via a gap to an open end of the at least one slit at the edge.

A right-angle waveguide probe antenna with a bandwidth greater than 15% of the center frequency of the operating band, as defined by a return loss over the frequency range better than or equal to 20 dBV. This invention is most relevant to a right-angle coaxial to an air-filled rectangular waveguide transition. The probe antenna is comprised of a flared section followed by a rectangular section resulting in an irregular convex pentagon shape with two right angles at the base which resembles an A-frame on top of a rectangle. The resultant A-frame probe can be connected to a coaxial feed cable and extended into a waveguide through an aperture. The A-frame probe operates as a TE10 mode waveguide radiator, and is sized and positioned such that the impedance of the probe antenna is closely matched to the impedance of the waveguide across a wider frequency band.

Antenna systems and methods employing an axial metallic corrugated choke ring attached to an offset reflector assembly and circumscribing (without contacting) a stationary metallic conical feed horn.

A radiofrequency assembly includes a module with an antenna assembly formed in a semiconductor integrated circuit. The semiconductor integrated circuit can carry out at least one of the following functions: transmitting an electromagnetic signal, and receiving an electromagnetic signal. The radiofrequency assembly further includes a horn-like structure with a base portion adapted to fit on the module. The horn-like structure has an extending horn-shaped portion an input opening that encloses the antenna assembly when the horn-like structure is fitted on the module.