An antenna array includes multiple array modules. Each array module includes at least on antenna element including a horn antenna coupled to a polarizer, and a two-piece waveguide filter. The two-piece waveguide filter includes a folded-back waveguide coupled to the horn antenna at one end and to a circuit layer at the other end. The horn antenna includes a multi-mode horn antenna. The two-piece waveguide filter includes a first piece and a second piece that are separately molded. A footprint of the two-piece waveguide filter is within a footprint of an aperture of the horn antenna.

The invention relates to a microwave circular polarizer including: a first outer conductor; a second outer conductor connected to the first outer conductor forming a first step discontinuity therewith; and a third outer conductor connected to the second outer conductor forming a second step discontinuity therewith. An inner conductor is provided which extends inside and is spaced apart from the first, second and third outer conductors. The first and second outer conductors are axially asymmetric with respect to the inner conductor, and the third outer conductor is axially symmetric with respect to the inner conductor. The microwave circular polarizer includes first and second rectangular waveguide ports in signal communication with an internal cavity through, respectively, a first rectangular aperture and a second rectangular aperture formed through the first outer conductor. The microwave circular polarizer further includes a first septum and a second septum.

A directional coupler (100) comprises two hollow bodies (200, 201) forming two waveguide portions. Each hollow body has an open end arranged at a first side (10) of the hollow body and another open end arranged at a second side (20) of the hollow body in opposite to the first side in a longitudinal direction (30) of the hollow body. The hollow body has a first cross section perpendicular to the longitudinal direction. A second cross section along the longitudinal direction defines a first plane of propagation of the electric field. The two waveguide portions have a common wall along the longitudinal direction (30) forming a septum (400) between the two waveguide portions on a second plane orthogonal to the first plane. The septum has an aperture (410) for coupling the two waveguide portions. The aperture has a shape comprising a part (420) slanted with respect to the longitudinal direction.

The described features include a scalable waveguide architecture for a waveguide device. The waveguide device may be split into one or more waveguide blocks instead of manufacturing increasingly larger single-piece waveguide devices. Described techniques provide for a radio-frequency (RF) seal between such waveguide blocks that may facilitate greater manufacturing tolerances while maintaining an effective RF seal at the junction of the waveguide blocks. The described techniques include channels within one or more waveguide blocks opening to the dielectric gap between the waveguide blocks. The channels may, for each of multiple waveguides joined at the interface between waveguide blocks, be included in one or both waveguide blocks and may be in a single waveguide dimension relative to the multiple waveguides, or extend for more than one waveguide dimensions.

A nonplanar metamaterial polarizer includes: a substrate including dielectric material transmissive to electromagnetic radiation and having a nonplanar shape; a first conductive pattern on a first side of the substrate; and a second conductive pattern on a second side of the substrate. The first and second conductive patterns are configured to alter the polarization of the electromagnetic radiation as it transmits through the substrate. In some cases, the first and second conductive patterns include split-ring resonators, and the nonplanar shape is a cylinder. An antenna system includes the nonplanar metamaterial polarizer and an antenna inside or adjacent to the nonplanar metamaterial polarizer and configured to transmit or receive the electromagnetic radiation through the nonplanar metamaterial polarizer while the nonplanar metamaterial polarizer alters the polarization of the transmitted or received electromagnetic radiation. In some cases, the antenna is a monopole antenna, a dipole antenna, a biconical antenna, or a discone antenna.

A polarizing screen for altering a polarization state of a radio frequency waveform radiated from a parallel plate waveguide (PPW) wherein the waveform has a centre frequency and a bandwidth, the polarizing screen comprising a plurality of developable sheets arranged stacked in parallel to each other in direction of a local normal vector of a first sheet at respective inter-sheet spacings, each sheet comprising an electrically conductive pattern forming a one-dimensional periodic structure of unit-cells in an extension direction, wherein the periodic structure is associated with a height measured orthogonally to the extension direction and orthogonally to the local normal vector of the shat, where each cell comprises an aperture configured to transmit the radio frequency waveform at a predetermined polarization state, wherein the height is determined in dependence of the centre frequency and/or the bandwidth of the radio frequency waveform such that the pre-determined polarization state is provided as well as matching between the PPW and a transmission medium of the radio frequency waveform.

The present invention relates to a waveguide-to-microstrip line transition package for superconducting film characterization. The package allows propagation and impedance properties thin-film microwave line superconductor to be characterized at millimeter wave frequencies as a function of frequency. The superconducting film's kinetic inductance can be varied by applying direct current along the ground plane via spring loaded probe. When implemented with a non-superconducting metal housing the present invention is highly suitable for measuring resonators with the quality factor, Q, ranges from 100 to 110.sup.4. Through the use of a housing realized from an appropriate superconducting bulk material or coating the upper end of this range of applicability can be readily extended to >110.sup.6.

Circularly polarized directional antennas and methods of fabrication are provided. An antenna comprises conductive elements above a conductive reflector. The conducting elements are spaced radially outward from the center axis. The elements may be spaced equidistantly about each other or may be spaced between 10 and 80 degrees apart. The elements may be straight or curved. The elements may be a parallel to the reflector or may curve away or toward the reflector. The lengths and widths of each conductive element are adjusted to create or receive a circularly polarized wave of particular rotation based on the location in the element system. The elements are located within a printed circuit board that is bonded to a coaxial cable feedline placed above a metallic reflector. Each conducting element comprises a metallic wire.

Apparatus and associated methods relate to determining, based on a detected portion of a projected pulse of quasi-optical energy backscattered by water particles within a divergent projection volume of a cloud atmosphere, properties of the backscattering water particles. The pulse of quasi-optical energy is projected into the divergent projection volume of the cloud atmosphere. The divergent projection volume is defined by an axis of projection and an angle of projection about the axis of projection. The portion of the projected pulse of optical energy backscattered by water particles within the divergent projection volume of the cloud atmosphere is received and detected. Various properties of the backscattering water particles, which can be determined from the detected portion of the projected pulse backscattered by water particles can include particle density and/or particle size.

An antenna comprises a pair of planar layers that are stacked in a direction perpendicular to a pair of layer planes along which the pair of planar layers extend and a separation layer at least partially separating the pair of planar layers. The pair of planar layers each end at a common layer end face and each provide a waveguide for transmission of electromagnetic waves parallel to the pair of layer planes. The waveguides end at the common layer face.