This document describes a folded waveguide for antenna. The folded waveguide may be an air waveguide and includes a hollow core that forms a rectangular opening in a longitudinal direction at one end, a closed wall at an opposite end, and a sinusoidal shape that folds back and forth about a longitudinal axis that runs in the longitudinal direction through the hollow core. The hollow core forms a plurality of radiation slots, each including a hole through one of multiple surfaces that defines the hollow core. The radiation slots are arranged on the one surface to produce a particular antenna pattern. The radiation slots and sinusoidal shape enable the folded waveguide to prevent grating lobes from appearing in the particular antenna pattern on either side of a horizontal-polarity, main beam, or to prevent X-band lobes from appearing in the particular antenna pattern on either side of a vertical-polarity, main beam.

Example radar systems are presented herein. A radar system may include radiating elements configured to radiate electromagnetic energy and arranged symmetrically in a linear array. The radiating elements comprise a set of radiating doublets and a set of radiating singlets. The radar system also includes a waveguide configured to guide electromagnetic energy between each of the plurality of radiating elements and a waveguide feed. The waveguide feed is coupled to the second side of the waveguide at a center location between a first half of the plurality of radiating elements and a second half of the plurality of radiating elements. The waveguide feed is configured to transfer electromagnetic energy between the waveguide and a component external to the waveguides. The radar system may also include a power dividing network defined by the waveguide and configured to divide the electromagnetic energy transferred by the waveguide feed based on a taper profile.

This document describes techniques, apparatuses, and systems for a waveguide with lobe suppression. A waveguide is described that includes a pipe for containing a dielectric, the pipe defining an open end to a longitudinal direction through the pipe. An array of radiating slots is formed through a surface of the pipe and in communication with the dielectric. To suppress grating lobes in an antenna pattern, the waveguide includes at least one parasitic groove that is separate from the pipe and with at least a portion of a length that is parallel to the array of radiating slots. In this way, the waveguide provides an antenna pattern where grating lobes are suppressed or substantially reduced.

A slot antenna apparatus that includes a waveguide including a sidewall and having an extending direction, a slot provided on the sidewall, and a dielectric member that is attached to the waveguide and is slidable in the extending direction with respect to the slot, the dielectric member including a first section and a second section, the first section covering the slot at a first slide position, the second section covering the slot at a second slide position next to the first slide position, and the first section and the second section having different relative permittivities or different thicknesses with each other.

An antenna system includes: a first sub-system comprising at least one first antenna element shaped and disposed to have a first electrical polarization, in a first direction, in response to excitation of the first sub-system; and a second sub-system comprising at least one second antenna element shaped and disposed to have a second electrical polarization, in a second direction, in response to excitation of the second sub-system; where the at least one first antenna element and the at least one second antenna element are complementary antenna elements; and where the first sub-system and the second sub-system are co-located such that first sub-system and the second sub-system in combination provide a slant-polarization for the antenna system.

Waveguide and/or antenna structures for use in RADAR sensor assemblies and the like. In some embodiments, the assembly may comprise a waveguide groove extending along an elongated axis on a first side of a block and an antenna structure operably coupled with the waveguide groove. The antenna structure may comprise an antenna slot extending along the elongated axis on a second side of the block opposite from the first side and the antenna slots may be positioned and configured to deliver electromagnetic radiation from the waveguide groove therethrough. Some embodiments may further comprise one or more grooves extending adjacent to the antenna slot, such as opposing grooves extending adjacent to the antenna slot.

This document describes a single-layer air waveguide antenna integrated on a circuit board. The waveguide guides electromagnetic energy through channels filled with air. It is formed from a single layer of material, such as a sheet of metal, metal-coated plastic, or other material with conductive surfaces that is attached to a circuit board. A portion of a surface of the circuit board is configured as a floor of the channels filled with air. This floor is an electrical interface between the circuit board and the channels filled with air. The single layer of material is positioned atop this electrical interface to define walls and a ceiling of the channels filled with air. The single layer of material can be secured to the circuit board in various ways. The cost of integrating an air waveguide antenna on to a circuit board this way may be less expensive than other waveguide-manufacturing techniques.

This document describes a waveguide with a beam-forming feature with radiation slots. The beam-forming feature of the waveguide includes recessed walls surrounding a plurality of radiation slots. The recessed walls of the waveguide may be walls of equal height and width, or they may include further features that manipulate the beam being formed for certain applications. Some examples of these further features are the inclusion of a choke on one wall, one wall having a height greater than a parallel wall, or the walls either including a step or a taper, such that the beam-forming feature is narrower near the surface of the waveguide with the radiation slots and wider further from the surface of the waveguide with the radiation slots. The beam-forming feature may reduce grating lobes in the radiation pattern thereby improving accuracy and performance of the host system.

This document describes techniques and apparatuses for a plastic air-waveguide antenna with conductive particles. The described antenna includes an antenna body made from a resin embedded with conductive particles, a surface of the antenna body that includes a resin layer with no or fewer conductive particles, and a waveguide structure. The waveguide structure can be made from a portion of the surface on which the embedded conductive particles are exposed. The waveguide structure can be molded as part of the antenna body or cut into the antenna body using a laser, which also exposes the conductive particles. If the waveguide is molded as part of the antenna body, the conductive particles can be exposed by an etching process or by using the laser. In this way, the described apparatuses and techniques can reduce weight, improve gain and phase control, improve high-temperature performance, and avoid at least some vapor-deposition plating operations.

This document describes techniques and apparatuses for a plastic air-waveguide antenna with conductive particles. The described antenna includes an antenna body made from a resin embedded with conductive particles, a surface of the antenna body that includes a resin layer with no or fewer conductive particles, and a waveguide structure. The waveguide structure can be made from a portion of the surface on which the embedded conductive particles are exposed. The waveguide structure can be molded as part of the antenna body or cut into the antenna body using a laser, which also exposes the conductive particles. If the waveguide is molded as part of the antenna body, the conductive particles can be exposed by an etching process or by using the laser. In this way, the described apparatuses and techniques can reduce weight, improve gain and phase control, improve high-temperature performance, and avoid at least some vapor-deposition plating operations.