# US 11,444,364 B2 · Folded waveguide for antenna > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,364 B2 - Document ID: US11444364B2 - Status: Granted - Kind: B2 - Application number: 17/131,534 - Filed: 2020-12-22 - Published: 2022-06-23 - Granted: 2022-09-13 - Earliest claimed: 2020-12-22 - Assignees: Aptiv Technologies AG - Applicants: Aptiv Technologies Limited - Inventors: Shawn Shi - Web page: https://patentgrep.com/patent/US11444364B2 ## CPC - H01P 3/123: with a complex or stepped cross-section, e.g. ridged or grooved waveguides (H01P3/14 takes precedence) - H01Q 21/0043: {Slotted waveguides (combination with horns H01Q13/0233)} - H01Q 1/3233: {particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems} - H01Q 13/22: Longitudinal slot in boundary wall of waveguide or transmission line {(H01Q13/203 takes precedence)} - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract 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. ## Claims ### Claim 1 An apparatus, the apparatus comprising: a folded waveguide comprising a hollow core, the hollow core forming: a rectangular opening in a longitudinal direction at one end; a closed wall at an opposite end; a sinusoidal shape that folds back and forth about a longitudinal axis that runs in the longitudinal direction through the hollow core; and a plurality of radiation slots, each of the radiation slots comprising a hole through one of multiple surfaces of the folded waveguide that defines the hollow core, the plurality of radiation slots being arranged on the one of the multiple surfaces to produce a particular antenna pattern for a device and an antenna element that is directly coupled to the opposite end of the hollow core. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein each of the plurality of radiation slots is configured to dissipate, from the hollow core, a portion of electromagnetic radiation that enters the rectangular opening before that portion of the electromagnetic radiation can reach the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein each of the plurality of radiation slots is sized and positioned on the one of the multiple surfaces to produce the particular antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the plurality of radiation slots is evenly distributed between the rectangular opening and the closed wall, and along the longitudinal axis that runs in the longitudinal direction through the hollow core. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein each adjacent pair of radiation slots from the plurality of radiation slots comprises two radiation slots that are separated along the longitudinal axis by a common distance to produce the particular antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the common distance is less than one wavelength of electromagnetic radiation that reaches the opposite end of the hollow core. ### Claim 7 (depends on 4) The apparatus of claim 4, wherein each adjacent pair of radiation slots from the plurality of radiation slots comprises two radiation slots that are separated along the longitudinal axis by a common distance to prevent grating lobes or X-band lobes within the particular antenna pattern. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein each radiation slot from the plurality of radiation slots comprises a lateral slot that is perpendicular to the longitudinal axis to produce a horizontal-polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein each radiation slot from the plurality of radiation slots comprises a longitudinal slot that is parallel to the longitudinal axis to produce a vertical-polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein a first half of the plurality of radiation slots comprises a longitudinal slot that is parallel to the longitudinal axis, and a second half of the plurality of radiation slots comprises a lateral slot that is perpendicular to the longitudinal axis to produce a circularly polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the folded waveguide comprises metal. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the folded waveguide comprises plastic. ### Claim 13 A system, the system comprising: an antenna element; a device configured to transmit or receive electromagnetic signals via the antenna; and a folded waveguide comprising: a hollow core forming: a rectangular opening in a longitudinal direction at one end; a closed wall at an opposite end that is directly coupled to the antenna element; a sinusoidal shape that folds back and forth about a longitudinal axis that runs in the longitudinal direction through the hollow core; and a plurality of radiation slots, each of the radiation slots comprising a hole through one of multiple surfaces of the folded waveguide that defines the hollow core, the plurality of radiation slots being arranged on the one of the multiple surfaces to produce a particular antenna pattern at the antenna element. ### Claim 14 (depends on 13) The system of claim 13, wherein the device comprises a radar device. ### Claim 15 (depends on 13) The system of claim 13, further comprising a vehicle comprising the antenna element, the device, and the folded waveguide. ### Claim 16 (depends on 13) The system of claim 13, wherein each of the plurality of radiation slots is configured to dissipate, from the hollow core, a portion of electromagnetic-radiation that enters the rectangular opening before that portion of the electromagnetic-radiation can reach the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 17 (depends on 13) The system of claim 13, wherein each of the plurality of radiation slots is sized and positioned on the one of the multiple surfaces to produce the particular antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 18 (depends on 13) The system of claim 13, wherein each radiation slot from the plurality of radiation slots comprises a lateral slot that is perpendicular to the longitudinal axis to produce a horizontal-polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core; wherein each radiation slot from the plurality of radiation slots comprises a longitudinal slot that is parallel to the longitudinal axis to produce a vertical-polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core; or wherein a first portion of the plurality of radiation slots comprises a longitudinal slot that is parallel to the longitudinal axis, and a second portion of the plurality of radiation slots comprises a lateral slot that is perpendicular to the longitudinal axis to produce a circularly polarized antenna pattern at the antenna element that is electrically coupled to the opposite end of the hollow core. ### Claim 19 (depends on 13) The system of claim 13, wherein each of the plurality of radiation slots comprises a hole through a particular surface of the multiple surfaces, the particular surface being one of two surfaces that folds back and forth about the longitudinal axis that runs in the longitudinal direction through the hollow core. ### Claim 20 (depends on 13) The system of claim 13, wherein each of the plurality of radiation slots comprises a hole through a particular surface of the multiple surfaces, the particular surface being one of two surfaces that is perpendicular to two other surfaces that fold back and forth about the longitudinal axis that runs in the longitudinal direction through the hollow core.