US-12627020-B2 - Waveguide with a curved-wall low-pass filter

US12627020B2US 12627020 B2US12627020 B2US 12627020B2US-12627020-B2

Abstract

A waveguide with a curved-wall low-pass filter is described herein. The waveguide comprises a low-pass filter portion configured to allow low-frequency electromagnetic energy therethrough and reject high-frequency electromagnetic energy. The low-pass filter portion comprises an input port, an output port, and a cavity feature that is formed between the input port and the output port. The cavity feature has a greater depth than respective depths of the input port and the output port. The cavity feature comprises a bottom wall that achieves the greater depth for the cavity feature. The bottom wall comprises at least one curved portion configured to allow the cavity feature to achieve the allowance of the low-frequency electromagnetic energy and the rejection of the high-frequency electromagnetic energy. The cavity feature may allow the waveguide to have as good or better performance than traditional means while being easier to manufacture and/or taking up less space.

Inventors

Syed An Nazmus Saqueb
Biswadeep Das Gupta
Navid RAZI

Assignees

Aptiv Technologies AG

Dates

Publication Date: 20260512
Application Date: 20230518

Claims (16)

1 . A waveguide comprising: a low-pass filter portion configured to allow low-frequency electromagnetic energy therethrough and reject high-frequency electromagnetic energy, the low-pass filter portion comprising: an input port; an output port; and a cavity feature formed between the input port and the output port, the cavity feature having a greater depth than respective depths of the input port and the output port, the cavity feature comprising: a top wall; and a bottom wall, disposed opposite the top wall, that achieves the greater depth for the cavity feature, the bottom wall comprising at least one curved portion configured to allow the cavity feature to achieve the allowance of the low-frequency electromagnetic energy and the rejection of the high-frequency electromagnetic energy, wherein the at least one curved portion of the bottom wall comprises a curved surface extending from the input port or the output port to an inner bottom planar surface of the bottom wall, and wherein the curved surface is convex relative to the cavity feature.
2 . The waveguide of claim 1 , wherein a length of the cavity feature between the input port and the output port is less than two times an operating wavelength.
3 . The waveguide of claim 1 , wherein the greater depth of the cavity feature is approximately an operating wavelength.
4 . The waveguide of claim 1 , wherein the greater depth of the cavity feature is approximately half a length of the cavity feature.
5 . A system comprising: the waveguide of claim 1 ; and a processor configured to generate the low-frequency electromagnetic energy.
6 . The waveguide of claim 1 , wherein the bottom wall further comprises a flat portion that is parallel to at least a portion of the top wall, the flat portion providing the greater depth, wherein: the curved surface extends from the input port to the inner bottom planar surface of the bottom wall; the at least one curved portion of the bottom wall comprises another curved surface extending from the inner bottom planar surface of the bottom wall to the output port; and the another curved surface is convex relative to the cavity feature.
7 . The waveguide of claim 6 , wherein the low-pass filter portion comprises a planar side wall extending from the bottom wall to the top wall.
8 . A waveguide comprising: a low-pass filter portion configured to allow low-frequency electromagnetic energy therethrough and reject high-frequency electromagnetic energy, the low-pass filter portion comprising: an input port; an output port, wherein the input port and the output port have different depths, and a cavity feature formed between the input port and the output port, the cavity feature having a greater depth than respective depths of the input port and the output port, the cavity feature comprising: a top wall; and a bottom wall, disposed opposite the top wall, that achieves the greater depth for the cavity feature, the bottom wall comprising at least one curved portion configured to allow the cavity feature to achieve the allowance of the low-frequency electromagnetic energy and the rejection of the high-frequency electromagnetic energy.
9 . The waveguide of claim 8 , wherein the top wall comprises i) a planar surface extending from the input port to the output port, or ii) a jog feature between two parallel portions.
10 . The waveguide of claim 9 , wherein: the top wall comprises the jog feature; and the jog feature is halfway between the input port and the output port.
11 . A waveguide comprising: a low-pass filter portion configured to allow low-frequency electromagnetic energy therethrough and reject high-frequency electromagnetic energy, the low-pass filter portion comprising: an input port; an output port; and a cavity feature formed between the input port and the output port, the cavity feature having a greater depth than respective depths of the input port and the output port, the cavity feature comprising: a top wall; and a bottom wall, disposed opposite the top wall, that achieves the greater depth for the cavity feature, the bottom wall comprising at least one curved portion configured to allow the cavity feature to achieve the allowance of the low-frequency electromagnetic energy and the rejection of the high-frequency electromagnetic energy, wherein the low-pass filter portion comprises a planar side wall extending from the bottom wall to the top wall, and the at least one curved portion of the bottom wall is concave relative to the cavity feature and either i) comprises a curved surface extending from the input port to the output port, or ii) comprises a plurality of curved surfaces extending in series from the input port to the output port, each of the plurality of curved surfaces being concave relative to the cavity feature.
12 . The waveguide of claim 11 , wherein the bottom wall comprises a first elliptical portion and a second elliptical portion, the first and second elliptical portions forming the greater depth.
13 . The waveguide of claim 12 , wherein: a first end of the first elliptical portion is substantially normal with the input port; and a second end of the second elliptical portion is substantially normal with the output port.
14 . The waveguide of claim 12 , wherein the first elliptical portion and the second elliptical portion meet forming an extension portion that extends towards the top wall away from the greater depth.
15 . The waveguide of claim 14 , wherein the extension portion extends less than half a distance from a bottom extent of the bottom wall to the input port or the output port.
16 . The waveguide of claim 11 , wherein: a first end of the bottom wall is substantially normal with the input port; and a second end of the bottom wall is substantially normal with the output port.

Description

BACKGROUND Some devices (e.g., radar devices) use electromagnetic (EM) signals to detect and track objects. The EM signals are transmitted and received using antennas which may be characterized in terms of gains, beam widths, or, more specifically, in terms of antenna patterns, which are measures of the antenna gains as functions of directions. Waveguides are often used to change or improve the antenna patterns. Waveguides often have various structures designed to guide, balance, or filter the EM signals. For example, a filter may be used to keep undesired signals from entering a portion of a waveguide. These filters are often hard to manufacture and/or are long structures in order to achieve good rejection properties, which makes them potentially expensive options in both cost and/or space. SUMMARY This document is directed to a waveguide with a curved-wall low-pass filter. Some aspects described below include a waveguide comprising a low-pass filter portion configured to allow low-frequency electromagnetic energy therethrough and reject high-frequency electromagnetic energy. The low-pass filter portion comprises: an input port; an output port; and a cavity feature formed between the input port and the output port. The cavity feature has a greater depth than respective depths of the input port and the output port. The cavity feature comprises a top wall and a bottom wall that is disposed opposite the top wall, that achieves the greater depth for the cavity feature. The bottom wall comprises at least one curved portion configured to allow the cavity feature to achieve the allowance of the low-frequency electromagnetic energy and the rejection of the high-frequency electromagnetic energy. In some implementations, a length of the cavity feature between the input port and the output port may be less than two times an operating wavelength. In some implementations, the greater depth of the cavity feature may be approximately an operating wavelength. In some implementations, the greater depth of the cavity feature may be approximately half a length of the cavity feature. In some implementations, the input port and the output port may have different depths. The top wall may comprise a jog portion between two parallel portions to achieve the different depths. The jog portion may be halfway between the input port and the output port or offset from a halfway point between the input port and the output port. In some implementations, the bottom wall may further comprise a flat portion that is parallel to at least a portion of the top wall, the flat portion providing the greater depth. The bottom wall may further comprise a first curved portion that connects the input port to the flat portion and a second curved portion that connects the output port to the flat portion. The first curved portion and the second curved portion may be cylindrical. A first end of the first curved portion may be tangent with the input port, and a first end of the second curved portion may be tangent with the output port. A second end of the first curved portion may be substantially normal with the flat portion, and a second end of the second curved portion may be substantially normal with the flat portion. In some implementations, the bottom wall may be elliptical to form the greater depth. A first end of the bottom wall may be substantially normal with the input port, and a second end of the bottom wall may be substantially normal with the output port. In some implementations, the bottom wall may comprise a first elliptical portion and a second elliptical portion, where the first and second elliptical portions form the greater depth. A first end of the first elliptical portion may be substantially normal with the input port, and a second the second elliptical portion may be substantially normal with the output port. The first elliptical portion and the second elliptical portion may meet forming an extension portion that extends towards the top wall away from the greater depth. The extension portion may extend less than half a distance from a bottom extent of the bottom wall to the input port or output port. Other aspects described below include a system comprising a processor configured to generate low-frequency electromagnetic energy and a waveguide as described above that is configured to guide the low-frequency electromagnetic energy and reject high-frequency electromagnetic energy. This Summary introduces simplified concepts of a waveguide with a curved-wall low-pass filter that is further described in the Detailed Description and Drawings. This Summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS A waveguide with a curved-wall low-pass filter is described with reference to the following drawings that use some of the same numbers throughout to reference like or examples of like features and