BACKGROUND

Radio detection and ranging (RADAR) systems can be used to actively estimate distances to environmental features by emitting radio signals and detecting returning reflected signals. Distances to radio-reflective features can be determined according to the time delay between transmission and reception. A radar system can emit a signal that varies in frequency over time, such as a signal with a time-varying frequency ramp. The radar system can then relate the difference in frequency between the emitted signal and the reflected signal in order to derive a range estimate of the object or surface that reflected the emitted signal.

Some radar systems may also estimate relative motion of reflective objects based on Doppler frequency shifts in the received reflected signals. In addition, a radar system may incorporate directional antennas for the transmission and/or reception of signals in order to associate each range estimate with a bearing. The directional antennas can also be used to focus radiated energy on a given field of view of interest enabling the surrounding environment features to be mapped using the radar system.

SUMMARY

In one aspect, the present application describes a system. The system may include a plurality of radiating elements configured to radiate electromagnetic energy and arranged in a linear array. The system also includes a waveguide feed and a waveguide configured to guide electromagnetic energy between (i) each of the plurality of radiating elements and (ii) the waveguide feed. The waveguide comprises a first side and a second side opposite the first side, where the radiating elements are coupled to the first side of the waveguide. 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 waveguide.

In another aspect, the present application describes a method. The method may involve feeding electromagnetic energy to a center of a waveguide by a waveguide feed. The waveguide comprises a first side and a second side opposite of the first side. The method may further involve propagating electromagnetic energy via the waveguide between (i) each of a plurality of radiating elements and (ii) the waveguide feed. The plurality of radiating elements is arranged in a linear array and coupled to the first side of the waveguide. The method also includes, for each radiating element, providing a portion of the propagating electromagnetic energy and radiating at least a portion of the propagating electromagnetic energy via each radiating element.

In yet another aspect, the present application describes a radar system. The radar system includes a plurality of radiating elements configured to radiate electromagnetic energy and arranged in a linear array. The plurality of radiating elements comprises a set of radiating doublets and a set of radiating singlets. The radar system further includes a waveguide feed and a waveguide configured to guide electromagnetic energy between (i) each of the plurality of radiating elements and (ii) the waveguide feed. The waveguide comprises a first side and a second side opposite the first side, where the plurality of radiating elements is coupled to the first side of the waveguide. 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 waveguide.

In still another aspect, a system is provided that includes means for radiating electromagnetic energy. The system includes means for feeding electromagnetic energy to a center of a waveguide by a waveguide feed. The waveguide comprises a first side and a second side opposite of the first side. The system further includes means for propagating electromagnetic energy via the waveguide between (i) each of a plurality of radiating elements and (ii) the waveguide feed. The plurality of radiating elements is arranged in a linear array coupled to the first side of the waveguide. The system includes means for providing a portion of the propagating electromagnetic energy for each radiating element. The system also includes means for radiating at least a portion of the propagating electromagnetic energy via each radiating element.

In another aspect, the present application describes an antenna system. The antenna system includes a first layer having a first portion of a feed waveguide coupled to a feed port. The antenna system also includes a second layer having a second portion of the feed waveguide and a first portion of a waveguide. The first portion of the feed waveguide is coupled to the second portion of the feed waveguide such that the feed waveguide causes propagation of electromagnetic energy in a direction parallel to a seam between the first layer and the second layer. In addition, the second portion of the feed waveguide is coupled to the first portion of the waveguide at a coupling point. The antenna system further includes a third layer having a second portion of the waveguide and a set of radiating elements arranged in a linear array. Each radiating element is coupled to the second portion of the waveguide, and wherein the coupling point aligns with a center of the linear array.

In a further aspect, the present application describes another method of radiating radar. The method involves feeding, at an antenna system, electromagnetic energy to a center of a waveguide by a feed waveguide. A first layer of the antenna system includes a first portion of the feed waveguide coupled to a feed port. The method further involves propagating electromagnetic energy via the waveguide between (i) the feed waveguide and (ii) each of a set of radiating elements arranged in a linear array. A second layer of the antenna system includes a second portion of the feed waveguide and a first portion of the waveguide. Particularly, the first portion of the feed waveguide is coupled to the second portion of the feed waveguide such that the feed waveguide causes propagation of electromagnetic energy in a direction parallel to a seam between the first layer and the second layer. In addition, the second portion of the feed waveguide is coupled to the first portion of the waveguide at a coupling point. The method also involves, for each radiating element, providing a portion of the propagating electromagnetic energy. A third layer of the antenna system includes a second portion of the waveguide and the set of radiating elements arranged in the linear array. Each radiating element is coupled to the second portion of the waveguide and the coupling point aligns with a center of the linear array. The method further involves radiating at least a portion of the propagating electromagnetic energy via each radiating element.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the figures and the following detailed description.

