Beam forming network for feeding short wall slotted waveguide arrays
View Patent ↗An example method for a beamforming network for feeding short wall slotted waveguide arrays. The beamforming network may include six beamforming network outputs, where each beamforming network output is coupled to one of a set of waveguide inputs. Further, the beamforming network may include a cascaded set of dividers configured to split electromagnetic energy from a beamforming network input to the six phase-adjustment sections. The cascade may include a first level of the cascade configured to split the electromagnetic energy from the beamforming network input into two first-level beamforming waveguides, a second level configured to split the electromagnetic energy from each of two first-level beamforming waveguides into two respective second-level beamforming waveguides, and a third level of the cascade configured to split the electromagnetic energy from one of two respective second-level beamforming waveguides into two respective third-level beamforming waveguides.
1. A radar system comprising:
a set of radiating waveguides located in a waveguide layer, each having a radiating waveguide input, wherein each radiating waveguide has a height and a width that are equal to that of each other radiating waveguide, wherein the set of radiating waveguides are aligned on a plane defined by a center of the width of at least one of the set of radiating waveguides and a length of the at least one of the set of radiating waveguides, and wherein each radiating waveguide is coupled to at least one radiating element located in a radiating layer; and
a beamforming network located in the waveguide layer, wherein the beamforming network comprises:
a beamforming network input;
a set of beamforming network outputs, wherein each beamforming network output is coupled to one of the radiating waveguide input; and
a cascaded set of dividers configured to split electromagnetic energy from the beamforming network input:
a first level of the cascaded set of dividers configured to split the electromagnetic energy from the beamforming network input into first-level beamforming waveguides;
a second level of the cascaded set of dividers configured to split the electromagnetic energy from each of first-level beamforming waveguides into respective second-level beamforming waveguides for each respective first-level beamforming waveguide, wherein one of the respective second-level beamforming waveguides for each respective first-level beamforming waveguide is coupled to one of the beamforming network outputs; and
a third level of the cascaded set of dividers configured to split the electromagnetic energy from one of the respective second-level beamforming waveguides for each respective first-level beamforming waveguide into respective third-level beamforming waveguides for each respective second-level beamforming waveguides, wherein each third-level beamforming waveguide is coupled to a respective one of the beamforming network outputs.
2. The radar system according to claim 1 , wherein the first level of the cascaded set of dividers is configured to divide power evenly between at least two first-level beamforming waveguides.
3. The radar system according to claim 1 , wherein each radiating waveguide of the set of radiating waveguides has a predetermined amplitude taper factor, and wherein the beamforming network is configured to provide an electromagnetic signal having an amplitude proportional to the predetermined amplitude taper factor of the respective radiating waveguide to the radiating waveguide input of the respective radiating waveguide.
4. The radar system according to claim 1 , wherein the cascaded set of dividers comprises reactive elements.
5. The radar system according to claim 1 , wherein the cascaded set of dividers comprises hybrids each having matched loads.
6. The radar system according to claim 1 , wherein each beamforming waveguide has a width equal to the width of each radiating waveguide.
7. The radar system according to claim 1 , wherein each radiating waveguide of the set of radiating waveguides has a predetermined phase shift defined by a length of a corresponding phase-adjustment section.
8. The radar system according to claim 1 , wherein each radiating element:
comprises a respective slot defined by a respective angular or curved path, and
has an effective length greater than the height of the respective radiating waveguide, wherein the effective length is measured along the respective angular or curved path of the respective slot.
9. The radar system according to claim 1 , wherein the at least one radiating element is configured to operate at approximately 77 Gigahertz (GHz) and propagate millimeter (mm) electromagnetic waves.
10. A method of radiating electromagnetic energy comprising:
receiving electromagnetic energy by a beamforming network input;
splitting the received electromagnetic energy with a cascaded set of dividers to form a set of electromagnetic energy streams coupled into a set of radiating waveguides, wherein the splitting comprises:
splitting the electromagnetic energy from the beamforming network input into first-level beamforming waveguides by a first level of the cascaded set of dividers;
splitting the electromagnetic energy from each of first-level beamforming waveguides into respective second-level beamforming waveguides for each respective first-level beamforming waveguide by a second level of the cascaded set of dividers, wherein one of respective second-level beamforming waveguides for each respective first-level beamforming waveguide is coupled to a respective one of the set of radiating waveguides; and
splitting the electromagnetic energy from one of respective second-level beamforming waveguides for each respective first-level beamforming waveguide into respective third-level beamforming waveguides for each respective second-level beamforming waveguides by a third level of the cascaded set of dividers, wherein each third-level beamforming waveguide is coupled to a respective one of the set of radiating waveguides;
coupling each respective output of the cascaded set of dividers into a respective radiating waveguide of the set of radiating waveguides located in a waveguide layer, wherein each radiating waveguide is coupled to at least one radiating element located in a radiating layer; and
for each radiating waveguide, radiating at least a portion of the respective electromagnetic energy stream by a radiating element.
11. The method according to claim 10 , further comprising dividing power evenly between the first-level beamforming waveguides by the first level of the cascaded set of dividers.
12. The method according to claim 10 , wherein each radiating waveguide of the set of radiating waveguides has a predetermined amplitude taper factor, and further comprising providing an electromagnetic signal having an amplitude proportional to the predetermined amplitude taper factor of the respective radiating waveguide to a radiating waveguide input of the respective radiating waveguide.
13. The method according to claim 10 , wherein the cascaded set of dividers comprises reactive elements.
14. The method according to claim 10 , wherein the cascaded set of dividers comprises hybrids each having matched loads.
15. The method according to claim 10 , wherein each beamforming waveguide has a width equal to the width of each radiating waveguide.
16. The method according to claim 10 , wherein each radiating waveguide of the set of radiating waveguides has a predetermined phase shift defined by a length of a corresponding phase-adjustment section.
17. The method according to claim 10 , wherein each radiating element:
comprises a respective slot defined by a respective angular or curved path, and
has an effective length greater than the height of the respective radiating waveguide, wherein the effective length is measured along the respective angular or curved path of the respective slot.
18. The method according to claim 10 , wherein the electromagnetic energy has a frequency of approximately 77 Gigahertz (GHz).