Waveguide-fed ultra wideband horn antenna array for e-band automotive radar application
An apparatus comprising a first waveguide portion, a second waveguide portion and an attachment. The first waveguide portion may comprise a first half of a waveguide input and a first layer of a two-layer waveguide board. The second waveguide portion may comprise a second half of the waveguide input and a second layer of the two-layer waveguide board. The attachment may be configured to connect the first waveguide portion to the second waveguide portion. The first half of the waveguide input may have a same height as the second half of the waveguide input. The two-layer waveguide board may be configured to implement a waveguide network for an antenna array. A horn antenna aperture for each antenna in the antenna array may be implemented on the first waveguide portion.
1 . An apparatus comprising:
a first waveguide portion comprising a first half of a waveguide input, a first half of waveguide outputs, a first half of a splitter structure, and a first layer of a two-layer waveguide board;
a second waveguide portion comprising a second half of said waveguide input, a second half of said waveguide outputs, a second half of said splitter structure, and a second layer of said two-layer waveguide board; and
an attachment configured to connect said first waveguide portion to said second waveguide portion, wherein
(i) said first half of said waveguide input and said first half of said splitter structure have a same height as said second half of said waveguide input and said second half of said splitter structure,
(ii) said two-layer waveguide board is configured to implement a waveguide network for an antenna array,
(iii) a horn antenna aperture for each antenna in said antenna array is implemented on said first waveguide portion,
(iv) said first half of said waveguide input and said second half of said waveguide input are configured to provide an input to said waveguide network, and
(v) said first half of said waveguide outputs and said second half of said waveguide outputs are configured to provide an output of said waveguide network that emits an electric field radiation pattern comprising (i) a symmetrical response in an elevation plane with a first gain that does not drop off until approximately −50 and +50 degrees, (ii) a wide and symmetrical response in an azimuth plane with a second gain that does not drop off until approximately −90 and +90 degrees, and (iii) an equal gain response at zero degrees in both said elevation plane and said azimuth plane.
2 . The apparatus according to claim 1 , wherein connecting said first waveguide portion to said second waveguide portion aligns said first half of said waveguide input and said second half of said waveguide input to form a rectangular waveguide input to said waveguide network.
3 . The apparatus according to claim 1 , wherein said first waveguide portion and said second waveguide portion are fabricated using plastic mold injection with surface plating.
4 . The apparatus according to claim 1 , wherein said attachment comprises at least one of a screw, a conductive glue or a non-conductive glue.
5 . The apparatus according to claim 1 , wherein said same height for said first waveguide portion and said second waveguide portion is implemented to limit a leakage of radio frequency (RF) energy.
6 . The apparatus according to claim 1 , further comprising an air gap in between said first waveguide portion and said second waveguide portion.
7 . The apparatus according to claim 1 , wherein said antenna array is configured to operate with a 10 GHZ ultra wide bandwidth.
8 . The apparatus according to claim 1 , wherein said waveguide network is configured to enable each antenna in said antenna array to achieve 13 GHz bandwidth and a 3 dB gain from −90 degrees to 90 degrees.
9 . The apparatus according to claim 1 , wherein (i) said splitter structure enables (a) said first half of said waveguide outputs to comprise a first half of four waveguide outputs, and (b) said second half of said waveguide outputs to comprise a second half of said four waveguide outputs and (ii) said waveguide network implements a 1 by 4 feed network.
10 . The apparatus according to claim 1 , wherein (i) said splitter structure enables (a) said first half of said waveguide outputs to comprise a first half of 16 waveguide outputs, and (b) said second half of said waveguide outputs to comprise a second half of said 16 waveguide outputs and (ii) said waveguide network implements a 2 by 8 feed network.
11 . The apparatus according to claim 10 , wherein (i) said 2 by 8 feed network comprises a plurality of splitter structures and (ii) said plurality of splitter structures are shaped to enable an amplitude distribution for said 16 waveguide outputs with a highest amplitude at a center-most of said 16 waveguide outputs and amplitude values that gradually decrease for each of said 16 waveguide outputs based on a distance from said center-most of said 16 waveguide outputs.
12 . The apparatus according to claim 1 , wherein said two-layer waveguide board is separated from a radar printed circuit board.
13 . The apparatus according to claim 1 , wherein said antenna array is configured to enable a radar sensor for a vehicle.
14 . The apparatus according to claim 13 , wherein said vehicle comprises a zone processor configured to receive input from said radar sensor and a plurality of inputs from other radar sensors, each configured to implement said apparatus.
15 . The apparatus according to claim 1 , wherein said waveguide network is configured as an air waveguide to compensate for radio frequency losses resulting from routing traces for said antenna array that enable a wide separation from each antenna in said antenna array.
16 . The apparatus according to claim 1 , wherein (i) said first half of said splitter structure and said second half of said splitter structure are configured to split said waveguide network from said first half of said waveguide input and said second half of said waveguide input into a plurality of branches each configured to extend to each of said first half of said waveguide outputs and said second half of said waveguide outputs and (ii) said splitter structure is configured to provide a symmetrical design for said plurality of branches about said first half of said waveguide outputs and said second half of said waveguide outputs.
17 . The apparatus according to claim 16 , wherein a shape of said first half of said splitter structure and said second half of said splitter structure are implemented with said same height and a specific shape to enable said plurality of branches to comprise an equal distance from said first half of said waveguide input and said second half of said waveguide input to each of said first half of said waveguide outputs and said second half of said waveguide outputs.
18 . An apparatus comprising:
a first waveguide portion comprising a first half of a waveguide input, a first half of four waveguide outputs and a first layer of a two-layer waveguide board;
a second waveguide portion comprising a second half of said waveguide input, a second half of said four waveguide outputs and a second layer of said two-layer waveguide board; and
an attachment configured to connect said first waveguide portion to said second waveguide portion, wherein
(i) said first half of said waveguide input has a same height as said second half of said waveguide input,
(ii) said two-layer waveguide board is configured to implement a waveguide network that implements a 1 by 4 feed network configured to achieve 25 GHz bandwidth for an antenna array,
(iii) a horn antenna aperture for each antenna in said antenna array is implemented on said first waveguide portion,
(iv) said first half of said waveguide input and said second half of said waveguide input are configured to provide 18 an input to said waveguide network,
(v) two of said four waveguide outputs on an outside of said 1 by 4 feed network provide an amplitude of a radio frequency signal that is 2.8 dB lower than said amplitude of said radio frequency signal of two of said four waveguide outputs on an inside of said 1 by 4 feed network, and
(vi) a phrase of each of said four waveguide outputs is equal.
19 . An apparatus comprising:
a first waveguide portion comprising a first half of a waveguide input, a first half of 16 waveguide outputs and a first layer of a two-layer waveguide board;
a second waveguide portion comprising a second half of said waveguide input, a second half of said 16 waveguide outputs and a second layer of said two-layer waveguide board; and
an attachment configured to connect said first waveguide portion to said second waveguide portion, wherein
(i) said first half of said waveguide input has a same height as said second half of said waveguide input,
(ii) said two-layer waveguide board is configured to implement a waveguide network that implements a 2 by 8 feed network for an antenna array, and
(iii) a horn antenna aperture for each antenna in said antenna array is implemented on said first waveguide portion,
(iv) said first half of said waveguide input and said second half of said waveguide input are configured to provide an input to said waveguide network, and
(v) said 2 by 8 feed network is configured to enable said antenna array to implement a long range radar with a narrow field of view configured to achieve 10 GHz bandwidth, a maximum gain of 19.1 dB and a −20 dB side lobe.