MM-wave resonant termination load embedded in a PCB substrate and antenna array including the same
An antenna array is provided that includes at least one active element and at least one passive element arranged around the active element. The passive element includes at least one feeding line disposed between a first ground layer and a second ground layer, a first patch located on the same plane as the first ground layer, and a second patch at least partially disposed between the feeding line and the first patch. The second patch is configured to be electromagnetically coupled to both the first patch and the feeding line. A radio-absorbing material is disposed adjacent to the first patch to improve electromagnetic performance.
1 . An antenna array comprising:
at least one active element; and
at least one passive element arranged around the at least one active element, and
wherein the at least one passive element including:
at least one feeding line disposed between a first ground layer and a second ground layer;
a first patch disposed on the same plane as the first ground layer;
a second patch at least partially disposed between the at least one feeding line and the first patch, wherein the second patch is configured to be electromagnetically coupled to the first patch and the at least one feeding line; and
a radio-absorbing material disposed adjacent to the first patch.
2 . The antenna array of claim 1 , wherein the at least one feeding line includes an excitation probe configured to be electromagnetically coupled to the second patch.
3 . The antenna array of claim 1 , wherein the radio-absorbing material includes a resistive film disposed in a gap between the first patch and the first ground layer.
4 . The antenna array of claim 1 , wherein the radio-absorbing material includes at least one of a radio-absorbing dielectric material, a radio-absorbing painting or a radio-absorbing adhesive.
5 . The antenna array of claim 1 , wherein the at least one passive element includes a printed circuit board (PCB), and
wherein the PCB includes the first ground layer and the second ground layer.
6 . The antenna array of claim 5 , wherein a size of the first patch is less than
λ
4
ε
,
where ε is a permittivity of the PCB, λ is a wavelength of an emitted/received signal in free space.
7 . The antenna array of claim 6 , wherein a size of the second patch is λ/2√{square root over (ε)}.
8 . The antenna array of claim 1 , wherein the at least one feeding line includes two feeding lines disposed to be orthogonal to each other.
9 . The antenna array of claim 1 , wherein the second patch has at least one of a square shape, a circle shape, or a square having a slot formed in a center therein.
10 . The antenna array of claim 1 , wherein the at least one passive element includes a plurality of plated through holes (VIAs) disposed around the radio-absorbing material and located corresponding to the first ground layer.
11 . The antenna array of claim 10 , wherein the at least one passive element includes a printed circuit board (PCB) including the first ground layer and the second ground layer, and
wherein a distance between each of the VIAs is not exceeding
λ
4
ε
,
where ε is a permittivity of the PCB, λ is a wavelength of an emitted/received signal in free space.