Phased array for millimeter-wave mobile handsets and other devices
An apparatus includes an antenna element. The antenna element includes a first portion of a multi-layer printed circuit board (PCB) and a cap covering at least part of the first portion of the multi-layer PCB. The multi-layer PCB includes multiple substrates, and the first portion of the multi-layer PCB includes a first slot through the multiple substrates. The cap includes a second slot and defines a space between the first portion of the multi-layer PCB and the cap. The cap and a conductive layer of the multi-layer PCB form a waveguide structure through which wireless signals radiate from the antenna element.
1. An apparatus comprising:
an antenna element comprising:
a first portion of a multi-layer printed circuit board (PCB), the multi-layer PCB comprising multiple substrates, a top layer of the multi-layer PCB comprising a conductive layer, the first portion of the multi-layer PCB defining a first slot extending from a top layer of the multi-layer PCB through the multiple substrates to a bottom layer of the multi-layer PCB, the first slot extending inward from an exterior lateral edge of the multi-layer PCB toward an interior of the multi-layer PCB; and
a cap covering a part of the top layer of the multi-layer PCB, the cap defining a second slot and further defining a space between a portion of the top layer of the multi-layer PCB and the cap, wherein the second slot is aligned with and disposed over the first slot such that the second slot is coextensive with the first slot when viewed along an axis perpendicular to the top layer of the multi-layer PCB;
wherein the cap and the top layer of the multi-layer PCB form a waveguide structure within the space between the cap and the top layer through which wireless signals radiate from the antenna element.
2. The apparatus of claim 1 , wherein the antenna element further comprises:
a mode transit cavity within the first portion of the multi-layer PCB; and
a feed line coupled to a feed line-to-waveguide transition that is adjacent to the mode transit cavity.
3. The apparatus of claim 2 , wherein the feed line-to-waveguide transition tapers from a narrower width at one end to a maximum width at an opposite end.
4. The apparatus of claim 1 , wherein:
the antenna element comprises a first antenna element; and
the apparatus further comprises at least one additional antenna element, each additional antenna element comprising an additional portion of the multi-layer PCB with an additional first slot and a portion of the cap or an additional cap having an additional second slot.
5. The apparatus of claim 4 , wherein:
each antenna element comprises a mode transit cavity within the multi-layer PCB;
different antenna elements are positioned on opposite sides of the multi-layer PCB; and
the antenna elements are offset so that the mode transit cavities of the antenna elements are located in different areas of the multi-layer PCB.
6. The apparatus of claim 4 , wherein:
the apparatus further comprises multiple power amplifiers, each power amplifier configured to feed one of the antenna elements; and
at least one of the caps extends over and thermally contacts one or more of the power amplifiers.
7. The apparatus of claim 4 , wherein:
multiple antenna elements are positioned on a single side of the multi-layer PCB;
a first slab covers at least part of the cap; and
a second slab covers at least part of an opposite side of the multi-layer PCB.
8. The apparatus of claim 1 , wherein the cap comprises a metallic structure.
9. The apparatus of claim 1 , wherein the cap comprises a second PCB.
10. A system comprising:
an antenna;
a transceiver configured to down-convert incoming signals received from the antenna and to up-convert outgoing signals to be transmitted by the antenna;
receive processing circuitry configured to process the down-converted incoming signals; and
transmit processing circuitry configured to generate the outgoing signals;
wherein the antenna comprises an antenna element, the antenna element comprising:
a first portion of-a multi-layer printed circuit board (PCB), the multi-layer PCB comprising multiple substrates, a top layer of the multi-layer PCB comprising a conductive layer, the first portion of the multi-layer PCB defining a first slot extending from a top layer of the multi-layer PCB through the multiple substrates to a bottom layer of the multi-layer PCB, the first slot extending inward from an exterior lateral edge of the multi-layer PCB toward an interior of the multi-layer PCB; and
a cap covering a part of the top layer of the multi-layer PCB, the cap defining a second slot and further defining a space between a portion of the top layer of the multi-layer PCB and the cap, wherein the second slot is aligned with and disposed over the first slot such that the second slot is coextensive with the first slot when viewed along an axis perpendicular to the top layer of the multi-layer PCB;
wherein the cap and the top layer of the multi-layer PCB form a waveguide structure within the space between the cap and the top layer through which wireless signals radiate from the antenna element.
11. The system of claim 10 , wherein the antenna element further comprises:
a mode transit cavity within the first portion of the multi-layer PCB; and
a feed line coupled to a feed line-to-waveguide transition that is adjacent to the mode transit cavity.
12. The system of claim 11 , wherein the feed line-to-waveguide transition tapers from a narrower width at one end to a maximum width at an opposite end.
13. The system of claim 10 , wherein:
the antenna element comprises a first antenna element; and
the antenna further comprises at least one additional antenna element, each additional antenna element comprising an additional portion of the multi-layer PCB with an additional first slot and a portion of the cap or an additional cap having an additional second slot.
14. The system of claim 13 , wherein:
each antenna element comprises a mode transit cavity within the multi-layer PCB;
different antenna elements are positioned on opposite sides of the multi-layer PCB; and
the antenna elements are offset so that the mode transit cavities of the antenna elements are located in different areas of the multi-layer PCB.
15. The system of claim 13 , wherein:
the system further comprises multiple power amplifiers, each power amplifier configured to feed one of the antenna elements; and
at least one of the caps extends over and thermally contacts one or more of the power amplifiers.
16. The system of claim 13 , wherein:
multiple antenna elements are positioned on a single side of the multi-layer PCB;
a first slab covers at least part of the cap; and
a second slab covers at least part of an opposite side of the multi-layer PCB.
17. The system of claim 10 , wherein the antenna, transceiver, receive processing circuitry, and transmit processing circuitry form part of a user equipment.
18. The system of claim 10 , wherein multiple antennas, multiple transceivers, the receive processing circuitry, and the transmit processing circuitry form part of an eNodeB.
19. A method comprising:
feeding signals to an antenna element, the antenna element comprising:
a first portion of-a multi-layer printed circuit board (PCB), the multi-layer PCB comprising multiple substrates, a top layer of the multi-layer PCB comprising a conductive layer, the first portion of the multi-layer PCB defining a first slot extending from a top layer of the multi-layer PCB through the multiple substrates to a bottom layer of the multi-layer PCB, the first slot extending inward from an exterior lateral edge of the multi-layer PCB toward an interior of the multi-layer PCB; and
a cap covering a part of the top layer of the multi-layer PCB, the cap defining a second slot and further defining a space between a portion of the top layer of the multi-layer PCB and the cap, wherein the second slot is aligned with and disposed over the first slot such that the second slot is coextensive with the first slot when viewed along an axis perpendicular to the top layer of the multi-layer PCB; and
radiating wireless signals from the antenna element through a waveguide structure formed within the space between the cap and the top layer of the multi-layer PCB.
20. The method of claim 19 , wherein:
the antenna element and at least one additional antenna element are positioned along one edge of the multi-layer PCB, each additional antenna element comprising an additional portion of the multi-layer PCB with an additional first slot and a portion of the cap or an additional cap having an additional second slot; and
the antenna elements are surrounded on four sides by a metallic case of a device that includes the antenna elements.