Low profile antenna apparatus
Disclosed is an antenna apparatus including a first subassembly having a plurality of antenna elements, and a second subassembly adhered to the first subassembly. The second subassembly may include a plurality of components of a beamforming network encapsulated within a molding material. One or more interconnect layers may be disposed on the molding material to electrically couple the plurality of components of the beamforming network to the plurality of antenna elements. Methods of fabricating the antenna apparatus are also disclosed.
1. An antenna apparatus comprising:
a first subassembly comprising a plurality of antenna elements; and
a second subassembly adhered to the first subassembly, the second subassembly comprising a plurality of components of a beamforming network encapsulated within a molding material, and further comprising one or more interconnect layers on the molding material that electrically couple the plurality of components of the beamforming network to one another and to the plurality of antenna elements.
2. The antenna apparatus of claim 1 , wherein the molding material has a first planar surface facing the one or more interconnect layers, and a second planar surface opposite the first planar surface.
3. The antenna apparatus of claim 1 , wherein first and second components of the plurality of components have different respective thicknesses.
4. The antenna apparatus of claim 1 , wherein first and second components of the plurality of components comprise different respective types of circuits.
5. The antenna apparatus of claim 4 , wherein the first component is an integrated circuit (IC) chip comprising at least one of an amplifier and a phase shifter, and the second component is a transmission line section comprising a combiner/divider network.
6. The antenna apparatus of claim 4 , wherein the first component is an integrated circuit (IC) chip comprising at least one of an amplifier and a phase shifter, and the second component is a feed-through transmission line.
7. The antenna apparatus of claim 6 , wherein the feed-through transmission line is a coaxial feed-through transmission line that extends from a first planar surface of the molding material to a second planar surface of the molding material opposite the first planar surface.
8. The antenna apparatus of claim 1 , wherein each of the plurality of components of the beamforming network has a surface co-planar with a surface of the molding material.
9. The antenna apparatus of claim 1 , wherein the plurality of antenna elements are on a first surface of the first subassembly, and the first subassembly further comprises an array of vias directly connected to the plurality of antenna elements and extending to a second surface of the first subassembly, wherein the second subassembly is adhered to the second surface of the first subassembly.
10. The antenna apparatus of claim 1 , wherein the first subassembly has a top surface and a bottom surface, the plurality of antenna elements are disposed at the top surface, and the first subassembly further comprising a ground plane disposed at the bottom surface.
11. The antenna apparatus of claim 1 , wherein the first and second subassemblies are adhered to one another by at least a plurality of ground-signal-ground (GSG) solder connections, each coupling one of the antenna elements to signal and ground contacts on the one or more interconnect layers.
12. The antenna apparatus of claim 1 , wherein the plurality of components includes an input/output port, a combiner/divider network, and a plurality of integrated circuit (IC) chips each electrically coupled to at least one of the antenna elements, wherein:
the input/output port routes a transmit radio frequency (RF) signal in a transmit direction to the combiner/divider network and/or routes a combined receive RF signal from the combiner/divider network in a receive direction;
the combiner/divider network is configured to divide the RF transmit signal into a plurality of divided transmit RF signals and/or combine a plurality of modified RF receive signals, each received from one of the IC chips, into the combined RF receive signal; and
each of the IC chips is configured to modify a respective one of the divided RF transmit signals to provide a modified RF transmit signal and output the same to the at least one antenna element coupled thereto and/or modify an RF receive signal provided from the at least one antenna element coupled thereto to provide one of the modified RF receive signals to the combiner/divider network.
13. The antenna apparatus of claim 1 , wherein:
the components comprise a plurality of integrated circuit (IC) chips arranged in rows and columns of a two dimensional array, each IC chip spaced from one another in a row direction and in a column direction and each directly underlying and electrically connected to at least two probe feeds that connect at least two corresponding antenna elements to the respective IC chip.
14. A method of forming an antenna apparatus, comprising:
forming a first subassembly comprising a plurality of antenna elements;
encapsulating a plurality of beamforming components of a beamforming network within a molding material to form an embedded component structure;
forming one or more interconnect layers on the embedded component structure, thereby forming a second subassembly, the one or more interconnect layers interconnecting the plurality of beamforming components; and
adhering and electrically connecting the first subassembly to the second subassembly so that the plurality of beamforming components are electrically coupled to the plurality of antenna elements.
15. The method of claim 14 , wherein the molding material is formed within the second subassembly with a first planar surface facing the one or more interconnect layers, and a second planar surface opposite the first planar surface.
16. The method of claim 14 , wherein first and second components of the plurality of components have different respective thicknesses.
17. The method of claim 14 , wherein first and second components of the plurality of components comprise different respective types of circuits.
18. The method of claim 17 , wherein the first component is an integrated circuit (IC) chip comprising at least one of an amplifier and a phase shifter, and the second component is a transmission line section comprising a combiner/divider network.
19. The method of claim 17 , wherein the first component is an integrated circuit (IC) chip comprising at least one of an amplifier and a phase shifter, and the second component is a coaxial feed-through transmission line.
20. The method of claim 14 , wherein said adhering and electrically connecting the first subassembly to the second subassembly comprises heating and cooling a plurality of ground-signal-ground (GSG) solder connections between respective signal pads and ground pads on each of the first and second subassemblies.
21. The method of claim 14 , wherein said forming one or more interconnect layers comprises forming a plurality of vias completely through the one or more interconnect layers for direct electrical connection of at least some of the beamforming components to respective ones of the antenna elements when the first and second subassemblies are adhered and electrically connected to one another.
22. The method of claim 14 , wherein said encapsulating a plurality of beamforming components comprises:
providing a carrier with adhesive foil adhered thereto;
placing the plurality of beamforming components on a surface of the adhesive foil;
applying the molding material in an uncured state around the beamforming components while placed on the adhesive foil surface;
curing the molding material to form an interim structure; and
removing the carrier and the adhesive foil from the interim structure to form the embedded component structure.
23. The method of claim 22 , further comprising forming a plurality of vias through the molding material after the curing thereof, for subsequent connection to at least one of the components through the one or more interconnect layers.
24. The method of claim 14 , further comprising:
attaching heat spreader tabs to respective major surfaces of at least some of the beamforming components prior to encapsulating the beamforming components.
25. An antenna apparatus formed by:
forming a first subassembly comprising a plurality of antenna elements;
encapsulating a plurality of beamforming components of a beamforming network within a molding material to form an embedded component structure;
forming one or more interconnect layers on the embedded component structure, thereby forming a second subassembly, the one or more interconnect layers interconnecting the plurality of beamforming components; and
adhering and electrically connecting the first subassembly to the second subassembly so that the plurality of beamforming components are electrically coupled to the plurality of antenna elements.