LGA- and BGA-based phased-array millimeter-wave antennas
A radio frequency module includes: a primary board including: an upper surface carrying a radio controller; and a lower surface carrying antenna control elements; a plurality of spacing elements affixed to the lower surface and having a predetermined height extending away from the lower surface; and a secondary board affixed to the primary board by the plurality of spacing elements, separated from the lower surface of the primary board by an air gap with the predetermined height; the secondary board supporting a phased array of antenna elements electromagnetically coupled with the antenna control elements.
1 . A radio frequency module, comprising:
a primary board including:
an upper surface carrying a radio controller;
a lower surface carrying antenna control elements; and
a baseband controller to transmit data received at the radio frequency module;
a plurality of spacing elements affixed to the lower surface and having a predetermined height extending away from the lower surface;
a secondary board affixed to the primary board by the plurality of spacing elements, separated from the lower surface of the primary board by an air gap with the predetermined height; the secondary board supporting a phased array of antenna elements electromagnetically coupled with the antenna control elements; and
an interposer mounted on the upper surface and carrying the radio controller, the interposer comprising a plurality of internal feed lines configured to connect a control port of the radio controller to the baseband controller.
2 . The radio frequency module of claim 1 , wherein the plurality of spacing elements include land grid array (LGA) elements with the predetermined height.
3 . The radio frequency module of claim 2 , wherein the plurality of LGA elements includes a first subset of LGA elements having a first length, and a second subset of LGA elements having a second length smaller than the first length.
4 . The radio frequency module of claim 3 , wherein the first subset of LGA elements have a first width, and wherein the second subset of LGA elements have a second width greater than the first width.
5 . The radio frequency module of claim 3 , wherein the second subset of LGA elements are square.
6 . The radio frequency module of claim 3 , wherein the second subset of LGA elements are disposed around a perimeter of the phased array of antenna elements.
7 . The radio frequency module of claim 3 , wherein the first subset of LGA elements are disposed within the perimeter of the phased array of antenna elements.
8 . The radio frequency module of claim 1 , wherein the predetermined height is between about 50 micrometers and about 200 micrometers.
9 . The radio frequency module of claim 1 , wherein the plurality of spacing elements include ball grid array (BGA) elements, each BGA element having a diameter equal to the predetermined height.
10 . The radio frequency module of claim 9 , wherein the plurality of BGA elements include a first subset of BGA elements disposed around a perimeter of the phased array of antenna elements, and a second subset of BGA elements disposed within the perimeter of the phased array of antenna elements.
11 . The radio frequency module of claim 1 , further comprising a communications interface on the upper surface of the primary board.
12 . The radio frequency module of claim 1 , wherein the communications interface comprises a Universal Serial Bus (USB) interface.
13 . The radio frequency module of claim 1 , wherein the phased array of antenna elements is controllable to receive and transmit signals at frequencies between about 57 GHz and about 71 GHz.
14 . The radio frequency module of claim 1 , further comprising:
a plurality of radio controller contacts on the upper surface of the primary board;
a feed network connecting the radio controller contacts with the antenna control elements, the feed network including:
a first layer connecting the radio controller contacts to a set of intermediate contacts between the upper surface and the lower surface, wherein the intermediate contacts are greater in number than the radio controller contacts; and
a second layer connecting the set of intermediate contacts to the antenna control elements.
15 . The radio frequency module of claim 1 , wherein the secondary board has an area smaller than an area of the primary board.
16 . The radio frequency module of claim 1 , wherein the second board has an area substantially equal to an area of the primary board.
17 . The radio frequency module of claim 16 , wherein the phased array of antenna elements are disposed in a portion of the area of the secondary board smaller than one half of the area.
18 . The radio frequency module of claim 1 , wherein the plurality of spacing elements include conductive pillars with the predetermined height.