TECHNIQUES FOR MAXIMIZING THE SIZE OF AN ANTENNA ARRAY PER RADIO MODULE

1 . An active antenna array of a millimeter-wave radio frequency (RF) module, comprising:

a multilayer substrate having at least a front layer, a back layer, and a plurality of middle layers;

a first antenna sub-array implemented in the front layer;

a second antenna sub-array implemented in the back layer; and

a plurality of middle antenna sub-arrays implemented in the plurality of the middle layers, wherein each of the first antenna sub-array, the second antenna sub-array, and the plurality of middle antenna sub-arrays is configured to radiate millimeter-wave signals at a different direction.

2 . The active antenna array of claim 1 , wherein each of the first antenna sub-array, the second antenna sub-array, and the plurality of middle antenna sub-arrays is configured to receive and transmit millimeter-wave radio signals.

3 . The active antenna array of claim 1 , wherein each of the first antenna sub-array, the second antenna sub-array, and the plurality of middle antenna sub-arrays is independently controlled.

4 . The active antenna array of claim 1 , wherein the plurality of middle antenna sub-arrays includes four antenna sub-arrays, each implemented in a different layer of the plurality of layers.

5 . The active antenna array of claim 4 , wherein two of the four antenna sub-arrays are implemented in a center of their respective middle layers, and the other two antenna sub-arrays are implemented in an edge of their respective middle layers.

6 . The active antenna array of claim 5 , wherein each of the two antenna sub-arrays implemented in the edge of a middle layer includes end-fire antenna elements.

7 . The active antenna array of claim 1 , wherein the multilayer substrate includes at least one ground layer, wherein the first antenna, the second antenna, and the plurality of middle antenna sub-arrays share the ground layer.

8 . The active antenna array of claim 1 , wherein each of the first antenna, the second antenna, and the plurality of middle antenna sub-arrays includes a number of radiating elements, wherein the number of radiating elements is greater than eight.

9 . The active antenna array of claim 8 , wherein a distance between each radiating element in the same antenna sub-array is between a half wavelength and a full wavelength of a millimeter-wave signal.

10 . The active antenna array of claim 8 , wherein the radiating elements of each of the antenna sub-arrays are at least printed on the substrate of their respective layer.

11 . The active antenna array of claim 8 , wherein each of the antenna sub-arrays is a phased array antenna.

12 . The active antenna array of claim 11 , wherein the millimeter-wave RF module further includes RF circuitry.

13 . The method of claim 12 , wherein the RF circuitry is configured to independently control the first antenna sub-array, the second antenna sub-array, and each of the plurality of middle antenna sub-arrays.

14 . The method of claim 13 , wherein the RF circuitry is further configured to control the phase per antenna in order to establish a beam-forming operation for the phased-array antenna.

15 . The active antenna array of claim 12 , wherein the millimeter-wave RF module further includes discrete electronic components providing a chip-board transition structure.

16 . The active antenna array of claim 15 , wherein the RF circuitry and the discrete electronic components are mounted on the front layer of the multi-layer substrate.