Multi-die and antenna array device

A multi-die packaged semiconductor device comprising:

• a panel of embedded dies including a plurality of radio frequency (RF) dies, wherein each RF die includes RF front-end circuitry, each RF die has an active side that includes a plurality of pads, each RF die has a back side exposed in a back side of the panel;
• a plurality of antenna connectors formed on a subset of the plurality of pads of each RF die;
• an array of antennas formed over a front side of the panel and connected to the plurality of antenna connectors;
• a mold compound layer formed over the front side of the panel, the mold compound layer having a front surface;
• a plurality of cavities formed in the front surface of the mold compound layer, wherein the antennas are located in the plurality of cavities and an air gap is formed in each cavity between an outer surface of each antenna and the mold compound layer to expose the outer surface of each antenna in the array of antennas, the air gap remaining in the multi-die packaged semiconductor device following manufacture of the multi-die packaged semiconductor device;
• and
• wherein at least a portion of each cavity is located between each antenna and the front side of the panel to expose an inner surface of each antenna.