Liquidmetal Technologies Inc (LQMT)

[JoTu]

perfect summery jrs5 and its backed up by the rumor the antenna needs internal space having it on one side/edge of the external frame won’t work thru just 1 cutout no room to have 4 antennas for each side and it would be too costly/power drain.
the internal mid frame also needs to be rf transparent for the mmwave antenna.
as payMEmf says demetallization.
https://www.fastcompany.com/90546391/source-only-one-of-apples-new-iphones-supports-the-fastest-5g

All the phones in the new iPhone 12 line will support the slower but more common Sub-6 type of 5G service, but only the largest, highest-end phone in the line, a 6.5-inch screen device likely called the iPhone Pro Max, will also support millimeter-wave 5G.

The source says only the largest phone in the line has room inside for the special antenna design required for millimeter wave and larger battery needed to accommodate millimeter wave’s significant power draw. Also, only the U.S., Korea, and Japan versions of the Pro Max will support millimeter-wave 5G.