Future smartphones may not need traditional metallic circuits if a start-up led by Apple one-time 5G chief, Ruben Caballero, gets its way.Apple ex-wireless lead is on a fresh missionA company called Keyssa is developing new ways to achieve high-speed, contactless connectivity.Its website describesmultiple ways this might work, from pairing set-top boxes to televisions to sharing data with a bump.But it possible the most compelling future implication may be in its use as an interconnect on a component basis inside devices.