Survey in 3D Electronics Alternative to PCBs 

Mention an electronic circuit and you are likely to picture a printed circuit board (PCB): a rigid rectangle in a characteristic green color with copper lines and a bewildering array of components soldered onto it. But does adding electronic functionality means using a PCB and thus requires shoehorning a rigid rectangle into the product?

Source: Survey in 3D Electronics Alternative to PCBs – Passive Components Blog