Circuit board structure

A circuit board structure, comprising:

• a first flexible circuit board comprising a first dielectric layer and a first conductive circuit on the first dielectric layer, the first dielectric layer having a first dielectric loss value, wherein the first dielectric loss value ranges from 0.003 to 0.01;
• a second flexible circuit board comprising a second dielectric layer and a second conductive circuit on the second dielectric layer, the second dielectric layer having a second dielectric loss value, wherein the second dielectric loss value ranges from 0.003 to 0.01;
• and
• a rigid board structure connecting the first flexible circuit board and the second flexible circuit board, the rigid board structure having a thickness direction, the first flexible circuit board and the second flexible circuit board being not overlapped in the thickness direction, wherein the rigid board structure comprises:
• a third dielectric layer having a third dielectric loss value less than each of the first dielectric loss value and the second dielectric loss value, wherein the third dielectric loss value ranges from 0.001 to 0.002 and the third dielectric layer directly connects to the first dielectric layer and the second dielectric layer;
• and
• a third conductive circuit on the third dielectric layer and electrically connecting the first conductive circuit to the second conductive circuit.