A continuous process for the fabrication of metal clad, laminated core structures, such as circuit board cores, wherein the copper layers on the laminate are used to form a waveguide which propagates microwave or RF radiation in TEM mode down the length of the structure for heating the core layers while the necessary pressure is applied. The TEM mode offers substantial advantages in the uniformity and control of processing in this environment. In particular, the system may be made tunable using the positioning or two pinch points, produced by rollers applying pressure to consolidate the layered material, which points create end chokes defining a heating and pressure region wherein the radiation is reflected. Alternatively, the metal layers may also be used as capacitor-like plates for applying RF energy across the layered material.