PCB Edge Fringing

When proper PCB layout design techniques such as trace routing, stack-up assignment, decoupling, bypassing, and proper termination are implemented, the radiation from the PCB itself can be minimised.  However, there are several other mechanisms of the PCB assembly remaining that can still be radiation sources, including the components themselves, cavity resonance effects of the power/signal return layers, and the edges of the PCB.  Edge effects can be particularly burdensome since it is the board edges that are in such close proximity to the chassis and hence these radiation fields can induce currents into the chassis frame.

There are numerous studies and papers which have been written that discuss various approaches or techniques pertaining to reducing radiation edge effects from the PCB.  The most common approach is termination. The problem with many of these techniques is that they can use additional components and valuable PCB real estate without actually reducing the energy.  In many cases, energy can be reflected, possibly creating additional internal cavity resonance effects and coupling to internal vias, also resulting in increased radiation.

The use of Icon’s cavity resonance absorber material applied along the edge of the printed circuit board reduces the edge radiation from the printed circuit board without using additional board real estate for more components or traces.  It also reduces the possibility of board resonance problems by dissipating the energy and not reflecting the energy back into the interior of the board.