HIGH FREQUENCY ISSUES

There are a number of physical effects that are negligible at lower frequencies becomes increasingly important at higher frequencies. Two of these effects are the skin effect and radiation effect.

SKIN EFFECT

The skin effect is caused by the finite penetration depth of an electromagnetic field into conducting material . this effect is a function of frequency and is given by

Therefore  decreases with the increase in frequency and so the electromagnetic fields are confined to regions increasingly near the surface as the frequency increases.  This results in themicrowave currents flowing exclusively along the surface of the conductor, significantly increasing the effective resistance of metallic interconnects.

RADIATION LOSS

For conductors and other components of comparable size to the signal wavelengths ,standing waves caused by reflection of the electromagnetic waves from the boundry of the component can greatly enhance the radiation of electromagnetic energy. These standing waves can be easily established either intentionally or unintentionally