High Frequency Behavior of Ceramic Multilayer Capacitors

The impedance of ceramic capacitors, made from different dielectric materials, was measured as a function of frequency from 1 MHz to 1 GHz. Most of the capacitors were of 0805 size and either end terminated or side terminated. The capacitance values ranged from a minimum of 50 pF to 100 nF. The high-frequency impedance measurements demonstrate that the inductance is a factor of two larger in end-terminated than in side-terminated ceramic muitilayer capacitors of size 0805. The inductance measured by two independent methods is 0.7 nH for the side-terminated 0805 capacitors. The inductance is only dependent on the geometry of the capacitor and independent of the dielectric material used. The capacitance and, in turn, the dielectric constant, remains constant for Z5U and X7R materials up to 100 MHz. For NPO materials the dielectric constant remains constant up to 1 GHz.