High frequency performance of integral capacitors in cofired ceramic substrates

Impedance measurements for an integral capacitor in GHz range up to 9 GHz has been achieved with resonant method using coaxial resonators. Two open-ended coaxial resonators were used in this resonant method. The one was reference and the other was target whose length was the same as that of the reference. The difference between the reference and target was that a device under test was located in the center of the reference resonator. The ESL and ESR were calculated from differences of the resonant frequencies and quality factors between reference and target resonators. The characteristics of the integral capacitor with BCN or BCZN as dielectric materials in the zero x-y shrinkage LTCC substrate were measured. We confirmed that the ESL was determined by the dimension of the capacitor and the ESR was determined by the electrode configurations. We also confirmed that the ESL and ESR of the integral capacitor were very small and these integral capacitors were good enough to be applied in high frequency circuits at least up to 9 GHz.