Broadband Characterization of Dielectric Films for Power-Ground Decoupling

We evaluated the dielectric permittivity and impedance characteristics of high dielectric constant polymer composite films. Such materials are being investigated by the electronic industry in response to the growing need for efficient integrated powerground de-coupling capacitance in microwave circuits and fast switching devices. In order to extend the dielectric measurements to the microwave range, we developed an appropriate expression for the input admittance of a thin film capacitance terminating a coaxial line. The theoretical model treats the capacitance as a distributed network and takes into consideration the wave propagation in the specimen section. The dielectric permittivity of several high dielectric constant materials for de-coupling capacitance applications was evaluated at frequencies of 100 MHz to 10 GHz, and the corresponding impedance characteristics were determined directly in time domain. Polymer resins filled with ferroelectric ceramics showed low impedance values and flat impedance characteristics over a broad frequency range, which makes these materials attractive for power-ground decoupling applications in high-speed electronic circuits.