Dielectric constant Signal velocity

For coaxial cables, the following electrical properties related to the dielectric constant of the core material and the dimensions determine the quaUty of the signal impedance, capacitance, attenuation, crosstalk, and time delay and velocity of propagation. 

Time Delay and Velocity of Propagation. Time delay is direcdy proportional to the square root of the dielectric constant and describes the time that it takes for a signal to travel through a cable. The lower the dielectric constant, the less time required for a signal to travel through a cable. 

FIGURE 13.3 Signal velocity as a function of dielectric constant. (Prepared by Shared Resources, Inc., 1991.)... 

Pis are used in mieroeleetronies industry as interdielectric layers, passivation layers and a-particle barriers. The electrical performance of Pis in these applications is dictated by its dielectric constant and can be further improved by reducing the dielectric constant. The propagation velocity of signal in microelectronic devices is inversely proportional to the square of the dielectric constant of the propagating medium. Therefore, signal propagation in microelectronics devices is faster, when the dielectric constant is low. Fnrther, lower dielectric constant materials reduce crosstalk between adjacent circuit lines and transmission delay time. 

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