As the name implies, volume resistivity is the amount of resistance exhibited by a material in a volume measurement, or how strongly that material opposes the flow of current. Resistivity is a material property, different than resistance, with a unique value for each material. It is often thought of as the resistivity of a material between two copper planes. Volume resistivity is related to conductance, as can be shown with the schematic representation of the microstrip transmission-line segment in Figure 2. The volume resistivity is the inverse of conductance G, with the inductance, resistance, and capacitance of this simple schematic represented by L, R, and C, respectively. Most high-frequency PCB materials have relatively high volume resistivity, so that leakage losses are typically not significant. Leakage losses can be a concern for RF/microwave applications using circuit materials having lower volume resistivity, such as those found in semiconductor-grade materials.
Electrical strength is associated with the dielectric strength of a circuit material. This parameter is presented in units of voltage per unit